Astm stp 1534 2012

Journal of ASTM International Selected Technical Papers STP1534 Film and Nucleate Boiling Processes JAI Guest Editors: K Narayan Prabhu Nikolai Kobasko ASTM International 100 Barr Harbor Drive PO Box C700 West Conshohocken, PA 19428-2959 Printed in the U.S.A ASTM Stock #: STP1534 Library of Congress Cataloging-in-Publication Data Film and nucleate boiling processes / JAI guest editors, K Narayan Prabhu, Nikolai Kobasko p cm (Journal of ASTM International Selected technical papers; STP1534) Includes bibliographical references and index ISBN 978-0-8031-7520-4 (alk paper) Nucleate boiling Film boiling Heat Transmission Change of state (Physics) I Prabhu, Narayan II Kobasko, N I (Nikolai Ivanovich) QC304.F44 2012 536’.44 dc23 2012003685 Copyright © 2012 ASTM INTERNATIONAL, West Conshohocken, PA All rights reserved This material may not be reproduced or copied, in whole or in part, in any printed, mechanical, electronic, film, or other distribution and storage media, without the written consent of the publisher Journal of ASTM International (JAI) Scope The JAI is a multi-disciplinary forum to serve the international scientific and engineering community through the timely publication of the results of original research and critical review articles in the physical and life sciences and engineering technologies These peer-reviewed papers cover diverse topics relevant to the science and research that establish the foundation for standards development within ASTM International Photocopy Rights Authorization to photocopy items for internal, personal, or educational classroom use, or the internal, personal, or educational classroom use of specific clients, is granted by ASTM International provided that the appropriate fee is paid to ASTM International, 100 Barr Harbor Drive, P.O Box C700, West Conshohocken, PA 19428-2959, Tel: 610-832-9634; online: http://www.astm.org/copyright The Society is not responsible, as a body, for the statements and opinions expressed in this publication ASTM International does not endorse any products represented in this publication Peer Review Policy Each paper published in this volume was evaluated by two peer reviewers and at least one editor The authors addressed all of the reviewers’ comments to the satisfaction of both the technical editor(s) and the ASTM International Committee on Publications The quality of the papers in this publication reflects not only the obvious efforts of the authors and the technical editor(s), but also the work of the peer reviewers In keeping with long-standing publication practices, ASTM International maintains the anonymity of the peer reviewers The ASTM International Committee on Publications acknowledges with appreciation their dedication and contribution of time and effort on behalf of ASTM International Citation of Papers When citing papers from this publication, the appropriate citation includes the paper authors, “paper title”, J ASTM Intl., volume and number, Paper doi, ASTM International, West Conshohocken, PA, Paper, year listed in the footnote of the paper A citation is provided as a footnote on page one of each paper Printed in Bay Shore, NY February, 2012 Foreword THIS COMPILATION OF THE JOURNAL OF ASTM INTERNATIONAL (JAI), STP1534, Film and Nucleate Boiling Processes, contains papers published in JAI that discuss heat quenching technologies based on several developments These developments include: the mechanism of film and nucleate boiling processes, calculating the duration of transient nucleate boiling mode, the accuracy of cooling curves and cooling rate measurements, the results of investigations based on use of noise control systems, and what are real and effective heat transfer coefficients The JAI Guest Editors are Prof K Narayan Prabhu, National Institute of Technology Karnataka, Department of Metallurigical and Materials Engineering, Surathkal, Mangalore, India and Dr Nikolai Kobasko, FASM, IQ Technologies Inc., Akron, OH, USA Contents Overview A Volume of Fluid Phase Change Model on Adaptive Octree Grids M W Akhtar and S J Kleis CFD-Simulation of Film Boiling at Steel Cooling Process T Kulju, J Pyykkönen, D C Martin, E Muurinen, and R L Keiski vii 28 Enhancement of Heat Transfer Characteristics of Transformer Oil by Addition of Aluminium Nanoparticles E Rajesh and K N Prabhu 45 Modeling and Simulation of Film and Transitional Boiling Processes on a Metallic Cylinder During Quenching P Stark and U Fritsching 61 Correlation Between