METHOD FOR THERMAL-IMAGING DETERMINATION OF TURBULENCE CHARACTERISTICS OF NON-ISOTHERMAL FLUX

摘要

FIELD: physics.;SUBSTANCE: method comprises measuring a temperature field using a thermal imager to obtain a thermal-imaging thermo-videogram and determine successive variation of temperature in an n-th number of frames, taken from a digital thermal-imaging film at each control pixel; selecting a vessel with a wall which is transparent for infrared radiation, filling said vessel with a liquid and measuring thermal flux in the area of the layer bordering with the inner surface of the wall of the vessel, wherein the method includes precise focusing of a microlens on the inner surface of the wall of the vessel; Then, based on the thermal-imaging thermo-videogram, determining the relationship between the amplitude of pulsations of thermal flux and time and, using direct Fourier transform, plotting spectral curves of pulsations of thermal flux at control points, from where the frequencies of variation of thermal flux are selected and compared; further, determining an exponential law and identifying portions of turbulent spectrum from the comparison results. The digital thermal-imaging film is captured with a frame frequency which is at least twice greater than the measured frequency of pulsations of the thermal flux.;EFFECT: high accuracy and reliability of obtained data.;2 cl, 4 dwg