Experimental investigation of a supersonic combustion solid fuel ramjet

An experimental parametric investigation of a solid-fuel supersonic combustion chamber in a scramjet configuration was conducted. A hydrogen-burning vitiated air heater was designed and built to simulate night conditions of Mach 5.5 in high and medium altitudes in a static test facility (stagnation temperatures and pressures of up to 1500 Ei and 50 atm, respectively), Flow and combustion phenomena were studied by pressure measurements along the fuel grain and by analyzing video images, digitized from the video recording of each test. Self-ignition and flameholding characteristics were consistent with results from previous works. Flow and combustion characteristics changed as inlet conditions extended, exhibiting initially choked or unchoked flow patterns. In the parametric investigation, incoming airflow conditions (total pressure, total temperature, and mass flow rate) defined the parametric space, yielding a regression rate power law of these parameters. Combustion efficiency was found to decrease with the increase of each of the inlet parameters. Increasing the diversion semiangle of the diverging section of the solid grain resulted in lower regression rate values.