Numerical and experimental investigation of single and two phase impinging jet heat transfer

NUMERICAL AND EXPERIMENTAL INVESTIGATION OF SINGLE AND TWO-PHASE IMPINGING JET HEAT TRANSFER ZHENGQUAN LOU NATIONAL UNIVERSITY OF SINGAPORE 2007 NUMERICAL AND EXPERIMENTAL INVESTIGATION OF SINGLE AND TWO-PHASE IMPINGING JET HEAT TRANSFER ZHENGQUAN LOU (Bachelor, SJTU) A THESIS SUBMITTED FOR THE DEGREE OF DOCTOR OF PHILOSOPHY DEPARTMENT OF MECHANICAL ENGINEERING NATIONAL UNIVERSITY OF SINGAPORE 2007 Summary Impinging jet heat transfer is one of the flow techniques used to cool or heat the target surfaces by fluid impingement on them. It is widely used in industrial applications ranging from drying of textiles and films, metal sheet manufacturing, gas turbine cooling to electronic component cooling. With the rapid increase of the heat dissipation in electronic components, impinging jet technique becomes more important to cool the hot chip. The objective of the current research was to test the heat transfer performance of impinging jet system under various boundary conditions. In this study, both numerical and experimental methods were used to examine the single and two-phase problems. For the single phase heat transfer, the effects of different boundary conditions and various parameters, e.g. geometric parameters, Biot number, fin structure and presence of a baffle in the jet flow, on the heat transfer performance were studied using a Computational Fluid Dynamics (CFD) method. The parameters such as Nusselt number, thermal resistance and heat flux, were obtained to evaluate the heat transfer performance of the impinging jet system. For the two-phase problem, a mixture model, incorporated with User Defined Functions (UDFs), were used to simulate the process of heat transfer and mass transfer. The current study discussed the effects of superheat of target plate, sub-cooled working fluid and various inlet velocities on the two-phase heat transfer performance. Moreover, visualization of two-phase process was obtained. i Other than the simulation work, an experiment was set up to test the heat transfer performance of single and two-phase problems with water and FC-72 as the working fluids. The parameters, e.g. impingement orientation, jet width and inlet velocity, were examined in the experiment. The simulation results and experimental results were compared and a reasonable agreement was obtained. Finally, on the basis of the verified simulation model, more predictions of two-phase micro-scale impinging jet were carried out in view of its promising application in industry. This dissertation addresses the numerical and experimental investigation of single and two-phase impinging jet heat transfer. The goal of this study is to contribute to a more detailed investigation of effects of various parameters on impinging jet heat transfer so as to improve the design of the current impinging jet system. In the current investigation, the relationships between the local Nusselt number Nu x , average Nusselt number Nu m , jet width W , jet height H , H / W and Re have been generalized. Also, the effects of subcooled water temperature, inlet velocity and superheat temperature of target plate on the heat transfer performance have been obtained. Distributions of temperature contour, velocity contour, velocity vector and volume fraction of vapor are obtained. The effect of surface roughness on the two-phase impinging jet heat transfer has also been examined. A dielectric fluid FC-72 has tested and the comparison between FC-72 and water is carried out. The advantages of FC-72 in the industrial application are reported. ii Acknowledgements I would like to express my sincere gratitude to my supervisors, Professor Arun S. Mujumdar and Assoc. Professor Christopher Yap, for their tremendous support and patient guidance. I am deeply grateful for their critical and crucial suggestions and comments on my research work. I am forever indebted to them for guiding me in the research world of impinging jet heat transfer. I would like to thank the lab officer of Air-conditioning Lab, Mr. Sacadevan Raghavan for his kindness and enthusiastic help in the preparation of the experimental equipment. I would also like to extend my thanks to my friends, Mr. Huang Lixin, Mr. Wang Shijun, Mr. Wu Zhonghua, Mr. Wang Xiangqi and many others. I am greatly obliged to my parents for their continuous supports from childhood to now. Finally, I am also grateful to NUS for its financial support for my Ph. D program. Zhengquan Lou Singapore December 2006 iii Table of contents Summary……………………………………………………………………………….…i Acknowledgements………………………………………………………… ……………iii Table of contents……………………………………………………………………… iv Nomenclature……………………………………………………………………………vi List of Figures………………………………………………………………………… .viii List of Tables…………………………………………………………………………….xii Publications arising from this thesis…………………………………………………… xiii Chapter Introduction…………………………………………………………….… 1.1 Background…………………………………………………………………… .…….1 1.2 Introduction of Impinging Jet Technique…………………………………… …….…9 1.3 Objectives ………………………………………………………………….… ……10 1.4 Scope……………………………………………………………….… ……11 Chapter Literature Review………….…….……….……………………….… .……13 2.1 Geometric effect ……………………………………………………………………14 2.2 Conjugate Heat Transfer……………………………………………….……… …16 2.3 Fin Structure……………………………………………………………….… … .…18 2.4 Effect of an Inserted Baffle ……………………………………………… …………21 2.5 Two-phase IJHT: Experimental Investigation……………………………… ………23 2.6 Two-phase IJHT: Numerical Investigation………………………………… .………27 Chapter Fundamentals of Single and Two-phase IJHT…………………… ……34 3.1 Description of the Basic Impinging Jet System………………………………………34 3.2 Modeling of Single-phase Simulation………………………………………… .……36 3.3 Fundamental Theory of Boiling Heat Transfer………………………………….……37 3.4 Models for Multiphase Flow and Heat Mass Transfer…………………… …………42 3.5 General Guidelines of Model Selection………………………………………………46 3.6 Conservation Equations and Other Equations……………………………… .………48 3.7 User-Defined-Functions……………………… …………………………… ………50 Chapter Effects of Geometric Parameters on Confined IJHT…………………… 52 4.1 Problem Description……………………………………………………….…………52 4.2 Calculation of Thermal Parameters ……………………………………….…………54 4.3 Results and Discussion……………………………………………………….………55 4.3.1 Effect of Jet Width W ………………………………………… ………….