Chemical Composition of Steel, Optimal Hardened Layer, and Optimal Residual Stress Distribution N I Kobasko 81 Duration of the Transient Nucleate Boiling Process and Its Use for the Development of New Technologies N I Kobasko 103 Effect of Accuracy of Temperature Measurements on Determination of Heat Transfer Coefficient during Quenching in Liquid Media N I Kobasko 126 Intensive Quenching of Steels Parts and Tools in Water Salt Solutions of Optimal Concentration N I Kobasko, A A Moskalenko, V V Dobryvechir, and L M Protsenko 142 Microstructure and Hardness Prediction at the Core of Steel Parts of Any Configuration during Quenching N Kobasko and S Guseynov 167 Experimental Investigation of the Onset of Subcooled Nucleate Boiling in an Open-Pool Nuclear Research Reactor A Z Mesquita, A L Costa, C Pereira, M A F Veloso, and P A L Reis 183 Boiling Heat Transfer of Butanol Aqueous Solution Augmentation of Critical Heat Flux S Nishiguchi and M Shoji 198 Heat Transfer Stages Recognition by Boiling Acoustic During Quenching F Ravnik and J Grum 209 Boiling Heat Transfer: An Overview of Longstanding and New Challenges I G Shekriladze 229 Modeling and Simulation of the Heat and Mass Transfer Characteristics of Binary Mixtures for Boiling Flow Applications V Srinivasan and D M Wang 285 Application of Numerical Methods to Simulate Direct Immersion Quenching Process V Srinivasan, D M Wang, D Greif, and M Suffa 315 Modeling Vertical Subcooled Boiling Flows at Low Pressures G H Yeoh, S C P Cheung, J Y Tu, and M K M Ho 349 Forced Convective Boiling of Ethylene Glycol/Water Mixtures Inside a Small Tube W Yu, D M France, and J L Routbort 376 Bubble Dynamics and Heat Transfer in Pool Boiling on Wires at Different Gravity J.-F Zhao and S.-X Wan 402 Author Index Subject Index 421 423 Overview The compendium on “Film and Nucleate Boiling Processes” discusses important problems connected with the quenching processes in heat treating industry as well as boiling problems related to the nuclear power industry Both for heat treating industry and for nuclear power industry, the formation of film boiling should be prevented During quenching, the film boiling (especially local one) results in considerable distortion, crack formation and poor mechanical properties of the material In the nuclear power industry, film boiling can lead to overheating of the nuclear reactor Hence, a study of film and nucleate boiling processes combined with the critical heat flux (CHF) densities are very important for the practice The duration of transient nucleate boiling process is widely discussed in STP1534 (see paper JAI103485) It has been established by the author that duration of transient nucleate boiling process is directly proportional to square of the thickness of steel parts and inversely proportional to thermal diffusivity of a material and depends on configuration of steel parts, liquid properties and its velocity The transient nucleate boiling (self–regulated thermal process) is followed by specific characteristics: the surface temperature during nucleate boiling is maintained at the level of the boiling point of the liquid which is used as a quenchant During this period real heat transfer coefficients and average effective heat transfer coefficients (HTCs) are considered Average effective generalized Biot numbers and Kondratjev numbers can be found which remain almost the same with varying size of probes Using established characteristics, the authors of the paper JAI103525 (Kobasko, Guseynov) predicted the microstructure and hardness at the core of steel parts of any configuration Also these characteristics were used by author of the paper JAI102788 (Kobasko) to evaluate correctly optimal quenched layer which provides optimal residual stress distribution after quenching Based on duration of nucleate boiling process, the new intensive two – step intensive quenching (IQ) technology was developed using water salt solutions of optimal concentration (JAI104173, Kobasko, Moskalenko, et al.) Rajesh and Prabhu (see paper JAI103354) investigated nanofluids as a quenchant It has been stablished by authors that the addition of Al nanoparticles to the base fluid decreases the wettability and improves its heat transfer capability The vapour phase stage existed for longer period of time for transformer oil than Al-transformer oil based nanofluids The dispersion of nanoparticles in the base fluid is believed to disrupt the vapour blanket stage in the early stage of the cooling