Flow visualization and experimental optimization of three inlet-side-dump liquid-fuel ramjet combustors

Abstract

Three distinct inlet-side-dump ramjet-combustor geometric configurations were investigated. Non-intrusive watertunnel flow-visualization techniques were utilized to qualitatively determine optimum flame-stabilization dome lengths and fuel-injection locations. The results were in good agreement with the results from previous studies. The optimum dome lengths which provided good fuel distribution and steady mixing all had lengths between 0.31 D and 1.4 D. Fuel injection in a narrow region on the upstream side of the inlet cross section was the only location capable of distributing fuel into the flame- holding region. Multiple injection locations in the inlet were required to distribute fuel uniformly into the main combustion region. The dual, axially-in- line side-dump configuration demonstrated the best potential for increasing performance across a wide range of operating conditions due to the ancillary combustion region between the inlets and the ability to control the size and strength of the region by varying air mass flow through the two inlet dumps.