………56 4.3.2 Effect of Jet Height H ………………………………………………… .…………59 4.3.3 Effect of Jet Reynolds Number……………………………………………… ……61 4.3.4 Effect of Surface Roughness………………………………………………….……62 4.3.5 Effect of the Inlet Velocity Profile …………………………………………………65 4.4 Summary of Chapter… …………………………………………………………… .66 Chapter Conjugate Heat Transfer under a Confined IJ……………………………68 5.1 Problem Description………………………………………………………………… 68 5.2 Results and Discussion……………………………………………………………… 70 5.2.1 Relationship between Bi x , Bim and k p …………………… ………………………70 iv 5.2.2 Relationship between Bi x , Bim and Nu ………………………………………… 75 5.2.3 Selection of Target Plate…………………………………………….………… .…77 5.3 Summary of Chapter… …………………………………………………………… .77 Chapter Simulation of Laminar IJHT to Finned Heat Sinks………………………79 6.1 Problem Description………………………………………………………….………79 6.2 Results and Discussion……………………………………………………….………83 6.2.1 Effect of Fin Number……………………………………………………….………83 6.2.2 Effect of Fin Height H f ……………………………………………………………86 6.2.3 Effect of Fin-to-spacing Ratio W f / S f ………………………………….…………89 6.3 Summary of Chapter… …………………………………………………………… .92 Chapter Numerical Investigation of Baffle Effect on IJHT……………….… ……93 7.1Problem description …………………………………………………………….……93 7.1.2 Numerical Simulation………………………………………………………………94 7.1.3 Formulation of Parameters…………………………………………………………95 7.2. Results and Analysis…………………………………………………………………97 7.2.1 Orientation of Baffle……………………………………………………… ………97 7.2.2 Locations of Vertical Baffle……………………………………………… .……100 7.2.3 Locations of Horizontal Baffle……………………………………………………104 7.3. Summary of Chapter… ……………………………………………………………106 Chapter Numerical Simulation of Two-phase IJHT…………………….…………108 8.1 Problem Description…………………………………………………………………108 8.2 Results and Discussion………………………………………………………………111 8.2.1. Effect of Subcooling………………………………………………………………112 8.2.2. Effect of Inlet Velocity v ………………………………………………… .……114 8.2.3. Effect of Superheat Target Plate …………………………………………………119 8.2.5 Visualizations of the Volume Fractions of Vapor…………………………………124 8.2.6 Investigations of Micro-impinging Jet ……………………………………………128 8.2.7 Effect of Surface Roughness………………………………………………………133 8.3 Summary of Chapter… …………………………………………………………….136 Chapter Experimental Investigation of Single and Two-phase IJHT……….……137 9.1 Experiment Setup and Procedure……………………………………………………137 9.2 Uncertainty of measurement………………………………………………… .……140 9.3 Results and Discussion ………………………………………………………… .…143 9.3.1 Heat Transfer Results…………………………………………………………… .143 9.3.2 Orientation Effect of Impinging Jet System……………………………………….147 9.3.3 Effect of Jet Width……………………………………………………………… .154 9.3.4 Comparison between FC-72 and Water ………………………………………… .158 9.4 Summary of Chapter… …………………………………………………………….160 Chapter 10 Conclusions and Recommendations…………………………….………162 10.1 New Contributions…………………………………………… …………… ……164 10.2 Recommendations in the Future Work………………… …………………………164 References…………………………………………………… .……………….………166 Appendices……………………………………………… .…………………….……175 v Nomenclature Bottom surface area of the heat sink m2 Top surface area of the heat sink Local Biot number at the stagnation point Average Biot number Local Biot number Specific heat m2 J/kg•K f hm hx H Hf Friction factor Average convective heat transfer coefficient W/m2•K Local convective heat transfer Jet height Fin height W/m2•K mm mm kf Thermal conductivity of the working fluid W/m•K kp Thermal conductivity of the target plate W/m•K k fin lb L M Nu Nu e Nu m ΔP q qx Re Sf Thermal conductivity of the plate-fin W/m•K Baffle length Target plate length flow rate Nusselt number at the stagnation point Effective Nusselt number Average Nusselt number Pressure drop between inlet and outlet Heat flux Local heat flux Reynolds number Spacing between two adjacent fins mm mm ml/min Pa W/m2 W/m2 ρuW / μ mm T fin Average temperature of the plate-fin K Tw u W Wf Wall temperature the target plate Inlet jet velocity Jet width Fin width K m/s mm mm wb X Y Width of the baffle Horizontal distance to the axis Vertical distance to the target plate mm mm mm Ab At Bi0 Bim Bi x Cp vi Greek symbol α Impingement orientation δ Target plate thickness ρ Fluid density μ Dynamic viscosity υ Kinematic viscosity θ af Thermal resistance mm kg/m3 kg/m•s m2/s K/W Subscripts f Working fluid x Local w Wall m Mean (or average) Stagnation point vii List of figures Fig. 1.1 Heat transfer coefficient attainable with natural convection, single-phase liquid forced convection and boiling for different coolants. Fig. 1.2 A conventional design of an electronic cooling device by a heat sink Fig. 1.3 A typical configuration of a heat pipe Fig. 1.4 Geometric configuration of the micro-channel the heat transfer .5 Fig. 1.5 Geometric configuration of an impinging jet system Fig. 1.6 Thermal resistance for various cooling fluids .6 Fig. 1.7 Flow chart of the current investigation of impinging jet heat transfer……… 12 Fig. 2.1 Classification of impinging jet heat transfer in term of various parameters… .13 Fig. 3.1a Geometric configuration of an impinging jet system………………………… .35 Fig. 3.1b An impinging jet system with a scheme of its vortex structure……………… .35 Fig. 3.2 Rising air bubble in water. Left: x − Velocity versus time. Right: Shape and flow field at t = for D / h = 32 . The contour shown for α = 10 − 12, , and, − 10 −12 …… 44 Fig. 4.1 Schematic diagram of the impinging jet domain…………………………… .53 Fig. 4.2 Grid information of the right half computational domain the impinging jet system 54 Fig. 4.3 Distributions of surface temperature along the plate with H / W as a parameter ………………………………………………………………………….…… .57 Fig. 4.4 Distributions of local Nusselt numbers Nu x along the plate with H / W as a parameter ……………………………………………………………………………… .57 Fig. 4.5 Relationship between pressure drop and H / W .……………………………… 58 Fig. 4.6 Distributions of local Nusselt numbers Nu x along the plate with H / W as a parameter ……………………………………………………………………………… .59 Fig. 4.7 Relationship between the local Nusselt numbers Nu x and H / W at the stagnation area . …………………………………………………………………………………… 61 Fig. 4.8 Distributions of local Nusselt number Nu m along the plate with Re as parameter . ………………………………………………………………………………62 Fig. 4.9 Correlation between the average Nusselt number Nu m , Reynolds number Re and H / W .