Pulse filamentary discharge in mixing layer of two gases

A subject of consideration is the dynamic of filamentary discharge generated along contact zone of two co-flown gases. The effects found are supposed to be applied for high-speed combustion enhancement due to non-equilibrium excitation of air/fuel composition and mixing acceleration of non-premixed multi-components flow. Experimental facility consists of blow-down wind tunnel PWT-50, system of the pulse-repetitive feeding (pulse-repetitive discharger PD-60/1.7), and diagnostic equipment (Schlieren device with spatial resolution not worse than 0.3 mm and temporal resolution tau<1 mus; set of pressure transducers, voltage, current, radiation measurements; spectroscopic system; etc.) The discharge channel diameter and dynamics are recorded by streak technique. The plasma temperature is estimated on the base of analysis of spectroscopic measurements. The pulse transversal discharge is excited by means of the pulse-repetitive power supply of the discharge made on the base of Tesla coil with impact excitation. The typical parameters of the tests are the following: air pressure Pap1 Bar, flow velocity V=0-500 m/s, discharge pulse duration in a range t=40-80 ns, maximal voltage, current and power are U_max=120 kV, I_max=2 kA, W_max=90 MW. Recently the effect of fast turbulent expansion of the post- discharge channel in high-speed flow was observed experimentally. The mechanism of similar phenomena was described earlier for ambient conditions. In this paper the detail mechanisms of instability development are discussed on the base of experimental results. The discharge position and dynamics of mixing layer depend on the discharge parameters and physical properties of gases involved. It is considered that the result of interaction can be controlled by means of small additives to the gas. A possible effect of medium non-homogeneity on the lightning location and dynamics is discussed on the basis of data received.