Vendetta Final Proposal Part 1 (3.4 MB) - Cal Poly

Figure 6.7 shows the off-design inlet area ratio that is required for the Vendetta. The equations used to find thedata are shown below. The actual inlet capture area is depicted by A 1 , with the area at the shock being A s , and the actualflow area being captured by the inlet as A 0i . As the Vendetta climbs, the engine requires a greater amount of inlet area fora constant mass flow rate.Mass Flow RatioA A A=A A A0i 0i s1 s 1Area RatioAA0i s ssρ V=ρ V0 0Inlet Area Ratio1.31.21.110.90.80.7Design Point0.60.50.40.30.20.100 0.5 1 1.5 2 2.5 3Mach NumberFigure 6.7 - Off Design Area Required for Engine Mass FlowThe inlet capture area was found by first estimating the mass flow rate required by the engine at the design point.The mass flow of the engine could be estimated using the following equation.•Mass Flow Estimation ( ) 2em= 26⋅FrontFaceDiameterThe front face diameter of 4 ft was used; this yielded a mass flow rate of approximately 415 slugs/sec. Now usingthe mass flow equation shown below, the area of the inlet could be found for the design mission.Mass Flow Equation•em=ρ AVOnce this was done the mass flow equation was used to calculate the area at different altitudes based onconservation of energy. For the desired design point of 1.6 Mach and an altitude of 55,000 ft it was found to be about 6ft 2 . Since different parts of the mission take place at several different altitudes above 50,000 ft, the inlet area was sized to6.5 ft 2 . By sizing the engine to 6.5 ft 2 air could be bypassed from the inlet to the air cooled fuel cooler. The inlet has a33