………………………………………………………………………………… .62 Fig. 4.10 Grid information of triangular, rectangular and sine roughness on the target plate . …………………………………………………………………………………….63 Fig. 4.11 Distributions of surface temperature along the rough target plate with Re = 80 . ……………………………………………………………………………………….63 Fig. 4.12 Comparison of local Nusselt numbers for different inlet velocity profiles . ….65 Fig. 5.1 Distributions of the surface temperature along the target plates for variable k p 71 Fig. 5.2 Distributions of heat flux q x along the target plate with variable k p ………… .71 Fig. 5.3 Distributions of the local Biot number Bi x for different material target plate . .72 viii Chapter 10 Conclusions and Recommendations Chapter 10 Conclusions and Recommendations This thesis presents numerical and experimental investigations of single and twophase impinging jet heat transfer under various operating conditions. Various parameter effects on the impinging jet heat transfer were tested numerically, e.g. geometric parameters, Biot number, fin structure and presence of a baffle in the jet flow. A simulation of two-phase problem was carried out using the mixture model in Fluent 6.2. For the single phase problem, the relationships between the local Nusselt number Nu x , average Nusselt number Nu m , jet width W , jet height H , H / W and Re have been generalized. Moreover, the effect of surface roughness on the single phase heat transfer performance has been obtained. Surface roughness generally deteriorate the single phase heat transfer performance due to the working fluid is trapped as recirculation eddies in the cavities of the rough plates. The conjugate heat transfer has been also studied numerically using different materials as the target plate. The correlations between the local and average Biot numbers and thermal conductivities of the target plates are generalized. Also, the relationships between the local and average Nusselt numbers and the average Biot number have been also obtained. Considering the factors such as the degree of temperature uniformity, average Nusselt number Nu m and industrial feasibility, the current prediction is valuable for the selection of the target plate in the impinging jet system. 162 Chapter 10 Conclusions and Recommendations For the single phase problem, the effect of a plate-fin heat sink has been studied with fin number, fin height, fin-to-spacing ratio as the parameters. Also, presence of a baffle in the flow region is studied with the changes of the baffle orientation, location and length. Average Nusselt number is obtained to evaluate the overall heat transfer performance. For the two-phase heat transfer, a mixture model, incorporated with UDFs, has been developed to simulate the boiling problem. In the current investigation, the effects of subcooled water temperature, inlet velocity and superheat temperature of target plate on the heat transfer performance have been obtained. Distributions of temperature contour, velocity contour, velocity vector and volume fraction of vapor are obtained. The effect of surface roughness on the two-phase impinging jet heat transfer has also been examined. The comparison between simulation and experimental results was carried out and the agreement is found to be good. On the basis of this verified simulation model, a prediction of two-phase micro-impinging jet heat transfer have been performed and it could be valuable for the design of micro-impinging jet system in industry. An experiment of impinging jet system has been set up to verify the simulation results. The effects of impinging orientation and jet width on impinging jet heat transfer were tested in the experiment. Moreover, both single phase and two-phase heat transfer were examined. For the single phase problem, the impinging orientation not affect the heat transfer performance significantly. However, for the two-phase problem, the impinging orientation affects the overall heat transfer performance greatly because of creation and movement of air and vapor bubbles. In addition, a range of the jet width W from 0.05 to 2.0 mm has been tested. From this investigation, it is found that small jet width can remove much higher heat flux that large jet width when the flow rate is kept 163 Chapter 10 Conclusions and Recommendations constant. Finally, a dielectric fluid FC-72 has tested and the comparison between FC-72 and water is carried out. The advantages of FC-72 in the industrial application are reported. 10.1 New Contributions 1) The effects of various parameters, e.g. jet width, jet height, Biot number, plate-fin heat sink and an embedded baffle, on single-phase impinging jet heat transfer have been studied. The current work has provided a study in the impinging jet system under particular operating conditions which are different with the studies in the literature; 2) The mixture model is adopted in Fluent 6.2 to simulate the two-phase impinging jet heat transfer. UDFs (User-Defined-Functions) are incorporated to the main model to simulate heat and mass transfer process. The effects of various parameters on the overall heat transfer performance have been discussed; 3) On the basis of the verified simulation model, a numerical investigation of microimpinging jet heat transfer has been carried out in view of its promising application in industry; 4) An experimental has been set up to test the thermal performance of single and twophase heat transfer using water and FC-72 as the working fluids. The simulation results and experimental results are compared and good agreements are obtained. 10.2 Recommendations in the Future Work 1) For the single phase impinging jet heat transfer, different types of impinging jet such as multiple round jets and declined jet could be further investigated. Also, effect of unsteady inlet velocity on the heat transfer performance can be investigated. 164 Chapter 10 Conclusions and Recommendations 2) For the two-phase problem, the simulation model could be improved further. Tracking the interface between vapor and water is still not so satisfactory. VOF model can be used to track the vapor-to-water interface. Moreover, for the two-phase problem, other models of computational fluid dynamics can be developed to improve the current simulation as there are still differences between experimental and simulation results. 