Effects of particle diameter and plate thickness on transpiration cooling for double-layer porous plates

Abstract

Transpiration cooling is a highly efficient active thermal protection technology, which has a great application prospect in the thermal protection of hypersonic vehicles. Nevertheless, the problem of large injection pressure caused by porous structure in transpiration cooling system has been ignored in previous studies. In this work, the transpiration cooling performance of double-layer sintered metal particle plates with different particle diameter combinations and plate thickness were simulated. The results showed that the cooling effectiveness of double-layer plates was improved when the particle diameter of the porous plate in direct contact with the main stream decreased. The inner plate particle diameter and plate thickness had little effect on cooling performance. By increasing inner plate particle diameter, the coolant injection pressure can be lowered by 41% while the structural thickness was maintained. Further reducing the thickness of the outer plate to 1/4 of the total thickness can reduce the injection pressure to 38% of the single plate, which provided an optimization direction for reducing engine power consumption caused by heat dissipation.

Porous ZrO2–ZrO2 ceramics with excellent mechanical strength and permeability for transpiration cooling

“…Currently, most heat transfer mediums in transpiration cooling adopt metal structures like porous stainless steel, 6–8 high‐entropy alloy, 9 and porous copper material 10–12 . These metal structures possess well mechanical strength and thermal conductivity, but they cannot be applied in high‐temperature environment 13,14 . Additionally, some ceramic structures, like porous ceramics 15–17 and three‐dimensional woven ceramic matrix composites, 18,19 are also used for heat transfer medium; it is a fantastic idea to overcome the high temperature resistance and lightweight problem, but there are still some shortcomings, including water oxygen corrosion and chemical reactions, when liquid water is used as a coolant because it has higher cooling efficiency than gas, 20,21 which seriously restricts the temperature limit of these porous ceramic structures 22–24 …”

“…[10][11][12] These metal structures possess well mechanical strength and thermal conductivity, but they cannot be applied in high-temperature environment. 13,14 Additionally, some ceramic structures, like porous ceramics [15][16][17] and threedimensional woven ceramic matrix composites, 18,19 are also used for heat transfer medium; it is a fantastic idea to overcome the high temperature resistance and lightweight problem, but there are still some shortcomings, including water oxygen corrosion and chemical reactions, when liquid water is used as a coolant because it has higher cooling efficiency than gas, 20,21 which seriously restricts the temperature limit of these porous ceramic structures. [22][23][24] Zirconium oxide (ZrO 2 ) ceramics have an excellent high melting point (2700 • C), mechanical properties, good resistance to heat shock, and high-temperature chemical stability; they are widely used as thermal protection materials for spacecraft.…”

Experimental investigation of the characteristic of vacuum spray cooling for tofu

“…Cooling is regarded as an effective method to improve the shelf life of food with high moisture content (Ditta et al, 2022;Zhang et al, 2022). Vacuum cooling (VC) has the advantages of fast cooling speed (Zhu et al, 2019a), uniform cooling temperature (Dong et al, 2012;Ding et al, 2016), low operating cost and low failure rate (Yesil et al, 2017;Kongwong et al, 2019) which has been widely used in fast food (Zhu et al, 2019b), distribution centecr (Feng and Li, 2015), central kitchen (Ozturk and Hepbasli, 2017) and other industries (Feng et al, 2016).…”