Scramjet engines are used at extreme temperatures and velocity. New control problems involving distributed parameter control have been found concerning investigations of the control of scramjet engines whose physical ...Scramjet engines are used at extreme temperatures and velocity. New control problems involving distributed parameter control have been found concerning investigations of the control of scramjet engines whose physical states are spatially interacted. Succeeding the existing theoretical studies on the distributed parameter control for scramjet engines, this paper puts forward a simplified distributed parameter control approach for scramjet engines aimed at engineering application. The simplified control procedure uses the classical proportional-integral（PI） compensation to control the target pressure distribution of scramjet engines, which is effective and applicable for practical implements. Simulation results show the validation of the simplified distributed parameter control procedure.展开更多
Both the fuel transfer control scheme and the knowledge of fuel temperature and pressure values before injection are important to a scramjet engine.A measurement method of the fluid temperature suitable for small chan...Both the fuel transfer control scheme and the knowledge of fuel temperature and pressure values before injection are important to a scramjet engine.A measurement method of the fluid temperature suitable for small channel is presented,and a fluid transfer control scheme of the area of injecting holes is designed using the balance equations of fluid mass,energy and entropy.A convective heat transfer experiment is conducted to evaluate the temperature measurement and the fluid transfer control design method of the heat absorbing supercritical hydrocarbon fuel.The results show that during the heating process the injecting pressure meets the requirement,and the fluid transfer control system works well.Such results suggest that the design method in the present work would be useful in the design of regenerative cooling for scramjet engines.展开更多
Chemical non-equilibrium flow was investigated for the scramjet single expansion ramp nozzle(SERN)with a strut-based liquid-kerosene-fueled combustor.Two-dimensional Reynolds-averaged NavierStokes(RANS)equations were ...Chemical non-equilibrium flow was investigated for the scramjet single expansion ramp nozzle(SERN)with a strut-based liquid-kerosene-fueled combustor.Two-dimensional Reynolds-averaged NavierStokes(RANS)equations were solved with the species conservation equation for continuous phase and the renormalization group(RNG)k-εturbulence model.Lagrangian discrete-phase model was analyzed for liquidkerosene droplets behavior in the supersonic stream.Combustion was simulated by kerosene surrogate fuel's10-species and 13-step reduced reaction kinetics mechanism with use of Arrhenius's laminar finite rate model.Parametric studies were carried out to estimate the influence of different fuel injection positions and equivalent mixture ratios on the SERN chemical non-equilibrium effects.Numerical calculation results show that the strutbased combustor enables convenient modeling of various SERN entry conditions,which is similar with many preceding investigations,by changing the injector strut position and controlling the mass flow rate of each injector.Chemical non-equilibrium effects function in the whole SERN,especially in the initial flow expansion region,leads to obviously higher SERN performance of the non-equilibrium flow than that of the frozen flow.Furthermore,the distributed fuel injection pattern plays a significant role in enhancing the combustion efficiency in combustor,but weakening the chemical non-equilibrium effects funciton in SERN.Additionally,while the equivalent mixture ratio increases,the SERN thrust coefficient and lift coefficient rise gradually,and the increment of non-equilibrium flow in relation to frozen flow becomes higher as well.To be specific,the equivalent mixture ratio is 0.6,the maximum increment of thrust coefficient and lift coefficient are 11.6% and 25% respectively.展开更多
文摘Scramjet engines are used at extreme temperatures and velocity. New control problems involving distributed parameter control have been found concerning investigations of the control of scramjet engines whose physical states are spatially interacted. Succeeding the existing theoretical studies on the distributed parameter control for scramjet engines, this paper puts forward a simplified distributed parameter control approach for scramjet engines aimed at engineering application. The simplified control procedure uses the classical proportional-integral（PI） compensation to control the target pressure distribution of scramjet engines, which is effective and applicable for practical implements. Simulation results show the validation of the simplified distributed parameter control procedure.
基金National Natural Science Foundation of China(No.51976233)National Science and Technology Major Project(No.2017-III-0005-0030).
文摘Both the fuel transfer control scheme and the knowledge of fuel temperature and pressure values before injection are important to a scramjet engine.A measurement method of the fluid temperature suitable for small channel is presented,and a fluid transfer control scheme of the area of injecting holes is designed using the balance equations of fluid mass,energy and entropy.A convective heat transfer experiment is conducted to evaluate the temperature measurement and the fluid transfer control design method of the heat absorbing supercritical hydrocarbon fuel.The results show that during the heating process the injecting pressure meets the requirement,and the fluid transfer control system works well.Such results suggest that the design method in the present work would be useful in the design of regenerative cooling for scramjet engines.
文摘Chemical non-equilibrium flow was investigated for the scramjet single expansion ramp nozzle(SERN)with a strut-based liquid-kerosene-fueled combustor.Two-dimensional Reynolds-averaged NavierStokes(RANS)equations were solved with the species conservation equation for continuous phase and the renormalization group(RNG)k-εturbulence model.Lagrangian discrete-phase model was analyzed for liquidkerosene droplets behavior in the supersonic stream.Combustion was simulated by kerosene surrogate fuel's10-species and 13-step reduced reaction kinetics mechanism with use of Arrhenius's laminar finite rate model.Parametric studies were carried out to estimate the influence of different fuel injection positions and equivalent mixture ratios on the SERN chemical non-equilibrium effects.Numerical calculation results show that the strutbased combustor enables convenient modeling of various SERN entry conditions,which is similar with many preceding investigations,by changing the injector strut position and controlling the mass flow rate of each injector.Chemical non-equilibrium effects function in the whole SERN,especially in the initial flow expansion region,leads to obviously higher SERN performance of the non-equilibrium flow than that of the frozen flow.Furthermore,the distributed fuel injection pattern plays a significant role in enhancing the combustion efficiency in combustor,but weakening the chemical non-equilibrium effects funciton in SERN.Additionally,while the equivalent mixture ratio increases,the SERN thrust coefficient and lift coefficient rise gradually,and the increment of non-equilibrium flow in relation to frozen flow becomes higher as well.To be specific,the equivalent mixture ratio is 0.6,the maximum increment of thrust coefficient and lift coefficient are 11.6% and 25% respectively.