3) In the future simulation model, the effect of dissolved air in the working fluid on the single and two-phase heat transfer can be discussed. Additionally, three dimensional simulation can be carried out with the increase of computational capacity of computers. 4) In the future experimental investigation, smaller scale impinging jet system (e.g. W < 0.2mm, H < 0.2mm ) can be set up to meet the high demand of heat removal in the future application. 5) In the experiment, other dielectric fluids with different boiling points can be tested and compared with the current experimental results. 165 References References Amon, C.H., Spectral element-Fourier method for unsteady conjugate heat transfer in complex geometry flows, J. Thermophys. Heat Transfer, Vol. 9, No. 2, pp. 247-253, 1995 Annaland, M. Van Sint, Deen, N.G., Kuipers, J. A. M., Numerical simulation of gas bubbles behaviour using a three-dimensional volume of fluid method, Chemical Engineering Science, Vol. 60, pp. 2999-3011, 2005 Augier, F., Morchain, J., Guiraud, P. and Masbernat, O., Volume fraction gradientinduced flow patterns in a two-liquid phase mixing layer, Chemical Engineering Science, Vol. 58, pp. 3985-3993, 2003 Auracher, Hein and Marquardt, Wolfgang, Experimental studies of boiling mechanisms in all boiling regimes under steady-state and transient conditions, Int. J. of Thermal Science, No. 41, pp. 586-598, 2002 Ayub, M., Sohaib, M., Rafique, M. and Khan, M. A., Computational modeling of gas liquid interfaces using different multiphase models, European Conference on Computational Fluid Dynamics, ECCOMAS, CDF, TU Delft, Delft Netherland, 2006 Bartoli, C., Marco, P. D. and Faggiani, S., Heat transfer and flow pattern at a cylinder impinged by a slot jet during incipient and nucleate boiling, Experimental Thermal and Fluid Science, Vol. 15, pp. 101-108, 1997 Basu, N., Troshko, A. and Nurnberg, G., Modeling of two-phase flow and boiling with FLUENT, Presented at RELAP5 UGM, West Yellowstone, Montana, July, 2003 Baydar, E. and Ozmen, Y., An experimental and numerical investigation on a confined impinging air jet at high Reynolds numbers, Applied Thermal Engineering, Vol. 25, pp. 409-421, 2005 Behzadmehr, A., Saffar-Avval, M. and Galanis, N., Prediction of turbulent forced convection of a nanofluid in a tube with uniform heat flux using a two phase approach, International Journal of Heat and Fluid Flow, In Press, Corrected Proof, 2006 Beitelmal, Abdlmonem H. and Saad, Michel A., Effects of surface roughness on the average heat transfer of an impinging air jet, Int. Comm. Heat Mass Transfer, Vol. 27, pp.1-12, 2000 Bergles, A. E. and Rohsenow, W. M., Bubble growth rates in highly subcooled nucleate boiling, Preprint presented at AIChe-ASME Heat Transfer Conference, Chem. Engng. Prog. Symp. Series No. 29, pp.95-109, 1958 Bi, X. M., Ph.D. Thesis, Dept. of Chemical Engineering, Mcgill University, Canada, 2001 Blažej, M., Glover, G. M. Cartland, Generalis, S. C. and Markoš, J., Gas–liquid simulation of an airlift bubble column reactor, Chemical Engineering and Processing, Vol. 43, pp. 137-144, 2004 166 References Bode, A., Kling, K., Schroder, Jens J. and Viertmann, Marco, Natural alternations in subcooled pool boiling heat transfer, Proceedings of the international engineering foundation 3rd conference, Germany, May 18th-23rd, 1999 Bourbon, C. and Milisi, V., Numerical simulation of boiling in a porous medium by using two-phase approach, Laboratoire MASTER-ENSCPB, France, 2003 Brignoni, L. A. and Garimella, S. V., Experimental optimization of confined air jet impingement on a pin fin heat sink, IEEE Transactions on Components and Packaging Technology, Vol. 22, No. 3, pp. 399-404, 1999 Bula, Antonio J., Rahman, Muhammad M. and Leland, John E., Axial steady free surface jet impinging over a flat disk with discrete heat sources, International Journal of Heat and Fluid Flow, Vol. 21, No. 1, pp. 11-21, 2000 Buyevich, Y.A. and Mankevich, V.N., Cooling of a superheated surface with a jet mist flow, Int. J. Heat Mass Transfer, Vol. 39, No.11, pp. 2353-2362, 1996 Carcasci, Carlo, An experimental investigation on air impinging jets using visualization methods, Int. J. of Thermal Science, No. 38, pp. 808-818, 1999 Chena, P., Sanyalb, J. and Dudukovica, M. P., CFD modeling of bubble columns flows: implementation of population balance, Chemical Engineering Science, Vol. 59, pp. 52015207, 2004 Cheng, P. and Wang, C. Y., A multiphase mixture model for multiphase, multicomponent transport in capillary porous media II: Numerical simulation of the transport of organic compounds in the subsurface, Int. J. of Heat Mass Transfer, Vol. 39, No. 17, pp. 3619-3632, 1996 Christopher, David M., Wang, Hao and Peng, Xiaofeng, Numerical analysis of the dynamics of moving vapor bubbles, International Journal of Heat and Mass Transfer, Vol. 49, No. 19-20, pp. 3626-3633, 2006 Clemens, J. M. Lasance and Robert E. Simons, Advances In High-Performance Cooling For Electronics, Philips Research LaboratoriesIBM Corporation, 2005 Collier, John G., and Thome, John R., Convective boiling and condensation, Clarendon press, Oxford, 1994 Croce, Giulio and D’Agaro, Paola, Numerical analysis of roughness effect on microtube heat transfer, Superlattices and Microstructures, Vol. 35, pp. 601-616, 2004 Dutta, S., Dutta, P., Jones, R. E. and Khan, J. A., Experimental study of heat transfer coefficient enhancement with inclined solid and perforated baffles, Inter. Mech. Engr. Congress and Exposition (IMECE), Dallas, TX, November, pp. 16-21, 1997 Dutta, P. and Dutta, S., Effect of baffle size, perforation and orientation on internal heat transfer enhancement, Int. J. Heat Mass Transfer, Vol. 41, pp. 3005-3013, 1998 Dutta, S., Dutta, P., Jones, R. E. and J. A., Heat Transfer Coefficient Enhancement with Perforated Baffles, ASME J. of Heat Transfer, Vol. 120, pp. 795-797, 1998 167 References Dutta, Prashanta and Hossain, Akram, Internal cooling augmentation in rectangular channel using two inclined baffles, International Journal of Heat and Fluid Flow, Vol. 26, No. 2, pp. 223-232, 2005 El-Sheikh, H. A. and Garimella, S. V., Enhancement of air jet impingement heat transfer using pin-fin heat sinks, IEEE Transactions on Components and Packaging Technology, Vol. 23, No. 2, pp. 300-308, 2000 Fairweather, M. and Hargrave, G. K., Experimental investigation of an axisymmetric