Investigation of Ethylene Fuel Combustion in a Dual-Mode Combustor

Abstract

Experiments and a quasi-one-dimensional equilibrium calculation were conduced to estimate performances of a dual-mode combustor with ethylene fuel injection in a directconnect wind-tunnel facility in JAXA Kakuda Space Center (JAXA-KSPC). In the facility, a gaseous H 2 fueled lean combustion heater was used to make high enthalpy flow. The high enthalpy flow was then accelerated with a Mach 2.5 supersonic nozzle. The experiments were executed with a rectangular dual-mode combustor with constant area section and following diverging section at various fuel equivalence ratios. Fuel injectors upstream of cavity flameholders were installed in the constant area section and the diverging section on opposite walls. Heat flux distributions in the streamwise were measured using heat flux transducers mounted flush with the combustor inner wall. The compositions of gas at the exit cross-section of the combustor were sampled using a water-cooled reaction-quench sampling probe. The compositions of sample gas were eccentrically located on the fuel injection side under both of scramjet and dual-mode operation. Therefore, there is a need to consideration of the non-uniformity to estimate state quantities like combustion efficiency and heat flux by quasi-one-dimensional calculation. Heat flux distributions calculated using the "two-flow tubes model" indicated good agreement to measured heat flux. The combustion efficiency defined as the fraction of the oxygen rate that reacted over the total oxygen flow rate was closer to the experimental value than that defined as the fraction of the reacted fuel rate. NomenclatureA = cross-sectional area H = lower heating value M = Mach number P = pressure T = Temperature Y i = mass fraction of chemical species i x = streamwise location from onset of duct divergence y = spanwise location from center of the duct z = height from center of the duct η c = local combustion efficiency Φ = bulk fuel-equivalence ratio = local fuel-equivalence ratio * Graduate Student, Department of Aerospace Engineering. Student Member AIAA. † Graduate Student, Department of Aerospace Engineering.

Development of the fuel heating device for the component test of aerospace propulsion systems

“…Most of these tests used the hydrogen or ethylene in room temperature as the propellant (Nojima, et al, 2014a(Nojima, et al, , 2014b. However, the propellant in actual system would be liquid HC namely ethanol (Yoshida, et al, 2009).…”