Experimental research on dynamic characteristics and control strategy of the pump-driven two-phase loop with dual evaporators

The pump-driven two-phase loop is a promising thermal management technology for avionics, but its dynamic characteristics and control strategy are not clear. A prototype of a pump-driven two-phase loop with a single/dual evaporator for cooling of avionics was developed and its dynamic characteristic under different heat loads and flow rates were studied. It was found that after the evaporator outlet reached saturation, increasing the flow rate would instead reduce the performance, due to the increasing flow resistance of the gas tube and pump power consumption. Based on this, a control strategy of controlling the vapor quality at the evaporator outlet to 0.9-0.95, by adjusting the speed of the pump, was proposed and verified under dynamic heat loads. The results showed that this control strategy ensured optimal system heat transfer performance while reduced the power consumption of the pump. In the experiments of the pumpdriven two-phase loop with dual evaporators, it was found that the branch with the larger heat load had a lower flow rate, and was more likely to be superheated. Therefore, in the control of a pump-driven two-phase loop with multiple evaporators, the branch with the maximum heat load should be taken as the control object.