Reference no: EM132227836

Question 1) Consider an axial compressor blade row. The inlet velocity is 150 m/s and is in the axial direction. The blade speed is 180 m/s and the relative outlet angle is 30° to axial. Assuming constant axial velocity through the blade row calculate the relative angle at the inlet and the absolute angular velocity and absolute flow angle at the outlet. Also compute the power supplied per unit mass flow, the change in rothalpy across the blade row, the change in relative stagnation enthalpy across the blade row and the change in static temperature across the blade row. Assume isentropic flow. Assume perfect gas air, C_p = 1004.5 J/kg°K.

Question 2) Consider the enthalpy-entropy diagram for an air turbine stage sketched below. The process 1 to 3 designates the real thermodynamic state change across the turbine stage. The static pressure and temperature at inlet state 1 are 3 bar and 300 °C respectively. The static pressure and temperature at outlet state 0 are 1 bar and 250 °C respectively. If we assume that the air behaves as a calorically perfect gas, with Cp=1004.5 J/kg*K, R=287 J/kg*K, determine the total¬to-total and total-to-static efficiencies for the stage, assuming that the absolute velocities at 1 and 3 are 75 and 50 m/s respectively.

Question 3) A water pump is designed to deliver 20MW when operating at 100 rpm under a head of 15 m. A geometrically similar scale test model is designed to develop 40 kW at a head of 5m. Calculate the geometric scale ratio and the scale model rotational speed.