Investigation of fully dispersed shock wave in droplets-gas mixture

液滴-气体混合物中完全分散的冲击波研究

基本信息

批准号：
09450073
负责人：
HIRAHARA Hiroyuki
金额：
$ 0.64万
依托单位：
Saitama University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09450073/
关键词：
Dispersed Shock Wave Droplets Shock Tube Relaxation Momentum relaxation Mie Scattering TVD Scheme Image Processing ミ-散乱

项目摘要

An experimental and numerical investigation was carried out for the dispersion of shock waves in droplet-gas mixture flows. The droplet size and number density were measured by means of Mie scattering technique behind the shock wave. Two-dimensional image of test field was obtained in the experiment and the image was analyzed in digital by personal computer. Under the assumption that the droplet size should not be changed in the region not far from the shock front, the distribution of number density is proportional to the extinction rate of incident light beam intensity, Since the density ratio of droplet is proportional to the reciprocal of velocity ratio which is valid from the mass conservation, finally, we can obtain the velocty slip ratio between the droplet and gas flow from number density distribution of droplet. The momentum relaxation length is determined from these results. Experimental result show that the relaxation region increases as the relative velocity decreases. The v … More alue is much higher than theoretically predicted one. It is concluded that the model equation of drag coefficient should be modified for the crowd particles and unsteady motion. On the other hand, the pressure distribution behind the shock wave was measured in detail in order to investigate the dispersion of shock wave, When the incident shock Mach number is 1.4, the pressure profile shows a partly discontinuous distribution just behind the shock front. Viscous effect between the droplets and gas flow plays a significant dissipation function in this region. The typical length of this region is about 15 mm for Ms=1.4. The thermal relaxation length is much more long and 10 times of this length. This is attributed that the momentum relaxation and thermal relaxation is dispersed. The pressure profile of weak shock wave is close to that predicted by Young and Guha(1991). Otherwise, the numerical prediction did not show such dispersion on the pressure profile. It is concluded that the viscous effect should be accounted in the calculation with more valid physical model against the nonlinear wave steepenning. Less

进行了一次实验和数值研究，以分散冲击波在液滴气体中。液滴的大小和数量密度是通过冲击波后面的MIE散射技术测量的。在实验中获得了测试场的二维图像，并通过个人计算机在数字化中分析了图像。在假设液滴尺寸不应在离冲击方面不远的区域不变的假设，数量密度的分布与入射光束强度的扩展速率成正比，因为液滴的密度比与速度比的倒数相吻合，该速度比与质量保护有效的速度比相互成比例，我们可以从质量保存中分配，我们可以从速度下的降落和流量的分配数量，并在数量之间获得数量的流量。动量松弛长度是根据这些结果确定的。实验结果表明，弛豫区域随着相对速度的降低而增加。 V…更大的Aliue远高于理论上的预测。结论是，应为人群颗粒和不稳定运动修改阻力佐证的模型当量。另一方面，详细测量了冲击波背后的压力分布以研究冲击波的分散，当入射冲击马赫数为1.4时，压力曲线在冲击锋后的部分不连续分布。液滴和气流之间的粘性作用在该区域起着显着的耗散功能。该区域的典型长度约为MS = 1.4。热松弛长度要长得多，并且是该长度的10倍。这归因于动量松弛和热放松被分散。弱冲击波的压力曲线接近Young and Guha（1991）所预测的压力曲线。否则，数值预测不会在压力曲线上显示这种分散。可以得出结论，应在计算中使用更有效的物理模型来考虑粘性效应，以针对非线性波陡峭。较少的