Two-phase heat transfer solutions for advanced thermal management in industrial and space applications

The rapid increase in power density in compact, high-performance engineering systems, particularly space platforms and small satellites, has intensified the demand for advanced thermal management strategies. Elevated heat fluxes, strict temperature uniformity constraints, and high reliability requirements challenge the effectiveness of conventional single-phase cooling approaches. Two-phase heat transfer technologies, characterized by high heat transfer coefficients and efficient exploitation of latent heat, emerge as a compelling solution to meet these evolving thermal demands. In particular, capillary-driven devices such as heat pipes and loop heat pipes, together with mechanically pumped two-phase loops, offer enhanced heat transport capability and improved temperature control under diverse operating conditions. This thesis investigates the operating principles and performance limits of these systems and develops a comparative assessment framework aimed at supporting the identification of the most suitable technology for given thermal requirements and operating conditions. In addition, selected case studies are presented, including the preliminary design of a condenser/radiator for an active pumped two-phase fluid loop within a CubeSat architecture, and the development and experimental assessment of a dedicated test bench for the thermal characterization of heat pipes. These applications provide practical insight into system integration aspects, testing methodology, and operational constraints in real-world scenarios.