The infrared radiation signature of the plume from solid propellants with different energy characteristics is not the same. Three kinds of double-base propellants of different energy characteristics are chosen to meas...The infrared radiation signature of the plume from solid propellants with different energy characteristics is not the same. Three kinds of double-base propellants of different energy characteristics are chosen to measure the infrared spectral radiance from 1000 cm 1 to 4500 cm 1 of their plumes. The radiative spectrum is obtained in the tests. The experimental results indicate that the infrared radiation of the plume is determined by the energy characteristics of the propellant. The radiative transfer calculation models of the exhaust plume for the solid propellants are established. By including the chemical reaction source term and the radiation source term into the energy equation, the plume field and the radiative transfer are solved in a coupled way. The calculated results are consistent with the experimental data, so the reliability of the models is confirmed. The temperature distribution and the extent of the afterburning of the plume are distinct for the propellants of different energy characteristics, therefore the plume radiation varies for different propellants. The temperature of the fluid cell in the plume will increase or decrease to some extent by the influence of the radiation term.展开更多
The coupling effects among lateral mode,longitudinal mode and torsional mode of a launch vehicle cannot be taken into account in traditional dynamic analysis using lateral beam model and longitudinal spring-mass model...The coupling effects among lateral mode,longitudinal mode and torsional mode of a launch vehicle cannot be taken into account in traditional dynamic analysis using lateral beam model and longitudinal spring-mass model individually.To deal with the problem,propellant analogy methods based on beam model are proposed and coupled mass-matrix of liquid propellant is constructed through additional mass in the present study.Then an integrated model of launch vehicle for free vibration analysis is established,by which research on the interactions between longitudinal and lateral modes,longitudinal and torsional modes of the launch vehicle can be implemented.Numerical examples for tandem tanks validate the present method and its necessity.展开更多
When the tunneling boring machine(TBM) cutterhead tunnels, the excessive vibration and damage are a severe engineering problem, thereby the anti-vibration design is a key technology in the disc cutter system. The stru...When the tunneling boring machine(TBM) cutterhead tunnels, the excessive vibration and damage are a severe engineering problem, thereby the anti-vibration design is a key technology in the disc cutter system. The structure of disc cutter contains many joint interfaces among cutter ring, cutter body, bearings and cutter shaft. On account of the coupling for dynamic contact and the transfer path among joint interface, mechanical behavior of disc cutter becomes extremely complex under the impact of heavy-duty, which puts forward higher requirements for disc cutter design. A multi-degree-of-freedom coupling dynamic model, which contains a cutter ring, a cutter body, two bearings and cutter shaft, is established, considering the external stochastic excitations, bearing nonlinear contact force, multidirectional mutual coupling vibration, etc. Based on the parameters of an actual project and the strong impact external excitations, the modal properties and dynamic responses are analyzed, as well as the cutter shaft and bearings' loads and load transmission law are obtained. Numerical results indicate the maximum radial and axial cutter ring amplitudes of dynamic responses are 0.568 mm and 0.112 mm; the maximum radial and axial vibration velocities are 41.1 mm/s and 38.9 mm/s; the maximum radial and axial vibration accelerations are 94.7 m/s2 and 58.6 m/s2; the maximum swing angle and angular velocity of cutter ring are 0.007° and 0.0074 rad/s, respectively. Finally, the maximum load of bearing roller is 40.3 k N. The proposed research lays a foundation for structure optimization design of disc cutter and cutter base, as well as model selection, modification and fatigue life of the cutter bearing.展开更多
The batch transportation process of several kinds of crude oil is accomplished by an entire coupled pipeline system,which exhibits complex thermo-hydraulic characteristics.Based on the coupled characteristics among so...The batch transportation process of several kinds of crude oil is accomplished by an entire coupled pipeline system,which exhibits complex thermo-hydraulic characteristics.Based on the coupled characteristics among soil,pipelines and devices(including pumps,heating furnaces and valves),a coupled simulation model of batch transportation for the crude oil pipeline system is established,and a novel coupled simulation algorithm is proposed.The simulation results are in good agreement with the field data of an actual crude oil pipeline system.In addition,based on the numerical simulation,thermo-hydraulic characteristics of pipeline system are investigated,and some new thermo-hydraulic characteristics are obtained.In the batch transportation process with constant flowrate,the change trends of temperature at the outlet of each pipeline segment are hysteretic and the change ranges of temperature become small along mileage.And the adjustment of devices influences thermohydraulic characteristics to some extent.In the batch transportation process with variable flowrate,the complex thermo-hydraulic characteristics are exhibited,which are induced by the comprehensive influence of the changes of oil type,flowrate and absorbed/released heat.Compared with the transportation process with constant flowrate,the high-viscosity oil exhibits similar minimum temperature and lower maximum pressure in the transportation process with variable flowrate,which means that the higher transportation safety of pipeline system is obtained.This study can provide a scientific reference for making the safer batch transportation scheme of crude oil pipeline system.展开更多
基金the National Natural Science Foundation of China(Grant No.11072032)
文摘The infrared radiation signature of the plume from solid propellants with different energy characteristics is not the same. Three kinds of double-base propellants of different energy characteristics are chosen to measure the infrared spectral radiance from 1000 cm 1 to 4500 cm 1 of their plumes. The radiative spectrum is obtained in the tests. The experimental results indicate that the infrared radiation of the plume is determined by the energy characteristics of the propellant. The radiative transfer calculation models of the exhaust plume for the solid propellants are established. By including the chemical reaction source term and the radiation source term into the energy equation, the plume field and the radiative transfer are solved in a coupled way. The calculated results are consistent with the experimental data, so the reliability of the models is confirmed. The temperature distribution and the extent of the afterburning of the plume are distinct for the propellants of different energy characteristics, therefore the plume radiation varies for different propellants. The temperature of the fluid cell in the plume will increase or decrease to some extent by the influence of the radiation term.
