Surface Microwave Discharge as Means of Ignition of Hydrocarbons in Air Streams

Abstract

Influence of non -equilibrium plasma of a surface microwave discharge on processes of ignition of a supersonic propane -air stream with Mach n umber �=2 is considered. Alcohol , gasoline and kerosene ignition under conditions of subsonic and supersonic air stream s is investigated too . Advances in aviation technology call for research and development aimed at creating new efficient means for reducing th e ignition time and controlling the combustion of supersonic fuel flow. A new solution to these problems is application of gas discharge. In the paper a surface microwave discharge was used for ignition of a supersonic propane -air stream and for ignition o f liquid hydrocarbon films under conditions of a subsonic and a supersonic air stream. For investigation of the possibility of the ignition of high -speed hydrocarbon flows using a surface microwave discharge an experimental design, which including a vacuu m chamber, a high pressure air receiver, a high pressure propane receiver, a system for propane -air mixing, a system for supersonic flow creation, a rectangular aerodynamic channel, a high voltage power supply source, a magnetron generator, a system for mi crowave energy input to the chamber, a synchronization unit, and diagnostic equipment, was used [1 -9]. A pulsed magnetron generator of the centimeter wavelength range serves as the microwave power source. The characteristics of the magnetron generator are: the wavelength � = 2.4 cm, pulsed microwave power W < 200 kW, and a pulse duration � = 5-200 ∝s. Ignition of propane -air supersonic flow was studied depending on the pulsed power (W = 30 -70 kW), microwave pulse duration ( � = 5-200 ∝s), and air mass consum ption (dm air /dt = 25 -120 g/s) propane mass consumption (dm propane /dt = 1-7 g/s); in this case, the equivalent ratio for propane varied from 0.3 to 2. Experiments were carried out on the installation consisting of a vacuum chamber, a receiver of a high press ure of air, a receiver of a high pressure of propane, a system for mixing propane with air, a system for producing a gas flow, a magnetron, a system for delivering microwave power into the chamber, an aerodynamic channel,