泄压前初始压力对底排装置内流场特性的影响

Effect of Initial Pressure Before Depressurization on Internal Flow-field Characteristics in Base Bleed Unit

为研究底排弹出炮口时瞬态压力卸载对底排装置燃烧场的影响,针对底排模拟装置,建立了二维轴对称非稳态模型,采用CFD软件对该装置在不同压降速率下的内流场特性进行了数值计算,分析了泄压前燃烧室不同初始压力对底排燃烧室内压力、温度和密度分布特性的影响。结果表明:初始压力越高,泄压时燃烧室最大降压速率越大,燃烧室轴线上的压差也越大,底排药剂燃烧产生的高温燃气对燃烧室内温度分布的影响越强,排气孔出口处燃气质量流率越高。在降压过程后期,不同工况下燃烧室轴向的压力和速度差异减小,而径向的温度差异增大,密度差异减小。

To study the effect of transient pressure-release when base bleed projectile is propelled out of gun muzzle on the combustion field characteristics in base bleed unit,a 2D-axisymmetric unsteady model was established for the base bleed simulator.By adopting CFD software,the characteristics of internal flow-field under different despressurization rates were simulated aiming at this device.The effect of different initial pressures in the base bleed combustion chamber on the distribution characteristics of pressure,temperature and density was studied with an emphasis.Results show that the higher the initial pressure,the faster the maximum depressurization rate during the pressure-release,and the larger the pressure difference on the combustion chamber axis.The effect of high-temperature combustion gas generated from base bleed propellant on the temperature distribution in the chamber is stronger,and the gas mass flux on the exhaust outlet is higher.At the later stage of depressurization,the differences of the axial pressure and gas flow rate in the chamber under different conditions decrease,while the radial temperature difference increases and the radial density difference decreases.