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2) a) to find out the final temperatura of gas we appy Gay-Lussac law : p1v1/t1=p2v2/t2 V1=10m^3 v2= p1=60psi I= 12 A t1=350 k V=250 V p2=0 I know I = v/r ohms law how to continue? time=150 s how to convert 60 psi to atm?How much is 1 psi in atm? b)to find the work done by the system on the surroundings: Work= integral of Pdv knowing that P2v2^n=p1v1^n=constant so work done by system on the surrounding is : work=(R(t1-t2)/n-1)) c)change in internal energy E=E2-E1 how to get E1 and E2?

thermodynamics tutorial on flow devices Q1) Air at 150Kpa and 300K is compressed to 1.5 MPa At 400 K The air flows at 0.5 Kg/s and heat is lost from the compressor at a rate of 16KJ/kg during the process Determine the power input to the compressor Past exam questions Q2) Water at 15 ˚C is fed to the top of a spray column by a centrifugal pump from a bulk storage tank at a rate of 50 kg/min. The storage tank is 15 m in diameter 3 m deep and the level within the tank is maintained at 2 m by a float valve connected to the mains water supply. The pump draws water from the bottom of the bulk storage tank at ground level and discharges it though a nozzle mounted in the roof of a spray tower 25m high. The pipes connecting the tank, pump and nozzle are all 5cm bore. The nozzle has an outlet diameter of 1 cm and is 3 cm long. The spray tower is vented to atmosphere and is drained at its base. a) Draw a diagram of this process b)The outlet velocity of the nozzles. c) The pressure at the inlet of the nozzle d) Power input by the pump assuming 100% efficiency. e) The pump actually operates at 80 % efficiency, recalculate the power input to the pump. Q3) A fire engine pumps water a a rate off 1000 kg/min from a river 3m below the fire engine to put out a fire on the 5th floor of a building 15m above the fire engine. The water is pumped through a hose 100 mm in diameter to a nozzle outlet diameter 15mm and 60 cm long.( assume outlet at 298 K and 1 atm pressure) Calculate( Stating all assumptions): a)The outlet velocity of the nozzles b)The pressure at the inlet of the nozzle c)Power input by the pump assuming 100% efficiency d)The pump actually operates at at 80 % efficiency recalculate the power input to the pump e)What could have happened to the 20 % of energy lost during the pumping stages. Explain your comments and state wheather this could have affected your previous calculations

Questions 4 Steam Quality Questions 20 m3 of Steam at 1 atm and 373.15K contains 1litre of water. What is the quality of the steam? 5 m3 of steam at 9.319 bar pressure and 450K contains 30litre of water what is the quality of the steam The steam quality at 1atm is 67% what is the specific volume of the mixture Steam table questions Direct extraction of data from tables 1) Critical point properties of water 2) Latent heat of vaporisation of water at 2.5 bar 3) Specific heat capacity of water at 45 c 4)enthalpy of ammonia at 20 c at 50 degrees c of superheat Interpolation 5) Calculate the saturated vapour pressure at 97.5 °C 6) Calculate the enthalpy of vaporisation 159.8 F 7) Calculate the internal energy of the saturated liquid at 1842Psi Double interpolation 8) Calculate the molar volume of superheated steam at 0.67MPa and 593.15 K 9) Calculate the enthalpy superheated steam at 9750mmhg and 465 °C 10) Calculate the internal energy of superheated steam at 58.5 bar and 1499.67 oR 11) Calculate the enthalpy of ammonia at 41°C and 7.2bar pressure Use of water property table on page 11 12) The steam quality at 150°C is 45% what is the specific volume of the mixture.(will need to interpolate data) Use of compressed water table on page 12 13) Enthalpy of compressed water at 229 °C and 300 bar pressure

1) convert these temperatures to degrees Kelvin K 25 ○C, 85.6 ○F, 3000 ○R 2) convert these temperature to degree ○C 900○R, 758 ○K, 600 ○F, 3) convert these pressures to bar g 1500 Psig, 1800pa (g), 45M H2Og, 9 ATM (a), 5000 mmHg(a) 4) convert these gauge pressures to absolute pressures 9 bar, 2300Psi, 1500 mmHg 760Nm2