impinging turbulent jet. 1., Velocity field. Experiments in Fluids, Vol. 33, pp. 464-471, 2002 FLUENT 6.2 User’s Guide, Vol. 1-4, Fluent Inc., 2005 Fujii, M., Nucleate pool boiling heat transfer from a porous heating surface (optimum particle diameter), Heat Transfer Jap. Res., Vol. 13, No. 1, pp. 76-91, 1984 Garimella, S. V. and Eibeck, P. A., Fluid dynamic characteristics of the flow over an array of large roughness elements, Procs. Inter. Society Conference on Thermal Phenomena in Electronic Systems, Austin, Texas, pp. 102-109, 1992 Garimella, S. V. and Schlitz, D. J., Effect of fin aspect ratio on heat transfer enhancement, SAE Paper No. 920547, SAE International Congress and Exposition, Detroit, Michigan, 1992 Genske, Petra and Stephan, Karl, Numerical simulation of heat transfer during growth of single vapor bubbles in nucleate boiling, International Journal of Thermal Sciences, Vol. 45, No. 3, pp. 299-309, 2006 Ghorai, Subhashini and Nigam, K.D.P., CFD modeling of flow profiles and interfacial phenomena in two-phase flow in pipes, Chemical Engineering and Processing, Vol. 45, pp. 55–65, 2006 Glover, G. M. Cartland and Generalis, S. C., Gas–liquid–solid flow modeling in a bubble column, Chemical Engineering and Processing, Vol. 43, pp. 117-126, 2004 He, Ying, Maruyama, Shigeo and Shoji, Masahiro, Numerical simulation of boiling heat transfer, Proceedings of the international engineering foundation 3rd conference, Germany, May 18th -23rd, 1999 Hidayat, Muslikhin and Rasmuson, Anders, Some aspects on gas–solid flow in a U-bend: Numerical investigation, Powder Technology, Vol. 153, No. 1, pp. 1-13, 2005 Hossain, A., Naser, J., Mcmanus, K. and Ryan, G., CFD investigation of particle deposition and distribution in a horizon pipe, Third International Conference on CFD in the Minerals and Process Industries, CSIRO, Melbourne, Australia, 10-12 Dec. 2003 Hsu, Y. Y. and Graham, R. W., Transport Processes in Boiling and Two-phase Systems, chaps. and 6, Hemisphere, New York, (2), 1976 Incropera, Frank P., Liquid cooling of electronic devices by single-phase convection, A Willey-Interscience Publication, pp. 55-69, 1999 Jamil, A. K., Jason, H. and Sarah, C. B., Enhancement of heat transfer with inclined baffles and ribs combined, J. of Enhanced Heat Transfer, Vol. 9, pp. 137-151, 2002 168 References Jang, Seok Pil, Kima, Sung Jin and Paik, Kyung Wook, Experimental investigation of thermal characteristics for a microchannel heat sink subject to an impinging jet using a micro-thermal sensor array, Sensors and Actuators, No.105, pp. 211–224, 2003 Kandlikar, Satish G. and Spiesman, Paul H., Effect of surface characteristics on flow boiling heat transfer, Proceedings of the international engineering foundation 3rd conference, Germany, May 18th -23rd, 1999 Kandlikar, Satish G., Further develpments in flow boiling map for subcooled flow boiling, Proceddings of the international engineering foundation 3rd conference, Germany, May 18th -23rd, 1999 Kandula, M., Mechanisms and predictions of burnout in flow boiling over heated surfaces with an impinging jet, Int. J. Heat Mass Transfer, Vol. 33, No. 9, pp. 1795-1803, 1990 Kanna, P. Rajesh and Das, Manab Kumar, Conjugate forced convection heat transfer from a flat plate by laminar plane wall jet flow, International Journal of Heat and Mass Transfer, Vol. 48, No. 14, pp. 2896-2910, 2005 Khalij, M., Moissette, S., Gardin, P., Borean, J. L. and Oesterle, B., Numerical study of boiling heat transfer in a heated channel ESSTIN-Henri Poincare University, France Kim, Ye Yong, Kim, Kui Soon, Jeong, Gi Ho and Jeong, Sooin, An experimental study on the quantitative interpretation of local convective heat transfer for a plate fin and tube heat exchanger using the lumped capacitance method, International Journal of Heat and Mass Transfer, Vol. 49, No. 1-2, pp. 230-239, 2006 Kirkup, L. and Frenkel, R. B., An Introduction to Uncertainty in Measurement, Cambridge Press, 2006 Koncar, Bostjan and Mavko, Borut, CFD simulation of subcooled flow boiling at low pressure, Int. Conf. Nuclear Energy in Central Europe, 2001 Kondo, Y., Matsushima, H. and Komatsu, T., Optimization of pin-fin heat sinks for impingement cooling of electronic packages, Transactions of ASME, Vol. 122, pp. 240246, 2000 Li, Hung-Yi, Chao, Shung-Ming and Tsai, Go-Long, Thermal performance measurement of heat sinks with confined impinging jet by infrared thermography, International Journal of Heat and Mass Transfer, Vol. 48, No. 25-26, pp. 5386-5394, 2005 Lin, Chu-Wei, Experimental study of thermal behaviors in a rectangular channel with baffle of pores, International Communications in Heat and Mass Transfer, Vol. 33, No. 8, pp. 985-992, 2006 Liovic, Petar and Lakehal, Djamel, Multi-physics treatment in the vicinity of arbitrarily deformable gas–liquid interfaces, Journal of Computational Physics, pp.1-32, 2006 Lörstad, Daniel and Fuchs, Laszlo, High-order surface tension VOF-model for 3D bubble flows with high density ratio, Journal of Computational Physics, Vol. 200, pp. 153–176, 2004 169 References Lou, Z.Q., Mujumdar, A. S. and Yap, C., Effects of geometric parameters on confined impinging jet heat transfer, Journal of Applied Thermal Engineering, Vol. 25, No. 17-18, pp. 2687-2697, 2005 Ma, C. F. and Tian, Y. Q., Experimental investigation on two-phase jet impingement heat transfer from simulated microelectronic heat sources, Int. Comm. Heat Mass Transfer, Vol. 17, pp. 399-408, 1990 Maveety, J. G. and Jung, H. H., Design of an optimal pin-fin heat sink with air impingement cooling, Int. Comm. Heat Mass Tranfer, Vol. 27, No. 2, pp. 229-240, 2000 McAdams, W. H., Kennel, W. E, Minden, C. S. L., Carl, R., Picornell, P. M. and Dew, J. E., Heat transfer at high rates to water with surface boiling, Ind. Engng. Chem., Vol. 41, No. 9, pp.1945-1953, 1949 Mitsutake, Y. and Monde, M., Ultra high critical heat flux during forced flow boiling heat transfer with an impinging jet, J. of Heat Transfer, Vol. 125, pp. 1038-1045, ASME, 2003 Moffat, R. J., Describing the uncertainties in experimental results, Experimental Thermal and Fluid Science, Vol. 1, pp. 3-17, 1988 Monde, M. and Katto, Y., Burnout in a high heat-flux boiling system with an impinging jet, Int. J. Heat Mass Transfer, Vol. 21, No. 3, pp. 295-305, 1978 Monde, M. and Mitsutake, Y., Critical heat flux in forced convective