The active regenerative cooling technology faces the bottleneck problem of insufficient heat transfer capacity when the scramjet flies at a higher Mach number.It is proposed to strengthen the heat transfer per-formance of the regenerative cooling channel with airfoil-fins.To verify the enhanced heat transfer effect of the airfoil-fin channel in principle,an experimental test platform for flow and heat transfer of ambient air in NA-CA0021 symmetrical airfoil-fin channels and NACA4822 asymmetric airfoil-fin channels(with cross-section sizes of 50 mm×50 mm)was built.The Nusselt number of the heated surface was obtained based on the steady-state liquid crystal technique.The results show that,the heat transfer intensities of NACA0021 symmetrical air-foil-fin channels and NACA4822 asymmetric airfoil-fin channels improve by 0.17%～17.1%and 18.4%～52.1%,respectively.Correspondingly,PECs are 1.04 and 1.24,respectively,with the volume flow of ambient air at 50 m3/h.The NACA4822 asymmetric airfoil-fin channel can enhance the heat transfer performance of the middle heating surface under the condition of a large flow rate.The flow pressure drop in the airfoil-fin channels also increases correspondingly,where the pressure drop in the NACA4822 airfoil-fin channel is the largest.The a-symmetry of the airfoil-fin causes the continuous accumulation of flow turbulence intensity,resulting in a signif-icant increase in the downstream pressure drop.The work is helpful for further research on the flow and heat transfer characteristics of supercritical fluids in airfoil-fin channels,and broadens the application temperature range of the active regenerative cooling technology for scramjets.
关键词
超燃冲压发动机/翼型肋通道/Nusselt数/压力损失
Key words
scramjet engine/airfoil-fin channel/Nusselt number/pressure loss
维普
万方数据