Simulation Analysis On Spreading Process Of Single Droplet Impingement Based On CLSVOF Method

Fuel spray impingement phenomenon is almost inevitable in high-speed, light-weight diesel engine. With the expansion of the scope of disel engine and the formulation and implementation of more stringent emissions regulations, in-depth study has become very necessary to get a clear understanding of the characteristics and mechanism of the spray/wall interaction and then to improve the performance of engine.In this article, the spreading process of single spherical droplet impingement has been studied using numerical simulation method. CLSVOF method of two-phase flow interface tracking was analyzed. Numerical simulation method of two-phase flow based on CLSVOF method and CSF model was studied. Numerical simulation method of wall wetting process based on CLSVOF method and Wang-Peng model was studied. Based on the previous work, the numerical simulation method of spreading process of droplet impingement was analyzed and the PSPDIS program was established. The spreading process of a single droplet impacting onto homoeothermic flat stainless steel wall was simulatied and analyzed using PSPDIS program, and its influence factors were studied.Numerical simulation methods and programs of two-phase flow, wall wetting and spreading of droplet impingement based on CLSVOF method have been obtained through the work of this article. It's found that, CLSVOF method inherits the advantages of VOF method and Level Set method, can successfully overcome the limitation of VOF method and Level Set method and realize precise tracking of phase interface of gas-liquid two-phase flow. Spurious currents can be reduced and calculation precision can be enhanced by apply CLSVOF method to gas-liquid two-phase flow simulation. Defect of Wang-Peng model in follow-back wetting process can be resolved to achieve precise simulation of wetting through model modifying. The spreading process of diesel droplet impingement has significant character of quasi-periodic vibration. Physical parameters of gas and liquid, wall parameters, hitting velocity have an effect on the spreading process of diesel droplet through inertia force, surface tension, surface free energy and its storage characteristic.The research results can provide theoretical basis for enriching and applying CLSVOF method, for in-depth study of simulation method of gas-liquid two-phase flow, wall wetting and the spreading process of droplet impingement, and for research on characteristics and mechanism of fuel impingement.