波瓣型燃气/空气混合装置的设计与模拟

Numerical Simulation and Design of a Lobe Mixer

关键词:  波瓣型混合器  空气涡轮火箭  混合效率  数值模拟

Key words:  Lobe mixer  Air turbine rocket  Mixing efficiency  Numerical simulation

摘要:

空气涡轮火箭或涡轮基组合冲压发动机中，混合装置对于提高燃烧效率具有重要的作用。为了提高燃气与空气的混合效率，针对波瓣型混合器提出了混合器出口轴向速度一致的原则来指导设计混合器。设计了两种不同类型的波瓣型混合器，并通过数值模拟分析了混合器出口截面形式和中心体端面对混合效率的影响。结果表明:混合器燃气与空气出口截面的面积比是波瓣型混合器设计的关键因素，恰当调整出口面积比使出口速度接近可以明显提高混合效率；中心体截面缩进和凸出会使混合效率降低。

Abstract:

Mixing device is very important to improve the combustion efficiency in air-turbo-rocket or turbine based combined cycle engine. To increase the mixing efficiency of fuel gas and air，the idea to make the axial velocity of two reactant fluids the same was proposed to direct the design of the lobed mixers. Two types of lobed mixers were designed and the outlet type of the lobe mixer and effect of the central body were analyzed through mixing efficiency by numerical simulation. Numerical analysis shows that the area ratio of gas to air is the key factor for lobe mixer design，a proper area ratio which leads to nearly equal velocity at mixer outlet can improve mixing efficiency apparently. The indentation and protrusion of central body tends to decrease the mixing efficiency in combustor.