Field Emission Microplasma Actuated Microchannel Flow

Flow actuation by dielectric barrier discharges (DBD) involve no moving parts and provide high power density for flow enhancement, heating and mixing applications in microthrusters, micropumps and microcombustors. Conventional micro-DBDs require voltages $\sim$ kV for flow enhancement of a few m/s for 500 $\mu $m high channel. However for gaps \textless 10 microns, field emission lowers the breakdown voltage following modified Paschen curve. We consider a micropump concept that takes advantage of the field emission from a micro-DBD with dielectric thickness of 3 $\mu $m and a peak voltage of -325 V at 10 MHz. At 760 Torr, for electrode thickness of 1 $\mu $m, Knudsen number with respect to the e-nitrogen collisions is 0.1. So, kinetic approach of particle-in-cell method with Monte Carlo collisions is applied in nitrogen at 300 K to resolve electron (n$_{\mathrm{e}})$ and ion (n$_{\mathrm{i}})$ number densities. Body force, \textbf{f}$_{\mathrm{\mathbf{b}}}=$ e\textbf{E}(n$_{\mathrm{i}}$-n$_{\mathrm{e}})$, where, $e $is electron charge and \textbf{E}is electric field. The major source of heating from plasma is Joule heating, \textbf{J.E}, where \textbf{J }is current density. At 760 Torr, for f$_{\mathrm{b,avg}}=$ 1 mN/cubic mm and \textbf{J.E}$=$ 8 W/cubic mm, micro-DBD induced a flow with a velocity of 4.1 m/s for a 64 mW/m power input for a channel height of 500 $\mu $m. The PIC/MCC plasma simulations are coupled to a CFD solver for analysis of the resulting flow actuation in microchannels at various Reynolds numbers.