Conjugate heat transfer simulation and additional thermal resistance analysis in pillow plate heat exchangers

Abstract

Pillow plate heat exchanger (PPHE) is a highly efficient heat exchanger element. The precise application of PPHE to heat exchanger scenarios can make a quantum leap in the field of heat exchangers. In this paper, we first added some missing power-law model relationships in the PPHE model. Including heat transfer and flow resistance coefficient of external flow channel, and heat transfer and resistance coefficient of non-circular welding spot models, which help to expand the heat transfer elements of welded plate heat exchangers. The focus of this paper is to investigate the heat transfer behavior more in line with the actual heat transfer process through conjugate convective heat transfer simulations. It is found that, in addition to the internal channel thermal resistance, outer channel thermal resistance, wall thermal resistance and fouling thermal resistance that exist in conventional heat exchangers, an additional thermal resistance exists in PPHE. The relationship between the magnitude of the additional thermal resistance and the Reynolds number of the flow in the inner channel outer channel can be represented by a power law model. This paper analyses in detail the causes of this additional thermal resistance, which will provide more accurate guidance for the design of PPHE heat exchangers.