Problems Part2

Technische Universität DRESDEN

Institut of Power Engineering

Chair of Technical Thermodynamics

Energy and Thermodynamics ENG EK 304Problems - Part II

Boston University Dresden Program

M. Mischke Energy and Thermodynamics ENG EK 304 Problems-Part II

Technische Universität Dresden

Institut of Power Engineering

Chair of Technical Thermodynamics

Problems to the course „Energy and Thermodynamics, ENG EK 304“

Boston University Dresden Program

4. edition, spring/summer 2012

Responsible: Dipl.-Ing. M. Mischke

Editorial deadline: 20. 05. 2012

ii

7 SECOND LAW

problem 7.1 (5.4)

An inventor claims to have developed a device that undergoes a thermodynamic cycle whilecommunicating thermally with two reservoirs. The system receives energy QC from the cold

reservoir and discharges energy QH to the hot reservoir while delivering a net amount of work to its

surroundings. There are no other energy transfers between the device an its surroundings. Using the

second law of thermodynamics, evaluate the inventors’ claim.

Solution: The system can not operate as assumed.

Problem 7.2 (6-7)

An air-conditioning unit maintains a home at 22◦C. The heat generated in the home from lighting,

appliances, and people is 6000 kJ/h, and heat that leaks through the structure from the environment

amounts to 18’000 kJ/h. If the air conditioner has a COP of 3.2,

1. find the required power input in kilowatts.

2. If electricity costs 9.8 cent/kWh and the units runs one-half of the time, find the daily

cost of operation.

Solution: (1.) 2.08 (2.) 2.95 Dollars

Problem 7.3 (6-9)

A refrigerator cycle with a COP of 2.7 is used to maintain the food compartment at 3◦C.

The compartment continuously receives 1260 kJ/h of heat form the environment. The

cost of electricity is $ 0.094/kWh, and the refrigeration motor runs one-third of the time.

Determine

1. the shaft power, in kW, that the cycle require when running, and

2. the cost of operating the unit in cents per day.

Solution: (1.) 0.13 (2.) 9.7


Problem: 7.4 (6-55)

A heat engine operates between boundary temperatures of 500 and 1400◦C. The heat engine

requires a heat input of 1300 kW to produce a net work output of 600 kW.

1. Show from thermal efficiency data whether this engine violates the second law.

2. Determine the heat-rejection rate, in kW, for the actual heat engine and for an internally

reversible engine having the same heat-input rate and operating between the same

boundary temperatures during heat addition and heat removal.

3. What is The COP for an internally reversible heat pump operating between the same

boundary temperatures?

4. If the data for the actual heat engine are valid when the device is operated as heat

pump, what would be its COP? Determine whether or not such operation is feasible.

Solution: (1.) no (2.) 700 ; 601 (3.) 1.86 (4.) no

Problem: 7.5 (6-80)

The working fluid in a heat-pump cycle is reported to receive 136.0 kJ/kg as heat trans-

fer at 4◦C and reject 145.2 kJ/kg as heat transfer at an average temperature of 34◦C. If

there are no other heat interactions, does the cycle violate the second law on the basis

of

1. the Clausius inequality, and

2. the Carnot principle extended to heat pumps?

Solution: (a) violation (b) violation

Problem: 7.6 (2005-2)

Two temperature reservoirs of 30◦C and 0◦C are available.

1. Determine the maximum efficiency of a heat engine using these temperature levels.

2. Determine the maximum coefficient of performance of a refrigerator and of a heat

pump using these temperature levels again.

3. Perform the same calculation for a higher temperature level of 400◦C (instead of 30◦C)

and a lower temperature level of 0◦C.

4. Is following statement true? "Thermodynamic machines are the more efficient the

higher the maximum temperature difference in the process is". Discuss using the

results above. (max. 3 sentences)

Solution: ....

2


Problem: 7.7 (6-28)

An internally reversible heat engine has a thermal efficiency of 60 percent with 600 kJ/cycle

of heat transfer added at a temperature of 447◦C.

1. Calculate the heat-rejection temperature, in degrees Celsius, and

2. the heat transfer rejected, in kJ/cycle.

3. For the same values of QH and TH , if an irreversible heat engine rejects 420 kJ/cycle,

find its thermal efficiency.

