To investigate the supersonic combustion patterns in scramjet engines, a model engine was tested T4 free-piston shock tunnel. The test had rectangular intake, which compressed freestream flow through series of four waves upstream combustor entrance. A cavity flame holder installed to improve ignition. condition fixed at Mach 7.6, an altitude 31 km. This experimental study investigated effects varying fuel equivalence ratios, influence holder, and cowl shape. As result, observed ratios...

The effects of flameholder configurations on combustion within a scramjet combustor are investigated through experiments, numerical simulation, andquasi-one-dimensional analysis. For the experimental test, blowdownwind tunnel with vitiated air heater is used. test model composed an isolator, fuel injectors, and diverging combustor. To investigate different configurations, three kinds exchangeable fuelinjection plates fabricated: no cavity, plain zigzag cavity. results indicate that cavity...

To develop technologies for the stable operation of electric propulsion systems, effects charge exchange (CEX) on exhaust plume a Hall thruster were studied using particle-in-cell direct simulation Monte Carlo (PIC-DSMC) method. For numerical analysis, an OpenFOAM-based code, pdFOAM, with simple electron fluid model was employed. In example problem D55 plume, results showed good agreement experimental measurements plasma potential. results, CEX enhanced Xe+ particle scattering near exit....

The Saffman–Taylor (S–T) instability mechanism in laminar premixed flames a Hele–Shaw cell is investigated using two-dimensional numerical simulations with an Arrhenius reaction model and Poiseuille assumption for the viscous effect. baseline calculations considering Darrieus–Landau (D–L) diffusive–thermal modes show results consistent classical linear theory. primary effect of variable transport properties found to be modification flame thickness, such that can properly normalized by actual...

From the view of environmental protection against use fossil fuels, a great number efforts have been exerted to find an alternative energy source. Hydrogen may become alternative. However, only product species hydrogen flame is H 2 O, which emits nonluminous radiation, so radiation from much smaller than that for hydrocarbon flame. The authors designed and fabricated laboratory-scale test furnace study thermal characteristics hydrogen-air diffusion In addition, effects addition reacting as...

Inlet unstart and buzz in scramjet engines must be prevented for the stable operation of engines. In present study, characteristics inlet start, phenomena a engine model are investigated using numerical analysis with RANS-based OpenFOAM solver. The results start case small computational domain that includes only inlet-isolator part good agreement existing experimental results. However, case, wide enough to consider interactions between upstream internal flow predict test model. show fairly...

This paper presents the results of performance test and numerical analysis a supersonic impulse turbine. The has been conducted using high pressure cold air. overall turbine nozzle behavior for various operating conditions have investigated. Experiment also to investigate nozzle-rotor clearance effect on performance. It found that degrades with increasing axial this phenomenon is mainly due increased stagnation loss in region.

Effects of flame holder configurations on the combustion within scramjet combustor are investigated by experiments and quasi-one-dimensional analysis. For test, a blowdown windtunnel with vitiated air heater is used. The test model composed an isolator, fuel injectors diverging combustor. In order to investigate effects configurations, three kinds injection plates, “No cavity”, “Plain Cavity” “zigzag cavity” made for exchange. As result, zigzag cavity showed highest value induced pressure...

The scramjet, one of the most promising candidates for future transport systems, has many advantages such as a simple configuration and high specific impulse. However, various characteristics scramjet engines in hypersonic environment are difficult to predict from theory. In present study, we investigated performance engine with types ground tests. An model (S1) was tested free-piston shock tunnel T4. showed active supersonic combustion good starting characteristics, but its operating range...

고성능 폐회로 액체로켓엔진 시스템에 적용되는 산화제 과잉 예연소기 내에서 발생하는 연소 압력 섭동 데이터에 대한 분석 결과를 수록하였다. 연소실험은 두 단계의 값을 순차적으로 형성하였는데 상대적으로 저압 조건에서만 78 Hz의 특성 주파수를 갖는 자발적인 섭동이 발생하였다. 이와 같은 불안정은 bulk mode에 해당하는 것으로 판단된다. 섭동의 세기는 rms 기준으로 연소실 정압 대비 13.3%에 해당하며, 설계압 구간(19.3 MPa)에서는 매우 안정적인 모습을 보였다. mode는 내부에서 압력파의 위상차가 없이 전체 공간에서 압력이 증가와 감소를 반복하는 Helmholtz 공진기와 비슷한 특성을 보이는 The paper includes the analytic results of pressure fluctuation data from combustion an oxidizer-rich preburner applicable to high-performance,...

Hall thrusters, a type of electric propulsion, are increasingly being used as propulsion systems for spacecraft. When evaluating the performance thruster through ground tests, it is essential to recognize influence higher background pressure inside vacuum chamber compared space conditions and correct values reflect those in actual environments. In this study, effects levels ranging from 3 60 μTorr on exhaust plume were analyzed using PIC-DSMC(Particle-in-Cell Direct Simulation Monte Carlo)...

The present study experimentally investigates dynamic characteristics of combustion occurring at highly excessive oxygen environments. Combustion experiments burning kerosene and liquid were conducted chamber pressures 5–20 MPa, their pressure fluctuations measured. systematic analysis data confirms that the is sound, with root-mean-square values below 3% pressures, except a single condition 8.9 which low-frequency bulk mode instability 78 Hz spontaneously occurred. application nonlinear...