Model of Ideal Electrohydrodynamic Thruster

The idea of using the electrohydrodynamic ionic wind pump effect in thruster applications is theoretically examined. Although this idea has been under discussion for many decades, there is still no commonly accepted view on electrohydrodynamic thrusters: for example, whether electrohydrodynamic thrusters are worthwhile, what level of thrust and thrust efficiency can be obtained from electrohydrodynamic thrusters, etc. In this paper, a simple one-dimensional model of an ideal electrohydrodynamic thruster for calculating thrust efficiency and thrust of electrohydrodynamic thrusters is presented. The maximum current that can be achieved for an ideal electrohydrodynamic thruster at a given voltage is also calculated. This allows the calculation of the maximum thrust that can be obtained from the thruster and the corresponding thrust efficiency. It is shown that, with an increase in the voltage, the maximum thrust and the corresponding thrust efficiency move in opposite directions: the thrust efficiency decreases, while the thrust increases. It is also shown that, at high altitudes, the performance of electrohydrodynamic thrusters (thrust and thrust efficiency) drops very fast; therefore, using electrohydrodynamic thrusters at altitudes greater than 5 km is apparently unrealistic. The model shows that maximum thrust cannot exceed 20-30 N/m(2) at sea level, even at breakdown voltage. The model illuminates the physical limitations of electrohydrodynamic thrusters and provides reasonable estimates of the performance limits of real electrohydrodynamic thrusters.