Solution: (1) 15 (2) 240 (3) 30 %

Problem: 7.8 (6-54)

An actual heat engine operates between boundary temperatures 1200 K and 500 K. A heat in-

put of 36’000 kJ/ min produces a net power output of 270 kW.

1. Determine numerically whether the heat engine violates the second law in terms of its

thermal efficiency.

2. Determine the heat rejection, in kilowatts, for the actual engine and for an internally

reversible engine having the same heat input and operating between the same boundary

temperatures

3. Now reverse the actual cyclic device, so that it operates as a heat pump. The work

input is 270 kW, and the heat rejected at 1200 K is 36,000 kJ/min. Determine the

coefficient of performance for the actual heat pump and for an internally reversible heat

pump operating between the same boundary temperatures.

4. On the basis of part c, is the actual heat-pump operation feasible considering the COP

values?

Solution: (1) no violation (2) 330 ; 250 (3) 2.22 ; 1.71 (4) not feasible

Problem: 7.9 (6-26)

An internally reversible heat engine has a thermal efficiency of 40 percent and the working-

fluid temperature is 15◦C during heat rejection. Find

1. the net power output, in kilowatt, and

2. the temperature of the working fluid during heat addition , in degrees Celsius, if the

heat supplied is 6000 kJ/h.

3. An actual heat engine operating between the same temperatures has a thermal effi-

ciency of 25 percent. For the same heat input, find the percent change in the rate of

heat rejection relative to the reversible case.

3


Solution: (1) 0.67 (2) 207 (3) 25 %

Problem: 7.10 (5.61*)

Two kilograms of water executes a Carnot power cycle. During the isothermal expansion,

the water is heated until it is a saturated vapor from an initial state where the pressure is 40

bar and the quality is 15 %. The vapor then expands adiabatically to a pressure of 1.5 bar

while doing 491.5 kJ/kg of work.

1. Sketch the cycle on p-v coordinates.

2. Evaluate the heat and work for each process, in kJ.

3. Evaluate the thermal efficiency.

Solution: (2) process; Q/kJ; W/kJ; 1-2 ; 2914; -330; 2-3 ; 0 ; -983; 3-4 ; -2140.2; 167.1;

4-1 ; 0 ; 373; (3) 26.5%

Problem: 7.11 (5.18*)

If the thermal efficiency of a reversible power cycle operating between two reservoirs is de-

noted by ηmax , develop an expession in therms of ηmax for COP of

1. a reversible refrigeration cycle operating between the same two reservoirs.

2. a reversible heat pump operating between the same two reservoirs.

Solution:

(a) (1-ηmax)/ηmax (b) 1/ηmax

Problem: 7.12 (5.21*)

A refrigeration cycle operating between two reservoirs recives energy QC from a cold reer-

voir at TC=280 K and rejects energy QH to a hot reservoir at TH=320 K. For each of the

following cases determine whether the cycle operates reversibly, irreversibly or is impossi-

ble.

1. QC=1500 kJ, Wcycle=150 kJ.

2. QC=1400 kJ, QH=1600 kJ.

3. QH=1600 kJ, Wcycle=400 kJ.

4. β=5.

Solution: (1.) imp. (2.) rev. (3.) irrev. (4.) irrev.

Problem: 7.13 (5.22*)

A reversible power cycle receives QH from a hot reservoir at temperature TH and rejects en-

ergy by heat transfer to the surrounding at temperature T0. The work developed by the power

4


cycle is used to drive a refrigeration cycle that removes QC from a cold reservoir TC and dis-

charges energy by heat transfer to the same surrounding at T0.

1. Develop an expression for the ratio QC/QH in terms of the temperature ratios TH/T0and TC/T0.

2. Plot QC/QH versus TH/T0 for TC/T0=0.85, 0.9 and 0.95 and versus TC/T0 for

TH/T0=2,3 and 4.

Solution: (1.) TC(TH-T0)/( TH(T0-TC))

Problem: 7.14 (5.53*)

At steady state, a refrigerator whose coefficient of performance is 3 removes energy by heat

transfer from a freezer compartment at 0 °C at the rate of 6000 kJ/h and discharges energy

by heat transfer to the surroundings, which are at 20 °C.

1. Determine the power input to the refrigerator and compare with the power input re-

quired by a reversible refrigeration cycle operating between reservoirs at these two

temperatures.