process The peak heat transfer coefficient increases with increase in the Al nanoparticle content in the oil The addition of 0.5 vol% nanoparticles enhances the peak heat transfer coefficient by about vii 58 % Nanofluids can also be successfully used for intensification of cooling at the second step of intensive quenching to improve mechanical properties of steel Nanofluids, as a new class of quenchants, are very promising for heat treating industry Ravnik and Grum (JAI103386) presented the data which show that expected frequency range during nucleate boiling process depends on the bubble size and immersion depth and can vary within 3–18 kHz Their findings are very important for designing new version of noise control system to evaluate duration of nucleate boiling processes Some results of investigations are also discussed in the paper (JAI104173, Kobasko, Moskalenko, et al.) Forced convective boiling of ethylene glycol/water mixtures inside a small tube were investigated by Wenhua Yu, France, and Routbort (see paper JAI103378) Equations for prediction of boiling heat transfer coefficients of water and ethylene glycol/water mixtures in small channels were developed by them These equations predict the experimental data well, and most of the predicted values are within ±30% of the experimental data Yeoh, Cheung, et al (JAI103374-10) presented the results of investigations connected with modeling vertical subcooled boiling flows at low pressures A new bubble departure model including the influence of the Marangoni effects has also been proposed by authors, which can predict the whole observation both in microgravity and in normal gravity The value of CHF (critical heat flux) in microgravity is lower than that in normal gravity, but it can be predicted well by the Lienhard-Dhir correlation Nishiguchi and Shoji (JAI103452) investigated boiling heat transfer of butanol aqueous solutions Boiling heat transfer, especially critical heat flux (CHF), of some aqueous solutions is enhanced by adding small amount of alcohol such as butanol Such aqueous solutions show nonlinear surface tension dependence on liquid temperature and are sometimes called as “Self-rewetting liquid”, being applied recently to thermal devices such as heat pipes However, the heat transfer characteristics of boiling of self-rewetting liquids are not fully understood In the present research, by employing butanol aqueous solution as a typical test solution, a fundamental boiling test is performed on a heated wire with special attention to CHF augmentation in order to observe the boiling phenomena and to address the fundamental issues The authors found that the dependence of CHF on liquid subcooling is peculiar With increasing subcooling, CHF decreases first , reaches a minimum and then increases CFD-Simulation of Film Boiling at Steel Cooling Process was carried out by Timo Kulju et al (JAI103382-10) Their paper analyzes film boiling phenomena on a flat, horizontal hot steel plate using the Volume of Fluid (VOF) method In this study, the model includes both convection and radiation induced mass and heat transfer, where the latter was found to be more viii important to maintain the film layer and film boiling at high temperatures The model estimated heat and mass transfer behavior at impingement velocities between 1-5 m/s and temperatures between 500-1300 K The initial results obtained with the simulation suggest that CFD simulation techniques represent a promising alternative for studying complex and difficult to measure phenomena such as high temperature film boiling, and hint at a new class of experimental methods for mechanistic analysis of fluid Also modeling and simulation of film and transitional boiling processes on a metallic cylinder during quenching were investigated by Paul Stark, Udo Fritsching (JAI103380-10) The authors showed that the bubble crowd model is able to investigate the separate boiling phases within one single numerical model approach Simulation results are discussed for the quenching of a circular cylinder in a facing water flow The initial flow velocity and the wall superheat (at temperatures above and below the Leidenfrost point) were varied to investigate their influence on the vapor formation and on the local as well as the averaged heat transfer rates Heat and Mass Transfer Characteristics of Binary Mixtures for Boiling Flow Applications were modeled and simulated by Vedanth Srinivasan and De Ming Wang (JAI103366-10) The authors proposed