Speaker
Description
For future space and energy applications, it is crucial that they can withstand high temperatures in (hyper)supersonic flows and high heat flux in nuclear fusion reactors. For instance, future hypersonic vehicles experience temperatures above 10,000 K at Mach number 20 due to viscous dissipation in the boundary layer [1]. Additionally, thermal requirements of high temperature components for nuclear fusion reactors are demanding under 10 MW/m2 in steady-state condition and 20 MW/m2 in transient conditions [2]. However, conventional thermal management techniques struggle to operate reliably under such harsh conditions. Therefore, the development of cooling technologies is essential to realize the full potential of future space and energy applications [3-7].
This presentation aims to introduce advanced cooling techniques based on thermal design procedures for future space and energy applications. Firstly, a comprehensive analysis of the thermal-fluid characteristics on applications will be presented [3-4]. Using experimental and simulated methods, the internal and external thermal-fluid characteristics of aircraft systems will be discussed, along with the cooling system requirements based on specific system conditions. Secondly, advanced cooling techniques that meet the system requirements will be presented [5-6]. Two approaches will be discussed. The first involves 3D cooling structures manufactured using additive manufacturing, a process that is not feasible with conventional manufacturing methods. The second approach focuses on phase change heat transfer processes, which can achieve higher heat transfer coefficients, which magnitude is at least one order higher magnitude than single-phase heat transfer processes. Thirdly, based on the thermal-fluid characteristics and advanced cooling techniques, a thermal design process will be proposed to ensure reliable system operation under harsh thermal conditions [2,7]. The thermal design procedure will be illustrated using the example of a nuclear fusion reactor, demonstrating how it can be applied to realize a reliable mechanical system.
I hope that this presentation helps to understand the importance of thermal management in future space and energy applications. Furthermore, researchers in thermal engineering will gain insights into the thermal design procedure, which can be applicable to various mechanical systems.
References
[1] C. Park, Nonequilibrium Hypersonic Aerothermodynamics, John Wiley and Sons, 1990
[2] N. Lee., et al., “Thermal design of helium cooled divertor for reliable operation”, Appl. Therm. Eng., 110, 1578-1588 (2017)
[3] J. Nam., et al., “Effect of Componential Camouflage on Aircraft's IR Multiband Susceptibility”, IEEE, Trans. Aero. Elec. Sys., 59(2) (2022)
[4] N. Lee., et al., “Flexible assembled metamaterials for infrared and microwave camouflage”, Adv. Opt. Mater., 10(11), 2200448 (2022)
[5] D. Lee., et al., “Enhancing thermal stability and uniformity in boiling heat transfer using micro-nano hybrid surfaces (MNHS)”, Appl. Therm. Eng. 130, 710-721 (2018)
[6] W-T. Hsu., et al., “Unidirectional wicking-driven flow boiling on tilted pillar structures for high-power applications”, 189, 122673 (2022)
[7] N. Lee., et al., “Nozzle-to-target distance effect on the cooling performances of a jet-impingement helium-cooled divertor”, 136, 803-808, (2018)
| Keywords | Heat transfer, Thermal management, Thermal design, Cooling techniques |
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