旋流式气液同轴式喷油器在加压空间中雾化特性的试验研究

在增压条件下对一种旋流式气液同轴喷油器的雾化特性进行研究。在不同的环境背压条件下,采用PDPA测量距离喷口处70mm的液雾分布,研究了环境背压、气液相对速度、以及燃油流速对索特平均直径（Sauter mean diameter,SMD）的影响规律。结果表明：当保证燃油流速一定、气液相对速度一定的条件下,SMD随环境背压的增大而减小;当环境背压及燃油流速一定的条件下,SMD随气液相对速度的增大而减小;当保证雾化空气压力以及环境背压一定的条件下,燃油流速对SMD的影响规律存在一个拐点,随着燃油流速的增加,SMD先增加后减小,在文中的试验条件下,燃油流速拐点值约为9．91m／s。根据试验数据整理出SMD与环境背压、气液相对速度及燃油流速的拟合公式。     

Effect of rare earths on oxidation resistance of heat resistant steel

The application of rare earths(RE) in the Ni saving heat resistant steel was studied by metalloscopy,scanning electron microscopy(SEM),energy dispersive spectrometer(EDS),X-ray difference(XRD).Because the diffusion of chromium was promoted by RE,a dense and adhesive Cr2O3 layer could form rapidly at the early oxidation stage,which played a effective protection role;the pinning effect of silicon dioxide was enhanced by RE in the internal oxidation layer,which had a block effect on the diffusion of metal ions and oxygen ions at later stage of oxidation and resulted in that the high temperature oxidation rate of RE heat resistant steel was decreased.