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Journal of Enhanced Heat Transfer

Impact factor: 0.562

ISSN Print: 1065-5131
ISSN Online: 1563-5074

Journal of Enhanced Heat Transfer

DOI: 10.1615/JEnhHeatTransf.2015012286
pages 195-230

TWO-PHASE FLOW REGIMES AND EVAPORATIVE HEAT TRANSFER IN INTERNALLY-GROOVED TUBES

Darin J. Sharar
General Technical Services, LLC, Wall, New Jersey, USA
Avram Bar-Cohen
Laboratory of the Thermal Management of Electronics, Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN 55455; and Defense Advanced Research Projects Agency (DARPA), Microsystems Technology Office, University of Maryland, College Park, MD

ABSTRACT

The limited accuracy and parametric range of two-phase heat transfer correlations for internally-grooved tubes have impeded the widespread application of this most promising technology. The success of regime-based analyses and correlations in providing improved predictive accuracy for heat transfer coefficients in smooth tubes has motivated this effort to explore the relationship between two-phase flow regimes and heat transfer rates in internally-grooved tubes. Following a brief introduction to the geometries and manufacturing techniques of internally-grooved tubes and a description of the state-of-the-art smooth tube flow regime maps, fundamental studies of thermofluid performance in internally-grooved tubes are reviewed and analyzed to demonstrate the relationship between flow regime and evaporative heat transfer rates. Then, the current state of two-phase flow regime maps and heat transfer coefficient correlations for internally-grooved tubes are summarized. Finally, recommendations for future internally-grooved tube research directions are given. The majority of the studies herein deal with halogenated fluids in conventional-sized tubes at standard temperature and pressure. However, studies of small diameter tubes, as well as alternative refrigerants and reduced pressure, are also considered.