磁流体能量旁路超燃冲压发动机的混合 和燃烧性能数值研究

为了研究磁流体能量旁路超燃冲压发动机(AJAX)的混合燃烧性能,采用三维数值方法,分别对磁流体发电器作用区和化学反应区进行模拟.在其他条件不变的情况下,改变磁场强度和载荷因子从而改变燃烧室的入口条件,得到不同磁流体条件下的混合效率和燃烧效率.计算结果显示:随着磁场强度的增加和载荷因子的减小,混合效率都提高了,最多提高了11.4%,在热离解不明显的燃烧室前半段,燃烧效率也都有所提高;在燃烧室后半段,不出现热离解时燃烧效率最多提高6.5%,此时磁流体装置的引入可使燃烧室长度缩短25%,可降低飞行器的几何尺寸,减轻飞行器质量;出现热离解时,燃烧效率会有所降低甚至低于无磁流体作用时的情况,因此应尽量避免磁场强度过大或载荷因子过小引起燃烧室入口静温过高造成热离解降低燃烧效率. 

Numerical study of mixing and combustion performance for magnetohydrodynamic-bypass scramjet

In order to study the mixing and combustion performances of magnetohydrodynamic(MHD)-bypass scramjet(AJAX),the three-dimensional numerical methods were used for the MHD generator flow and the chemical reaction flow,respectly.The combustion entrance conditions were varied by altering the MHD conditions,the mixing efficiencies and combustion efficiencies were got.The results show that as the magnetic field strength increases or load factor decreases,the mixing efficiency is increase,the improved maximum value of mixing efficiency is 11.6%.In the front part of chamber where the thermal dissociation is not sensible,the combustion efficiency is increase;in the latter part of the chamber,while the thermal dissociation is no present,the combustion efficiency are increase,the improved maximum value of combustion efficiency is 6.5%,the combustion chamber is shorten by 25%,reduce the geometric sizes and mass of the vehicle;while the thermal dissociation is present,the combustion efficiency are reduced even lower than the no-MHD case,so it should try to avoid larger magnetic field strengths or smaller load factors to reduce the temperature of the combustion entrance,which cause the thermal dissociation reduce the combustion efficiency.