Rankine cycle exam questions Q1 A steam plant is designed on the basis of an idealised Rankine cycle where the plant raises steam at 3MPa and 350 °C. The steam is then expanded through a turbine and fed to a condenser that operates at a pressure of 12 kPa. i) Draw a flow diagram and sketch a temperature–entropy diagram for the process. You should ensure that you label the four key stages of the process on each diagram. ii) Determine the thermal efficiency of the process iii) In reality the pump and turbine are found to operate with efficiencies of 60% and 70% respectively. Given this determine the thermal efficiency of the actual plant iv) State how the thermal efficiency of the plant could be increased (use diagrams to support your answer). Q2 real rankine power cycle question A steam plant is operated on a real cycle shown below. The pump operates on a efficiency of 75% and the turbine operates on an efficiency of 70% determine the thermal efficiency of the cycle. And the plant power output for a mass flow of 10kg/s Q2a The real steam plant is redesigned and its is discovered that the plant can be run at 20MPa by adding a second pump (efficiency 90%) Calculate the change in efficiency of the modified plant The new heat input to the system and the heat lost in the condenser comment on the quality of the steam in the turbine

Thermodynamics tutorials Carnot cycle q1 A domestic fridge uses refrigerant R 134 as the working fluid and operates on a standard idealised Carnot type cycle A) Draw the typical flow diagram for the refrigerator and sketch the temperature-entropy diagram for the process. B) Explain how the refrigerator works with reference to the diagrams produced for part 1 . C) State the Clausius version of the second law of thermodynamics and explain why the refrigerator you have described meets the requirements of Clausius’s Statement. 2) The ice box for the fridge must be kept at a constant temperature of -14 ○C to prevent bacterial growth in the food stored there. For a refrigerant flow 1.5 kg/s calculate: D) The heat removed from the ice box. The coefficient of performance of the cycle and comment on your answer. In practice ideal Carnot cycles are not suitable to model real refrigeration cycles. Explain why this is so. 3)A heat pump is used to heat a domestic house to give a room temperature of 25°C by pumping low grade heat from the atmospheric air 5 °C. “The heat pump described above obeys the second law of thermodynamics as stated by Clausius”: a)Is this statement correct and if the pump obeys the second law give a clear explanation of why it obeys said law. b)Sketch the typical flow diagram for the heat pump c)Use your diagram to explain how the heat pump works. 4)The heat pump operates on freon 134a and follows a standard Carnot cycle. The condenser delivering heat to the room is supplied with saturated vapour at 30 ○C that is condensed to give saturated liquid also at 30°C. Assuming the air temperature is an average 15 °C for a refrigerant flow of 0.02kg/s, calculate: a)The heat delivered to the room b)The heat transferred from the air c)The work done by the compressor d)The coefficient of performance of the cycle and comment on your answer e)If the air temperature drops by 5 degrees in a bad winter will the coefficient of performance of the cycle increase or decrease comment on your answer.

Tutorial on multi flow systems Past exam question B3. Three process water streams meet at a junction mix and leave as a combined flow. Stream 1 is at 90 ˚C and flows at a rate of 1 kg/s. Stream 2 is at 50 ˚C and flows at a rate of 2kg/s. Stream 3 is at 30 ˚C . The total outlet flow is known to be 6 kg/s i) Determine the flowrate of stream 3 [4 marks] ii) Determine the final temperature of the outlet stream [8 marks] The junction is replaced with a heated tank 2 m in diameter and 2 m deep. The liquid level in the tank is observed to rise at a rate of 0.5m per hour. iii) Recalculate the flowrate of stream 3 into the tank [4 marks] iv) Calculate the temperature of the out let stream heeeeeeeeeeelllllpppp meeeeeeeeeee!pleeeeeeeeeeaaaaaaaaaaaasssssssssssseeeeeeeeeeeeeeeeeeeeee!

