A mathematical method for thermal design of printed circuit heat exchanger with actual flow distributors

•A mathematical method is proposed based on the modified Picard’s iterative method.•The thermal hydraulic performance in different plate structures is analyzed.•The inner channel shows larger heat transfer rate than other channels.•The proposed method provides a precise and fast prediction for temperature fields. In the traditional thermal design of printed circuit heat exchanger (PCHE), the thermal hydraulic characteristic in the flow distributor is generally ignored. In this paper, a mathematical method considering the thermal hydraulic characteristic in the flow distributor is proposed. It could quickly and accurately predict the temperature and pressure fields of fluids for different plate structures. The maximum mean relative deviation of outlet temperature is 10.59% in the plates with five channels. The proposed method shows better performance on computing time than the three-dimensional numerical method. The inner channel shows larger heat transfer rate in comparison with that in the outer channel when the length of channels is the same. The lowest and highest outlet temperatures in hot channels are 622.18 K and 792.91 K in the plate structures where hot fluid flows in a zigzag pattern and cold fluid flows straight. A maximum deviation of 10.36 W in heat transfer rate between the traditional thermal design method and this method when the length of the counter flow region is equal to the length of the flow distributor. The mathematical method could quickly obtain the thermal hydraulic characteristic of the plates and provide guidance for the selection of plate structures for the preliminary thermal design.