Numerical Analysis of Solid Fuel Scramjet Operating at Mach 4 to 6

Abstract

Numerical simulations were performed to analyze the performance of solid fuel scramjet (SFSCRJ) operating at Mach 4 to 6, with the primary goal being to investigate the feasibility of low takeover speed for SFSCRJ. The numerical model was created based on previous experiments with a constant area isolator added before combustor. Airflow is changed to subsonic in isolator and return to supersonic in the diverging section at the Mach 4 condition. The flow was not thermally choked at higher Mach condition, with a series of compression and expansion waves generating in the flameholding zone. The effect of flight Mach number is discussed from a viewpoint of total pressure recovery and combustion efficiency. The results show the feasibility of SFSCRJ operating at low flight Mach. To investigate the effect of inflow condition on combustor performance, different contraction ratios in the inlet are assumed at flight Mach 5 condition, resulting in different pressures at the entrance of isolator for numerical simulations. It is found that the performance of combustor is enhanced with the increase of inflow static pressure. There exists a tradeoff between the improved performance of combustor and the increased total pressure loss in the inlet. Nomenclature P = pressure T = temperature Y = mass fraction u = velocity H = isolator radius  = density M = Mach number f = friction force m  = mass flow rate F i = impulse function at the entrance of the isolator F e = impulse function at the exit of the isolator  = combustion efficiency

A Preliminary Research on Combustion Characteristics of a Novel-Type Scramjet Combustor

“…So far, there are three types of the typical structures of scramjet combustor, i.e., the cavity- [2,3,[6][7][8][9][10][11][12][13][14][15], strut- [5,16], and backward-facing step-based combustor [4,[17][18][19][20]. The strut-based combustor was first proposed by Waidmann et al [21]; they used hydrogen as the fuel to investigate the combustion characteristic of a typical strut-based scramjet combustor (DLR (German Aerospace Center) scramjet) via experimental approach; in this investigation, the flow features were clearly captured, and the chamber pressure was found to be enhanced with increasing of hydrogen mass flow rate.…”

Numerical Study on the Solid Fuel Rocket Scramjet Combustor with Cavity

“…More and more research is being conducted in the scramjet field due to the important scientific significance and application value [1][2][3][4][5][6][7]. At the same time, because of the complex measurement system and costly experimental apparatus, computational fluid dynamics (CFD) on the scramjet has attracted the attention and appreciation of scientists [8][9][10][11][12][13][14].…”

“…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.…”