燃焼駆動式ＣＯ２ガスダイナミックレーザーの特性 Ｉ 超音速ノズル開口比の影響

Abstract

Characteristics of a combustion-driven CO2 Gasdynamic Laser (CO2 GDL), which should be a radiation heating simulator for re-entry of a planetary probe and AOTV, are experimentally and theoretically obtained. In the present GDL system carbon dioxide CO2 produced in the combustion process of liquid benzene C6H6 with gaseous oxygen CO2 is used as lasing media associated with the energy-pumping gaseous nitrogen N2. The influence of gas components on the small-signal gain is investigated using four expansion ratios of 5, 7.5, 10 and 15, which have common throat height 1.0mm. The experimental results show that the small-signal gain increases as the nozzle expansion ratio increases and that the maximum gain obtained is 0.2m-1 at the expansion ratio of 10 and 15. Comparison is made between the experimental and theoretical results based on the Anderson model, and fairly reasonable agreement is obtained. The theoretical results show that the small-signal gain decreases when combustion pressure increases and the maximum small-signal gain is obtained by optimum composition of combustion pressure and expansion ratio which are able to be produced in several GDL system.