CFD를 이용한 덕트 형상변화에 따른 판형열교환기 성능 해석

Abstract

The use of plate heat exchangers have considerably increased in the past two decades. It has been used in chemical process, power industries, and standard heat transfer equipment in a board range of heating and cooling applications. The main advantages of plate heat exchangers are low volume/surface ratio, flexibility, and high thermal effectiveness. In spite of development of plate heat exchangers, there is still a lack of generalized solutions available in open literature for calculation of heat transfer and pressure drop. Besides, most of the studies mainly focused on the heat transfer and pressure drop of plate heat exchangers and how a corrugation angle and duct of plate affected the flow and analysed characteristics. The thermal-hydraulic performance of a plate heat exchanger was strongly influenced by the geometry of the plate corrugation and by the exchanger configuration. In order to improve the turbulent generation inside, the channels angle between the flow direction and the corrugation orientation should be increased. However, the turbulent in a space can increase the convection heat transfer coefficient but it also increases the pressure drop. Consequently, the optimum design has been required in the plate heat exchangers to maintain the high performance for wide operating conditions. Moreover, the analytical model must properly consider the effect of the plate heat exchanger configuration and design with consideration of flow pattern. The objective of this work is to investigate the performance characteristics of plate heat exchanger in the heating and cooling applications. To achieve the objective of this study, the performances of plate heat exchanger were analyzed by using simulation study with the operating condition and verified by using experiment study. In this study, the commonly used plate heat exchanger model was developed firstly, and the performance variation and system characteristics were investigated by using developed model. The performance of plate heat exchanger were analyzed and optimized with the variation of Re number, duct angle, control volume, turbulent model, duct type and so on. As a result, the minimum control volume was found that duct number was above 10. The friction factor of the k-ε turbulent model was most similar with that of the Martin’s model. Besides, BSLRS and SSGRS turbulent model with Reynolds stresses doesn’t seem to be suitable for the optimal turbulent model for simulation of plate heat exchanger. The friction factor of plate heat exchanger increased with a rise of duct angle and decreased with an increase of Re number. In addition to, the sine-duct shows the smallest friction factor, but the trapezoidal duct represents the highest one due to non-uniform distribution and high turbulent generation. Therefore, the duct angle, Reynolds number and duct shape should be considered simultaneously in order to design a high performance plate heat exchanger. Through this study, the basic performance data of plate heat exchanger can be achieved and proposed to the manufacture company in order to develop a high-efficiency the plate heat exchanger.