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第13届国际传热学会年报

ISBN 打印: 1-56700-226-9 (CD)
ISBN 在线: 1-56700-225-0

THE SEARCH FOR OBJECTIVE HEAT TRANSFER AND PRESSURE DROP MODELS FOR FLOW CONDENSATION IN HORIZONTAL TUBES

DOI: 10.1615/IHTC13.p30.210
page 27

Leon Liebenberg
Department of Mechanical and Aeronautical Engineering, University of Pretoria, Pretoria, 0002, South Africa

Josua Petrus Meyer
Department of Mechanical and Aeronautical Engineering, University of Pretoria, Pretoria, Private Bag X20, Hatfield, 0028, South Africa

Abstract

Flow regimes influence the heat and mass transfer processes during two-phase flow, inferring that any accurate prediction of heat transfer and pressure drop during flow condensation should be based on the analysis of the prevailing flow pattern. Many correlations for heat transfer coefficient and pressure drop during flow condensation completely ignored flow regime effects, and treated flows as either annular or non-stratified flow, or as stratified flow. This resulted in correlations of poor accuracy and limited validity and reliability. Current heat transfer coefficient, pressure drop, and void fraction models are, however, based on the local flow pattern, resulting in deviations of around 20% from experimental data. There are, however, several inconsistencies and anomalies regarding these models, which are discussed in this paper. A generalised solution methodology for two-phase flow problems still remains an elusive goal, mainly because gas-liquid flow systems combine the complexities of turbulence with those of deformable vapour-liquid interfaces. The paper focuses on the state-of-the-art in correlating flow condensation in micro-fin tubes, and proposes future research areas to help path the way for the development of a unified and accurate two-phase flow model.

IHTC-13 Digital Library

Measurement of fluid temperature with an arrangement of three thermocouples FLOW BOILING OF A HIGHLY VISCOUS POLYMER SOLUTION