Nihon Kikai Gakkai ronbunshu (May 2018)
Experiment and numerical simulation of flow characteristics in chevron type plate heat exchangers
Abstract
For the development of industrial heat pump system supplying a high-temperature heat source, the application of chevron type plate heat exchanger is being considered. In the present study, experiments and numerical simulation on flow characteristics in single chevron channel with chevron angle 30°, 45° and 65° were respectively performed. In the experiment, the pressure drop of the whole chevron channel and local pressure drops in each chevron channel were measured and path lines were also observed. Besides, numerical simulation reproduced the experimental results well. From both of the experimental and simulation results, it was confirmed that the pressure drop of the chevron channel became larger with increasing the chevron angle due to the strong mixing of fluids in the respective furrows of adjacent chevron plates especially in the high chevron angle channel. In such the high chevron angle channel, velocity and pressure drop gradient distributions were almost uniform in the channel width direction normal to main flow. While, in the small chevron angle channel, the fluids mixing between furrows of adjacent plates was weak and the velocity and pressure drop gradient distributions were markedly large in the width direction. Furthermore, it was found that large pressure drops occurred in the inlet and outlet regions where the channel had flow width expansion and contraction, respectively. The large pressure drops in the inlet and outlet regions affected the overall pressure drop in the chevron channel, especially in the low chevron angle channel. For each chevron angle channel, the local friction factor was obtained and the loss coefficient for the flow expansion and contraction at inlet and outlet regions was determined. Based on these results, the prediction method of overall pressure drop in the chevron channel was proposed.
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