This paper focuses on the investigation of an aft mixing chamber diaphragm in a hybrid rocket motor. Both numerical and ex- perimental researches are carried out to study its effects on the motor performances. The hyb...This paper focuses on the investigation of an aft mixing chamber diaphragm in a hybrid rocket motor. Both numerical and ex- perimental researches are carried out to study its effects on the motor performances. The hybrid rocket motor with star fuel grain is utilized. The 90% hydrogen peroxide （HP） oxidizer and hydroxyl terminated polybutadiene （HTPB） based fuel are adopted as propellants. The diaphragm configuration settled in the aft mixing chamber includes four circular-holes with a uni- form circumferential distribution. For both motors with and without the diaphragm, three-dimensional numerical simulations with gaseous combustions considered are carried out to study the flow field characteristics and motor performances. The com- parison results show that the diaphragm can improve the mixing of the oxidizer and fuel. It has evident effect on increasing the motor efflciencies. Two firing experiments are conducted with full scale motors to investigate the effects of the diaphragm. The diaphragm used in the test is composed of a central steel framework and a closed thermal insulation layer. With the dia- phragm employed, the combustion efficiency increases from 93.9% to 97.34% and the specific impulse efficiency increases from 80.77% to 87.28%, which verifies the positive effect of the diaphragm. Both numerical and experimental studies indicate that the scheme of the aft mixing chamber diaphragm proposed in the paper can improve the efficiencies of the hybrid rocket motor obviously.展开更多
The ASIC is widely used in the field of high energy physics. Astroparticle experiments benefit from high integration, smallsize and low power consumption. In this paper an analog chip named ARCHGARD (Analog Readout Ch...The ASIC is widely used in the field of high energy physics. Astroparticle experiments benefit from high integration, smallsize and low power consumption. In this paper an analog chip named ARCHGARD (Analog Readout Chip for High energyGamma Ray Detector) for high energy physics experiment is introduced. ARCHGARD is a readout chip, in chartered 0.35 mSiGe technology, for photomultipliers (PMT) array readout. The chip is designed for the Large High Altitude Air Shower Ob-servatory (LHAASO) project. The ASIC integrates 16 independent and auto-triggered channels with variable gain and variableshaping time. It provides analog output for charge measurement, which is performed from 1 up to 3000 photo-electrons (p.e.).The integral nonlinearity of the whole input range is less than 1% and the equivalent input noise is less than 1/10 p.e. Eachchannel has a trigger output for time measurement.展开更多
The present paper focuses on the analysis of a synthetic jet device (with a zero net massflow rate) on a separated boundary layer. Separation has been obtained on a flat plate installed within a converging-diverging t...The present paper focuses on the analysis of a synthetic jet device (with a zero net massflow rate) on a separated boundary layer. Separation has been obtained on a flat plate installed within a converging-diverging test section specifically designed to attain a local velocity distribution typical of a high-lift LPT blade. Both experimental and numerical investigations have been carried out. Unsteady RANS results have been compared with experiments in terms of time-averaged velocity and turbulence intensity distributions. Two different Reynolds number cases have been investigated, namely Re = 200,000 and Re = 70,000, which characterize low-pressure turbine operating conditions during take-off/landing and cruise. A range of synthetic jet aerodynamic parameters (Strouhal number and blowing ratio) has been tested in order to analyze the features of control-separated boundary layer interaction for the aforementioned Reynolds numbers.展开更多
文摘This paper focuses on the investigation of an aft mixing chamber diaphragm in a hybrid rocket motor. Both numerical and ex- perimental researches are carried out to study its effects on the motor performances. The hybrid rocket motor with star fuel grain is utilized. The 90% hydrogen peroxide （HP） oxidizer and hydroxyl terminated polybutadiene （HTPB） based fuel are adopted as propellants. The diaphragm configuration settled in the aft mixing chamber includes four circular-holes with a uni- form circumferential distribution. For both motors with and without the diaphragm, three-dimensional numerical simulations with gaseous combustions considered are carried out to study the flow field characteristics and motor performances. The com- parison results show that the diaphragm can improve the mixing of the oxidizer and fuel. It has evident effect on increasing the motor efflciencies. Two firing experiments are conducted with full scale motors to investigate the effects of the diaphragm. The diaphragm used in the test is composed of a central steel framework and a closed thermal insulation layer. With the dia- phragm employed, the combustion efficiency increases from 93.9% to 97.34% and the specific impulse efficiency increases from 80.77% to 87.28%, which verifies the positive effect of the diaphragm. Both numerical and experimental studies indicate that the scheme of the aft mixing chamber diaphragm proposed in the paper can improve the efficiencies of the hybrid rocket motor obviously.
基金supported by the Large High Altitude Air Shower Observatory (LHAASO) Project
文摘The ASIC is widely used in the field of high energy physics. Astroparticle experiments benefit from high integration, smallsize and low power consumption. In this paper an analog chip named ARCHGARD (Analog Readout Chip for High energyGamma Ray Detector) for high energy physics experiment is introduced. ARCHGARD is a readout chip, in chartered 0.35 mSiGe technology, for photomultipliers (PMT) array readout. The chip is designed for the Large High Altitude Air Shower Ob-servatory (LHAASO) project. The ASIC integrates 16 independent and auto-triggered channels with variable gain and variableshaping time. It provides analog output for charge measurement, which is performed from 1 up to 3000 photo-electrons (p.e.).The integral nonlinearity of the whole input range is less than 1% and the equivalent input noise is less than 1/10 p.e. Eachchannel has a trigger output for time measurement.
基金The support of the Italian Ministry of the University and Scientific Research(MIUR)under the PRIN project number 2007R3AXLH is greatly acknowledged
文摘The present paper focuses on the analysis of a synthetic jet device (with a zero net massflow rate) on a separated boundary layer. Separation has been obtained on a flat plate installed within a converging-diverging test section specifically designed to attain a local velocity distribution typical of a high-lift LPT blade. Both experimental and numerical investigations have been carried out. Unsteady RANS results have been compared with experiments in terms of time-averaged velocity and turbulence intensity distributions. Two different Reynolds number cases have been investigated, namely Re = 200,000 and Re = 70,000, which characterize low-pressure turbine operating conditions during take-off/landing and cruise. A range of synthetic jet aerodynamic parameters (Strouhal number and blowing ratio) has been tested in order to analyze the features of control-separated boundary layer interaction for the aforementioned Reynolds numbers.
