Hypervelocity Scramjet Mixing Enhancement

摘要

Exploration and utilization of space, both near Earth and within the solar system, and eventually, interstellar, is a continuing national interest. A major key to the effective utilization and exploration of space is an efficient, convenient, and cost-effective launch system into low Earth orbit. While major strides are being made in payload miniaturization, launcher performance/cost will remain a critical issue. One set of options for more effective launchers involves air-breathing propulsion, perhaps operating over portions of the ascent in a 'combined cycle' mode. A particularly critical component of hypersonic air-breathing propulsion systems is the combustor, which is, historically, heavy due to requisite size/length and high aerodynamic and thermal loading and responsible for major portions of the total engine losses. One of the prime determinants of combustor efficiency is the distance required to 'mix and burn,' and therefore, effective mixing enhancement (including adequate fuel penetration) can provide a significant contribution to the viability of airbreathing hypersonic propulsion. The penetration and mixing enhancement problem for hypersonic air breathers must obviously be worked within the context of overall engine efficiency and thrust production. There are a multitude of extant mixing enhancement techniques, the problem is obtaining a resultant net performance enhancement when the additional losses associated with the mixing enhancement approach are accounted for.