(a) Explain the basic conditions for the type of flow known as Fanno flow. [ 5 marks] (b) Considering Fanno flow, sketch the variation of entropy relative to the Mach number. Identify the point where maximum entropy occurs. [5 marks] (c) For adiabatic frictional flow in a pipe of constant cross sectional area, the critical length L is defined as the length of the pipe required to accelerate the inlet flow (atx=0m ) with Mach number Ma to sonic conditions at the outlet (atx=Lm). This is given by the expression: DfL=[Ma21Ma2]+[2(+1)ln(2+(1)Ma2(+1)Ma2)] Explain what happens if the length of the pipe is already greater than the critical length L: You may consider only subsonic inlet flow. [5 marks] (d) Air enters a pipe of diameter 0.03m at stagnation pressure P0=200kPa and stagnation temperature T0=500K. The inlet velocity is V1=100m/s. The frictional factor of the pipe is f=0.02. Assuming adiabatic frictional flow, determine the following: (i) The critical length L for these conditions. [5 marks] (ii) The mass flow if the length L of the pipe is 15m. [5 marks] [Total 25 marks]