High-impulse, low-power, digital microthrusters using low boiling temperature liquid propellant with high viscosity fluid plug

High-impulse, low-power, multiple-shot digital microthrusters have been developed using low boiling temperature liquid propellant with high viscosity fluid plug. The low boiling temperature propellant is used for reducing the electrical input power required for blast pressure build-up, while the high viscosity fluid plug is intended to withhold the propellant pressure for the high-impulse blast. The three-layer microthrusters in the size of 7 mm x 13 mm x 1.5 mm have been fabricated by surface micromachining as well as bulk micromachining techniques. We experimentally verify the effect of the key parameters, such as propellant-plug pairs, pulse width of input electrical voltage and heater size, on the impulse output characteristics of the microthruster. The maximum output impulse-bit of 6.4 x 10(-8) ns is obtained from the fabricated microthruster using perfluoro normal hexane (FC72, C6F6) propellant and oil plug for 7 Hz, 1 m pulse width and 0.4 W electrical power input. (C) 2002 Elsevier Science B.V. All rights reserved.