Investigating thermo-hydraulic behavior of pillow plate heat exchangers using entropy generation approach

Abstract

Pillow plate heat exchanger (PPHE) is a modern type of plate heat exchanger composed of wavy shape parallel plates. Adjustment of the geometrical parameters has been broadly made to enhance the heat transfer performance of PPHEs. However, there has been limited attention to the thermo-hydraulic features and entropy generation of fluid flow through such heat exchangers. Addressing this gap could help further understanding of such heat exchangers. In the present study, Ansys CFX is used to simulate turbulent flow and heat transfer in inner pillow plate channels. The local entropy generation due to thermal effects and friction is calculated as a post processed task. The influence of the channel height, Prandtl number, diameter and arrangement of spot welds on the overall entropy generation of pillow plates are analyzed. The results indicate that by increasing the channel height, thermal entropy generation increases. Besides, increasing the spot weld diameter leads to a higher frictional loss in pillow plate channels, while the effect of spot weld size on thermal entropy generation is negligible. Also, the spot weld arrangement significantly affects the thermal and hydraulic characteristics of PPHEs. The results show that exergy analysis can be considered as a potential tool for investigating thermo-hydraulic behavior of PPHEs.