question 4&5

Question 4 [15 Marks] 5kg of saturated water vapor at 150C are cooled at constant temperature to a saturated liquid. Using the steam tables: a) What is the pressure? (476.8kPa) b) What is the change in total volume? (1.958m3) (3) c) What is the change in total internal energy? (9693kJ) (3) d) What is the change in total enthalpy? (10 571kJ) (3) e) Is H=U+PV verifiable? Justify. (3) Page 1 of 2 Compiled by: Dr MM Mabuza Copyright@2023 Chemical Thermodynamics 2A (CTDCHA2) - 2023 Question 5 [20 MARKS] Steam enters a turbine at 4000kPa and 500C and leave as saturated vapour at 80 kPa as shown in Figure 1 Figure 1: Schematic of a Steam Turbine. The inlet and the outlet pipe diameters are assumed to be the same at 5cm. If the inlet velocity is 200m/s : a) From the general energy balance equation, derive an expression to determine the turbine power output. (8) b) Calculate the mass flow rate for this system. (4.548kg/s) (8) c) Calculate the power output. (3543kW) (4)