boiling mass transfer model, based on detailed empirical analysis of the heat transfer coefficients pertinent to binary systems and was fully implemented within the commercial CFD code AVLFIRE® It was used to study the heat and mass transfer characteristics of boiling flows inside a rectangular duct The authors underlined that their model can be easily extended to simulate multiphase flow in complex systems such as a cooling water jacket for automotive applications As a result of complex investigations (film boiling, nucleate boiling and critical heat flux densities), it is possible to use numerical methods of calculations and make computer simulations to accurately predict heat transfer modes Application of Numerical Methods to Simulate Direct Immersion Quenching Process was also investigated by Vedanth Srinivasan et al (JAI103364-10) Authors presented the results of the numerical computations carried out to simulate the direct immersion quenching process of several test pieces using a recently developed and implemented quenching simulation methodology within the commercial CFD code AVLFIRE® Numerical coupling between the simulation domains, involving the fluid and the solid metal region, were achieved through an AVL Code Coupling Interface (ACCI) feature The computed information adjudges the presence of intense non-uniformity in the temperature distribution within the solid region which is of grave importance in evaluating the stress and fatigue patterns generated in the quenched object Experimental investigation of the onset of subcooled nucleate boiling in an open-pool nuclear research reactor was carried out by Mesquita et al (JAI103193-10) The investigations were done in the IPR-R1 TRIGA nuclear ix ZHAO AND WAN, doi:10.1520/JAI103379 407 FIG 3—Heat transfer curves in microgravity normal gravity on Earth, which are not shown here The first heat transfer mode is single-phase natural convection in normal gravity The experimental data of single-phase natural convection are compared in Fig with the prediction of the commonly used correlation of Kuehn and Goldstein [8] An agreement is quite evident in normal gravity Similar results are also observed in the VCPB experiments, in which all points of the measured data in normal gravity condition locate in a range of 630 % around the prediction of the correlation of Kuehn and Goldstein [8] These comparisons guarantee the correctness of the experimental data obtained In microgravity, weak single-phase convection may exist due to small residual gravity aboard the satellite Comparing the results of space experiments with the predictions of the correlation of Kuehn and Goldstein 8, it is indicated that the residual gravity during the space experiment is in the range of ð103 –105 Þ g0 (here g0 denotes the gravity on Earth), which is consistent with the estimated value in the range from 103 to 105 g0 based on previous measurements aboard the same satellites, and then further confirms the data correctness In the TCPB experiments, the onset of boiling occurs at the 16th step as twomode transition boiling both in space and on the ground The sequence of pictures in Fig (for magnitude estimation, the distance between the two copper poles is 30 mm) corresponds to the onset of boiling in microgravity About 0.12 s after the beginning of the 16th step, a large amount of vapor springs out throughout the wire with a very irregular interface Due to the surface tension, a large spherical bubble is eventually formed It stays on the wire continuously without 408 JAI  STP 1534 ON FILM AND NUCLEATE BOILING PROCESSES FIG 4—Comparisons of the experimental data in different gravity with the predictions of the correlation of Kuehn and Goldstein [8] enclosing the wire in the subsequent experiments, and coalesces continually up adjacent small bubbles The boiling reached a steady state in about s after the beginning of the 16th step The superheat of the onset of boiling is 83 C, which is independent of, or at least, dependent much weakly on gravity It ought to be pointed out that the actual superheat of the onset of boiling will locate in the range between the 15th and 16th set-point, or 42 to 83 C, due to the limitation of the present control method The heat flux, however, decreased in microgravity to about 40 % of that in normal gravity, while about 20 % decrease for two-mode transition boiling was found in our preliminary experiments in the drop tower Beijing [9] On the contrary, heat fluxes of nucleate