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Laboratory 1

Prof. Viktor M. Bojko
Head of Laboratory
Head of Laboratory, Prof. Viktor M. Bojko
 
Tel.: (383) 354-30-40
Fax: (383) 330-72-68
E-mail: bvm [at] itam.nsc.ru
Areas and methods of research
  • Development of new optical methods of flow parameters record in experimental facilities of the Institute. 
  • Customization  of the known optical methods of flow diagnostics for the work in big experimental facilities of the Institute.
  • Generation of new scientific results important for the developing  aerospace products.
  • Creation and investigation of new film functional materials for panoramic diagnostics of temperature, skin friction, pressure in near-wall flows.
  • Investigation of near-wall flow topology involving thin-film coatings at sub-, super- and hypersonic velocities.
  • Creation of new hybrid nano-structured liquid-crystal systems with controlled characteristics for optical and micro-electronic devices.
 
Main results
  • A new modification of the laser-Doppler anemometry (LDA) method with the direct spectral analysis has been developed on the base of the static multiple path Fizeau standard (LDA-Fizeau). The LDA-Fizeau was tested and approved in the experiments on the sub- and supersonic gas and two-phase flows with highly-concentrated disperse phase within the velocity range of 20 – 600 m/s. 

    The calibration measurements of the linear velocity of the rotating disk have been performed by the LDA-Fizeau method and by the tachometric method, as well as the comparative simultaneous measurements of the gas flow velocity (LDA-Fizeau and PIV diagnostics). 
     
  • The technology of formation of polymer-disperse liquid crystals has been developed; the crystals contain a polymer, liquid crystals, carbon and inorganic nano-size admixtures.
     
  • Thermo-indicating films have been developed. 
    Film characteristics:  
    – optimal film thickness, μm 20–30;
    – working temperature range, °С from –5 to +150;
    – threshold sensitivity, W/cm2 5÷10–4;
    – spatial resolution, lines/mm 5–7;
    – time constant, s 0.02–0.3;
    – cycle numbers above 5,000;
    – lifetime, years above 5.
    – films are not toxic

    <FIGURE>

    Flow visualization (a) and temperature map (b) on the surface of a flying wing with 3D roughness. Vinf = 15 m/s. The height of the roughness element in 0.98 mm, diameter 1.6 mm.
     
  • Pressure-sensitive polymer-liquid crystals doped by luminophore have been developed.
     
  • The LC compositions have been developed for the diagnostics of shear stresses of skin friction.
     
  • LC-visualization (top) and tangential stresses map in the flow around the trapezoid protuberance with the roughness on the leading edge in a narrow channel. Vinf = 87 m/s.
     
  • LC-visualization and tangential stress map in the flow around  the rectangular protuberance in a narrow channel. Vinf = 80 m/s. 
     
  • The polymer-liquid crystal films with the light transmission controlled by the electric field have been developed.
     
  • The software for digital processing of the patterns of panoramic distributions of  the temperature, friction, pressure has been developed
Equipment, facilities
Gas and fluid test bench
The optical equipment complex for the diagnostics of high-velocity gas and two-phase flows. 
 
The gas and fluid test bench with high repetitiveness of modes and flow parameters is used for the adjustment and tests of the optical diagnostics methods. 
 
The main purposes: 
  • tests and adjustment of the opticalой diagnostics methods for non-stationary high-velocity high-gradient one- and two-phase flows; 
  • experimental investigation of the physical regularities of aerodynamic dispersion of fluids in high-velocity high-gradient flows; 
  • testing of sprayers, acquisition of qualitative and quantitative data about the parameters of operation of various sprayers, including ones with big (industrial-scale) fluid flowrates. 
 
The optical diagnostics system includes: 
  • shadow and Schlieren visualization of the structure of supersonic gas and two-phase jets; 
  • the high-sensitive shadow method with an adaptive visualizing display (ТМ АВТ) for the visualization of the structure of the subsonic gas and two-phase jet (developed in ITAM SB RAS); 
  • visualization of the structure of the subsonic gas and two-phase jet by the laser-knife method; 
  • PIV diagnostics of the gas jet velocity field; 
  • measurement of the disperse composition of the spray cone by the small-angle scattering method; 
  • measurement of the local velocity of the gas and disperse phases by the laser-Doppler anemometry (LDA) method with the direct spectral analysis has been developed on the base of the static multiple path Fizeau standard (developed in ITAM SB RAS). 
Shock wind tunnel UТ-4М 
The purpose is analysis of major physical regularities of the interaction between shock waves and liquid and solid particles related with acceleration, deformation, atomization, evaporation, ignition an combustion of drops and solid particles in the relaxation zone behind the shock wave front.
 
Shock wind tunnel parameters: 
 
КВД and КНД length is 0.8 and 5 m; electrically controlled pneumatic valve;
test section channel cross section is 5252 mm2; the process gases are air, oxygen;
the initial pressure P =  0.01 – 0.1 MPa; the pushing gas is air, helium at Р = 0.8 – 10 MPa; shock wave Mach number range is М = 1.1 – 4.5. 
 
Optical diagnostics of fast processes
 
To provide the ultimate spatial (~10 m) and temporal (~10 – 8 s) resolution of the optical schematic of visualization, the method of flash filming is used; it means that the exposure extent, frame count and rate are controlled by the light source, and the optical-mechanical photo-recorder is used for the spatial frame separation.
The stroboscopic light source is the base unit in the complex; it is based on the ruby 
Laser with the Q-switching (developed in ITAM SB RAS). 
 
Stroboscope parameters: 
 
wavelength is 0.694 um; mpulse number from 1 to 50; impulse duration is ~ 30 – 50 ns; inter-impulse gap is from 10 to 100 microseconds in 1 microsecond with the instability of ±0.1 microseconds;  synchronization accuracy is  ±0.1 microseconds;  impulse energy is ~0.05 J.
 
The fast trigged photo recorder  with a revolving mirror polygon records the images on a high-resolving photo film 35 mm wide, the sizes of the exposed area are 24x260 mm2. The frame size, frame count and gaps between them, with due regard to the duration of permanent  parameters behind the shock wave front are chosen in virtue of the optimal spatial and temporal resolution.