丙醇-生物柴油斯特林发动机喷雾特性试验研究

Experimental Study on Spray Characteristics of n-Propanol-Biodiesel in a Stirling Engine

斯特林发动机的喷射压力和背压均低于柴油机,一般采用压力涡流和引射耦合的喷雾方式。为研究丙醇-生物柴油混合燃料的在斯特林发动机上的喷雾特性,本文建立了基于斯特林发动机的喷雾可视化试验系统,研究了喷射压差、丙醇含量及喷孔直径对丙醇-生物柴油混合燃料斯特林发动机的喷雾特性的影响。结果表明:与柴油相比,丙醇-生物柴油混合燃料对喷射压差的敏感性较小;在不同喷雾阶段,丙醇含量对喷雾的影响呈现不同规律,在喷雾趋于稳定后,P50BD50、P75BD25和纯生物柴油的喷雾贯穿距明显大于P25BD75和柴油;喷孔直径越大,喷雾锥角越大、喷雾贯穿距越小;引射作用对喷雾形态有质的影响,在可观测范围内,已无明显的雾束结构,引射是低压差下斯特林发动机实现良好雾化的关键。

The injection pressure and back pressure of Stirling engine are lower than those of diesel en-gine,generally,spray mode of pressure vortex and ejection coupling is adopted.In order to study the spray characteristics of n-propanol-biodiesel blended fuel in a Stirling engine,an experimental appara-tus with spray visulization of Stirling engine was established in this paper,so as to study the effects of in-jection pressure difference,n-propanol content and nozzle diameter on the spray characteristics of the n-propanol-biodiesel blended fuel in a Stirling engine.The results show that the sensitivity of n-propanol-biodiesel blend fuel to injection pressure difference is less than that of diesel;in different spray stages,the influence of n-propanol content on spray shows dfferent rules.After spray is stabilized,the spray penetration distance of P50BD50,P75BD25 and pure biodiesel is significantly greater than P25BD75 and diesel;the larger the nozzle diameter,the larger the spray cone angle and the smaller the spray penetra-tion distance;ejection has a qualitative effect on the spray shape.In the observable range,there is no obvious spray beam structure.Ejection is the key to realizing the good spray in a Stirling engine at low pressure difference.