喷射条件对气溶胶烟幕释放效果的影响

为了研究气溶胶颗粒在高速气流中的形成状态及遮蔽效果,构造基于高速射流的喷射型红外遮蔽冷烟幕,对该流场进行数值求解,研究不同喷射条件对气溶胶烟幕遮蔽区的影响效果,气溶胶烟幕颗粒扩散利用离散相模型模拟,对两相流流场进行非稳态计算,通过Lambert-Beer定律求解气溶胶烟幕的透射率分布,计算得到烟幕低透射区的变化规律,并分析了射流喷射压力和气溶胶粒子喷射流量的影响.结果表明:低透射区呈类锥形,当粒子喷射流量较小时,下游局部扩散的低透射率区呈团状,不能对红外辐射形成有效遮蔽,增加粒子喷射流量时,低透射率区连续分布,气溶胶烟幕遮蔽效果提升.射流喷射压力的提高可以增加低透射区范围,压比过高时射流出现膨胀波系,膨胀波段射流核心区局部透射率升高,遮蔽效果下降.研究结果对射流喷嘴的合理设计及喷射压力,流量的合理选取具有一定的参考意义.

Effects of Jet Conditions on Aerosol Smoke Distribution

In order to study the formation state and shielding effect of aerosol particles in high-speed airflow, a jet type infrared shielding cold smoke screen based on high-speed jet was constructed. The flow field was numerically solved. The effects of different jet conditions on the obscuration area of aerosol smoke were studied. The dispersion of aerosol smoke particles was simulated by discrete phase model and the unsteady flow field of two-phase flow was calculated. The transmittance distribution of aerosol smoke was solved by Lambert Beer law. The variation law of low transmission area was obtained. In addition, the influence of jet pressure and aerosol particle flow rate on the change of low transmission area was analyzed. The results show that the low transmission area is cone-shaped. When the particle jet flow rate is small, the low transmittance area of local diffusion in the downstream is a cluster, which can not effectively shield the infrared radiation. When the particle spray flow rate is increased, the low transmittance area is continuously distributed, and the shielding effect of aerosol smoke is improved. When the pressure ratio is too high, the expansion wave system appears, and the local transmittance of the jet core increases, and the shielding effect decreases. This study provides a reference for the reasonable design of jet nozzle and the reasonable selection of jet pressure and flow rate.