Numerical 2D simulation and research on internal flow field and external flow field of rocket motor nozzle using FLUENT software. Analyze the flow condition of internal flow field and external flow field, and accordin...Numerical 2D simulation and research on internal flow field and external flow field of rocket motor nozzle using FLUENT software. Analyze the flow condition of internal flow field and external flow field, and according to add in the amount of the different gas components, obtain the clear distribution of contour of density flow field, pressure flow field and various material components and so on. Simulation results agree with the results observed from the test on the ground, and provide reference for solid rocket motor development.展开更多
The determination of an accurate center of rotation of rocket motor nozzle or other object to be measured is of great interest across a wide range of applications,such as rocket,missile,robotics,industry,spaceflight,a...The determination of an accurate center of rotation of rocket motor nozzle or other object to be measured is of great interest across a wide range of applications,such as rocket,missile,robotics,industry,spaceflight,aviation and human motion analysis fields,particularly for clinical gait analysis.A new approach was proposed to estimate the moving objects' instantaneous center of rotation and other motion parameters.The new method assumes that the two segment of object to be measured are rigid body which rotates around a center of rotation between each other relatively.The center of rotation varies with time in the global coordinate system but is fixed in the local coordinate system attached to each segment.The models of rocket motor nozzle and its movement were established.The arbitrary moving object's corresponding to motion equations were deduced,and the least square closed-form solutions of the object's motion parameters were figured out.It is assumed that the two high speed CCD cameras mounted on the 750 nm infrared(IR) filter are synchronized and calibrated in advance.The virtual simulation experiment using 3D coordinates of markers was conducted by synchronized stereo image sequences based on 6-DOF motion platform and the experimental results prove the feasibility of our algorithm.The test results show that the precision of x,y,z component on center of rotation is up to 0.14 mm,0.13 mm,0.15 mm.展开更多
Experimental and numerical studies are carried out on a 6-cell tile-shaped aerospike nozzle, a 6-cell aerospike nozzle with round-to-rectangle primary nozzles and a 1-cell linear aerospike nozzle. Good altitude compen...Experimental and numerical studies are carried out on a 6-cell tile-shaped aerospike nozzle, a 6-cell aerospike nozzle with round-to-rectangle primary nozzles and a 1-cell linear aerospike nozzle. Good altitude compensation capacities and high efficiencies are obtained in the tests. The efficiencies of 6-cell tile-shaped aerospike nozzle and 1-cell linear aerospike nozzle at design altitude approach to 100 %, and that of 6-cell aerospike nozzle with round-to-rectangle primary nozzles in the same condition is about 95 % due to the imperfect cell contour and manufacturing defects. Numerical results are in good agreements with test data. The effects of ambient pressure on exhaust and then on base behavior are analyzed, The effects of variation in the amount of base bleed on performance are also examined in the tests.展开更多
Nozzle damping is one of the most important factors in the suppression of combustion instability in solid rocket motors.For an engineering solid rocket motor that experiences combustion instability at the end of burni...Nozzle damping is one of the most important factors in the suppression of combustion instability in solid rocket motors.For an engineering solid rocket motor that experiences combustion instability at the end of burning,a wave attenuation method is proposed to assess the nozzle damping characteristics numerically.In this method,a periodic pressure oscillation signal which frequency equals to the first acoustic mode is superimposed on a steady flow at the head end of the chamber.When the pressure oscillation is turned off,the decay rate of the pressure can be used to determine the nozzle attenuation constant.The damping characteristics of three other nozzle geometries are numerically studied with this method under the same operating condition.The results show that the convex nozzle provides more damping than the conical nozzle which in turn provides more damping than the concave nozzle.All the three nozzles have better damping effect than that of basic nozzle geometry.At last,the phase difference in the chamber is analyzed,and the numerical pressure distribution satisfies well with theoretical distribution.展开更多
An improved constant volume cycle （CVC） model is developed to analyze the nozzle effects on the thrust and specific impulse of pulse detonation rocket engine （PDRE）. Theoretically, this model shows that the thrust...An improved constant volume cycle （CVC） model is developed to analyze the nozzle effects on the thrust and specific impulse of pulse detonation rocket engine （PDRE）. Theoretically, this model shows that the thrust coefficient/specific impulse of PDRE is a function of the nozzle contraction/expansion ratio and the operating frequency. The relationship between the nozzle contraction ratio and the operation frequency is obtained by introducing the duty ratio, by which the key problem in the theoretical design can be solved. Therefore, the performance of PDRE can be accessed to guide the preliminary shape design of nozzle conveniently and quickly. The higher the operating frequency of PDRE is, the smaller the nozzle contraction ratio should be. Besides, the lower the ambient pressure is, the larger the expansion ratio of the nozzle should be. When the ambient pressure is 1.013 × 105 Pa, the optimal expansion ratio will be less than 2.26. When the ambient pressure is reduced to vacuum, the extremum of the optimal thrust coefficient is 2.236 9, and the extremum of the specific impulse is 321.01 s. The results of the improved model are verified by numerical simulation.展开更多
文摘Numerical 2D simulation and research on internal flow field and external flow field of rocket motor nozzle using FLUENT software. Analyze the flow condition of internal flow field and external flow field, and according to add in the amount of the different gas components, obtain the clear distribution of contour of density flow field, pressure flow field and various material components and so on. Simulation results agree with the results observed from the test on the ground, and provide reference for solid rocket motor development.
