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航空发动机轴承腔油气两相流动状态下的壁面油膜分布和流动速度直接影响其润滑和换热特性。考虑油滴变形和二次油滴沉积效应作用,通过油滴变形和运动、油滴/腔壁碰撞过程质量和动量转移以及二次油滴运动和沉积分析,获得油滴沉积过程的质量和动量转移;在此基础上利用根据力平衡原理和质量守恒原理建立的壁面油膜分布和流动的力学模型获得壁面油膜的厚度和速度分布。分析和探讨了油滴变形对油滴速度和运行轨迹的影响,变形和二次沉积效应对油滴质量和动量转移以及壁面油膜厚度和速度分布的影响。计算结果表明:考虑变形后油滴所受阻力增加,其运动速度减小,运行轨迹更加弯曲,一次质量转移增加,一次动量转移减小;二次油滴的数量很大,其沉积质量和动量转移是轴承腔中油滴质量和动量转移的主要部分;油滴变形和二次沉积效应作用下壁面油膜的厚度和流动速度都明显增大,润滑油加速排出。
Aero-engine bearing cavity oil-gas two-phase flow state wall film distribution and flow velocity directly affect the lubrication and heat transfer characteristics. Considering the effects of oil droplet deformation and secondary oil droplet deposition, the mass and momentum of oil droplet deposition process are obtained through the deformation and movement of oil droplets, the mass and momentum transfer of oil droplet / cavity wall collision and the secondary oil droplet movement and sedimentation analysis On the basis of this, the thickness and velocity distribution of wall oil film were obtained by using the mechanical model of wall oil film distribution and flow established by principle of force balance and mass conservation. The effects of oil droplet deformation on the droplet velocity and trajectory, the effects of deformation and secondary deposition on the droplet mass and momentum transfer, and the wall oil film thickness and velocity distribution were analyzed and discussed. The calculation results show that: after considering the deformation resistance, the resistance of the oil drop increases, the velocity decreases, the trajectory is more curved, the mass transfer increases and the first momentum transfer decreases. The second oil droplet has a large amount of sediment mass and momentum The transfer is the main part of the mass and momentum transfer of the oil drop in the bearing cavity. The thickness and the flow velocity of the oil film on the wall surface are obviously increased under the effect of oil drop deformation and secondary sedimentation effect, and the lubricant oil is expelled expeditiously.