2. If electricity costs 8 cents per kWh, determine the actual and minimum costs, each in

$/day.

Solution: (1.) Wcycle 2000 (2.) 1.07; 0.23

5

8 ENTROPY AND ENTROPY BALANCE

Problem 8.1 (7-901)

given a rigid tank, water substance, heat transfer from environment, Volume 0.100 m3,

overall mass of water substance 2.0 kg, pressure 500 kPa, heat transfer to the water 284 kJ

Find

1. pressure after Q transfer in kPa,

2. change in entropy in kJ/K.

Solution: (1) 700 (2) 2.84

Problem: 8.2 (ex-7-3)

A rigid, insulated tank contains 1.2 kg of nitrogen gas at 350 K and 1 bar. A pad-

dle wheel inside the tank is driven by a pulley-weight mechanism. During the experiment

25 kJ of work is done on the gas through the mechanism. Assume ideal-gas behavior.

Find

1. the entropy generation for the nitrogen, in kJ/K, and

2. whether the process is reversible, irreversible, or impossible.

3. Then sketch a T- s diagram for the process.

Solution: (1) 0.0687 (2) irreversible


Oxygen gas is heated at constant pressure from 300 K to

(a) 500 K and

(b) 800 K.

Evaluate the molar entropy change, in kJ/kmolK, for both sets of temperature increments

by means of

(1) a specific-heat value at the average temperature and

(2) ideal-gas s0 data in Table A-23 for oxygen.

Solution: (a) 15.38 ; 15.38 (b) 31.01 ; 30.60



One-half kilogram of air is compressed in a piston-cylinder device from 300 K and 120 kPa

to 500 K and 940 kPa.

1. Determine the entropy change, in kJ/K.

2. Determine the direction of any heat transfer by using the entropy balance.

Solution: (1) -0.0363 (2) out

Problem: 8.5 (7-5)

Two tanks of the same volume are connected by a pipe containing a valve. Initially the

valve is closed, one tank is evacuated, and the other tank contains 40 g of steam at 15

bars and 280◦C. The valve is opened, and the steam flows into the evacuated tank until

pressure equilibrium is reached. During the process heat transfer occurs from a reservoir

at 500◦C until the steam temperature at the end of the process is 440◦C in both tanks.

Determine

1. the final equilibrium pressure, in bars,

2. the heat transfer to the steam, in kilojoules,

3. the entropy change of the steam, in kJ/K , and

4. the entropy production within the composite steam and heat-transfer

Solution: (1) 10 (2) 11.0 (3) 0.0300 (4) 0.0158

Problem: 8.6 (7-23)

A rigid tank with a volume of 0.04 m³contains oxygen at an initial state of 87◦C and 1.5

bars. During a process paddle-wheel work is carried out by applying a torque of 13 Nm for

25 revolutions, and a heat loss of 3.74 kJ occurs to the surroundings at 18◦C. The tem-

perature of the enclosure where heat transfer occurs is taken as the average of the oxygen

temperatures during the process. Determine

1. the final temperature, in kelvins, and

2. the entropy change of the oxygen,

Solution: (1) -0.00501 (2) 0.00599

Problem: 8.7 (10-54)

Carbon monoxide and argon in separate streams enter an adiabatic mixing chamber in a 2:1

mass ratio. At the inlet the carbon monoxide is at 120 kPa and 300 K, and the argon is at 120

kPa and 450 K. The mixture leaves at 110 KPa. Determine

7


1. the final temperature of the mixture in kelvins, and

2. the change of entropy flow separately for each substance in (kJ/K)/s

3. the entropy production for the process, in kJ/K per kilomole of mixture.

Solution: (1) 330 (2) 0.428 ; 0.137832464 (3) 5.87

Problem: 8.8 (7-23)

A rigid tank with a volume of 0.04 m³ contains oxygen at an initial state of 87◦C and 1.5

bars. During a process paddle-wheel work is carried out by applying a torque of 13 Nm for

25 revolutions, and a heat loss of 3.74 kJ occurs to the surroundings at 18◦C. The tem-

perature of the enclosure where heat transfer occurs is taken as the average of the oxygen

temperatures during the process. Determine

1. the final temperature, in kelvins, and

2. the entropy change of the oxygen,

3. the entropy generation within the tank and

4. the total entropy generation for the overall process, all answers in kJ/K.

