中文摘要：

应用三维CFD软件对纯大豆生物柴油与常规柴油在喷油嘴喷孔内部的流动进行数值仿真，模拟得到不同压力条件下两种燃油的质量流量、空穴分布、喷孔出口动量和有效喷射速度。计算结果表明：相同压力条件下，生物柴油密度较大，导致质量流量比常规柴油高；并且由于其较大的黏度使临界空穴条件更严格，因此相同压力条件下空穴强度低于常规柴油；同时生物柴油的喷孔出口动量与有效喷射速度也较小，而两者的流量系数与面积系数相差不大。综上所述，预测纯生物柴油的油气混合过程比常规柴油差。

英文摘要：

Flow behavior of pure soybean oil and conventional diesel in nozzle hole was numerically simulated using 3-D CFD software to obtain their mass flow, cavitation distribution, momentum and effective velocity at nozzle hole outlet under different pressure conditions. The calculated results show that the former leads to injected delivery increasing due to its greater density and exhibits lower cavitation trend because of the higher viscosity under the same pressure conditions. Momentum and effective velocity at the hole outlet for soybean oil are lower. However, flow coefficients and area coefficients for both fuels are similar. Consequently,it is predicted that air-fuel mixing process of soybean oil would become worse.