射流宽度对激波会聚起爆的影响分析
Investigation on the influence of jets width on initiation by shock wave focus
-
摘要: 为了研究射流入射喷口宽度对环形激波聚焦爆震起爆的影响,以氢气和空气混合物为例,对不同射流入射喷口宽度的环形激波聚焦爆震起爆过程进行了数值模拟。结果表明,当入射射流的温度为一定值时,不同宽度的环形射流入射喷口对应着不同入射压力 Pin 的临界值,当 Pin 大于该临界值时,其形成的激波聚焦才能够形成高温、高压区域,从而起爆爆震波;随着入射喷口宽度的增加,射流的入射强度增大,其对应的临界入射压力随之增大。Abstract: In order to optimize the geometry of film cooling, the heat transfer performance of a novel hole with doubleoutlet injection was investigated by numerical simulation. The N-S equation was solved by Fluent. The realizable k-ε model and enhanced wall function were used. The emphasis is focused on the heat transfer coefficient ratio and heat flux ratio. The results show that the heat transfer coefficients increase with increasing blowing ratios and decrease with increasing x/d, especially near the hole. The heat transfer coefficient ratios increase with increasing x/d at the blowing ratios of 0.5 and 1.0. The heat transfer coefficient ratios increase firstly and then decrease with increasing x/d at the blowing ratios of 1.5 and 2.0. The film cooling with double outlets hole injection takes a role in reduction of the heat flux from the gas to the blade. The heat flux ratios decrease when the blowing ratios increase from 0.5 to 1.0 and increase when the blowing ratios increase from 1.0 to 2.0. The heat flux ratios increase with increasing x/d, resulting in decreasing film cooling performance.