A new pressurized feed system of the dual-thrust hybrid rocket motor for flight is presented in this paper.The feed system supplies 90% hydrogen peroxide (90%H 2 O 2) with two different flows of 4.5 and 2 kg s 1.The o...A new pressurized feed system of the dual-thrust hybrid rocket motor for flight is presented in this paper.The feed system supplies 90% hydrogen peroxide (90%H 2 O 2) with two different flows of 4.5 and 2 kg s 1.The oxidizer flow is changed through regulating the mass flow of the high-pressure gas and switching the performance modes of the unique oxidizer flow control valve simultaneously.The models of the gas storage container,pressure regulator valve,control orifice,propellant tank,oxidizer flow control valve and cavitating venturi are generated and used to compute the instantaneous pressure,temperature and mass flow rate.There is a good agreement between the simulated and experimental results.Parameter sensitivity analysis is also conducted.It is found that the throat diameter of the cavitating venturi in feed line 1 is the main factor affecting the mass flow in both boost and sustaining phase.Other parameters have limited effects on the mass flow rate and the transition time of the system.展开更多
A weld joint is composed of three principal zones viz., base metal, Heat Affected Zone (HAZ), and weld zone. Thus, the variation in mechanical behavior exists not only among these zones, but also from point to point i...A weld joint is composed of three principal zones viz., base metal, Heat Affected Zone (HAZ), and weld zone. Thus, the variation in mechanical behavior exists not only among these zones, but also from point to point in each individual zone. Being destructive in nature, the conventional method of mechanical testing cannot successfully used to estimate the variation in the mechanical behavior at different zones of the weld joint. Moreover, the conventional method of mechanical testing cannot characterize the material using small amount of material. In this respect, Ball Indentation (BI) methodology was considered to be useful approach, since it can characterize the mechanical properties of a material using very small amount of material in non destructive manner. The present work is an attempt to characterize the variation in the mechanical properties among each zone (global variation), and from point to point in each zone (local variation) of the similar weld joint used in nuclear application using BI approach. For this purpose, the similar weld joint of two SS-304 LN pipe lines was investigated using BI approach.展开更多
Capillary columns are used in both capillary liquid chromatography and capillary electrochromatography. The design for capillary liquid chromatography is discussed in comparison with capillary gas chromatography. The ...Capillary columns are used in both capillary liquid chromatography and capillary electrochromatography. The design for capillary liquid chromatography is discussed in comparison with capillary gas chromatography. The difference of diffusion coefficient in gas and liquid phase is a key role. The study for obtaining a high performance capillary liquid chromatography is discussed. Capillary electrochromatography is recently interesting for its instinct ability to realize a high performance chromatography. Capillary electrochromatography with and without pressurized flow is reviewed briefly. Instrumentation for capillary electrochromatography with pressurized flow is discussed. The port of splitting, and gradient elution of both solution and potential are described. The new findings of both the variation of column resistance and capacity factor according to the value of applied electric voltage are also discussed.展开更多
文摘A new pressurized feed system of the dual-thrust hybrid rocket motor for flight is presented in this paper.The feed system supplies 90% hydrogen peroxide (90%H 2 O 2) with two different flows of 4.5 and 2 kg s 1.The oxidizer flow is changed through regulating the mass flow of the high-pressure gas and switching the performance modes of the unique oxidizer flow control valve simultaneously.The models of the gas storage container,pressure regulator valve,control orifice,propellant tank,oxidizer flow control valve and cavitating venturi are generated and used to compute the instantaneous pressure,temperature and mass flow rate.There is a good agreement between the simulated and experimental results.Parameter sensitivity analysis is also conducted.It is found that the throat diameter of the cavitating venturi in feed line 1 is the main factor affecting the mass flow in both boost and sustaining phase.Other parameters have limited effects on the mass flow rate and the transition time of the system.
文摘A weld joint is composed of three principal zones viz., base metal, Heat Affected Zone (HAZ), and weld zone. Thus, the variation in mechanical behavior exists not only among these zones, but also from point to point in each individual zone. Being destructive in nature, the conventional method of mechanical testing cannot successfully used to estimate the variation in the mechanical behavior at different zones of the weld joint. Moreover, the conventional method of mechanical testing cannot characterize the material using small amount of material. In this respect, Ball Indentation (BI) methodology was considered to be useful approach, since it can characterize the mechanical properties of a material using very small amount of material in non destructive manner. The present work is an attempt to characterize the variation in the mechanical properties among each zone (global variation), and from point to point in each zone (local variation) of the similar weld joint used in nuclear application using BI approach. For this purpose, the similar weld joint of two SS-304 LN pipe lines was investigated using BI approach.
文摘Capillary columns are used in both capillary liquid chromatography and capillary electrochromatography. The design for capillary liquid chromatography is discussed in comparison with capillary gas chromatography. The difference of diffusion coefficient in gas and liquid phase is a key role. The study for obtaining a high performance capillary liquid chromatography is discussed. Capillary electrochromatography is recently interesting for its instinct ability to realize a high performance chromatography. Capillary electrochromatography with and without pressurized flow is reviewed briefly. Instrumentation for capillary electrochromatography with pressurized flow is discussed. The port of splitting, and gradient elution of both solution and potential are described. The new findings of both the variation of column resistance and capacity factor according to the value of applied electric voltage are also discussed.
