实际射流参数对加热条件下液体燃料射流不稳定性的影响

Effects of Injecting Parameters on the Breakup of Liquid Jets Under Heating Conditions

利用线性热不稳定性理论,对黏性液体射人高温气体介质所对应的色散方程进行了数值求解.利用所得到的计算结果,研究了加热条件下射流速度、气液密度比、液体黏度、温度梯度及液体种类等实际射流参数对射流最大扰动增长率及占优波数的影响规律.研究结果表明:对于加热条件下Reyleigh模式的液体射流,气液密度比、温度梯度是射流破碎的失稳因素,而射流速度、液体黏度则是液体射流破碎的促稳因素;对于Taylor模式的液体射流,射流速度、温度梯度、气液密度比是射流破碎的失稳因素,而液体黏度是液体射流破碎的促稳因素.研究结果同时证明了液体种类的改变对射流不稳定性的影响是多种因素共同作用的结果.

Based on the linear thermocapillar instability theory, the dispersion equation of a liquid jet injected into a hot air medium is derived and calculated. Using the calculated results, the effects of jet parameters, such as jet speed, density ratio, liquid viscosity, temperature gradient and type of liquid, on the maximum growth rate and the dominant wavenumber of the instability of liquid jets are studied in detail. It shows that for liquid jets under Reyleigh regime, density ratio and temperature gradient are positive factors which help the breakup of liquid jets, whereas jet speed and liquid viscosity are nega tive factors instead. On the other hand, for a liquid jet under Taylor regime, jet speed, density ratio and temperature gradient are all positive factors, whereas the liquid viscosity is negative factor. It also shows that the type of liquid has a very complex effect on the breakup of liquid jets.