Supersonic flow imaging via nanoparticles

Due to influence of compressibility, shock wave, instabilities, and turbulence on supersonic flows, current flow visualization and imaging techniques encounter some problems in high spatiotemporal resolution and high signal-to-noise ratio (SNR) measurements. Therefore, nanoparticle based planar laser scattering method (NPLS) is developed here. The nanoparticles are used as tracer, and pulse planar laser is used as light source in NPLS; by recording images of particles in flow field with CCD, high spatiotemporal resolution supersonic flow imaging is realized. The flow-following ability of nanoparticles in supersonic flows is studied according to multiphase flow theory and calibrating experiment of oblique shock wave. The laser scattering characteristics of nanoparticles are analyzed with light scattering theory. The results of theoretical and experimental studies show that the dynamic behavior and light scattering characteristics of nanoparticles highly enhance the spatiotemporal resolution and SNR of NPLS, with which the flow field involving shock wave, expansion, Mach disk, boundary layer, sliding-line, and mixing layer can be imaged clearly at high spatiotemporal resolution.

[1]  Ellen K. Longmire,et al.  Simultaneous two-phase PIV by two-parameter phase discrimination , 2002 .

[2]  Walter R. Lempert,et al.  Accuracy limits for planar measurements of flow field velocity, temperature and pressure using Filtered Rayleigh Scattering , 1998 .

[4]  Michel Stanislas,et al.  Main results of the Second International PIV Challenge , 2005 .

[5]  A. Melling,et al.  Seeding gas flows for laser anemometry , 1986 .

[6]  M. Koochesfahani,et al.  Molecular Tagging Velocimetry (MTV) measurements in gas phase flows , 1999 .

[7]  R. Teets.  Accurate convolutions of coherent anti-Stokes Raman spectra. , 1984, Optics letters.

[8]  Christian Rey,et al.  Particle Image Velocimetry in Mach 3.5 and 4.5 Shock-Tunnel Flows , 2002 .

[9]  C. Carter,et al.  Molecular Filtered Rayleigh Scattering applied to combustion and turbulence , 1999 .

[10]  C. Carter,et al.  Simultaneous Rayleigh imaging and CH-PLIF measurements in a lifted jet diffusion flame , 2000 .

[11]  Gregory S Elliott,et al.  On the use of filtered Rayleigh scattering for measurements in compressible flows and thermal fields , 2005 .

[12]  J. Dutton,et al.  Accuracy and resolution issues in NO/acetone PLIF measurements of gas-phase molecular mixing , 2002 .

[13]  W. Wiscombe.  Improved Mie scattering algorithms. , 1980, Applied optics.

[14]  Winfried Stricker,et al.  Application of spontaneous Raman and Rayleigh scattering and 2D LIF for the characterization of a turbulent CH4/H2/N2 jet diffusion flame , 1998 .

[15]  James F. Meyers.  Doppler global velocimetry - The next generation? , 1992 .