The PDRE test model used in these experiments utilized kerosene as the fuel, oxygen as oxidizer, and nitrogen as purge gas. The solenoid valves were employed to control intermittent supplies of kerosene, oxygen and pu...The PDRE test model used in these experiments utilized kerosene as the fuel, oxygen as oxidizer, and nitrogen as purge gas. The solenoid valves were employed to control intermittent supplies of kerosene, oxygen and purge gas. PDRE test model was 50 mm in inner diameter by 1.2 m long. The DDT （deflagration to detonation transition） enhancement device Shchelkin spiral was used in the test model. The effects of detonation frequency on its time-averaged thrust and specific impulse were experimentally investigated. The obtained results showes that the time-averaged thrust of PDRE test model was approximately proportional to the detonation frequency. For the detonation frequency 20 Hz, the time-averaged thrust was around 107 N, and the specific impulse was around 125 s. The nozzle experiments were conducted using PDRE test model with three traditional nozzles. The experimental results obtained demonstrated that all of those nozzles could augment the thrust and specific impulse. Among those three nozzles, the convergent nozzle had the largest increased augmentation, which was approximately 18%, under the specific condition of the experiment.展开更多
An experiment for rocket engine inducer cavitating flow is conducted on a new experimental platform.The experiment platform,using water as working medium,can be used to investigate the steady and unsteady flows of cav...An experiment for rocket engine inducer cavitating flow is conducted on a new experimental platform.The experiment platform,using water as working medium,can be used to investigate the steady and unsteady flows of cavitating and noncavitating turbopumps.The experimental platform is designed as a flexible and versatile apparatus for any kind of fluid dynamic phenomena relating to high performance liquid rocket engine turbopumps.Design details for the platform is introduced.Various extend of cavitation images and dynamic pressure impulse are obtained,which provides a reference for cavitating flow study in rocket engine inducer.展开更多
During the experiment of gas/liquid coaxial swirl injector conducted with air and water under atmosphere environment, it is observed that the injector may selfoscillate. The self oscillation periodically occurs and va...During the experiment of gas/liquid coaxial swirl injector conducted with air and water under atmosphere environment, it is observed that the injector may selfoscillate. The self oscillation periodically occurs and vanishes with the increasing velocity of the gas flow.A theoretical model is presented based on the experiment investigation. Simulation of the acoustic process has been performed and conclusions consistent with the experiment can be drawn from the theoretical model, which explains the exPeriment phenomena quite well. At last, the comparison between phenomena of the self oscillation and some experiments of LRE indicates that some instability phenomena in oxygen/hydrogen propellant rocket engine may be the related to self oscillation in coaxial injectors展开更多
The pintle injector used for a liquid rocket engine is a newly re-attracted injection system famous for its wide throttle ability with high efficiency. The pintle injector has many variations with complex inner struct...The pintle injector used for a liquid rocket engine is a newly re-attracted injection system famous for its wide throttle ability with high efficiency. The pintle injector has many variations with complex inner structures due to its moving parts. In order to study the rotating flow near the injector tip, which was observed from the cold flow experiment using water and air, a numerical simulation was adopted and a verification of the numerical model was later conducted. For the verification process, three types of experimental data including velocity distributions of gas flows, spray angles and liquid distribution were all compared using simulated results. The numerical simulation was performed using a commercial simulation program with the Eulerian multiphase model and axisymmetric two dimensional grids. The maximum and minimum velocities of gas were within the acceptable range of agreement, however, the spray angles experienced up to 25% error when the momentum ratios were increased. The spray density distributions were quantitatively measured and had good agreement. As a result of this study, it was concluded that the simulation method was properly constructed to study specific flow characteristics of the pintle injector despite having the limitations of two dimensional and coarse grids.展开更多
基金National Natural Science Foundation of China (501- 06012, 50336030)Program for New Century Excellent Talents in Uni-versity(NCET-04-0960)
文摘The PDRE test model used in these experiments utilized kerosene as the fuel, oxygen as oxidizer, and nitrogen as purge gas. The solenoid valves were employed to control intermittent supplies of kerosene, oxygen and purge gas. PDRE test model was 50 mm in inner diameter by 1.2 m long. The DDT （deflagration to detonation transition） enhancement device Shchelkin spiral was used in the test model. The effects of detonation frequency on its time-averaged thrust and specific impulse were experimentally investigated. The obtained results showes that the time-averaged thrust of PDRE test model was approximately proportional to the detonation frequency. For the detonation frequency 20 Hz, the time-averaged thrust was around 107 N, and the specific impulse was around 125 s. The nozzle experiments were conducted using PDRE test model with three traditional nozzles. The experimental results obtained demonstrated that all of those nozzles could augment the thrust and specific impulse. Among those three nozzles, the convergent nozzle had the largest increased augmentation, which was approximately 18%, under the specific condition of the experiment.
文摘An experiment for rocket engine inducer cavitating flow is conducted on a new experimental platform.The experiment platform,using water as working medium,can be used to investigate the steady and unsteady flows of cavitating and noncavitating turbopumps.The experimental platform is designed as a flexible and versatile apparatus for any kind of fluid dynamic phenomena relating to high performance liquid rocket engine turbopumps.Design details for the platform is introduced.Various extend of cavitation images and dynamic pressure impulse are obtained,which provides a reference for cavitating flow study in rocket engine inducer.
文摘During the experiment of gas/liquid coaxial swirl injector conducted with air and water under atmosphere environment, it is observed that the injector may selfoscillate. The self oscillation periodically occurs and vanishes with the increasing velocity of the gas flow.A theoretical model is presented based on the experiment investigation. Simulation of the acoustic process has been performed and conclusions consistent with the experiment can be drawn from the theoretical model, which explains the exPeriment phenomena quite well. At last, the comparison between phenomena of the self oscillation and some experiments of LRE indicates that some instability phenomena in oxygen/hydrogen propellant rocket engine may be the related to self oscillation in coaxial injectors
基金supported by Advanced Research Center Program(NRF-2013R1A5A1073861)through the National Research Foundation of Korea(NRF)grant funded by the Korea government(MSIP)contracted through Advanced Space Propulsion Research Center at Seoul National University
文摘The pintle injector used for a liquid rocket engine is a newly re-attracted injection system famous for its wide throttle ability with high efficiency. The pintle injector has many variations with complex inner structures due to its moving parts. In order to study the rotating flow near the injector tip, which was observed from the cold flow experiment using water and air, a numerical simulation was adopted and a verification of the numerical model was later conducted. For the verification process, three types of experimental data including velocity distributions of gas flows, spray angles and liquid distribution were all compared using simulated results. The numerical simulation was performed using a commercial simulation program with the Eulerian multiphase model and axisymmetric two dimensional grids. The maximum and minimum velocities of gas were within the acceptable range of agreement, however, the spray angles experienced up to 25% error when the momentum ratios were increased. The spray density distributions were quantitatively measured and had good agreement. As a result of this study, it was concluded that the simulation method was properly constructed to study specific flow characteristics of the pintle injector despite having the limitations of two dimensional and coarse grids.
文摘阐述了脉冲爆震火箭发动机的工作原理及其特点。设计并建立了整套脉冲爆震火箭发动机实验模型。以液体燃料航空煤油为燃料、氧气为氧化剂、压缩氮气为隔离气体,在内径为25 mm,长度为0.8 m的爆震管内产生了充分发展的爆震波。测量了不同工作频率下的爆震波压力,并对其进行了分析。实验结果表明,在设计的实验模型中,采用低的点火能量(50 m J)能够在较短的距离内产生充分发展的爆震波。
