Effects of Coolants of Double Layer Transpiration Cooling System in the Leading Edge of a Hypersonic Vehicle

Abstract

As a promising and efficient active cooling method, double layer transpiration cooling is introduced into the design of the cooling system in the leading edge of a hypersonic vehicle. The physical model is built combined with hypersonic transpiration cooling, film cooling, heat conduction, porous media heat conduction and convection heat transfer. In addition, effects of different kinds of coolants are considered to reveal cooling mechanisms in different operation conditions. A comprehensive turbulence model validation and mesh independence study are provided. Flow characteristics caused by flow impingement, separation, transition and interaction with the cooling flows are displayed and analyzed in the work. When different kinds of coolants supplied at the same mass flow rate, the coolants with low densities, i.e., H2 and He, have the lowest peak temperature compared with the coolants with large densities, i.e., N2 and CO2. The coolants with low densities have a large ejecting velocity which provides large kinetic energy to penetrate deeply in the porous media. In addition, when the ejecting velocity is large enough, a recirculation is formed in front of the leading edge and pushes the high temperature region located in stagnation region away from the leading edge. However, when the coolants are ejected at the same velocity, the coolants with large densities exhibit better cooling performance.

Aerodynamic Effects and Heat Flux Augmentation of a Transpiration Cooled Hypersonic Sharp Leading Edge

“…Numerical studies have considered distributed mass fluxes on leading edges, either using a flow solver to calculate outflow distributions [32,33,[36][37][38], or using a prescribed outflow [39,40]. These numerical studies used leading edges on the order of 2-10 mm.…”

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

“…In recent years, some innovative porous media transpiration cooling structures have been presented, one of which is a doublelayer or multi-layer composite porous structure with various features (Wolfersdorf, 2005;Luo et al, 2021). and Wang (Shi and Wang, 2008) investigated the transpiration cooling in a double-layer porous structure.…”

Research on the Hole Length Ratio of Fan-Shaped Holes in Flat Plate Film Cooling

“…Rogers et al, 2017 conducted an experimental study on cross-flow-supplied full-coverage film cooling for a sparse film cooling hole array and found that the adiabatic film cooling effectiveness generally increased with the streamwise position and generally increased as the blowing ratio increased. Luo et al, 2021 studied the application of film cooling to the cooling system of the leading edge of hypersonic aircraft and found that low-density coolant air has the lowest peak temperature compared with high-density coolant air. El-Gabry et al, 2013 used infrared radiation thermography, liquid crystal thermography, and thermocouples to measure flow field temperature and film cooling efficiency and used hotwire anemometry to measure velocity and turbulence quantities.…”