boiling in microgravity are the same or only slightly enhanced compared with those in normal gravity (Fig 6) According to Straub [1], there are two mechanisms for boiling heat transfer The primary one is phase change on the heating surface, while bubble motion and other factors belong to the second one If gravity plays a key role, bubble motion will be the dominant factor In microgravity, however, correlations based on bubble motion, such as Rohsenow’s correlation, cannot be available Phase change underneath the growing bubbles can contribute more heat flux to counteract the drastic change in bubble sizes Thus, experiments in microgravity can be very helpful to reveal the primary mechanism of boiling heat transfer Figure shows the scaling of CHF with the gravity Contrary to the traditional viewpoint on CHF, it is found that the trend of CHF in different gravity can be predicted much well by the Lienhard–Dhir–Zuber model [10], established FIG 5—A sequence of pictures of bubble development after the onset of boiling in microgravity The time interval between sequent images is 1/25 s ZHAO AND WAN, doi:10.1520/JAI103379 409 410 JAI  STP 1534 ON FILM AND NUCLEATE BOILING PROCESSES FIG 6—Microgravity efficiency on heat transfer of nucleate boiling in microgravity on the mechanism of hydrodynamic instability, although the value of R is far beyond the initial application range of the LD-Zuber model This observation is consistent with Straub [1] Furthermore, comparing the trend of CHF in Fig with the common viewpoint on the scaling of CHF, it is inferred,p asffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi pointed outffi by Di Marco and Grassi [11], that the dimensionless radius R ¼ R ðqL  qG Þg=r, or the Bond number Bo ¼ 4R , may not be able to scale the effects adequately and separate groups containing gravity due to the complex competition of different mechanisms for small cylinder heaters To interpret this phenomenon, a parameter, named “the Limited Nucleate Size dLN ,” was introduced Some factors, such as the kind of fluid, wall roughness, and material property, can affect this parameter It is, however, assumed to be independent of gravity based on the observation of no change of the wall superheat at the onset of boiling in different gravity conditions, as well as general knowledge of nucleation Then, a non-dimensional coefficient C ¼ dLN =dwire was also introduced If C is small, the occurrence of the CHF will be caused by the mechanism of hydrodynamic instability, while it will be caused by the mechanism of local dryout if C is large In the latter case, bubble can easily enwrap the wire to form a local dryout area due to its larger size relative to the wire Further researches are needed for the delimitation of the two mechanisms In order to reveal the influences of subcooling and cylinder diameter on CHF, a new series of experimental data of CHF on cylinders in normal gravity have been obtained using the VCPB device FC-72 and acetone were used as the working liquids, which were degassed carefully before experiments Three ZHAO AND WAN, doi:10.1520/JAI103379 411 FIG 7—Scaling of CHF with gravity diameters, namely 25, 60, and 100 lm, are used for the heaters The range of the subcooling is from K to about 50 K It is found from these experiments that the fully developed nucleate boiling region on smaller wire will become narrower The same trend is also observed for the gap between CHF and the minimum heat flux of film boiling) It becomes narrower and narrower with the decrease of the heater diameter However, it exists even in the saturated pool boiling on the smallest wire in the present study 1=2 The dependence of the Kutateladze number K ¼ qCHF =fqg hlg 1=4 ẵrgql  qg ị g on the subcooling in the boiling experiments of FC-72 and acetone is shown in Figs and 9, respectively The subscript “sat” denotes the corresponding values at saturated boiling Although the data locate in the similar range of the Bond number for the two working fluids, the dependence of CHF on the subcooling in acetone differs from that in FC-72 Comparing with the predictions by most common used correlations for subcooling influence, a much stronger enhancement of CHF in acetone can be observed, while the same behaviors as in large cylinder heaters can be observed in the present experiments on small wires in FC-72 The scaling behaviors of CHF in the corresponding experiments at saturated conditions are shown in Figs 10 and 11, respectively Different trends were