Temperature Measurement Based On Background Oriented Schlieren

In this paper, basic principles and methods of background oriented schlieren techniques and traditional schlieren technology are first introduced. The advantages and disadvantages of background oriented schlieren are also analyzed. Then, We summarize the applications of background oriented schlieren techniques and traditional schlieren technology in the combustion, heat and mass transfer, and wind tunnel tests field etc. the advantages and disadvantages of background oriented schlieren are analyzed too.By using only a digital camera and a structured background, background oriented schlieren can get the light projection in one direction of the temperature field. The image was processed by Particle Image Velocimetry Software to obtain the deflection angle of light. Deflection angle of light passing over flame of Bunsen burner were used to reconstruct index of refraction field from algebraic reconstruction technology. Then the Gladstone-Dale relation and the Idea-Gas Equation were used to obtain the temperature field. Comparing the temperature field with the results which were got by the sodium line-reversal method, this technology can get excellent Temperature field.Finally, the background oriented schlieren technique is adopted to test a natural convection boundary layer temperature distribution of a transverse pipe. And fluent software is used to get around the boundary layer flow and the general distribution of temperature, this temperature boundary layer and the background Image are used to obtain the pattern of mesh, and then three-dimensional reconstruction of the temperature field are used to get the quantitative measurement of natural convection boundary layer temperature under transverse tube. This technique provides a simple and practical way for the temperature boundary layer observations and measurements in experiments and engineering applications.