无旋锥形液膜表面波不稳定性试验研究

Experimental Research of Instability of Surface

关键词:  针栓式喷注器  锥形液膜  色散方程  破碎长度

Key words:  Pintle injector  Conical sheets  Dispersion equation  Breakup length

摘要:

为了研究针栓式喷注器无旋锥形液膜表面波不稳定特性，采用高速摄影获得了不同压降下表面波波动图像，测量了液膜表面波破碎点波长、振幅以及破碎长度等特征信息。利用试验结果修正了无旋锥形液膜色散方程中的参数[C]和[ln(ηbη0)]，并求解了色散方程。研究了喷注压降对液膜破碎长度、破碎时间以及破碎点波长的影响。结果表明:随着喷注压降的增加，液膜破碎长度和破碎时间均降低，并且降低趋势越来越缓，液膜表面波发展的非线性增强，理论值与试验值的偏差由3.9%增大到29.2%；液膜破碎位置处扰动波长随喷注压降的增加而降低，并且试验值比理论值偏大50%左右，无旋锥形液膜破碎模型可定性分析针栓式喷注器液膜表面波不稳定性。

Abstract:

To study instability characteristics of surface wave on irrotational conical sheets of pintle injectors，fragmenting images in different injection pressure drop were obtained using high-speed photography. And feature information，like surface wave length at the breakup point，wave amplitude，and breakup length，were measured. Then，after modifying the parameters[C]and [ln(ηbη0)] in the dispersion equations using the experimental data，the equations were solved. Effects of injection pressure drop on breakup length，breakup time and wave length at the breakup point were studied. The results indicate that both the breakup length and breakup time decrease with increasing of the injection pressure drop，and the decreasing tendency becomes slow. In addition，the deviation between theoretical data and experimental data increases from 3.9% to 29.2% because the developing nonlinearity of the surface wave of conical sheets enhances. Surface wave length at the breakup point reduces as the injection pressure drop rises，and the experimental data is 50% bigger than the theoretical data. The breaking model of irrotational conical sheets can be used to qualitatively analyse instability of surface wave of pintle injectors.