高超声速气流中支板液体喷注的数值研究

NUMERICAL INVESTIGATION OF STRUT LIQUID INJECTION UNDER HYPERSONIC FLOW

斜爆轰发动机燃烧室爆轰燃烧是预混燃烧,发动机进气道燃料预混是斜爆轰发动机运行的前提和关键.现有研究多集中于气相燃料,针对更加接近工程实际的液体燃料研究较少.高超声速来流与液相作用伴随着更多流动物理过程,影响参数多,研究更为复杂.文章采用数值模拟手段,求解二维可压缩雷诺时均Navier-Stokes(RANS)方程,结合CLSVOF(coupled level set and volume of fluid)相界面捕捉方法.以高超声速横向来流与液相射流作用模型,系统研究了来流马赫数、液相射流角度和速度对液相燃料破碎、输运及混合的动力学行为的影响规律.在高超声速气流作用下,射流液柱受压力梯度影响向下游弯曲随气流运动,逐步呈现出液柱、连续液膜、液丝状、液块状和气液混合层5种液相演化形态.液相射流角度和速度对液相连续液膜特征和破碎距离有一定作用,进而对下游截面液相分布以及剪切层扰动造成影响.来流马赫数对压力梯度有一定作用,通过压力梯度对下游液相分布的纵向高度造成影响.综合参数分析,液相燃料射流穿透深度与总压损失成正比,改变射流角度是增加穿透深度、提升发动机性能更为有效的方式.

The detonation in the oblique detonation engine combustion chamber is premixed combustion.Fuel premixing in the engine inlet is the prerequisite and key to the operation of the oblique detonation engine.Most research focused on gas phase fuels,but there are fewer studies on liquid fuels for applications.The interaction between hypersonic flow and liquid is a complex physical flow process.There are many influencing parameters of gas-liquid interaction,making the research more complex.This paper uses numerical simulation methods to solve the twodimensional compressible Reynolds time-averaged Navier-Stokes(RANS)equation,combined with the CLSVOF(coupled level set and volume of fluid)phase interface capture method.The interaction model between hypersonic incoming flow and liquid jet is considered.The influence of the incoming Mach number,jet angle and velocity on liquid fragmentation,transport and mixing was systematically studied.The results show that under the action of hypersonic flow,the liquid column moves in the flow direction affected by the pressure gradient.The liquid phase has five evolving forms:liquid column,continuous liquid film,liquid filament shape,liquid block shape and gas-liquid mixed layer.The angle and velocity of the jet have an impact on the characteristics of the liquid continuous film and the breakup distance.This in turn affects the downstream liquid distribution and shear layer disturbance.The inflow Mach number affects the normal height of the downstream liquid distribution through the pressure gradient.Through parameters analysis,the liquid penetration depth is directly proportional to the total pressure loss.Changing the jet angle is a more effective way to increase penetration depth and improve engine performance.