Semi-freejet

Three types of combushon test facility are used to evaluate the combushon efficiencies of ducted rockets direct-connect flow (DCF) test, semi-freejet (SFJ) test, and freejet (FJ) test, as shown in Fig. 15.13. Pressurized heated air or cooled air is supplied to the DCF, SFJ, and FJ test facilihes. The pressure and temperature of the airflow are adjusted by means of an air control system to simulate the air condihons during flight of the ducted rocket projechle. In the case of the DCF test, the airflow is supplied to the ramburner from a pressurized air tank through a directly connected pipe. No air-intakes are used in the DCF test. Thus, the pressure and temperature of the air in the ramburner are as directly supplied from the pressurized air tank. No supersonic flow or shock waves are formed during the supply of air to the ramburner. In the DCF test, the combustion efficiency in the ramburner is measured as a function of the air-to-fuel flow ratio, s. The combustion charac-... 

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