5. Is the overall process reversible, irreversible, or impossible?

Solution: (1) 320 (2) -0.00501 (3) 0.00599 (4) 0.00784 (5) irrev

Problem: 8.9 (7-38)

A constant-temperature region at 80◦C receives heat transfer from a 3-kg piece of copper

that cools from 200 to 100◦C. Determine

1. the entropy change of the copper, in kJ/K,

2. the total entropy generation associated with the composite copper and heat- transfer

regions, and

3. whether the process is reversible, irreversible, or impossible.

Solution: (1) -0.284 (2) 0.055 (3) irrev

8

9 -THERMODYNAMIC CYCLES

Problem: 9.1 (8-1)

Oxygen is compressed adiabatically in a piston-cylinder device from an initial state of 27◦C

and 100 kPa. The work input is 2142 kJ/ kmol and the process is internally reversible. Using

Table A-23 for property data, find

1. the final temperature, in kelvins,

2. the final pressure, in kilo pascals.

Solution:

(1) 400 (2) 280

Problem: 9.2 (8-3)

Nitrogen at 3 bars, 400K, and 120 cm³ is allowed to expand adiabatically and reversibly to

1.70 bars in a closed system. Determine


2. the work output, in kilojoules, and

3. the final volume, in cubic centimeters.

Solution:

(1) 340 (2) 0.0136 (3) 180

Problem: 9.3 (8-13)

A horizontal, insulated, and rigid cylinder is separated into two sections (A and B) by a fric-

tionless, nonconducting piston. Each section initially contains a monatomic gas at 100 kPa

and 300 K in a volume of 2.70 L. An electric resistor on side A is energized from an external

battery until the pressure on both sides reaches 232 kPa. Determine

1. the final temperature on side B, in kelvins,

2. the work done on the gas on side B, in kilojoules,

3. the final temperature on side A, in kelvins and

4. the amount of electrical work added in kilojoules.


Solution:

(1) 420 (2) 0.162 (3) 972 (4) 1.07

Problem: 9.4 (8-47)

Steam at 1.5 bars and 120◦C expands isentropically through a nozzle to 1.0 bar.

1. If the inlet velocity is negligible, find the discharge velocity in m/s

2. For a flow rate of 20 kg/min, find the exit area of the nozzle, in square centimeters.

Solution:

(1) 373 (2) 14.9

Problem: 9.5 (7-6)

Tow tanks of the same volume are connected by a pipe containing a valve. Initially the valve

is closed, one tank is evacuated, and the other tank contains 200 g of refrigerant 134a at 7

bars and 100◦C. The valve is opened, and the refrigerant 134a flows into the evacuated tank

until pressure and temperature equilibrium prevails. During the process heat is removed from

the refrigerant 134a to the atmosphere at 20◦C until the pressure at the end of the process

is 3.2 bars in both tanks. Determine

1. the final equilibrium temperature, in degrees Celsius,

2. the heat transfer from the refrigerant 134a, in kilojoules,

3. the entropy change of the refrigerant 134a, in kJ/K, and

4. the total entropy generation for the process, in kJ/K.

Solution:

(1) 60 (2) -6.59 (3) -0.00802 (4) 0.0145

Problem: 9.6 (7-32)

Two kilograms of nitrogen gas is heated in a piston- cylinder apparatus form 0 to 250◦C,

the pressure remaining constant at 1.013 bar. During the process a heat transfer of 228

kJ occurs to the nitrogen from a constant-temperature heat source held at 300Ã¸C. Deter-

mine

1. the entropy change of the nitrogen,

2. the entropy change of the heat source, and

3. the total entropy production for the overall process, in kJ/K.

Solution: (1) 1.365 (2) -0.398 (3) 0.965

10


Problem: 9.7 (7-81)

Air is compressed polytropically and reversibly in steady flow from 100 to 500 kPa. The

initial temperature is 300 K and n is 1.28. Determine

1. the work required, and

2. the heat transfer, in kJ/kg.

3. Finally, find the total entropy generation if the environmental temperature is 300 K.

Solution: ...

Problem: 9.8 (7-22)

Contained in a constant-pressure closed system is 0.5 kg of hydrogen gas at 6 bars and 17◦C

Heat transfer in the amount of 798 kJ is added to the gas from a thermal reservoir at 450

K. Calculate


2. the entropy change of the hydrogen, in kJ/K, and

3. the entropy production within an enlarged system that includes the heat transfer region,

in kJ/K.

