Experimental Investigation of the Pressure Characteristics in Air-Breathing Laser Propulsion
Ming Wen, Yan-Ji Hong, Jian Yang and Tiejun Zhou
Keeping the single pulse energy of the CO2 laser constant, the impulse coupling coefficients of air-breathing laser propulsion are measured at various air pressures using a high precision impact pendulum system and the corresponding altitude characteristics. The results show that the impulse coupling coefficient is about 35dyne.s/J with less than 5% fluctuation when the air pressure varies from 2.8 x 104 Pa to 1 x 105 Pa and the altitude from 0km to 10km. When the air pressure is less than 2.8 x 104 Pa and the altitude is greater than 10km, the impulse coupling coefficients decrease following a quadric curve. At a pressure of 1 x 103 Pa and altitude of 31km, the impulse coupling coefficient is only 9.7dyne.s/J i.e. a drop of 75%. These results, which can be explained as due to the angle of the thrust, are consistent with those of German work using a parabolic device.