Abstract
The thermal management of systems has always been a major topic, evolving alongside technological advancements. In recent decades, the scientific community has intensified efforts to reduce the energy consumption of cooling systems, particularly due to their contribution to global warming. Simultaneously, technological progress has led to increasingly compact and powerful machines, exacerbating thermal management challenges. In industries such as battery-powered vehicles, electronic devices, and satellites, thermal management remains a key limitation in further development. More recently, the emergence of flexible electronics and deployable space systems has introduced new challenges for thermal control.This thesis investigates a specific type of passive two-phase heat exchanger known as the pulsating heat pipe (PHP), commonly described as a serpentine arrangement of capillary pipes filled with a working fluid. Compared to conventional thermal management systems, PHPs operate independently of gravity, require no active components such as pumps, and feature a simple, meshless design. Their reliability and versatility, coupled with high miniaturisation potential, position PHPs as a promising heat exchanger technology for space applications.
The primary objectives of this research were to characterise the impact of bending on the thermofluidic behaviour of PHPs and to evaluate the performance of flexible PHP designs. A parabolic flight campaign was conducted to experimentally assess different configurations of a flat polymeric PHP under varying gravity levels (normal-, hyper-, and micro-gravity). The results enabled a comprehensive analysis of the combined effects of bending and gravitational variation across different geometries and working fluids. The thermofluidic behaviour was examined using a novel vapour bubble detection and tracking method based on infrared image processing, which was specifically developed for this study. Additionally, a complementary investigation was carried out on a new 3D-printed flat polymeric PHP design to explore the effects of alternative channel path geometries in promoting flow circulation under bending conditions. This research contributes to the advancement of flexible PHP technologies by providing a comprehensive critique of current designs, generating original experimental data for validation against simulation models, presenting a novel image processing algorithm, and offering insights for space applications.
| Date of Award | Mar 2025 |
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| Original language | English |
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| Supervisor | Nicolas Miche (Supervisor), Marco Marengo (Supervisor) & Anastasios Georgoulas (Supervisor) |