Application and experimental study of pump-assisted two-phase loop for cooling distributed heat sources in infrared payloads

Abstract

Spaceborne infrared payloads contain multiple distributed heat-generating components with large heat-load variations and stringent temperature-control requirements. Conventional parallel two-phase cooling systems are prone to flow maldistribution, vapor blockage, and local overheating, which limit their application in high-precision thermal control. To address these challenges, a pump-assisted serial two-phase cooling loop using R134a was proposed for the thermal management of distributed heat sources in infrared payloads. A coupled thermal–hydraulic model considering vapor-quality evolution, pressure-drop accumulation, and pump–loop matching was established to predict the flow and heat transfer characteristics of the loop. Based on the theoretical model, a ground experimental platform was constructed and tested under dynamic heat-load conditions ranging from 135 W to 665 W. The experimental results demonstrated stable operation over the entire heat-load range without significant flow instability, vapor blockage, or dry-out phenomena. The maximum heat-source temperature remained below 293 K, while the overall temperature rise was limited to approximately 5 K despite a nearly fivefold increase in heat load. Furthermore, the predicted pressure characteristics agreed well with experimental measurements, with a maximum deviation below 6.1%, validating the proposed model. The results indicate that the pump-assisted serial two-phase cooling loop can effectively improve temperature uniformity, suppress local overheating, and eliminate flow maldistribution associated with conventional parallel configurations. This study provides theoretical and experimental support for the thermal management design of distributed infrared payloads and other spaceborne multi-heat-source systems.