subcooled boiling with multiple impinging jets, J. of Heat Transfer, Vol. 118, No. 1, 1996 Monde, M. and Okuma, Y., Critical heat flux in saturated forced convective boiling on a heated disk with an impinging jet-CHF in L-regime, Int. J. Heat Mass Transfer, Vol. 28, No. 3, pp. 547-552, 1985 Monde, M., Kitajima, K., Inoue, T. and Mitsutake, Y., Critical heat flux in a forced convective subcooled boiling with an impinging jet, Heat transfer, Vol. 7, pp. 515-520, 1994 Mudawar, I. and Wadsworth, D.C., Critical heat flux from a simulated chip to a confined rectangular impinging jet of dielectric liquid, Int. J. Heat Mass Transfer, Vol. 34, No. 6, pp. 1465-1479, 1991 Narayanan, V. J., Seyed-Yagoobi and Page, R. H., An experimental study of fluid mechanics and heat transfer in an impinging slot jet flow, Int. J. of Heat and Mass Transfer, Vol. 47, pp. 1827-1845, 2004 Narumanchi, Sreekant V. J., Amon, Cristina H. and Murthy, Jayathi Y., Influence of pulsating submerged liquid jets on chip-level thermal phenomena, Transaction of the ASME, Vol. 125, pp. 347-353, 2003 Narunmachi, S. V. J., Amon, C. H. and Murthy, J. Y., Influence of pulsating submerged liquid jets on chip-level thermal phenomena, Transactions of the ASME, Vol. 125, September, 2003 Nigam, M. S., Numerical simulation of buoyant mixture flows, Int. J. of Multiphase Flow, Vol. 29, pp. 983-1015, 2003 170 References Pence, D.V., Boeschoten, P.A. and Liburdy, J.A., Simulation of compressible micro-scale jet impingement heat transfer, J. of Heat Transfer, Vol. 125, ASME, 2003 Pike, F. P., Miller, P. D. and Beatty, K. O., Jr., The effect of gas evolution on surface boiling at wire coils, Heat Transfer-St. Louis, Chem. Engng. Prog. Symp. Series, Vol. 17, No. 51, pp. 13-19, 1955 Pnueli, David, Transient cooling by a liquid spray of a surface heated above the boiling temperature, Int. Comm. Heat Mass Transfer, Vol. 17, pp. 537-544, 1990 Poh, H. J. and Kumar, K., Heat transfer from a laminar impinging jet of a power law fluid, Int. Comm. Heat Mass Transfer, Vol. 31, No. 2, pp. 241-249, 2004 Qiu, Yu Hao and Liu, Zhen Hua, Critical heat flux in saturated and subcooled boiling for R-113 jet impingement on the stagnation zone, Applied Thermal Engineering, Vol. 25, No. 14-15, pp. 2367-2378, 2005 Qiu, Yu-hao and Liu, Zhen-hua, Critical heat flux of steady boiling for saturated liquids jet impinging on the stagnation zone, Int. J. of Heat and Mass Transfer, No. 48, pp. 45904597, 2005 Rahman, M. M. and Bula, A. J., Numerical modeling of conjugate heat transfer during free liquid jet impingement, ASME AES, Vol. 38, pp. 475-486, 1998 Rahman, M. M., Bula, A. J. and Leland, J., Conjugate heat transfer during free jet impingement of a high Prandtl number fluid, Numer. Heat Transfer, Part B, Vol. 36, pp. 139-162, 1999 Renardy, Y. and Renardy, M., PROST: a parabolic reconstruction of surface tension for the Volume of Fluid method, J. Comput. Phys., Vol. 183, pp. 400–421, 2002 Rhee, D. H., Yoon, P. H. and Cho, H. H., Local heat/mass transfer and flow characteristics of array impinging jets with effusion holes ejecting spent air, Int. J. of Heat and Mass Transfer, Vol. 46, pp. 1-13, 2003 Rice, Jeremy, Faghri, Amir and Cetegen, Baki, Analysis of a free surface film from a controlled liquid impinging jet over a rotating disk including conjugate effects, with and without evaporation, International Journal of Heat and Mass Transfer, Vol. 48, No. 2526, pp. 5192-5204, 2005 Roy, Subrata, Nasr, Karim, Patel, Paresh and AbdulNour, Bashar, An experimental and numerical study of heat transfer off an inclined surface subject to an impinging airflow, Int. J. of Heat and Mass Transfer, No. 45, pp. 1615-1629, 2002 Ruch, M. A., Boiling heat transfer to a Freon-113 jet impinging upward onto a flat, heated surface, Int. J. of Heat and Mass Tran., No. 18, pp. 51-60, 1975 Rudman, M., A volume-tracking method for incompressible multifluid flows with large density variations, Int. J. Numer. Methods Fluids, Vol. 28, pp. 357-378, 1998 Rudman, M., Volume-tracking methods for interfacial flow calculations, Int. J. Numer. Methods Fluids, Vol. 24, pp. 671-691, 1997 171 References Ruocco, Gianpaolo, Entropy generation in conjugate heat transfer from a discretely heated plate to an impinging confined jet, Int. Communications in Heat and Mass Transfer, Vol. 24, No. 2, pp. 201-210, 1997 Sarghini, F. and Ruocco, G., Enhancement and reversal heat transfer by competing modes in jet impingement, International Journal of Heat and Mass Transfer, Vol. 47, No. 8-9, pp. 1711-1718, 2004 Sasao, K., Honma, M., Nishihara, A. and Atarashi, T., Numerical analysis of impinging air flow and heat transfer in plate-fin type heat sinks, J. of Electronic Packaging, Vol. 123, pp. 315-318, 2001 Seyedein, Seyed Hossein, Simulation of fluid flow and heat transfer in impingement flows of various configurations, Master’s thesis, department of chemical engineering, Mcgill University, Montreal, Canada, 1993 Shah, A., Sammakia, B. and Srihari, H., A numerical study of the thermal performance of an impingement heat sink-fin shape optimization, IEEE Int. Society Conference on Thermal Phenomena, pp. 298-306, 2002 Shi, Y. L., Ray, M. B. and Mujumdar, A. S., Effects of Prandtl number on impinging jet heat transfer under a semi-confined laminar slot jet, Int. Comm. Heat Mass Transfer, Vol. 30, No. 4, pp. 455-464, 2003 Stefanescu, S., Mehregany, M., Leland, J. and Yerkes, K., Micro jet array heat sink for power electronics, Proceedings of the IEEE Micro Electro Mechanical Systems, MEMS, pp. 165-170, 1999 Taghipour, Fariborz, Ellis, Naoko and Wong, Clayton, Experimental and computational study of gas–solid fluidized bed hydrodynamics, Chemical Engineering Science, Vol. 60, No. 24, pp. 6857-6867, 2005 Taha, Taha and Cui, Z. F., CFD modelling of slug flowinside square capillaries, Chemical Engineering Science , Vol. 61, pp. 665-675, 2006 Tandiroglu, Ahmet, Effect of flow geometry parameters on transient entropy generation for turbulent flow in circular tube with baffle inserts, Energy Conversion and Management, In Press, Corrected Proof, 2006 Tandiroglu, Ahmet, Effect of flow geometry parameters on transient heat transfer for turbulent flow in a circular tube with baffle inserts, International Journal of Heat and Mass Transfer, Vol. 49, No. 9-10, pp. 1559-1567, 2006 Tang, H. and