The efficiency of using simple heat pipes with a relatively low thermal conductivity for cooling transmit/receive modules

Abstract

In this paper, we solved the problem of increasing the cooling efficiency of the basic version of the transmit/receive (T/R) module with a heat sink tilted in its working position while increasing its thermal power by a factor of 2 (from 112 W to 224 W). The purpose of the work is to confirm the correctness of the proposed strategy of cheap modernization of the T/R module through the use of inexpensive flat gravity heat pipes (HP) with a threaded evaporator and a relatively low effective thermal conductivity (3000 W/(m•°C)). The novelty of the work is the substantiation by the results of comparative numerical simulation of the possibility and efficiency of using such HPs in the basic version of the cooling system for T/R module and the determination of the critical geometric parameters and relationships necessary for this. It is shown that the integration of 16 flat HPs of a simplified design into the base of the radiator made it possible to reduce the maximum temperature non-uniformity of the mounting surface at an air speed of 1 m/s by more than two times and reduce the maximum temperature of the hottest transistor at 20.5 °C. The temperature non-uniformity of 8 transistors decreased from 10.5 °C to 1.6 °C. The minimum thermal impedance of the HP cooling system (0.06 °C/W) is half that of the base case. The correctness of the proposed strategy of cheap modernization of T/R modules is confirmed and the prospects of using HPs of a simplified design with working fluids with a freezing temperature below 0 °C are shown, which allows expanding the temperature range of operating conditions. The originality of the modernized cooling system and its world novelty are confirmed by the patent for the invention.