In this paper the theoretical model is built for ZEpHyR(ZARM Experimental Hybrid Rocket) main engine which is being developed at ZARM institute,Bremen,Germany.The theoretical model is used to estimate the temperature ...In this paper the theoretical model is built for ZEpHyR(ZARM Experimental Hybrid Rocket) main engine which is being developed at ZARM institute,Bremen,Germany.The theoretical model is used to estimate the temperature of exhaust gas.The Conjugate Gradient Method(CGM) with Adjoint Problem for Function Estimation iterative technique is used to solve the Inverse Heat Conduction Problem(IHCP) to estimate the heat flux and internal wall temperature at the throat section of the nozzle.Bartz equation is used to calculate the convective heat transfer coefficient.The exhaust gas temperature is determined using the estimated heat flux,the wall temperature at internal surface of nozzle and the heat transfer coefficient.The accuracy of CGM iterative scheme to solve the IHCP is also investigated and its results are presented.展开更多
It is difficult and high-cost to detect flame fronts by laser-sheet diagnostics under microgravity （μg）, thus image processing is critical to obtain valuable information from the raw data. In the present study, pre...It is difficult and high-cost to detect flame fronts by laser-sheet diagnostics under microgravity （μg）, thus image processing is critical to obtain valuable information from the raw data. In the present study, premixed V-flames were detected under μg by OH planar laser-induced fluorescence （PLIF） and an effective method based on active contour model （ACM） is presented for automatic detecting and tracking flame fronts in the PLIF images. ACM can effectively detect the flame front in the images with low contrast and noises. Compared with other methods of flame front detection, the advantage of this method is that the image smoothing and image enhancement are not necessary for the correct detection of flame fronts in raw PLIF images.展开更多
文摘In this paper the theoretical model is built for ZEpHyR(ZARM Experimental Hybrid Rocket) main engine which is being developed at ZARM institute,Bremen,Germany.The theoretical model is used to estimate the temperature of exhaust gas.The Conjugate Gradient Method(CGM) with Adjoint Problem for Function Estimation iterative technique is used to solve the Inverse Heat Conduction Problem(IHCP) to estimate the heat flux and internal wall temperature at the throat section of the nozzle.Bartz equation is used to calculate the convective heat transfer coefficient.The exhaust gas temperature is determined using the estimated heat flux,the wall temperature at internal surface of nozzle and the heat transfer coefficient.The accuracy of CGM iterative scheme to solve the IHCP is also investigated and its results are presented.
基金This work was partially supported by Natural Science Foundation of China under Grant No. 50276061.
文摘It is difficult and high-cost to detect flame fronts by laser-sheet diagnostics under microgravity （μg）, thus image processing is critical to obtain valuable information from the raw data. In the present study, premixed V-flames were detected under μg by OH planar laser-induced fluorescence （PLIF） and an effective method based on active contour model （ACM） is presented for automatic detecting and tracking flame fronts in the PLIF images. ACM can effectively detect the flame front in the images with low contrast and noises. Compared with other methods of flame front detection, the advantage of this method is that the image smoothing and image enhancement are not necessary for the correct detection of flame fronts in raw PLIF images.