Wrobel, L.C., Modelling the interfacial flow of two immiscible liquids in mixing processes, International Journal of Engineering Science, Vol. 43, pp. 1234-1256, 2005 Tasnim, Syeda Humaira and Collins, Michael R., Numerical analysis of heat transfer in a square cavity with a baffle on the hot wall, International Communications in Heat and Mass Transfer, Vol. 31, No. 5, pp. 639-650, 2004 Thyrum, G., Critical Aspects of Modeling Heat Pipe Assisted Heat Sinks, 2002, http://www.thermacore.com/pdfs/critical.pdf 172 References Tihon, Jaroslav, Institute of Chemical Process Fundamentals, Academy of Sciences of the Czech Republic, http://www.icpf.cas.cz/flore/topics/impjet.htm, 2005 Tomiyama, A., Sou, A., Minagawa, H. and Sakaguchi, T., Numerical analysis of a single bubble by VOF method, JSME Int. J. Ser. B, Vol. 36, No.1, pp. 51–56, 1993 Tong, L. S. and Tang, Y. S., Boiling heat transfer and two-phase flow, second edition, Series in Chemical and Mechanical Engineering, Taylor & Francis Publisher, pp. 7-117, 1997 Tsubokura, M., Kobayashi, T., Taniguchi, N. and Jones, W. P., A numerical study on the eddy structures of impinging jets excited at the inlet , International Journal of Heat and Fluid Flow, Vol. 24, No. 4, pp. 500-511, 2003 Tu, J. Y., The influence of bubble size on void fraction distribution in subcooled flow boiling at low pressure, Int. Comm. Heat Mass Transfer, Vol. 26, No. 5, pp. 607-616, 1999 Tu, J. Y. and Yeoh, G. H., On numerical modeling of low-pressure subcooled boiling flows, Int. J. Heat Mass Transfer, Vol. 45, pp. 1197-1205, 2002 Venart, J. E. S., Sousa, A. C. M. and Jung, D. S., Nucleate and film boiling heat transfer in R-11: the effects of enhanced surfaces and inclination, Proc. 8th Int. Heat Transfer Conf., Vol. 4, pp. 2019-2024, 1986 Voke, P. R., and Gao, S., Numerical study of heat transfer from an impinging jet, Int. J. Heat Mass Transfer, Vol. 41, No. 4-5, pp. 671-680, 1998 Wang, Chao-Yang and Beckermann, C., A two-phase mixture model of liquid-gas flow and heat transfer in capillary porous media-I: Formulation, Int. J. of Heat Mass Transfer, Vol. 36, No. 11, pp. 2741-2158, 1993 Wang, Chao-Yang and Beckermann, C., A two-phase mixture model of liquid-gas flow and heat transfer in capillary porous media-II: Application to pressure-driven boiling flow adjacent to a vertical heated plate, Int. J. of Heat Mass Transfer, Vol. 36, No. 11, pp. 2159-2768, 1993 Wang, D., Yu, E. and Przekwas, A., A computational study of two-phase jet impingement cooling of an electronic chip, IEEE SEMI-THERMTM Symposium, 1999 Wang, E. N., http: //www.stanford.edu/^enwang/research.htm Wang, E. N., Zhang, L., Jiang, L., Koo, J. M., Goodson, K. E. and Kenny, T. W., Micromachined jet arrays for liquid impingement cooling of VLSI chips, Solid-State Sensor, pp. 46-49, Actuator and Microsystems Workshop, Hilton Head Island, South Carolina, 2002 Wang, E. N., Zhang, L., Jiang, L., Koo, J. –M., Maveety, J., Sanchez, E., Goodson, K. E. and Kenny, T. W., Micromachined jets for liquid impingement cooling of VLSI Chips, Journal of Micro Electronic Mechanical Systems, 2003 Wang, X. and Monde, M., Critical heat flux in forced convective subcooled boiling with a plane wall jet, effect of subcooling on CHF, Heat and Mass transfer, Vol. 33, No. 1/2, pp. 167-175, 1997 173 References Wang, X. S., Dagan, Z. and Jiji, L. M., Conjugate heat transfer between a laminar impinging liquid jet and a solid disk, Int. J. Heat Mass Transfer, Vol. 32, No. 11, pp. 2189-2197, 1989 Woodfield, Peter Lloyd, Monde, Masanori and Mozumder, Aloke Kumar, Observations of high temperature impinging-jet boiling phenomena, International Journal of Heat and Mass Transfer, Vol. 48, No. 10, pp. 2032-2041, 2005 Wu, S., Mai, J., Tai, Y. C. and Ho, C. M., Micro Heat Exchanger by Using MEMS Impinging Jets, IEEE, pp. 171-176, 1999 Yang, C., Cooling of electronic component with jet impingement boiling, Ph.D thesis, National University of Singapore, 2001 Yang, Yue-Tzu and Tsai, Shiang-Yi, Numerical study of transient conjugate heat transfer of a turbulent impinging jet, International Journal of Heat and Mass Transfer, In Press, Corrected Proof, 2006 Yilmaz, M., The effect of inlet flow baffles on heat transfer, International Communications in Heat and Mass Transfer, Vol. 30, No. 8, pp. 1169-1178, 2003 Yoon, H. Y., Koshizuka, S. and Oka, Y., Numerical simulation of heat transfer in subcooled pool boiling, Nuclear Engieering Research Laboratory, 2004 Yu-hao Qiu, Zhen-hua Liu,Critical heat flux of steady boiling for saturated liquids jet impinging on the stagnation zone, International Journal of Heat and Mass Transfer, Vol. 48, pp. 4590-4597, 2005 Zhang, Y., and Finch, J. A., A note on single bubble motion in surfactant solutions, J. Fluid Mech., Vol. 429, pp. 63–66, 2001 Zheng, N. and Wirtz, R. A., Cylindrical pin-fin fan-sink heat transfer and pressure drop correlations, IEEE Transactions on Components and Packaging Technologies, Vol. 25, No. 1, 2001 Zhou, D. W., Ma, C. F. and Yu, J., Boiling hysteresis of impinging circular submerged with highly wetting liquids, Int. J. of Heat and Fluid Flow, No. 25, pp. 81-90, 2004 Zhuang, Y., Ma, C. F. and Qin, M., Experimental study on local heat transfer with liquid impingement flow in two-dimensional micro-channels, Int. J. Heat Mass Transfer, Vol. 40, No. 17, pp. 4055-4059, 1997　 174 Appendices Appendices Relative (Slip) Velocity and the Drift Velocity The relative velocity (also referred to as the slip velocity) is defined as the velocity of a secondary phase ( p ) relative to the velocity of the primary phase ( q ): ρ ρ ρ v pq = v p − v q (1) The mass fraction for any phase ( k ) is defined as ck = α k ρk ρm (2) ρ The drift velocity and the relative velocity ( v qp ) are connected by the following expression: n ρ ρ ρ v dr , p = v pq − ∑ c k v qk (3) k =1 Fluent's mixture model makes use of an algebraic slip formulation. The basic assumption of the algebraic slip mixture model is that to prescribe an algebraic relation for the relative velocity, a local equilibrium between the phases should be reached over short spatial length scale. The form of the relative velocity is given by: τ p (ρ p − ρ m ) ρ ρ v pq = a f drag ρ p (4) where τ p is the particle relaxation time ρ p d p2 τp = 18μ q (5) ρ d is the diameter of the particles (or droplets or bubbles) of secondary phase