4. Is the process reversible, irreversible, or impossible?

Solution: (1) 401 (2) 2.333 (3) 0.560

Problem: 9.9 7-59

Air enters a compressor at 1 bar and 27°C at rate of 2 kg/min and leaves at 5.8 bars and

227◦C. The power required to operate the compressor is 7.12 kW. The average temper-

ature of the external surface where heat transfer occurs may by taken to be the average

air temperature at the inlet and exit, and the surrounding temperature is 22◦C. Deter-

mine

1. the rate of heat transfer, in k/h,

2. the entropy change of the air, in kJ/Kmin,

3. the entropy production within the compressor in kJ/Kmin, and

4. the total entropy production for the composite flow and heat-transfer region, in kJ/Kmin

5. Is the process irreversible or impossible?

Solution: (1) -1292 (2) 0.026 (3) 0.080 (4)0.099

11


Problem: 9.10 (7-22)

Contained in a constant-pressure closed system is 0.5 kg of hydrogen gas at 6 bars and 17◦C

Heat transfer in the amount of 798 kJ is added to the gas from a thermal reservoir at 450

K. Calculate


2. the entropy change of the hydrogen, in kJ/K, and

3. the entropy production within an enlarged system that includes the heat transfer region,

in kJ/K.

4. Is the process reversible, irreversible, or impossible?

Solution:

(1) 401 (2) 2.333 (3) 0.560

Problem: 9.11 (10-47)

An equimolar mixture of helium and argon enters a turbine at 660 K and expands adiabatically

through a 4.5:1 pressure ratio to a temperature of 400 K. Determine

1. the actual work output, in kJ/kg of mixture, and

2. the isentropic turbine efficiency.

Solution: (1) 246 (2) 0.872

Problem:9.12 15-9

The compression ratio of an Otto cycle is 8:1. Before the compression stroke of the cycle be-

gins the pressure is 0.98 bars and the temperature is 27◦C. The heat transfer to the air per cy-

cle is 1430kJ/kg. Employing data from Table A-22, determine

1. the pressure and temperature at the end of each process of the cycle,

2. the thermal efficiency,

3. the mean effective pressure, in bars, and

4. the volume flow rate of air, measured at conditions at the beginning of compression,

needed to produce 120 kW, in m³/min.

Solution:

(1) (98;1759;5880;388)kPa ; (300;673;2250;1188)K (2) 0.50 (3) 9.38 (4) 8.77

Problem: 9.13 2006-1

12


An air-standard CARNOT cycle in a reciprocating cylinder-piston-device rejects 100 kJ/kg

as heat transfer to a sink at 300 K. The minimum and maximum pressures in the closed cycle

are 0.10 and 17.4 MPa, respectively. Perform all calculations on the basis of the air table.

State 1 is the one with highest pressure and temperature.

1. Sketch the cycle in p,v an T,s diagram, add the numbers of the states.

2. Name the processes ( e.g. isobaric expansion)

3. Find p,v,T values at the four states.

4. Find the change of internal energy, heat transfer and work transfer on unit-mass base

of the four processes.

5. Calculate the thermal efficiency by two methods: using heat/work data and using

temperatures.

6. Make a statement about the efficiency of any real process working between the same

thermal reservoirs.

Solution:

13

10 EXERGY

Problem: 10.1 (09-51)

A hydrocarbon oil is to be cooled in a heat exchanger from 440 to 320K by exchanging

heat with water which enters the exchanger at 20◦C at a rate of 3000 kg/h. The oil flows

at a rate of 750 kg/h and has an average specific heat of 2.30 kJ/kgK. Compute the change

in flow availability, in kJ/h, for

1. the hydrocarbon oil stream and

2. the water stream.

3. Find the the loss in exergy for the overall process.

4. the irreversibility of the process, in kJ/h, if TO = 17◦C.

