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Wang J.-R.,Northwestern Polytechnical University | He G.-Q.,Northwestern Polytechnical University | Li Q.,Northwestern Polytechnical University | Chao K.,Xian Institute of Aerospace Propulsion
Tuijin Jishu/Journal of Propulsion Technology | Year: 2013

In order to investigate the flow instability in a segmented SRM(solid rocket motor), numerical analyses based on LES(large eddy simulation) were carried out for a potential pressure oscillation characteristics in the chamber when the burning surface regression was at 0 mm, 160 mm and 280 mm, respectively. The numerical results indicate that initial stage flow instability is mostly caused by the parietal vortex-shedding in the chamber shortly after the motor firing. As the burning surface regresses continuously, the restrictors expose to the hot gases. The chamber flow instability is mostly induced by the obstacle vortex-shedding generated due to the effects of the residual annular thermal protection. Correspondingly, the frequency of pressure oscillation is decreased gradually as compared with that of initial stage. Source


Xu T.-W.,Northwestern Polytechnical University | Tian W.-P.,Xian Institute of Aerospace Propulsion | Wang J.-R.,Xian Institute of Aerospace Propulsion
Tuijin Jishu/Journal of Propulsion Technology | Year: 2015

According to the flight conditions of the tactical SRM (Solid Rocket Motor), a three-dimensional numerical model of two-phase flow was established for overload conditions. Flow field calculations were carried out for three different types of working conditions under small and medium-sized overload, respectively. The parameter distribution of the condensed particles in combustion chamber was analyzed, and a preliminary analysis of the effects of aggregation state of particles on the insulation ablation was performed. The results show that: (1) When the lateral acceleration is larger than a certain degree, an accumulation belt will be formed on the cylinder section of the motor insulator surface as particle concentration increasing slowly on the bearing surface along flow direction. However, particle distribution is sparse on the non-bearing surface. (2) The contribution of motor overload on the particle velocities is not significant. The main reason is that the axial acceleration of particles is mainly derived from the gas itself. (3) To some extent, particle aggregation zone shows the position of relatively severe ablation environment in the combustion chamber of motor. The insulation ablations mainly due to the low velocities of particles aggregation lead to the increasing of heat increment on the local insulator surface, and cause particles focalized secondly. Thus, under low and medium acceleration with long operation time, in order to alleviate the harsh ablation environment of local insulator in chamber combustion, according to the known particle distribution parameters, the design of motor should increase the thickness of local insulator, and adjust the flying attitude to make the bearing surface rendering acceleration alternating and increase the rotation action of motor. ©, 2015, Tuijin Jishu/Journal of Propulsion Technology. All right reserved. Source


Wang C.-G.,Northwestern Polytechnical University | Tian W.-P.,Northwestern Polytechnical University | Ren Q.-B.,Xian Institute of Aerospace Propulsion | Yang D.-M.,Xian Institute of Aerospace Propulsion | Chen C.,China Aerospace Science and Technology Corporation
Tuijin Jishu/Journal of Propulsion Technology | Year: 2012

In order to achieve the pulse start of solid rocket motor, one soft pulse separation device(PSD) was designed. The process of bearing pressure and opening up was simulated, and its strain and stress distribution was obtained. When the PSD bore 10MPa pressure coming from I pulse chamber, the max stress and strain of PSD or grain were smaller than the material limits, which proved that the structure of PSD was reliable. The XFEM was used to simulate its failure process, and the PSD was opened up reliably under 1.3 MPa pressure. The verification monomial test was designed to verify the accuracy of simulation, and the bearing capability and failure form of PSD were satisfied with the design requirements. The PSD can be applied to pulse motor. The simulation techniques, test methods and conclusions are useful for designing pulse solid rocket motor. Source


Wang W.,Northwestern Polytechnical University | Li J.,Northwestern Polytechnical University | Wang C.-G.,Xian Institute of Aerospace Propulsion | Tian W.-P.,China Aerospace Science and Technology Corporation | Ren Q.-B.,Xian Institute of Aerospace Propulsion
Tuijin Jishu/Journal of Propulsion Technology | Year: 2013

Circular plates with large deflection and fracture mechanics theory were employed to investigate calculating formula of stress intensity factor of prefab gap at the condition of inner pressure, and the relationship between the opening pressure and physical dimension of hard pulse separation device (PSD) in order to achieve the feasible configuration of metal diaphragm, which plays the important role in dual-pulse solid rocket motor. Moreover, six monomial tests of metal diaphragm were conducted to validate the computing precision of designing formula. In addition, three kinds of scale experiments, namely, the compressive, opening and associated test, were performed to explore working characters of pulse separation device. The results indicate that the error between the experimental conclusions and designing results is 4.394% and the method can be applied to confirm the physical dimension of metal diaphragm. The performances of bearing capacity, seal, working characters and ablation are demonstrated and the PSD agrees well with the requirements. Source


Wang C.-G.,Northwestern Polytechnical University | Tian W.-P.,Northwestern Polytechnical University | Yang D.-M.,Xian Institute of Aerospace Propulsion | Shi H.-B.,Xian Institute of Aerospace Propulsion | Zhu T.,Xian Institute of Aerospace Propulsion
Tuijin Jishu/Journal of Propulsion Technology | Year: 2012

To investigate the heat transfer for pulse separation device (PSD)of pulse solid rocket motor, formulae of two charring models were developed and the results were compared with the actual engine test results. Charring model 1 has a 20% error, and charring model 2 has a 6.7% error, charring model 2 has a better accuracy. The heat conduction for PSD is computed and the results were compared for the depth and the temperature distribution of the PSD. The results does not consider charring has a 14.3% error, and the results consider charring has a 10% error. The results show that the charring model 2 gives a preferable explanation, and the simulated results agree well with the theoretical value when the charring is considered. The conclusions are helpful for designing pulse solid rocket motor configuration. Source

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