| dc.description.abstract | Effective thermal management is a challenge in spacecrafts due to demands of higher power operating sensors and devices in satellites resulting in high-temperature rise. The use of a two-phase passive heat transfer device, such as oscillating heat pipes (OHPs), can effectively increase heat transfer rate and spread out heat as a radiator panel due to its lightweight, high performance, and reliability. However, OHPs have limited thermal capacitance and thus, remain susceptible to rapid temperature rise during periods of transient high-power operation. Integrating phase change materials (PCMs) with OHP radiator panels can serve to buffer temperature below a key target temperature for some period of time due to the latent heat of PCMs. Here, we present a validated reduced-order numerical model for a hybrid OHP-PCM slab and apply this model to analyze the transient thermal response of a hybrid OHP-PCM radiator panel. This model is validated against experimental data collected from an OHP panel. We apply this model to assess design tradeoffs associated with panel geometry and material thermophysical properties. The transient thermal loading conditions of the hybrid OHP-PCM panel is observed for different PCMs, including octadecane, gallium, and composite material (with relative volume fractions of 0.9 octadecanes and 0.1 aluminum). The transient temperature rise under loads of 1 kW, 3 kW, and 10 kW were evaluated for different thickness of PCMs, ranging from 0.001 m to 0.01 m. The area of hybrid OHP-PCM radiator panel is 0.25 m2. The hybrid OHP-PCM model for octadecane is limited by the rate of heat transport due to low thermal conductivity. However, gallium and composite (with 0.9 VF octadecane and 0.1 VF aluminum) are not limited by the rate of heat transport due to high thermal conductivity but rather are limited by the volume of the system. Similarly, for a desired thermal buffering time, the composite material takes less mass to reach the same temperature during the transient state compared to gallium. The numerical model can be used as a design tool to investigate the mass and volume tradeoffs of hybrid OHP-PCM panels. | |
