Applications of Laser Speckle Photography for Thermal Flow Problems

‚aser speckle photography measures projected beam deßection of a phase object. „he beam deßection measured at the solid surface will directly determine the wall-temperature gradient. „hus, the laser-speckle photogra-phy allows the evaluation of the convection-heat-transfer coe¦cients without the need to correct for conduction and radiation heat losses, which otherwise would be necessary. Selected results and brief discussions are presented for several natural convection-heat-transfer problems. Second, high-temperature applications of laser speckle photography shows potential as a nonintrusive means of measuring ßame temperature. A fairly good agreement is shown in comparison of the laser speckle data with intrusive thermocouple data. Suggestive discussions are made to further improve the accuracy and sensitiv-ity of the laser speckle photography technique in high-temperature applica-tions. Finally, tomographic reconstruction of laser speckle photography data is discussed using density computer-synthesized phantom Þelds. „he conven-tional algebraic reconstruction technique (AR„) has been modiÞed to apply for the laser speckle tomography. „he reconstruction accuracy of AR „ is compared with Fourier convolution (FC) technique particularly under a lim