also observed Thus, in a small Bond number, there may exist some other parameters, which may be material-dependent, in addition to the Bond 412 JAI  STP 1534 ON FILM AND NUCLEATE BOILING PROCESSES FIG 8—Dependence of CHF on the subcooling of pool boiling of FC-72 FIG 9—Dependence of CHF on the subcooling in pool boiling of acetone ZHAO AND WAN, doi:10.1520/JAI103379 413 FIG 10—Scaling behavior of CHF in pool boiling of FC-72 FIG 11—Scaling behavior of CHF in pool boiling of acetone 414 JAI  STP 1534 ON FILM AND NUCLEATE BOILING PROCESSES number that plays important roles in the CHF phenomenon The new parameter will determine the range in which interactions between the influences of the subcooling and size on CHF will be important, and then different scaling behaviors and mechanisms of CHF will be observed Bubble Behaviors In the fully developed nucleate boiling regime in microgravity, the oscillation due to coalescence of adjacent bubbles is the primary reason of bubble departure according to the analysis of the recorded video images A similar conclusion was also made by Straub [1] Before their departure from the wire in microgravity, it is also observed that there exists a forward-and-backward lateral motion of discrete vapor bubbles along the wire They could change their moving direction backward when encountering another bubble and reach a new steady velocity Figure 12 shows the position X along the wire and the lateral velocity U of a typical bubble of about 0.9 mm in diameter during its forward-and-backward lateral motion The lateral velocity is about 20 mm/s, unless it comes in collision with and bounces off an adjacent bubble Generally, the lateral velocity increases with the decrease of the bubble size This kind of lateral motion can lead to the lateral coalescence between adjacent bubbles, and then the new bubble detaches due to its surface oscillation For example, the above bubble coalesces with another bubble when it moves back to nearly its initial position The following motion after its departure is shown FIG 12—Lateral motion of a typical bubble ZHAO AND WAN, doi:10.1520/JAI103379 415 in Fig 13, where Y and V denote the distance of the bubble away from the wire and its departure velocity A hypothesis was proposed by Zhao et al [9] that adjacent bubbles entrain each other in thermo-capillary or Marangoni flow surrounding them during nucleate boiling of subcooled liquids The entrainment manifests itself as motion of the bubbles toward each other, which promotes their coalescence A scale analysis on this phenomenon leads to formulas of the characteristic pffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi velocity of the lateral motion UM ¼ rT DT=qL Db and its observability qffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi Ob ¼ UM =UB ¼ g1 rT DT 2L =qL D5b The prediction of UM is 30 mm/s for a bubble of mm in diameter The observability Ob will be 105=2  in normal gravity and 105=2  in 105 g0 , respectively Thus, the lateral motion can be difficult to be observed in normal gravity but easy to be observed in microgravity It is consistent with the experimental observations In long-term microgravity, four regimes and three critical bubble diameters are observed in the case of discrete vapor bubbles, as shown in Fig 14 Tiny vapor bubbles form and grow on the heater surface until their sizes exceed the first critical value, and then depart slowly from the wire Above the second critical value, however, a bubble may stay on the wire, oscillate along the wire, and coalesce with adjacent bubbles, until its size exceeds the third critical value and it will depart from the wire again The behaviors of tiny bubbles are observed both in microgravity and in normal gravity, while the last two kinds of bubble behaviors are observed only in microgravity aboard the satellite None of the FIG 13—Departure of the former bubble 416 JAI  STP 1534 ON FILM AND NUCLEATE BOILING PROCESSES FIG 14—Bubble departure in the case of discrete vapor bubble in microgravity common used models, in which the Marangoni effect is neglected at all, can predict the present observation in microgravity Recently, Zhao et al [12] proposed a qualitative model based on the model of Lee [13] to predict the bubble departure diameter, in which the Marangoni effect is taken into account, as shown in Fig 14, where the abscissa Db denotes bubble diameter, while the ordinate f ðyÞ denotes the resultant force acting on the bubble If the resultant force is