论文部分内容阅读
由于超声速流动受到可压缩性、激波、不稳定性以及湍流等因素的影响,现有流动显示与成像技术在流场结构的高时空分辨率和高信噪比测量中存在一定的问题.为此,本文提出了基于纳米粒子的平面激光散射技术(NPLS),该技术以纳米粒子作为示踪粒子,以脉冲平面激光作为光源,通过CCD记录流场中的粒子图像实现超声速流动的高分辨率成像.根据多相流体动力学理论和斜激波校准实验研究了纳米粒子在超声速流动中的跟随性问题.根据光散射理论深入分析了影响纳米粒子散射光强的各种因素.理论和实验研究结果表明,纳米粒子的动力学行为和光散射特性大大提高了NPLS技术的时空分辨率和信噪比,能够再现激波、膨胀波、马赫盘、边界层、滑移线和混合层共存的精细流场结构.
Because of the influence of compressibility, shock wave, instability and turbulence, the existing flow display and imaging technology have some problems in the high spatio-temporal resolution and high signal-to-noise ratio measurement of flow field structure. In this paper, nanoparticle-based planar laser light scattering (NPLS) is proposed in this paper. The nanoparticle is used as the tracer particle, and the pulse plane laser is used as the light source to record the particle image in the flow field by CCD to realize the high-resolution Imaging.According to the theory of multi-phase fluid dynamics and the experiment of oblique shock calibration, the follow-up problems of nanoparticles in supersonic flow were studied.According to the theory of light scattering, various factors influencing the light intensity of nanoparticles were deeply analyzed. Theoretical and experimental studies The results show that the dynamic behavior and light scattering properties of nanoparticles greatly improve the spatiotemporal resolution and signal-to-noise ratio of NPLS, and can reproduce the fine flow of coexistence of shock wave, expansion wave, Mach plate, boundary layer, slip line and mixed layer Field structure.