Speaker
Description
Efficient thermal management in carbon fibre reinforced polymers (CFRPs) is crucial for many space applications. When used in the vicinity of heat-generating components, the relatively poor thermal conductivity of CFRPs requires additional measures to transport and remove heat, in order to keep the structure within its required operating temperature range. Prior work has explored the integration of thermally conductive materials, such as metallic inclusions, into the composite. However, this can introduce thermal expansion mismatches, degrade mechanical performance, and increase mass. This work presents a novel approach to thermal management in CFRP structures that embeds pulsating heat pipes (PHPs) directly within composite laminates. PHPs are passive, two-phase heat transfer devices that generate self-sustained pulsating fluid flow in a network of partially filled, meandering channels, driven by temperature-induced pressure oscillations. To fabricate CFRP PHPs, a sacrificial material vaporisation technique is employed to form continuous, sealed microchannel networks within the cured composite. This is achieved without introducing foreign materials or compromising structural homogeneity. Operation of the embedded PHPs demonstrated an over 400% improvement in thermal conductivity compared to solid CFRP, with performance governed by orientation, channel geometry, internal surface roughness, and anisotropic through-thickness thermal conductivity of the material. The pulsating fluid flow was captured in-situ using high-frame-rate 2D radiography during PHP operation. The utilisation of embedded PHPs could transform a CFRP structure into a multifunctional composite, combining load-bearing capabilities with integrated thermal management.