Theories And Experiments Research On Optical Of Complex Flow Field

Optical Computerized Tomography (OCT) is an important means for the study of flow field; however, the limited data for the reconstruction is currently the foremost problem of OCT practically applied. In this dissertation, theoretical and experimental researches on the OCT of incomplete data are exposited systematically, by which three-dimensional temperature distribution of the complex pneumatic flow field is reconstructed and tested. All the contents of the research include the following main parts:First, a new kind of algebra reconstruction technique is presented according to the feature of reconstruction in the OCT of incomplete data. In this technique, the fixed ultra relaxation coefficient usually determined artificially is abandoned and an unfixed ultra relaxation coefficient is introduced. Also the property matrix including the prior knowledge is adopted in this algorithm. The results indicate that the algorithm with property matrix and unfixed ultra relaxation coefficient can reconstruct the flow field of incomplete data satisfactorily, improve the reconstruction precision greatly, and match the measured results.Second, with the help of Fabry-Perot rotary interferometer developed by Professor He Anzhi, the OCT is firstly used in the research on the heatelimination of a real aeroengine blade. The three-dimension temperature distribution and the temperature topography of the blade are reconstructed. The reconstructed results match the measurements and this will provide the experimental foundation for the design of aeroengine blade.After analyzing the characteristic frequency spectrum of the field to be tested, a method to determine the sampling range and to choose the effective information content is developed based on the distribution of characteristic frequency spectrum density in the sampling, by which the maximum frequency spectrum density can be obtained within the limited sampling angle range. On the basis of this method, the satisfactory reconstructed results will be obtained even within the limited sampling angle range.Lastly, a new three-dimensional tomography with the fusion of virtual and real experiments is proposed, which is the combination of Computational Fluid Dynamics...