The combustion behavior of the aluminum particles near the burning surface of the aluminized composite propellant was studied. The combustion of the strand in the strand burner and the computational fluid dynamics (CFD) around the burning aluminum particle were performed. The temperature histories from combustion experiments and the temperature distributions from CFD were obtained. The temperature fluctuations of the burning aluminum particles in the temperature histories were observed. The aluminum particles ignite and burn near the burning surface. When the aluminum particles ignite much nearer the burning surface, the temperature gradient is increased in the reaction zone. The burning aluminum particle made a streamline shaped high temperature area around it. Therefore the burning aluminum particle could increase the temperature of the combustion gas widely, the temperature gradient near the burning surface was increased and the burning rate was increased.
The Gas Hollow Tungsten Arc (GHTA) welding experiments on aluminum pipe were carried out in a simulated space environment and a ground 1G vacuum environment. The square butt welding joints with non root gap on aluminum pipe were made by orbital welding with filler metal using DC-pulsed power supply in the vacuum chamber under the 10-2G and 1G gravity conditions. The butt welding phenomenon during the aluminum DC-pulsed GHTA welding with filler metal recorded in the high-speed video image were analyzed and also the macrostructure and mechanical properties of the butt weld joints were investigated. As the result, it was clarified that the arc discharge and melting-solidifying process during DC-pulsed GHTA welding were insensitive to the gravity condition, because the welding phenomenon greatly receives the effect of the impulsive arc pressure in pulsed current. And also, the GHTA welding experiments under simulated space environment proved that the DC-pulsed GHTA welding process with filler metal could produce the defect-free aluminum butt welding joints with the enough strength safely.
The background oriented schlieren (BOS) technique is one of the visualization techniques that enable the quantitative measurement of density information in the flow field with very simple experimental setup. The principle of BOS technique is similar to the conventional schlieren technique which exploit the vending of light rays passing through the density gradient. BOS utilize the background and measure the displacement of the background image quantitatively by image analysis. In this report we propose the stripe-patterned background oriented schlieren (SPBOS) technique using striped background pattern. A measurement of supersonic flow field around an asymmetric body is tested at a JAXA-ISAS supersonic wind tunnel to realize the three-dimensional and quantitative density measurement.
This paper addresses the design problem of flight controllers for suppressing aircraft motions due to turbulences, i.e. design problem of Gust Alleviation (GA) flight controllers. As LIght Detection And Ranging (LIDAR) system which can detect even Clear Air Turbulences (CAT) has recently been developed, flight controllers which exploit the prior turbulence data that are obtained using LIDAR system have been desired. In this note, we extend our previously proposed method to the even realistic situations in which there exist plant uncertainties and the measurement errors in current state variables for aircraft motions as well as in the prior turbulence data. We successfully propose a design method of GA flight controllers for our problem using Model Predictive Control (MPC). Numerical simulation results which demonstrate the applicability of our proposed method for GA feasibility study are included.