Direct-Connect Test of Solid Scramjet with Symmetrical Structure

Abstract

The solid scramjet has become one of the most promising engine types. In this paper, we report the first direct-connect test of a solid scramjet with symmetrical structure, carried out using boron-based fuel-rich solid propellant as fuel. During the test, which simulated a flight environment at Mach 5.6 and 25 km, the performance of the solid scramjet was obtained by measuring the pressure, thrust, and mass flow. The results show that, due to the change in the combustion area of the propellant and the deposition of the throat in the gas generator during the test, the equivalence ratio gradually increased from 0.54 to 0.63. In a solid scramjet, it is possible to obtain a symmetrical distribution of the flow field within the combustor. Moreover, in a multi-cavity combustor, the combustion state expands from the cavity to the center of the flow channel. The performance of the solid scramjet increased during the test, reaching a combustion efficiency of about 42%, a total pressure recovery coefficient of 0.35, and a thrust gain specific impulse of about 418 s. The solid scramjet with symmetrical structure is feasible. The cavity configuration adopted in this paper can reduce the ignition delay time of fuel-rich gas and improve the combustion efficiency of gas-phase combustible components. The shock trains in the isolator are conducive to the recovery of the total pressure. The performance of the solid scramjet is limited by the low combustion efficiency of the particles.

Experimental Investigation of Solid Rocket Scramjet Based on Central Strut

“…Huang et al [24] investigated the influence of the cavity and its position on the performance; results show that the cavity can significantly improve combustion efficiency, and the effect of the cavity location on performance is related to particle distribution. Yang et al [25,26] proposed a modular solid scramjet combustor with a Symmetrical Structure and improved the mixing and combustion of the fuel-rich mixture by the narrow/lobe cavity.…”

High Calorific Values Boron Powder: Ignition and Combustion Mechanism, Surface Modification Strategies and Properties

“…Among these fuels, Li and Zr are prone to spontaneous combustion and explosion in air [ 9 ]; the combustion products of Be are highly toxic [ 10 ]; and the calorific value of Fe is low. Therefore, B [ 11 ], Al [ 12 , 13 , 14 ], and Mg [ 15 ] are commonly used as metal fuels in propellants. Additionally, B is superior in calorific value to Al and Mg, as it shows a gravimetric value that is 2.1 and 1.9 times greater and a volumetric value that is 3.2 and 1.6 times greater than that of Mg and Al, respectively [ 16 ].…”