Evaporation Condensation and Heat transfer Part 7 docx

⎧ ⎪ ⎪ ⎪ ⎪ ⎪ ⎪ ⎨ ⎪ ⎪ ⎪ ⎪ ⎪ ⎪ ⎩ ∑ ∑ ∑ k hhh Cr Ar B CODYRUN [...]... disturbances: Part I – adiabatic pressure drop, International Journal for Heat and Mass Transfer, Vol 54, Issue 7- 8, pp 15 87 – 1598 Meyer, J.P & Olivier, J.A (2011b) Transitional flow inside enhanced tubes for fully developed and developing flow with different types of inlet disturbances: Part II – 260 Evaporation, Condensation and Heat Transfer heat transfer, International Journal for Heat and Mass Transfer, ... inside heat transfer area m2 m2 Ao Inner tube outside heat transfer area m2 Cp Specific heat Inner diameter of tube J/kg.°C m f L mi Darcy-Weisbach friction factor Tube length Inner-tube fluid mass flow rate m kg/s mo Annulus fluid mass flow rate kg/s Di Nu Nusselt number based on D i Pr Prandtl number Differential pressure drop Δp Pa 258 Evaporation, Condensation and Heat Transfer Qi Heat transfer. .. Condensation and Heat Transfer 0,048 0,043 0,038 0,033 0,028 170 0 1900 2100 2300 2500 270 0 2900 3100 Fig 9 Fully developed adiabatic friction factors for the enhanced tubes Fig 10 Heat transfer results for smooth and enhanced tubes for developing and fully developed flow 2 57 Heat Transfer in the Transitional Flow Regime 5 Conclusion As modern chillers might operate in the transitional flow regime, heat transfer. .. Engineering, Vol 97, pp 225-233 Nunner, W (1956) Heat transfer and pressure drop in rough tubes, VDI-Forschungsheft, 455B5-39 Obot, N.T., Esen, E.B & Rabas, T.J (1990) The role of transition in determining friction and heat transfer in smooth and rough passages, International Journal of Heat and Mass Transfer, Vol 33, No 10, pp 2133 - 2143 Obot, N.T., Das, L., Vakili, D.E & Green, R.A (19 97) Effect of Prandtl... on smoothtube heat transfer and pressure drop, International Communications in Heat and Mass Transfer, Vol 24, No 6, pp 889 – 896 Oliver, D.R (1962) The effect of natural convection on viscous-flow heat transfer in horizontal tubes, Chemical Engineering Science, Vol 17, pp 335-350 Olivier, J.A (2009) Single-phase heat transfer and pressure drop of water inside horizontal circular smooth and enhanced... inserts, International Journal of Heat and Mass Transfer, Vol 50, pp 3 176 - 3189 Ghajar, A.J & Tam, L.M (1990) Laminar-transition-turbulent forced and mixed convective heat transfer correlations for pipe flows with different inlet configurations, HTD, Fundamentals of Forced Convective Heat Transfer, ASME, Vol 181, pp 15-23 Ghajar, A.J & Tam, L.M (1994) Heat transfer measurements and correlations in the transition... different inlet configurations, Experimental Thermal and Fluid Science, Vol 8, pp 79 -90 Ghajar, A.J & Tam, L.M (1995) Flow regime maps for a horizontal pipe with uniform wall heat flux and three inlet configurations, Experimental Thermal and Fluid Science, Vol 10, pp 2 87- 2 97 Gnielinski, V (1 976 ) New Equation for Heat and Mass Transfer in Turbulent Pipe and Channel Flow, International Chemical Engineering,... to nine times and heat transfer up to four times compared with empty smooth 246 Evaporation, Condensation and Heat Transfer tubes In a follow-up study, García et al (20 07) reported that at a Reynolds number of around 1 000, wire inserts increase the heat transfer coefficient up to eight times; while the friction factor increases with approximately 40% Furthermore, not only tube roughness and enhancement... the overall heat transfer coefficient and the sum of the resistances, given by αi = 1 Ai ⎡ 1 1 ⎤ − Rw − ⎢ ⎥ UA α oA o ⎦ ⎣ −1 (1) UA is the overall heat transfer coefficient, which can be obtained by means of the overall heat transferred and the log-mean temperature difference, calculated from the inlet and outlet temperatures of the inner tube and annulus UA = Qi Tlmtd (2) Qi is the heat transferred... (2005) Experimental study of heat transfer enhancement with wire coil inserts in laminar-transition-turbulent regimes at different Prandtl numbers, International Journal of Heat and Mass Transfer, Vol 48, pp 4640 - 4651 Heat Transfer in the Transitional Flow Regime 259 García, A., Solano, J.P Vicente, P.G & Viedma, A (20 07) Enhancement of laminar and transitional flow heat transfer in tubes by means . friction and heat transfer in smooth and rough passages. Later on they (Obot et al., 19 97) took measurements of heat transfer and pressure drop in smooth tubes in laminar, transitional and turbulent. to nine times and heat transfer up to four times compared with empty smooth Evaporation, Condensation and Heat Transfer 246 tubes. In a follow-up study, García et al. (20 07) reported that. re-entrant and c) bellmouth Evaporation, Condensation and Heat Transfer 248 Prior to and after the honeycomb, a wire mesh was placed with the wires having a diameter of 0.8 mm and the OAR