An electrostatic, on/off microvalve designed for gas fuel delivery for the MIT microengine

The MIT micro-gas turbine engine requires an integrated fuel-metering device in order to implement on-board engine control. Graded fuel control can be achieved with an array of on/off valves. Each valve in the array must withstand an annealing temperature of 1100°C during fabrication and open against 1 MPa of supply pressure at 400°C operating temperature. This paper presents the design, fabrication and testing of an electrostatic, on/off silicon prototype valve. Tested with nitrogen at room temperature, the valve opened against a differential pressure of 0.9 MPa with 136 V and delivered a mass flow rate of 45 sccm (3.38 g/h). At 0.1y MPa upstream pressure, the helium leak-rate was measured to be 6×10^-3 sccm. The valve showed no sign of failure after being continuously actuated for more than 10⁵ cycles. The prototype valve will serve as the base-line design for the engine fuel valve array.