Ideal gas equation tutorial questions Q1) 5 moles of gas are heated in a container 10 litre in volume to a temperature of 600 ° F. What is the pressure of the gas? Q2) A balloon is filled with helium at 60F to a pressure of 1.1 Psi(g).The balloon will burst at 1.3 Psi(g) Assume the volume of the balloon does not change how much can the balloon be heated until it bursts? Q3) A car has a four cylinder 2 litre internal combustion engine running on iso-octane. Cylinder one is charged with a stoichiometric mixture of oxygen and iso-octane with the piston fully extended. The cylinder chamber is 10 cm long in this position. reaction 2C8H18 +25O2è 18H2O + 16CO2 1) How many moles of gas are charged to the empty cylinder to raise the pressure to 1 bar (abs) at a temperature of 25 °C? 2) The piston is moved to its closed position 1cm form the cylinder head isothermally compressing the gas what is the increase in pressure? 3) The gas is ignited and burnt to completion. Assuming no initial temperature rise what is the increase in moles in the system and the associated change in pressure? 4) The heat of reaction raises the temperature in the cylinder to 600°C. What is the change in pressure of the system? 5) The piston now extends to its full extension. What is the change in pressure? 6) The cooling water drops the temperature of the cylinder to 100°C. What is the new pressure in the cylinder? 7) The cylinder now closes back up to eject the exhaust gases from the cylinder what is the number of moles left in the cylinder assuming the pressure drops to 1 bar (abs)? please help me to sove them!heeeeeeeeeeeellllllppppppppp!!!

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Question 1 Pressure vessel contains helium (10kg ) at 50 °C and 550 Kpa The Tank is agitated by a fan rated at 500 watts for 3 hours calculate the work done on the system by the fan over the three hours (5400KJ) the temperature rise in the tank (173°C) The final pressure of the system (844 KPa) Given the Cv of the helium is constant at 3.1156 kJ/kg/°C Question 2 A gas manometer tank 10 m3 of nitrogen pressure 60 psi 350 K is heated by a resistance heater at 12 amps and 240 volts for 150 seconds the gas expands to maintain a constant pressure in the system. Assume on heat losses calculate the final temperature of the gas (560K) The work done by the system on the surroundings (2.478 MJ) The change in the internal energy of the system(22.2MJ) Cp= 2.06 KJ/Kg/ºK Question1 More tricky question Air at 1bar and 25°C is compressed to 5 bar and 25 °C by two different processes A) cooling at constant pressure followed by heating at constant volume B) heating at constant volume followed by cooling at constant pressure Calculate the heat and work requirements plus changes in internal energy and enthalpy of the air for each path Given the temperature changes are small the cp and cv can be considered constant CV= 20.78 and Cp= 29.10Jmol-1K-1 at 25°C and 1 bar the molar volume of air is 0.02479m3mol-1 please help me to solve these problems I would aprecciated so much i am so strugging with these problems!helpppppppppppppppp meeeeeee!

1) A rigid walled tank 5m3 contains helium at 10 bar. The cylinder is heated from 10 °C to 50 ° C. What is the work done during the heating cycle. 2)An expanding gas storage vessel contains 5 m3 of methane at 1.1 bar. On a hot day the gas is heated from 20 °C to 35 °C. What work is done by the gas on its surroundings 3) One mole of CO2 is charged to a piston at 10 bar pressure 293K. The piston is allowed to expand to 4 times its volume isothermally. What work is done on the surroundings? The gas behaves ideally A more complicated example using a polyatomic gas Part1 CO2 is charged at 2 bar to a piston at 298 K volume 0.5 m3. It is known to vary as polytonic gas PV2=C. The gas is allowed to expand isothermally to twice its volume what work is done by the system Part 2 A Spring force (5 kN/m extension) is added to retain the piston what work is done this time if the expansion is the same and how much work is done against the spring the piston area is 0.1 m2 4)A polytonic gas which expands according to PV2=C is charged to a piston at 3 bar.The piston is allowed to move and the pressure in the cylinder drops to 0.6 bar. Calculate the work done by the system on the surroundings 5)A polytonic gas which expands according to PV2=C is charged to a piston at 20 bar. The piston is allowed to expand from a volume of 0.05m3 to 0.1m3 The piston is then cooled isobarically and the volume shrinks back to its original value of 0.05m3. The piston is locked in place and the system is heated until the pressure reaches the starting pressure of 20 bar. Calculate the work done for each stage and the net work done during the total cycle 6) )An ideal gas is charged to a piston at 0.5 bar the piston is compressed isothermally to 0.1 of its original volume calculate the work done on the system by the surroundings 7) A piston –cylinder contains 0.05m3 of a gas initially at 200kPa. At this state a linear spring that has a spring constant of 150kN/m is touching but not exerting a force on the piston. The piston is now heated causing the piston to rise and compress the spring until the cylinder volume has doubled. The cross sectional area of the piston is 0.25m2 calculate the final pressure in the cylinder and the total work done by the gas please help me to solve these problems I would aprecciated so much i am so strugging with these problema!helpppppppppppppppp meeeeeee!