一种两相流点火模型及数值模拟

底排点火具对底排药剂点火的不一致性是引起底部排气弹射程散布的重要因素之一。为了研究导致点火不一致性的因素和揭示点火机理,分析了某155 mm底部排气弹出膛口后点火具对底排药柱二次点火的过程和特点。基于气体—颗粒两相射流理论,提出了一种两相流强化点火模型。该模型综合考虑了纯燃气与两相射流耦合过程,以及固体—气体或液体—气体两相流对固体底排药的热辐射、热对流和热传导复合传热机制。针对底排装置出膛口后的二次点火过程进行了数值模拟,计算得到了底排药剂软化时间和点火延迟时间,数值模拟结果与实验结果基本吻合。该模型对固体火药类似点火过程具有普适性。

A Two-phase Flow Model and Numerical Simulation of Ignition

The inconsistent ignition of base bleed igniter for base bleed grain is one of the important factors resulting in rang dispersion. For the sake of investigation the inconsistent causes of ignition and reveal the ignition mechanism of base bleed igniter, the reignition process and characteristics of base bleed grain ignited by igniter after a 155 mm base bleed projectile flied out of the gun muzzle was analyzed. A two-phase flow strengthened ignition model was established based on gas-particle two-phase jet theory. In the model, the coupling process of pure gas and two-phase jet, and a complex heat transfer mechanism, including heat radiation, heat convection and heat conduction, of solid-gas or liquid-gas two-phase flow in solid base bleed grain were considered. To obtain the ignition softening time and ignition delay time of base bleed grain, the reignition process was numerically simulated. The numerically simulated results were basically in agreement with the experimental results. The model is suitable for solid propellant which has the similar ignition process.