Question

B4 (a) Ste the parameter that is normally used to differentiate between incompressible and compressible flow conditions. What value is normally chosen for this parameter to signify a change from one condition to another? (5%] For isentropic flow conditions, sketch a subsonic and a supersonic nozzle (b) Sketch also a subsonic and a supersonic diffuser. [1096] (c) A converging-diverging nozzle is attached at one end to a large supply tank that contains air, and at the other end to a receiver tank that contains a vacuum pump. The air in the supply tank has an ambient temperature of 350 K and an ambient pressure of 1 MPa (absolute). At the exit from the converging-diverging nozzle, the pressure is measured to be 87.5 kPa (absolute). The converging-diverging nozzle exit has a cross-sectional area of 0.001 m. If the flow in the nozzle may be assumed to be isentropic, calculate (15%] (i) the Mach number at the nozzle exit; (ii) te pressure at the throat [1096] ii the temperature at the throat; (10%] (iv) the velocity at the throat [3096] (v) the area of the throat. (vi) te change in specific enthalpy between the supply tank and the nozzle exit if the nozzle may be assumed to be adiabatic. [ 1096] DATA The ratio of specific heats for air y-1.4 The specific gas constant for air R 287 J/kg K

Answer 1

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