Comparative experimental study on series–parallel heat transfer characteristics of flat heat pipes

•A new parallel heat dissipation of flat heat pipes was proposed for cooling high heating equipment.•The parallel heat dissipation method can realize the double-sided arrangement of heat sources of multiple components and complete the rapid heat transfer process while increasing the heat flux exponentially.•There is a 32.4% and 83.8% reduction in the temperature of heat source and the total thermal resistance respectively in comparison with other cooling method.•The 1A2 heat dissipation module with two flat heat pipes in parallel has the best heat dissipation effect.•When parallel heat dissipation is used, the heat pipe with high capillary force should be selected as the bottom layer. In this study, a thermal performance test rig for heatpipes with different connection modes is independently designed to explore the steady-state and transient thermal performance of series–parallel flat heat pipes under different heat source powers. The dynamic thermal performance changes of three parallel modules, 1A2,2A1,3A2, and three series modules, 12A,21A,23A, under different power conditions are compared and analysed. The experimental results show that the total thermal resistance of the parallel modules is the lowest, followed by the total thermal resistance of the traditional module, and the total thermal resistance of the series modules is the highest. The minimum total thermal resistance of the parallel module is 0.02 K/W. At the 23.6 W input power, the parallel heat dissipation has the lowest heat source temperature of 74 °C and the slowest heat source heating rate of 3.2 °C/min in comparison with other heat dissipation methods. Further, under the parallel connection condition, the standard deviation of condenser and evaporator of the No. 2 heat pipe is reduced by 0.45 and 6 respectively, indicating that the sintered flat heat pipe has better temperature equalization than the grooved flat heat pipe. Different from the other two dissipation methods, the maximum temperature of the heat pipe in parallel heat dissipation is only 57.2 °C, which can satisfy the heat dissipation requirements of the heat source. It is important to mention that the parallel heat dissipation method of the flat heat pipe proposed in this investigation can realize the double-sided arrangement of heat sources of multiple components and accomplish the rapid heat transfer process while increasing the heat flux exponentially, which provides technical support for solving the problem of high heat