Investigation of Thermal-Hydraulic Characteristics of Pillow Plate Heat Exchangers Using CFD

摘要

The compactness and desirable thermal characteristics of plate heat exchangers (PHXs) have made them a strong competing heat exchanger technology in the heating, ventilating, air conditioning and refrigeration (HVACR) industry. The miniaturization of plate heat exchangers has become a focal point of attention in recent research. It is desirable to utilize less material and refrigerant charge to obtain the same heat transfer performance. Pillow plate heat exchangers (PPHXs) consist of wavy plates that are welded together with a certain pattern using spot welding, sealed at the edges, and then inflated in a hydroforming process. The complex wavy structure of the pillow plates creates an excellent heat transfer medium with a fully developed turbulent flow between the plates. Thus, PPHXs are used in various single-phase as well as two-phase applications in the industry. This paper presents an investigation of the effect of critical geometrical parameters and flow conditions, on the thermal-hydraulic performance of PPHXs. The pillow surface is created using ANSYS structure simulation resembling the actual manufacturing process. The flow between two adjacent pillow plates is then investigated using Computational Fluid Dynamics (CFD) in ANSYS Fluent. The post-processed data from the CFD simulations is used to run an optimization study to maximize the heat transfer coefficient and minimize the pressure drop. The preliminary results show that the heat transfer coefficient can be up to 3 times higher than the selected baseline while the pressure drop can be reduced by 30%.