Starting Characteristics of Hypersonic Pre-cooled Turbojet Inlet

Abstract

In this study, bypass door area for the Hypersonic Precooled Turbojet Engine to restart the variable intake is estimated. Total pressure recovery and mass capture ratio of the variable air intake is acquired by the supersonic wind tunnel testing of the half scale intake model. Pressure loss and temperature effectiveness of the precooler is acquired by direct connect firing tests of the engine. Using these results, area of the bypass door by which the intake can start is estimated. The bypass door area to restart the intake depends on the precooler's cooling capability. If the engine runs on liquid hydrogen, area of the bypass door is 1800mm 2~2 000mm 2 (A byp_eng /A 0 =0.26~0.29). If the liquid nitrogen is used for the coolant of the precooler, area of the bypass door is 2600mm 2~2 700mm 2 (A byp_eng /A 0 =0.37~0.39). NomenclatureA 0 = Intake Capture Area A byp_eng = Bypass Door Area A cmp_eng = Compressor Stator Outlet Area A e_eng = Smallest section area of the core engine (stator outlet area) A th = Intake Throat Area H cowl = Intake Capture Cowl height H th = Throat Height of the intake 2 nd ramp η pcool = Temperature effectiveness of the precooler(air side) m a = Engine Air Flow Rate MCR = Intake Mass Capture Ratio Ntu = Number of Heat Transfer of the precooler P t_intake = Intake Outlet Total Pressure P t_pcool = Precooler Outlet Total Pressure R = Heat Capacity Flow Rate of the precooler T t_intake = Intake Outlet Air Temperature T t_pcool = Precooler Outlet Air Temperature TPR = Intake Total Pressure Recovery