positive, the bubble will depart from the wire surface On the contrary, a negative resultant force will be corresponding with bubble staying on the wire The agreement between the prediction and observations is much satisfied Figure 15 shows a typical growth process of a discrete vapor bubble observed in the space experiment There exists some oscillation at the beginning due to a sudden change of the heater temperature from 90 C to 88 C During the bubble growing, the heater temperature was controlled as a constant of 88 C for about 30 s, and then stepped downward to a new value of 85 C It is found that the bubble growth rate can be written as d ¼ Csn , where C and n are empirical parameters According to the present measurement, the exponent could change from 1/3 at the beginning to 1/5 when the oscillation is diminished It means that the vapor bubble grows more slowly than the expectation of the above model, in which n ¼ 1=2 was adopted, and the growth rate could decrease with its size increase It suggests that further revision for the above bubble departure model is needed The models mentioned above imply an assumption that the temperature distribution along the vapor bubble is not affected by evaporation and condensation, just like the case of Marangoni migration of gas bubbles in bulk liquid with temperature gradient This is contrary to Straub [1,14] In his opinion, the kinetics of evaporation is strong enough to keep the interface almost isothermal and then no Marangoni convection could be observed in saturated pool boiling The Marangoni convection observed at subcooled boiling is caused by the inert ZHAO AND WAN, doi:10.1520/JAI103379 417 FIG 15—Typical growth process of a discrete bubble gas accumulation The vapor pressure decreases at the upper part of the interface and then the saturation temperature decreases locally However, Straub [1,14] also pointed out that temperature gradients at the interface in the thin microwedge cannot be excluded, where much strong evaporation occurs This contradicts his above opinion directly The isothermal condition, however, is the result of the classical equilibrium thermodynamics The evaporation and condensation are typically nonequilibrium processes Recently, non-equilibrium interfacial conditions have been adopted by many researchers to describe the interface of a liquid with phase change, for example, Oron et al [15], Margerit et al [16], Ward and Duan [17], and Sefiane [18] Li et al [19] made a comprehensive review on the interfacial conditions with phase change It is pointed out that none of the nonequilibrium interfacial conditions have received common acceptance presently Much more work is needed Summary In the past years, steady pool boiling of degassed R113 on thin platinum wires have been studied systematically in our laboratory, including experiments in long-term microgravity aboard RS-22, in short-term microgravity in the drop tower Beijing, and in normal gravity A temperature-controlled heating method is used both in the space experiment and in the ground experiments, while a voltage-controlled heating method is also used in normal gravity Slight enhancement of nucleate boiling heat transfer is observed in microgravity The 418 JAI  STP 1534 ON FILM AND NUCLEATE BOILING PROCESSES value of CHF in microgravity is lower than that in normal gravity, but it can be predicted well by the Lienhard–Dhir correlation, although the dimensionless radius in the present case is far beyond its initial application range The scaling of CHF with gravity is thus much different from the traditional viewpoint A further revisit on the scaling of CHF with heater radius in normal gravity, which is focused on the case of a small Bond number, has also been performed in our laboratory using different kinds of working fluids at different subcooling conditions It is found that interactions between the influences on CHF of the subcooling and heater radius will be important for the case of a small Bond number, and that there may exist some other parameters, which may be material-dependent, in addition to the Bond number that play important roles in the CHF phenomenon with a small Bond number On the contrary, dramatic changes of bubble behaviors are very evident in different gravity conditions Three critical diameters are observed for bubble departure in long-term microgravity Considering the influence of the Marangoni effects, the different characteristics of bubble behaviors in microgravity have been