ES 202 Fluid and Thermal Systems Tutorial for Week Eight 2 6 03 Page 1 1 Provide the information requested in the table for WATER When specifying the phases use the following abbreviations CL compressed subcooled liquid SL saturated liquid SM saturated mixture SV saturated vapor SHV superheated vapor Use NA for items that are not applicable at a particular state Use ND for items that cannot be fully specified Pressure P kPa Temperature T C 1 2000 200 2 1000 200 3 1553 8 200 State Phase 4 Quality x 200 Specific Volume v m3 kg Specific Internal Energy u kJ kg Specific Enthalpy h kJ kg Specific Entropy s kJ kg K 0 100 5 100 2658 1 6 100 800 7 100 20 Plot the states on the P v and T v diagrams below Positions may be approximate but relative positions should be correct when compared with other states and saturation curves P T v v ES 202 Fluid and Thermal Systems Tutorial for Week Eight 2 6 03 Page 2 2 Calculate the change in a internal energy b enthalpy c entropy for 2 kg of air from an initial temperature of 20 deg C and an initial pressure of 100 kPa to o 200 deg C and 350 kPa o 2000 deg C and 700 kPa Perform your calculation by using i property table ii average specific heats 3 For the same initial state as previous problem if the process is isentropic what will the final temperature be if the final pressures are the same as those in the previous problem 4 An adiabatic compressor compresses air from room conditions 20 deg C and 100 kPa to 300 deg C and 550 kPa Determine its isentropic efficiency Reason out your calculation using a basic definition b appropriate approximation ES 202 Fluid and Thermal Systems Tutorial for Week Eight 2 6 03 Page 3 and examine the simplification introduced by your approximation 5 Consider a steam power plant that operates on a simple ideal Rankine cycle and has a net power output of 30 MW Steam enters the turbine at 7 MPa and 500 deg C and leaves the turbine at 10 kPa It then enters a condenser at 10 kPa and is cooled by running cooling water from a lake through the tubes of the condenser at a rate of 2000 kg s a Show the cycle on a T s diagram with respect to the saturation lines b Determine the work and heat transfer per unit mass flow for each process of the cycle c Determine the thermal efficiency of the cycle d Determine the temperature rise of the cooling water as it flows through the condenser e Repeat all of the above if the isentropic efficiency of the pump and turbine are 80 and 75 respectively 6 Water contained in a piston cyliner assembly undergoes two processes in series from an initial state where the pressure is 10 bar and the temperature is 400 deg C Process 1 The water is cooled as it is compressed at a constant pressure of 10 bar to the saturated vapor state Process 2 The water is further cooled at constant volume to 150 deg C a Determine the overall work for the overall process b Determine the overall heat transfer for the overall process water ES 202 Fluid and Thermal Systems Tutorial for Week Eight 2 6 03 Page 4 c Sketch the whole process path on a P v a T v and a P T diagram clearly indicates the two phase region 7 A mass of 12 kg of saturated refrigerant 134a vapor is contained in a piston cylinder device at 200 kPa Now 150 kJ of heat is transferred to the refrigerant at constant pressure while a 110V source supplies current to a resistor within the cylinder for 6 minutes Process A a Determine the current supplied if the final temperature is 70 deg C vapor liquid b If a latch is placed on the wall of the cylinder to restrain motion of the piston Process B from the beginning what do you expect to be the main difference Determine the current in this case c Show the process on a P v a T v and a P T diagram clearly indicates the twophase region d If the refrigerant is replaced by an ideal gas how would you solve the problem differently