Exam 3: 1—Air in a Nozzle (30%)d.cd-p.aih Air with a mass flow rate of 5 lb/s enters a horizontal nozzle at a steady state at T1=800oR and 50 lbf/in2 with velocity 10 ft/s(h1=191.81 Btu/lb). The exit T2 = 570oR and velocity 1510 ft/s (h2=136.26 Btu/lb). There is heat loss from the nozzle walls: Q (Btu/lb). (a) What is the specific volume of air v1 (ft/lb) at the inlet? (b) find the inlet area (ft2). (c) the velocity heads V12/2 and V22/2 (Btu/lbm) at inlet and outlet. (d) Use the energy equation to find the heat loss Q (Btu/lbm). Air is an ideal gas. #2—Steam Turbine (30%) d.dg-p.aih Steam enters a turbine operating at steady state with a mass flow 10 kg/min, a specific enthalpy 3100 kJ/kg, and a velocity of 30 m/s. At the exit, the enthalpy is 2300 kJ/kg, velocity 45 m/s. The elevation of the inlet is 3m higher than the exit. Heat transferred away from the turbine is 1.1 kJ/kg of stream flow. Let g = 9.81 m/s2. Find the velocity and elevation heads (in kJ/kg) V12/2 , V22/2 , and g(z1-z2); and work output Ws from turbine in kW. #3—Velocity of Sound (40%) Venetian atmosphere is composed mostly of CO2 (96.5%). We assume it to be 100% CO2. The pressure P is 93 bar, and temperature T is 740K. CO2 gas obeying the Redlich-Kwong (RK) equation of state P RT a v b T v (v b ) where R = gas constant = 0.08314 m3.bar/(kmol.K), a = 64.43 bar.sqrt(K).(m3/kmol)2, b = 0.02963 m3/kmol. v = molar volume = 0.654 (m3/kmol). (a) Find the velocity of sound c (m/s) in the Venetian atmosphere (using RK equation). (b) Find the velocity of sound if the atmosphere were an ideal gas: P v = RT! 2 C P c 2 v p where Cp/Cv = 1.36. CO2 has MW = 44. C v T v