explained A new bubble departure model has also been proposed, which can predict the whole observation both in microgravity and in normal gravity Acknowledgments The present study is supported financially by the National Natural Science Foundation of China under Grant No 10972225 The first writer also wants to thank Mr Gang Liu, Ms Na Yan, and Mr Yanghui Lu, the graduate students who had made large contributions on the present subject in the past years References [1] [2] [3] [4] [5] [6] [7] [8] Straub, J., “Boiling Heat Transfer and Bubble Dynamics in Microgravity,” Adv Heat Transfer, Vol 35, 2001, pp 57–172 Di Marco, P., “Review of Reduced Gravity Boiling Heat Transfer: European Research,” J Jpn Soc Microgravity Appl., Vol 20(4), 2003, pp 252–263 Kim, J., “Review of Reduced Gravity Boiling Heat Transfer: US Research,” J Jpn Soc Microgravity Appl., Vol 20(4), 2003, pp 264–271 Ohta, H., “Review of Reduced Gravity Boiling Heat Transfer: Japanese Research,” J Jpn Soc Microgravity Appl., Vol 20(4), 2003, pp 272–285 Zhao, J F., “Two-Phase Flow and Pool Boiling Heat Transfer in Microgravity,” Int J Multiphase Flow, Vol 36(2), 2010, pp 135–143 Wan, S X., Zhao, J F., Liu, G., and Hu, W R., “TCPB Device: Description and Preliminary Ground Experimental Results,” 54th Int Astronautical Cong., Bremen, Germany, Sept 29–Oct 3, 2003 Zhao J F., Lu, Y H., and Li, J., “CHF on Cylinders– Revisit of Influences of Subcooling and Cylinder Diameter,” ECI Int Conf on Boiling Heat Transfer, Floriano´polis, Brazil, May 3–7, 2009 Kuehn, T H and Goldstein, R J., “Correlating Equations for Natural Convection Heat Transfer Between Horizontal Circular Cylinders,” Int J Heat Mass Transfer, Vol 19, 1976, pp 1127–1134 ZHAO AND WAN, doi:10.1520/JAI103379 419 [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] Zhao, J F., Wan, S X., Liu, G., and Hu, W R., “Experimental Study on Subcooled Pool Boiling in Microgravity Utilizing Drop Tower Beijing/NMLC,” Proc 5th Int Symp Multiphase Flow, Heat Mass Transfer and Energy Conversion, Xi’an, China, 2006, L Guo, X Chen, and Z Lin, Eds., Xi’an Jiaotong University Press, Xi’an, China, Vol 4, pp 1730–1735 Lienhard, J H and Dhir, V K., “Hydrodynamic Prediction of Peak Pool Boiling Heat Fluxes from Finite Bodies,” J Heat Transfer, Vol 95, 1973, pp 152–158 Di Marco, P and Grassi, W., “About the Scaling of Critical Heat Flux with Gravity Acceleration in Pool Boiling,” Proc XVII UIT Nat Heat Transfer Conf., Ferrara, 1999, pp 139–149 Zhao, J F., Liu, G., Wan, S X., and Yan, N., “Bubble Dynamics in Nucleate Pool Boiling on Thin Wires in Microgravity,” Microgravity Sci Technol., Vol 20(2), 2008, pp 81–89 Lee, D J., “Bubble Departure Radius Under Microgravity,” Chem Eng Commun., Vol 117, 1992, pp 175–189 Straub, J., “Highs and Lows of 30 Years Research of Fluid Physics in Microgravity, a Personal Memory,” Microgravity Sci Technol., Vol 18(3–4), 2006, pp 14–20 Oron, A., Davis, S H., and Bankoff, S G., “Long-Scale Evolutions of Thin Liquid Films,” Rev Mod Phys Vol 69, 1997, pp 931–980 Margerit, J., Colinet, P., Lebon, G., Iorio, C S., and Legros, J C., “Interfacial NonEquilibrium and Benard-Marangoni Instability of a Liquid-Vapor System,” Phys Rev E, Vol 68(4), 2003, pp 041601 Ward, C A and Duan, F., “Turbulent Transition of Thermocapillary Flow Induced by Water Evaporation,” Phys Rev E, Vol 69(5), 2004, pp 056308 Sefiane, K., “Gravitational Effects on Evaporative Convection at Microscale,” Microgravity Sci Technol., Vol 18(3–4), 2006, pp 25–28 Li, Z D., Zhao, J F., Lu, Y H., and Li, J., “Origin of Thermocapillary Convection in Pool Boiling,” Chin J Space Sci., Vol 28(1), 2008, pp 38–43 421 Author Index A Moskalenko, A A., 142-166 Muurinen, E., 28-44 Akhtar, M W., 1-27 N C Nishiguchi, S., 198-208 Cheung, S C P., 349-375 Costa, A L., 183-197 D Dobryvechir, V V., 142-166 P Pereira, C., 183-197 Prabhu, K N., 45-60 Protsenko, L M., 142-166 Pyykkoănen, J., 28-44 F France, D M., 376-401 Fritsching, U., 61-80 G Greif, D., 315-348 Grum, J., 209-228 Guseynov, S., 167-182 H Ho, M K M, 349-375 R Rajesh, E., 45-60 Ravnik, F., 209-228 Reis, P A L., 183-197 Routbort, J L., 376-401 S Shekriladze, I G., 229-284 Shoji, M., 198-208 Srinivasan, V., 285-314, 315-348 Stark, P., 61-80 Suffa, M., 315-348 K Keiski, R L., 28-44 Kleis, S J., 1-27 Kobasko, N I., 81-102, 103-125, 126-141, 142-166, 167-182 Kulju, T., 28-44 M Martin, D C., 28-44 Mesquita, A Z., 183-197 T Tu, J Y., 349-375 V Veloso, M A F., 183-197 W Wan, S.-X., 402-419 Wang, D M., 285-314, 315-348