ES 202 Fluid and Thermal Systems Tutorial for Week Nine 2 13 03 Page Mayhew Sanders Exam 2 Problem 1 40 points DO NOT INTERPOLATE USE CLOSEST TABULATED VALUE An adiabatic steam turbine operates at steady state The steam enters the turbine at 3 5 MPa and 450oC and exits at 0 1 MPa The mass flow rate through the turbine is 25 kg s The isentropic efficiency of the turbine is 0 71 1 FIND a Power output of the turbine in kW b Exit temperature and phase 2 Problem 2 40 points DO NOT INTERPOLATE USE CLOSEST TABULATED VALUE An adiabatic compressor draws 5 kg s of air ideal gas at 1 atm pressure 101 kPa 27 C and delivers air at 5 atm and 247 C Find a 15 points the required power input in kW b 15 points the compressor efficiency and c 10 points the rate of entropy production in kJ K sec Problem 3 20 points DO NOT INTERPOLATE USE CLOSEST TABULATED VALUE a 1 2 5 points Find the specific entropy kJ kg K of R 134a at 0 9 MPa and 12 C b 5 points Find the specific volume m3 kg of R 134a at 0 9 MPa and x 0 5 c 10 points Find the exit temperature of an adiabatic reversible R 134a compressor with saturated vapor at 0 18 MPa at the inlet and an exit pressure of 0 5 MPa 1 ES 202 Fluid and Thermal Systems Tutorial for Week Nine 2 13 03 Page 2 Lui Richards Exam 2 Problem 1 32 points Complete the information in the table for refrigerant 134a R 134a Entries that require calculations are worth 4 points Entries that only require a simple look up are worth 2 points For phase indicate whether it is a compressed liquid CL saturated liquid SL saturated mixture SM saturated vapor SV or superheated vapor SHV For properties and quality provide a number or indicate it is not applicable N A State Phase T o C P MPa 1 60 2 60 3 60 0 8 4 60 3 0 5 SV x 3 m kg h s kJ kg kJ kg K 172 71 0 9527 3 0 For answers that require calculations show your work below as you feel necessary Full credit will be given if we only have to punch your numbers into a calculator ES 202 Fluid and Thermal Systems Tutorial for Week Nine 2 13 03 Page 3 Problem 2 34 points A saturated mixture of water with an initial quality of 50 a pressure of 100 kPa and mass of 2 kilograms is contained in a piston cylinder device During a constant pressure process the water is heated to a temperature of 200oC vapor a Sketch the process on a P v and a T v diagram Clearly label the initial state final state and the process line liquid b Determine the magnitude and direction of the work and heat transfer for the process in kJ heating Additional discussion If the constant pressure process is replaced by a constant temperature process how will the analysis be different Problem 3 34 points One way to provide air for cooling the passengers on an airliner is to expand high pressure air through an adiabatic steady state turbine as shown in the figure The inlet and outlet information is shown on the figure The inlet volumetric flow rate is 0 2 m3 s and the turbine has an isentropic efficiency of 75 Assume air can be modeled as an ideal gas and use the ideal gas tables Do not interpolate use closest values P1 600 kPa T1 127oC V 1 0 2 m 3 s a Sketch the process on a T s diagram b Determine the power output from the turbine in kW c Determine the outlet air temperature Turbine turbine 75 P2 100 kPa ES 202 Fluid and Thermal Systems Tutorial for Week Nine 2 13 03 Page Hydrostatics Determine the minimum vertical force F required to hold the gate closed if its width into the page is w Neglect the weight of the gate and assume the hinge is frictionless F Fluid density h O Hinge A L1 Open to atmosphere L2 B 4