Pillow plate heat exchanger, NURBS, CFD
The compactness and desirable thermal characteristics of plate heat exchangers have made them a strong competing heat exchanger technology in the heating, ventilating, air conditioning and refrigeration 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 (PPHEs) 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, PPHEs are used in various single-phase as well as two-phase applications in the industry. This paper presents a parametric study on the effect of critical geometrical parameters and flow conditions, on the thermal-hydraulic performance of PPHEs. The pillow surface is created using a Non-Uniform Rational B-Splines (NURBS) algorithm. The flow between two adjacent pillow plates is then investigated using computational fluid dynamics (CFD). A PPHE with optimum geometric parameters for single-phase water flow is presented.