The present paper describes the potential application of ceramic matrix composites to aero-engine components by reviewing the related published papers and our experience in this field. It contains the material requirements for aero-engines, trends in aero-engine materials use, Japanese projects related to ceramic matrix composites (CMCs) and potential application of CMCs to aero-engines, such as combustors, nozzle flaps, bladed disks and others. From the point of application to aero-engines, the remaining research and development issues are discussed to some extent. Material developments, particularly of the interface and fibers for high temperature, are still required and stressed.

Potential application of ceramic matrix composites to aero-engine components

Unstart/restart hysteresis characteristics analysis of an over–under TBCC inlet caused by backpressure and splitter

Combined cycle engine research in japanese hypr program

Hypersonic wavecatcher intakes and variable-geometry turbine based combined cycle engines

Wind-tunnel tests are conducted to study the characteristics of the shock train in the curved variable-section diffuser for hypersonic inlets. The test model is equipped with a forebody, a contracting entrance, a dump mixing duct, and an aft plug. Tests are performed at nominal freestream Mach numbers of 4.0, 5.0, and 6.0, and the corresponding inlet Mach numbers of the diffuser are 2.05, 2.59, and 3.06, respectively. Results indicate that at an inlet Mach number of 2.05, the surface pressure distributions in the shock train are similar at different backpressure ratios and can be well predicted by the modified Waltrup formula, but the length of the shock train is increased by 32 % due to the curved duct, the incident shock waves, and the incident expansion waves at the inlet plane. At higher inlet Mach numbers, the similarity disappears and the distributions of the surface pressure are not easy to predict. At different measurement points in the shock train, the instantaneous surface pressures vary obviously and almost synchronously, suggesting the oscillatory motions of the shock train. At an inlet Mach number of 2.59, the base frequency of the oscillations is about 19 Hz and the maximum fluctuating range of the instantaneous surface pressure is as high as 21.6% of the ideal pressure rise of the shock train. The static pressure fluctuations at different points in the shock train correlate strongly but are almost unrelated with those of the exit survey point, which indicates that the oscillation of the shock train is not likely induced by the pressure fluctuations far downstream of the shock train.

Preliminary Study of Shock Train in a Curved Variable-Section Diffuser

Control of the intake shock-position in the test rig for ramjet engine

HYPR90-T Turbo Engine Research for HST Combined Cycle Engine

The sub-scale model engine of the ramjet for the hypersonic transport was designed and tested in a freejet air stream of Mach 5 in the Ramjet Engine Test Facility of the National Aerospace Laboratory, Kakuda Research Center. In the latest test, newly designed low external drag model engine was tested and inlet terminal shock control technique was demonstrated. The terminal shock position in the supersonic inlet was detected and controlled with the fuel flow rate. In the fuel zoning test, the increase of the fluctuation of the shock position and pressure in the inlet and the decrease in the margin to unstart were observed. Sensing the fluctuation of shock position or pressure in the inlet is recommended to avoid unstart. The measured net thrust of the model engine decreased by 45% when the bleed air increased from 1% to 12 %. The difference between the experimental net thrust and the calculated net thrust is 7 % of the calculated net thrust. Nomenclature Dext Engine external drag Da Inlet additive drag by spillage dA boundary area of inlet spillage Ft Measured thrust Fn Net thrust Pa Average pressure at inlet spillage boundary Introduction The propulsion system for the hypersonic transport of MachS class has been researched and developed in the HYPR project. Combined cycle engine of the tandem type which integrates a low-bypass turbofan of variable bypass ratio and a ramjet was chosen by the evaluation. Figure 1 is one of the candidate sketches investigated in this research. This engine system is installed under the airframe or the wing. The ramjet is used to accelerate from Mach 2.5 to 5 and to cruise at Mach 5. 2-D Intake VCE Turbofan \

Experimental approach to the HYPR Mach 5 ramjet propulsion system

The combined engines of air-breathing engine and rocket engine are promising as engines for single stage spaceplanes. High thrust to weight ratio at acceleration phase and high specific impulse at landing phase is required for the engines. The authors examine the engine concept that combines the pre-cooled turbojet engine with supersonic combustion ramjet engine and rocket engine. The precooled turbojet engine can achieve both high thrust to weight ratio and high specific impulse by controlling the equivalence ratio. In this study, the change of thrust to weight ratio and specific impulse is calculated with parameter of the equivalence ratio on the pre-cooled turbojet engine. The weight that can be left for the following flight is estimated with an assumed flight condition. The test that combined the pre-cooling heat exchanger with the turbojet engine was carried out on the fuel lean combustion mode for landing phase.

Ryoji Yanagi

Papers

Combined cycle engine research in japanese hypr program

Control of the intake shock-position in the test rig for ramjet engine

HYPR90-T Turbo Engine Research for HST Combined Cycle Engine

Experimental approach to the HYPR Mach 5 ramjet propulsion system

A study on pre-cooled turbojet-scramjet-rocket combined engines