基金Sponsored by the National Natural Science Foundation of China(Grant No. 50275040)
文摘The determination of an accurate center of rotation of rocket motor nozzle or other object to be measured is of great interest across a wide range of applications,such as rocket,missile,robotics,industry,spaceflight,aviation and human motion analysis fields,particularly for clinical gait analysis.A new approach was proposed to estimate the moving objects' instantaneous center of rotation and other motion parameters.The new method assumes that the two segment of object to be measured are rigid body which rotates around a center of rotation between each other relatively.The center of rotation varies with time in the global coordinate system but is fixed in the local coordinate system attached to each segment.The models of rocket motor nozzle and its movement were established.The arbitrary moving object's corresponding to motion equations were deduced,and the least square closed-form solutions of the object's motion parameters were figured out.It is assumed that the two high speed CCD cameras mounted on the 750 nm infrared(IR) filter are synchronized and calibrated in advance.The virtual simulation experiment using 3D coordinates of markers was conducted by synchronized stereo image sequences based on 6-DOF motion platform and the experimental results prove the feasibility of our algorithm.The test results show that the precision of x,y,z component on center of rotation is up to 0.14 mm,0.13 mm,0.15 mm.
文摘Experimental and numerical studies are carried out on a 6-cell tile-shaped aerospike nozzle, a 6-cell aerospike nozzle with round-to-rectangle primary nozzles and a 1-cell linear aerospike nozzle. Good altitude compensation capacities and high efficiencies are obtained in the tests. The efficiencies of 6-cell tile-shaped aerospike nozzle and 1-cell linear aerospike nozzle at design altitude approach to 100 %, and that of 6-cell aerospike nozzle with round-to-rectangle primary nozzles in the same condition is about 95 % due to the imperfect cell contour and manufacturing defects. Numerical results are in good agreements with test data. The effects of ambient pressure on exhaust and then on base behavior are analyzed, The effects of variation in the amount of base bleed on performance are also examined in the tests.
文摘Nozzle damping is one of the most important factors in the suppression of combustion instability in solid rocket motors.For an engineering solid rocket motor that experiences combustion instability at the end of burning,a wave attenuation method is proposed to assess the nozzle damping characteristics numerically.In this method,a periodic pressure oscillation signal which frequency equals to the first acoustic mode is superimposed on a steady flow at the head end of the chamber.When the pressure oscillation is turned off,the decay rate of the pressure can be used to determine the nozzle attenuation constant.The damping characteristics of three other nozzle geometries are numerically studied with this method under the same operating condition.The results show that the convex nozzle provides more damping than the conical nozzle which in turn provides more damping than the concave nozzle.All the three nozzles have better damping effect than that of basic nozzle geometry.At last,the phase difference in the chamber is analyzed,and the numerical pressure distribution satisfies well with theoretical distribution.
基金supported by the National Natural Science Foundation of China(No.11472167)
文摘An improved constant volume cycle （CVC） model is developed to analyze the nozzle effects on the thrust and specific impulse of pulse detonation rocket engine （PDRE）. Theoretically, this model shows that the thrust coefficient/specific impulse of PDRE is a function of the nozzle contraction/expansion ratio and the operating frequency. The relationship between the nozzle contraction ratio and the operation frequency is obtained by introducing the duty ratio, by which the key problem in the theoretical design can be solved. Therefore, the performance of PDRE can be accessed to guide the preliminary shape design of nozzle conveniently and quickly. The higher the operating frequency of PDRE is, the smaller the nozzle contraction ratio should be. Besides, the lower the ambient pressure is, the larger the expansion ratio of the nozzle should be. When the ambient pressure is 1.013 × 105 Pa, the optimal expansion ratio will be less than 2.26. When the ambient pressure is reduced to vacuum, the extremum of the optimal thrust coefficient is 2.236 9, and the extremum of the specific impulse is 321.01 s. The results of the improved model are verified by numerical simulation.
