| Due to the hydraulic pump suction,oil circulation,oil oscillation and other reasons during the working process of the hydraulic system,,it is inevitable that a amount of gas will be mixed in the hydraulic oil,which will cause cavitation of hydraulic components,hydraulic cylinder crawling,and oil temperature rise.It poses a threat to the stability and reliability of the hydraulic system,but the current method for removing bubbles in the hydraulic system is relatively lacking,and theoretical research is insufficient.Therefore,it is of great significance to carry out research on the law of gas-liquid swirling flow and bubble separation to achieve efficient separation of hydraulic oil and mixed gas.This article takes the gas-liquid cyclone separator as the research object,introduces its working principle and influencing factors of bubble separation,analyzes bubble dynamics and gas-liquid cyclone theory,proposes a reliable and efficient gas-liquid cyclone structure,and develops CFD(Computational Fluid Dynamics)flow field simulation analysis,and finally uses PIV(Particle Image Velocimetry)visualization experiment to verify the above research results.(1)The flow law of gas-liquid swirl and the bubble separation mechanism is analyze.The flow field distribution law of the gas-liquid swirling process is clarified.The main form is a combined vortex formed by a free vortex and a forced vortex.At the same time,the overall interface force composed of drag force,virtual mass force,lateral force and buoyancy force on the bubble is analyzed,which provides a theoretical basis for the study of swirl flow distribution.(2)Through the comparative analysis of orthogonal experiment design and simulation,aiming at improving the separation efficiency and reducing the overflow split ratio,the five influencing factors of the overflow diameter,underflow diameter,swirl cylinder diameter,overflow invasion depth and height are carried out.The structure is optimized,and the influence degree of the five factors is analyzed,and the optimal structure combination is finally obtained.(3)Using the Euler-Euler gas-liquid two-phase flow turbulence model,the simulation analysis was carried out on the gas volume fraction,gas-liquid pressure distribution,gas-liquid velocity distribution,and multi-scale bubble distribution under swirling conditions.The law of gas-liquid swirling flow and separation under different gas contents.(4)Using similarity theory and based on PIV visualization experiment methods,a gas-liquid cyclone test platform was built to carry out the formation process of cyclone,gas-liquid cyclone flow law,gas nucleus accumulation and elimination pulsation law,and gas nucleus size change law.The research has verified the correctness of the theoretical analysis.Based on the above research results,the law of gas-liquid cyclone flow and bubble separation are finally obtained,which provides theoretical support for the design and application of cyclones. |
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