同轴气流引射式喷嘴流动特性数值研究

摘要

Numerical simulation and analysis were carried out on the internal two-phase flow field of a new coaxial air-injected atomizer by turbulence model RNG k-εand multi-fluid mixture model. The effect of inlet gas pressure on gas and liquid flow characteristic was studied, while the simulation results verified with experimental data. Results show that the pressure value of central field in mixing chamber is negative value, which guarantees that liquid could be injected into atomizer. The turbulence kinetic energy increases with the inlet gas pressure increasing, which enhances the mixing of liquid and gas and improves atomization quality. However, the liquid flow rate reached the peak value when the inlet gas pressure is equal to 0.1MPa. Therefore, the inlet gas pressure should be controlled in reasonable range.%采用RNG k-ε湍流模型，结合混合双流体模型对同轴气流引射式喷嘴的内部流动特性进行了数值模拟，考察进气压力对喷嘴流动特性的影响，得到气液流量变化规律，并与试验结果进行了对比，验证了模型的可靠性。研究结果表明，由于同轴气流引射式喷嘴内部存在中心负压区域，实现了对液体的引射。随着进气压力增大，喷嘴出口的湍动能增大，液体体积分数减小，气液混合效果增强，有利于提高雾化质量。液体流量随着进气压力的增大呈先增大后减小的变化趋势，因此，进气压力需要控制在合理范围内。