两相流振荡流动特性的可视化实验研究

为了解决活塞内冷油腔中气液两相流的振荡传热问题,设计并搭建了由柴油机改装的往复振荡实验装置,利用高速摄像技术对内冷油腔实验件中气液两相流的振荡流动过程进行了可视化观测实验,分析在不同转速和液体填充率下实验件中气液两相流在起振阶段和充分振荡阶段的振荡流动形态。结果表明：在起振阶段,气液两相的分界面明显,没有强烈的湍流混合运动,在充分振荡阶段,液体的运动规律及流动形态呈周期性变化;转速主要影响气液两相流的湍流强度,填充率主要影响气液两相流的流动形态。研究结果揭示了内冷油腔中气液两相流的振荡流动规律,可为高强化活塞的结构优化设计提供参考。

Visualization experiment study on oscillatory flow characteristics of two-phase flow

In order to solve the oscillatory heat transfer problem of gas-liquid two-phase flow of cooling oil gallery of piston, a reciprocating oscillatory experimental device reformed by diesel engine was designed and established. The oscillatory flow process of gas-liquid two-phase flow in a test piece was visualized by high-speed camera technology, and the oscillatory flow patterns of gas-liquid two-phase flow in the test piece at initial and full oscillation stage under different rotation speed and liquid filling rate were analyzed respectively. The results show that at initial oscillation stage, the interface between gas and liquid is obvious, and there is no intense turbulent mixing motion. At full oscillation stage, the movement law and flow pattern of liquid change periodically. Rotational speed mainly affects the turbulence intensity of gas-liquid two-phase flow, while the liquid filling rate mainly affects the flow pattern of gas-liquid two-phase flow. The research results reveal the oscillatory flow rules of gas-liquid two-phase flow in cooling oil gallery, and also provide a reference for the structural optimization design of the highly-intensified piston in the future.