Ignition enhancement of lean kerosene air mixture by multichannel jet enhanced plasma igniter

Abstract

Reliable and fast ignition is one of the biggest challenges for the development of advanced propulsion systems. In this study, a novel multichannel jet enhanced plasma ignition strategy is proposed. Based on the flow control strategy, the plasma synthetic jet is used to enhance the spark discharge, to enlarge the spark size, and to increase the ignition energy. The multichannel jet enhanced plasma igniter (MJEPI) discharge characteristics, spark evolution, and the ignition process in a single-head swirl combustor were studied and compared with those of the traditional spark igniter. The discharge efficiency can be improved from 33.5% to 42.7% compared with the traditional spark igniter. The heating ratio has a great influence on the performance of MJEPI. A positive return can be obtained only when the heating ratio is greater than about 13.6. The MJEPI significantly enlarges the initial flame kernel which maintains its strength throughout the ignition process. Due to the enhancement of heat exchange and mass transport of the larger initial flame kernel, the lean ignition limit can be extended by 26%-32% at different air flow and the ignition time is obviously reduced by 29.7%. It can be concluded that the MJEPI is worthy to be further studied.