A Common Method for Calculation of Flow Boiling and Flow Condensation Heat Transfer Coefficients in Minichannels With Account of Nonadiabatic Effects

Abstract

Flow boiling and flow condensation are often regarded as two opposite or symmetrical phenomena; however, their description with a single correlation has yet to be suggested. In the case of flow boiling in minichannels there is mostly encountered the annular flow structure, where bubble generation is not present. A similar picture holds for the case of inside tube condensation, where annular flow structure predominates. In such a case the heat transfer coefficient is primarily dependent on the convective mechanism. In this article a method developed earlier by the authors is applied to calculations of the heat transfer coefficient for flow condensation. The modifications of interface shear stresses between flow boiling and flow condensation are considered through incorporation of the so-called blowing parameter, which differentiates between these two modes of heat transfer. Satisfactory consistency with well-established correlations for condensation has been found, as well as with selected experimental data.

Acknowledgments

The work presented in this paper was partially funded by the Polish Ministry for Science and Education research project N512 459036 for the years 2009–2012.

Dariusz Mikielewicz is a professor of thermal sciences at the Gdańsk University of Technology (GUT), Gdańsk, Poland. He received his M.Sc. degree from the Gdańsk University of Technology (1990), and his Ph.D. degree from the University of Manchester (1994). In 2002 he presented his habilitational dissertation at the Gdańsk University of Technology. In years 1994–1996 he worked as an engineer at the Berkeley Nuclear Laboratories, Gloucestershire, UK. He has been teaching at the GUT since 1996. He has been an elected member to the Science Council in the years 2004–2008. His research contributions were in the field of modeling of mixed convection, two-phase flows, and recently renewable energy. He is currently working on enhanced heat transfer and condensation in heat exchangers.

Jarosław Mikielewicz has been the director of the Institute of Fluid-Flow Machinery of Polish Academy of Sciences, Gdańsk, Poland, since 1998. He completed his higher education studies and all the academic qualifications at the Faculty of Mechanical Engineering of the Gdańsk University of Technology. The title of professor in technical sciences was awarded to him by the State Council in 1979. He had been the head of the Thermodynamics and Heat Transfer Division at IFFM PAS since 1972. He has been serving as president of the Committee for Thermodynamics and Combustion for several years now. In 2004 Doctor Honoris Causa distinction was awarded to him by Cracow University of Technology and in 2009 by Koszalin University of Technology.