基金supported by the National Special Funds for Astronautics(Grant No.51320103)China Academy of Launch Vehicle Technology for their financial support
文摘The coupling effects among lateral mode,longitudinal mode and torsional mode of a launch vehicle cannot be taken into account in traditional dynamic analysis using lateral beam model and longitudinal spring-mass model individually.To deal with the problem,propellant analogy methods based on beam model are proposed and coupled mass-matrix of liquid propellant is constructed through additional mass in the present study.Then an integrated model of launch vehicle for free vibration analysis is established,by which research on the interactions between longitudinal and lateral modes,longitudinal and torsional modes of the launch vehicle can be implemented.Numerical examples for tandem tanks validate the present method and its necessity.
基金Project(51375001) supported by the National Natural Science Foundation of ChinaProject(2013CB035400) supported by the National Basic Research Program of China
文摘When the tunneling boring machine(TBM) cutterhead tunnels, the excessive vibration and damage are a severe engineering problem, thereby the anti-vibration design is a key technology in the disc cutter system. The structure of disc cutter contains many joint interfaces among cutter ring, cutter body, bearings and cutter shaft. On account of the coupling for dynamic contact and the transfer path among joint interface, mechanical behavior of disc cutter becomes extremely complex under the impact of heavy-duty, which puts forward higher requirements for disc cutter design. A multi-degree-of-freedom coupling dynamic model, which contains a cutter ring, a cutter body, two bearings and cutter shaft, is established, considering the external stochastic excitations, bearing nonlinear contact force, multidirectional mutual coupling vibration, etc. Based on the parameters of an actual project and the strong impact external excitations, the modal properties and dynamic responses are analyzed, as well as the cutter shaft and bearings' loads and load transmission law are obtained. Numerical results indicate the maximum radial and axial cutter ring amplitudes of dynamic responses are 0.568 mm and 0.112 mm; the maximum radial and axial vibration velocities are 41.1 mm/s and 38.9 mm/s; the maximum radial and axial vibration accelerations are 94.7 m/s2 and 58.6 m/s2; the maximum swing angle and angular velocity of cutter ring are 0.007° and 0.0074 rad/s, respectively. Finally, the maximum load of bearing roller is 40.3 k N. The proposed research lays a foundation for structure optimization design of disc cutter and cutter base, as well as model selection, modification and fatigue life of the cutter bearing.
基金supported by the fund of the Beijing Municipal Education Commission(No.22019821001)Award Cultivation Foundation from Beijing Institute of Petrochemical Technology(No.BIPTACF-002)。
文摘The batch transportation process of several kinds of crude oil is accomplished by an entire coupled pipeline system,which exhibits complex thermo-hydraulic characteristics.Based on the coupled characteristics among soil,pipelines and devices(including pumps,heating furnaces and valves),a coupled simulation model of batch transportation for the crude oil pipeline system is established,and a novel coupled simulation algorithm is proposed.The simulation results are in good agreement with the field data of an actual crude oil pipeline system.In addition,based on the numerical simulation,thermo-hydraulic characteristics of pipeline system are investigated,and some new thermo-hydraulic characteristics are obtained.In the batch transportation process with constant flowrate,the change trends of temperature at the outlet of each pipeline segment are hysteretic and the change ranges of temperature become small along mileage.And the adjustment of devices influences thermohydraulic characteristics to some extent.In the batch transportation process with variable flowrate,the complex thermo-hydraulic characteristics are exhibited,which are induced by the comprehensive influence of the changes of oil type,flowrate and absorbed/released heat.Compared with the transportation process with constant flowrate,the high-viscosity oil exhibits similar minimum temperature and lower maximum pressure in the transportation process with variable flowrate,which means that the higher transportation safety of pipeline system is obtained.This study can provide a scientific reference for making the safer batch transportation scheme of crude oil pipeline system.
