丙醇-生物柴油斯特林发动机喷雾特性试验研究

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。

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

The injection pressure and back pressure of Stirling engine are lower than those of diesel engine, 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 apparatus with spray visulization of Stirling engine was established in this paper, so as to study the effects of injection 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 different 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 penetration distance; ejection has a quali tative 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.