p , a is the 175 Appendices secondary-phase particle's acceleration. The default drag function f drag is taken from Schiller and Naumann: f drag = + 0.15 Re 0.687 (Re ≤ 1000 ) (6) f drag = 0.0183 Re (Re ≤ 1000 ) (7) ρ and the acceleration a is of the form ρ ρ ρ ρ ρ ∂v m a = g − (v m ⋅ ∇ )v m − ∂t (8) The simplest algebraic slip formulation is the so-called drift flux model, in which the acceleration of the particle is given by gravity and/or a centrifugal force and the particulate relaxation time is modified to take into account the presence of other particles. In turbulent flows the relative velocity should contain a diffusion term due to the dispersion appearing in the momentum equation for the dispersed phase. Fluent adds this dispersion to the relative velocity: ( ρ p − ρ m )d p2 ρ v ρ v pq = a − m ∇α q 19 μ p f drag α pσ D (9) where ( vm ) is the mixture turbulent viscosity and ( σ D ) is a Prandtl dispersion coefficient. When solving a mixture multiphase calculation with slip velocity, formulations for the drag function can be directly prescribed. The available choices are: • Schiller-Naumann (the default formulation) • Morsi-Alexander • Symmetric • Constant • User-defined functions 176 Appendices In this simulation, an energy function for heat transfer, liquid and vapor functions for mass transfer were written in source code to solve heat and mass transfer process. Volume Fraction Equation for the Secondary Phases From the continuity equation for secondary phase p , the volume fraction equation for secondary phase p can be obtained: n ∂ (α p ρ p ) + ∇ ⋅ (α p ρ p vρm ) = −∇ ⋅ (α p ρ p vρdr , p ) + ∑ (m&qp − m&pq ) ∂t q =1 177 (10) [...]... conjugate heat transfer under a confined impinging jet" , International Journal of Thermal Sciences, submitted Z.Q Lou, C Yap and A.S Mujumdar, "Numerical Investigation of Baffle Effect on Micro -Impinging Jet Heat Transfer" , International Journal of Thermal Sciences, Submitted, 2005 Z.Q Lou, C Yap and A.S Mujumdar, "Numerical Investigation of Two- phase Impinging Jet Heat Transfer" , Journal of Applied... rapid increase of heat dissipation rate required by electronic components, single phase heat transfer will eventually not be sufficient to meet the demand Thus, two- phase heat transfer (boiling heat transfer) has become a topic receiving increasing attention of major interest in the electronic cooling field Compared with single phase heat transfer, twophase heat transfer can increase the heat transfer effectiveness... geometry of the target plate is a key factor which affects the heat transfer effectiveness of the impinging jet system A target plate using a finned heat sink under an impinging jet affects heat transfer performance significantly Therefore, an investigation of fin design under an impinging jet is worthy of a further study Many experimental and numerical investigations of a heat sink under an impinging jet. .. Visualizations of the single and two- phase heat transfer for the +45° inclined impingement …………………………………………………………………………….151 Fig 9.12 Visualizations of the single and two- phase heat transfer for the sideways impingement…………………………………………………………………………… 153 Fig 9.13 Visualizations of the single and two- phase heat transfer for the upward impingement …………………………………………………………………………….154 Fig 9.14a Comparison of heat fluxes... roughness, impinging orientation, fin structure, an inserted baffle etc On the basis of the verified simulation model, a numerical investigation of the micro -impinging jet was also carried out 1.4 Scope In the current investigation, the study was mainly focused on the single and twophase impinging jet heat transfer Both numerical and experimental investigations were carried out For the single phase problem,... laminar impinging jet heat transfer to finned heat sink" ,Proceedings of ASME:2005 Summer Heat Transfer Conference 2005, Published on CD/Presented, San Francisco, USA Z.Q Lou, C Yap and A.S Mujumdar, "Experimental Investigation of Single Phase and Boiling Heat Transfer of Pure Water Under a Micro -impinging Jet Heat Transfer" ECI Conference on Boiling, Spoleto 7-12 May 2006 Z.Q Lou, C Yap and A.S Mujumdar,... developed to simulate two- phase problem in the impinging jet system 1.3 Objectives The main objective of the current studies was to examine the heat transfer performance in the impinging jet system under various operating conditions In this study, both numerical and experimental methods were used to examine the single and two- phase problems For the single phase heat transfer, the effects of different operating... Mujumdar and C Yap, "Effects of geometric parameters on confined impinging jet heat transfer" , Journal of Applied Thermal Engineering, Vol 25, No 17-18, Dec 2005, pp 2687-2697 Z.Q Lou, C Yap and A.S Mujumdar, "A Numerical Study of a Heat Sink Fin under a Laminar Impinging Jet" , Journal of Electronic Packaging, 2006 (Accepted) Z.Q Lou, C Yap and A.S Mujumdar, "Numerical investigation of laminar impinging jet. .. focused mainly on the air jets with jet width on the order of several millimeters However, more compact configurations and higher heat transfer performance are demanded because of the rapid increase of heat flux dissipation rates A micro -impinging jet of a dielectric fluid FC-72 is examined experimentally in the current study A few investigations of micro -impinging jet heat transfer were reported in... investigation of IJHTis presented Fig 1.7 11 Chapter 1 Introduction Fig 1.7 Flow chart of the current investigation of the impinging jet heat transfer 12 Chapter 2 Literature Review Chapter 2 Literature Review In this chapter, a brief overview of previous investigations on impinging jet heat transfer is presented Here, the review is classified by related research topics Classifications of impinging jet heat transfer . of single and two-phase impinging jet heat transfer. The goal of this study is to contribute to a more detailed investigation of effects of various parameters on impinging jet heat transfer so. NUMERICAL AND EXPERIMENTAL INVESTIGATION OF SINGLE AND TWO-PHASE IMPINGING JET HEAT TRANSFER ZHENGQUAN LOU NATIONAL UNIVERSITY OF SINGAPORE. USA Z.Q. Lou, C. Yap and A.S. Mujumdar, " ;Experimental Investigation of Single Phase and Boiling Heat Transfer of Pure Water Under a Micro -impinging Jet Heat Transfer& quot; ECI Conference