Numerical and Experimental study on the Solid Fuel Scramjet Combustor with a cavity flame holder

Abstract

The specific thrust level and variation rule of solid fuel scramjet combustor were researched both by numerical and experimental methods. A methane-burning vitiated air heater was designed and made to simulate flight environment of Mach 6 at 25km altitude. Based on the two dimensional flow field structures, a new quasi-one dimensional numerical method was established. The typical unsteady matter of solid fuel scramjet combustion and flow was transformed into a steady calculation of every moment in this method. And it can be used to simulate the parametric changing process of combustor quickly. Self-ignition and fuel regression rate characteristics in current experiment were consistent with results from previous works. And the agreement between the numerical and experimental results was generally good too. The specific thrust can reach the level of (600 ~ 800) N/kg· s in the designed flight environment. It was found that the specific thrust decrease with the total pressure loss increase during the working process. NomenclatureA = area B = pre-exponential factor of solid fuel pyrolysis c p = specific heat at constant pressure c ps = specific heat of solid fuel d = diameter dA = unit area increments D e = hydraulic diameter f dF = unit friction dm = unit mass increments f dQ = unit heat increments f f = friction coefficient F = thrust h = convective heat transfer coefficient H = flight altitude h g = effective vaporization heat m = mass flow rate Ma = Mach number f Nu = Nusselt number Pr = Prantdtl number p = pressure q = effective combustion heat of solid fuel Q = The low calorific value of solid fuel 1 PhD student, School of Aerospace Engineering, 2 r = fuel regression rate L = perimeter t = combustor working time T f = fluid temperature near the wall T so = initial temperature of solid fuel v = velocity Greek  = dynamic coefficient of viscosity  = heat conductivity coefficient of fluid  = density  = combustion efficiency  = gradient Subscripts a = ground atmospheric environment ground = ground test condition e = at the exit of combustor f = fluid flight = flight environment parameters i = time coordinate point ideal = ideal condition j = axial coordinate point s = solid phase sp = specific w = wall 0 = total parameter

Experimental Investigation of Solid Rocket Scramjet Based on Central Strut

“…However, most of them were focused on the side wall injection form, which injects the fuel-rich primary gas into the combustor from the inner wall position and enhances the mixing by adjusting the injection angle or adopting different cavity structures. There are some problems in this injection form, such as the large total pressure loss, uneven combustion heat release, and easy ablation of the cavity [27][28][29]. Therefore, in this paper, a new scheme of solid rocket scramjet based on the central strut injection was proposed, and the ground experiment and numerical simulation with different equivalence ratios under the flight condition of Mach 6, 25 km were carried out.…”

Numerical Study on the Solid Fuel Rocket Scramjet Combustor with Cavity

“…However, compared with the liquid fuel scramjets, solid fuel scramjets have the same advantages as traditional solid fuel engines, such as simple structure, high energy density, good maneuverability, and long storage time, etc. Therefore, the solid fuel scramjet has gradually developed in the recent decades [13,[19][20][21][22][23][24][25][26][27][28][29][30][31]. Main achievements of the solid fuel scramjet are summarized below.…”

“…The results showed that the total pressure recovery and the combustion efficiency was 35% and 48%, respectively. Wang et al [24,25] conducted numerical and experimental studies on the specific thrust level and variation rule in the solid fuel scramjet combustor. The results pointed out that the specific thrust could reach about 600-800 N/kg•s in the preconcerted flight conditions, and the specific thrust decreased with the total pressure recovery increase during the operating process.…”