Solution: (1) -13.25 (2) 2.13 (3) -11.12 (4) 0.038

11 GAS POWER SYSTEMS

Problem: 11.1 (9.11)

An air-standard Otto cycle has a compression ratio of 7.5. At the beginning of compression

p1= 85 kPa and T1=32°C. The mass of the air is 2 g, and the maximum temperature in the

cycle is 960 K. Determine

1) the heat rejection, in kJ

2) the net work, in kJ

3) the thermal efficiency

4) the mean effective pressure, in kPa

Solution:

(1) -0,2227 kJ (2)-0,2538kJ (3) 53,3% (4)142,2

Problem:11.2 (9.13)

Consider a modification of the air-standard Otto cycle in wich the insentropic compression

and expansion

processes are each replaced with polytropic processes having n = 1.3. The compression ratio

is 9

for the modified cycle. At the beginning of compression p1= 1 bar and and T1= 300 K.

Determine

1) the heat transfer and work per unit mass of air, in kJ/kg, for each process in the modified

cycle


3) the mean effective pressure, in bar

Solution:


(1) process; q; w; 1-2; -62,42; 267,9; 2-3; 1259,15; 0; 3-4; 34,28; -923,9: 4-1; -574,98;

0

(2) 0,507 (3) 5,86

Problem: 11.3 (9.32)

An air standard dual cycle has a compression ratio of 9. At the beginning of compression

p1= 100 kPa

and T1= 300 K. The heat addition per unit mass of air is 1400kJ/kg, with one half added

at constant

volume and one half added at constant pressure. Determine

1) the temperature at the end of each heat addition process, in K.

2) the net work of the cycle per unit mass of air, in kJ/kg


4) the mean effective pressure in kPa

Solution:

(1) T 3=1509,8K;TT 4=2076,5K; (2)-715,37; (3) 0,511; (4) 934,8

Problem: 11.4 (9.49)

The compressor and turbine of a simple gas turbine each have isentropic efficiency of

90%.

The compressor-pressure ratio is 12. The minimum and maximum temperatures are 290 K

and

1400 K, respectively. On the basis of an air-standard analysis, compare the values of (a) the

net work

per unit mass of air flowing, in kJ/kg (b) the heat rejected per unit mass of air flowing, in

kJ/kg

(c) the thermal efficiency to the same quantities evaluated for an ideal cycle

Solution:

cycle; ideal cycle (a) -338,66; -446,7; (b) -552,92; -478,2; (c) 0,38;0,483

16


Problem: 11.5 (9.55)

Reconsider Problem 11.4, but include a regenerator in the cycle. For regenerator effective-

ness

values ranging from 0 to 100%, plot

a) the heat addition per unit mass of air flowing, in kJ/kg

b) the thermal efficiency

Solution:

17

12 VAPOR POWER SYSTEMS

Problem: 12.1 (8.6)

Water is working fluid in an ideal Rankine cycle. Saturated vapor enters the turbine at 18

MPa.

The condenser pressure is 6 kPa. Determine

1) the net work per unit mass of steam flowing, ín kJ/kg

2) the heat transfer to the steam passing through the boiler, in kJ/kg of steam flow-

ing


4) the heat transfer to cooling water passing through the condenser, in kJ/kg of steam

condensed

Solution:

(1) -921,6; (2) 2339,5; (3) 0,394; (4) -1417,9

Problem:12.2 (8.28)

Water is the working fluid in an ideal Rankine cycle. Steam at 10 MPa, 600°C enters the

first

stage turbine and expands through the first-stage turbine to 0,7 MPa and then is reheated

to 480°C.

If the net power output of this cycle is 100MW determine

1. the rate of heat transfer to the working fluid passing through the steam generator, in

MW.

2. the thermal efficiency.

3. the rate of heat transfer to cooling water passing through the condenser in MW.

Solution:


(1); 245,7(2) 0,407; (3) 145,7

Problem: 12.3 (8.43)

Modify the ideal Rankine cycle of Problem 12.1 to include superheated vapor entering the

first

turbine stage at 18 MPa, 560°C, and one open feedwater heater operating at 1 MPa.

Saturated liquid

exits the open feedwater heater at 1 MPa. Determine for the modified cycle

1) the net work, in kJ/kg of steam entering the first turbine stage


3) the heat transfer to cooling water passing through the condenser in kJ/kg of steaming

entering

the first turbine-stage

Solution:

(1); -1268,3(2) 0,476; (3) -1394,1

Problem: 12.4 (8.44)

Reconsider the cycle of Problem 12.3, but include in the analysis that each turbine stage

and pump has

an isentropic efficiency of 85%.

Solution:

(1); -1100,7(2) 0,414; (3) -1558,3

19

Problems Part2

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