Daisaku Masaki

Firing Test of a Hypersonic Turbojet Engine Installed on a Flight Test Vehicle

Hypersonic turbojet engine with pre-cooling system is tested under sea level static condition. The engine is installed on a flight test vehicle, which will fly at Mach 2 speed by a free fall experiment from a stratospheric balloon. Liquid hydrogen fuel and gas hydrogen fuel is supplied to the engine from a tank and cylinders installed in the vehicle. Designated operation of major components of the engine is confirmed. Corrected rotation speed, corrected air flow rate and pressure ratio of the compressor is raised by pre-cooling with liquid hydrogen fuel. Corrected air flow rate and pressure ratio at the pre-cooling operation is reduced comparing from that without pre-cooling on the same corrected rotation speed. There is a deep temperature distortion at the inlet of the compressor and it may cause the performance reduction. Large amount of liquid hydrogen is supplied to the pre-cooler in order to obtain enough pre-cooling performance for Mach 5 flight. Then, fuel rich combustion at the after-burner is adopted. Cowl part of variable geometry nozzle is made with C/C composite material and it has no damage after the combustion test. Operation of the core engine by liquid hydrogen is attained by using a control valve with small effective diameter.

Performance Evaluation of Hypersonic Pre-Cooled Turbojet Engine

Pre-cooled turbojet engine is investigated to realize Mach 5 class hypersonic transport aircraft. The engine has been demonstrated under sea level static and Mach 2 flight conditions using hydrogen as fuel. In this study, Mach 4 propulsion wind tunnel test is performed and the performance of air intake, pre-cooler, core engine and exhaust nozzle are obtained. Liquid nitrogen is supplied to the pre-cooler as a coolant in place of liquid hydrogen. Gaseous hydrogen is supplied to the main burner to drive the turbine with the combustion gas. A protective screen is placed in front of the pre-cooler to prevent damages of it from high-speed particles. Bypass door is placed in front of the core engine to start the mixed compression air intake at low speed operation of the core engine. As a result, the engine performance data is obtained without any damage of pre-cooler. Air intake is started by the effect of bypass door at low speed operation of the core engine.

Mach 4 Wind Tunnel Experiment of Hypersonic Pre-Cooled Turbojet Engine

Pre-cooled turbojet engine is investigated to realize Mach 5 class hypersonic transport aircraft. The engine has been demonstrated under sea level static and Mach 2 flight conditions using hydrogen as fuel. Presently, Mach 5 propulsion wind tunnel test using liquid hydrogen is planned and the engine components such as pre-cooler, core engine, afterburner and exhaust nozzle are under development. The engine components were tested under Mach 4 simulating condition by connecting the pre-cooler inlet to an air supply facility. The engine was tested in a propulsion wind tunnel with Mach 4 flight condition. Liquid nitrogen was supplied to the pre-cooler as a coolant in place of liquid hydrogen. Gaseous hydrogen was supplied to the main burner to drive the turbine with the combustion gas. As a result, high temperature structure and cooling system was proved to endure Mach 4 high temperature airstream. Wind-mill starting sequence of the core engine under Mach 4 flight condition was confirmed. Gross thrust of the core engine was obtained as an initial evaluation of elemental performance.

Preliminary Design Investigation of Electromagnetic Motors for Turbofan-Drive Assist

This paper describes the procedure and status of the preliminary design investigation of a motor-assisted turbofan propulsion system used for scheduled testing. The applied motor configuration was described earlier for use of turbo/hybrid electric propulsion device. Review of earlier research emphasized the potential of the motor configuration for motor motion assistance of a conventional and/or near future turbofan propulsor. Earlier studies showed the motor configuration’s potential for motor motion assistance of a conventional turbofan propulsor or one developed in the near future. The experiment plan uses a miniaturized turbofan engine model developed at JAXA to assess multi-variable model-based optimization control with an actual turbofan engine. The modification and preliminary design procedure and analytical results are then shown in order. In the context of numerical analysis, the present design motor is expected to be applicable as an independently powered assist measure for turbofan engine control. Finally, some perspectives are given of the potential of this motor configuration for use in multi-dimensional applications.