Review of aerospace-oriented spray cooling technology

Motivated by the concept of energy-optimized air/space vehicles, the design of more-electric and all-electric vehicles has become increasingly popular. With the advance of micro-electro-mechanical systems, on-board electronic/electrical devices become more integrated and miniaturized. It means that these highly-advanced devices should rely on a high heat-flux dissipation method to maintain an effective and safe operation. Spray cooling, universally recognized as the next-generation cooling scheme, has been extensively utilized in the thermal protection of the ground-based electric/electronic equipment. In contrast, the aerospace-oriented spray cooling (AOSC) application is extremely rare. It can be attributed to the fact that the research into the space/air-oriented spray cooling technologies is still in its infancy, which leads to a lack in the knowledge of alternations of flow patterns and heat transfer behaviors caused by the complicated space or high-altitude space. This paper presents a comprehensive review of the up-to-date published articles on AOSC and divides these published articles into four categories: 1) investigation into the effect of gravity on the cooling performance; 2) investigation into the effect of environmental pressure on the cooling performance; 3) study of the effect of acceleration and vibration on the cooling performance; 4) investigation of the aerospace spray cooling system. Additionally, comments, perspectives, and orientations are provided, in which several promising contributions are highlighted. This paper aims to promote the practical application of the AOSC system which could facilitate the development of the energy-optimized green air/space vehicle. •A review of aerospace-oriented spray cooling technology is performed.•Gravity plays a significant role in the flow pattern and heat & mass transfer.•A heat transfer enhancement can be gained by flash Boiling/evaporation.•Gravity-immune spray cooling systems promote its practical aerospace application.•Affordable ground-based research method for aerospace application is imperative.