Structural Design and Experimental Investigation of a High-Performance Cold Plate

When designing a spacecraft, engineers face some challenges in developing an effective thermal control subsystem. A spacecraft is subjected to internal thermal loads caused by the heat dissipated from electrical and mechanical equipment, as well as external thermal loads, which vary depending on the type of orbit throughout the mission. To ensure that all the avionic systems maintain their allowable temperature ranges throughout the spacecraft’s operational life, the thermal control system must be carefully designed and optimized. Today, the exploration and utilization of space are becoming increasingly common. With the expected rise in long-duration missions, such as the Lunar Gateway, thermal control systems are becoming even more essential and critical, not only to manage the temperature of avionics boxes but also to ensure crew comfort. Cold plates are a standard solution in spacecraft applications and play a crucial role in the active thermal control system loop. Traditional “tube and plate” cold plates, despite extensive evaluation, are not thermally efficient due to the high number of components, junction elements, and different materials that limit performance. This highlights the need to improve their design to enhance efficiency, reduce weight, and optimize overall system performance. This work is divided into three primary sections. The opening chapter reviews the current state of cold plate technology, outlining the limitations of existing designs and examining alternative approaches for better performance. The second chapter investigates the structural characterization of the introduced layout. The structural assessment was carried out using finite element models, which evaluated mechanical integrity under operational loads, considering realistic boundary conditions, interface constraints, material properties, and temperature-dependent behaviour. Several configurations were analysed to study the impact of manufacturing choices, geometry, and lightweight materials such as open-cell aluminium foam on stiffness, displacement, and safety margins. Mesh convergence studies, sensitivity analyses, and comparative studies, foam-including and foam-excluding configurations, were conducted. The third chapter presents the results of the performance tests carried out on two representative samples of the designs under investigation and supports the transition from steel to aluminium through compatibility tests between the coolant and the wetted surfaces. The results of this thesis work led to the development of innovative cold plates incorporating foam as a load-bearing component, resulting in increased structural stiffness while maintaining low mass and improving thermal performance.