Experimental Study Of Characteristic And Stability Of Flames With Plasma Jet

Flame stabilization technology is the key technology of supersonic combustion. In order to further improve engine performance, a new mechanism for stable combustion of low resistance is needed which can also improve fuel burn rate. Based on this demand, we propose the technology of plasma jet-activated combustion. In the propagation region of plasma jet, there has a large number of plasma and active particles which induce the formation of activated region of flames, this region which exist in the combustion chamber continuously can lead the fuel oil to ignite reliably. It also can be used to control combustion, prompt the combustion process to occur in expected region.As a preliminary exploration of plasma jet-activated combustion technology, this paper try to experimental study the variation law of flame characteristics and stability on the influence of plasma jet. The present thesis investigates and solves the following problem mainly:1. Via experimental study on the properties of atmospheric pressure argon plasma jet, with the increase of voltage and argon flow rate, we find that the length of plasma jet firstly become longer and then shorten. And the components of argon plasma jet are measured in atmospheric environment. The results show that besides argon spectral lines, there also contain OH and oxygen lines. We also experimental demonstrate that the plasma jet can spread in ceramic tube, the transmission distance can be more than 30cm.2. For characteristics of the flame, with the influence of plasma jet, we experimental study the typical characteristics of the methane diffusion flame and methane-air premixed flame. With different discharge voltage, the flame detachment height, flame height and other characteristic parameters with the variation of methane flux were studied. We find that the catastrophe and hysteresis of the flame has been changed. Furthermore, using topological methods to modeling the bifurcation characteristics of flame appeared on the influence of plasma jet.3. For stability of the flame, with different discharge voltage, we experimental study the variation law of blowoff boundary methane diffusion flame. The results show that the plasma jet can induce the formation of'active nucleus of flames', thus enhancing the stability of the flame. Also, the variation law of stabilization concentration boundary of methane-air premixed flame is studied.