Questions and Answers of Thermodynamics Concepts And Applications

Electrical heating elements heat a 5-gal/min flow of water at 30 psig from 62 F to 164 F. The barometric pressure is one standard atmosphere. Determine (a) The wattage required (b) The
Cool air enters a classroom at 12.8°C. The cool air is heated by the students in the room, by the lights in the room, and by heat transfer through the classroom walls. The total heat-transfer rate
Saturated liquid water at 0.3 MPa enters a steady-flow boiler. Inside the boiler, the water is heated at constant pressure to 580K. The potential and kinetic energies are negligible.A. Determine the
Air undergoes a steady-flow, constant-pressure heating process at 150 kPa from 20°C to 150°C. Determine the increase in the specific internal energy of the air and the mass-specific heat addition,
Superheated steam (8 MPa, 900 K) enters a turbine with a flow rate of 0.16 kg/s. The steam exits at 16 kPa. Determine the power produced by the turbine if the expansion process is isentropic, i.e.,
In a coal-fired power plant, steam enters a turbine at 800 K and 4 MPa at a rate of 189 kg/s. The steam expands and exits the turbine at 100 kPa with a quality of 0.97. Determine the power produced
Air enters an adiabatic steady-flow gas turbine at 650 K and 550 kPa and leaves at 430 K and 100 kPa. The mass flow rate of the is 45.5 kg/s. Treat the air as an ideal gas and use average
Air at 400°C and 0.4MPa is steadily supplied to an adiabatic gas turbine. The air leaves the turbine at 200°C and 0.10135 MPa. Neglecting changes in potential energy and kinetic energy, determine
Steam enters an adiabatic turbine at 800 K and 6.0 MPa and leaves at 700 K and 3.0 MPa. The mass flow rate is 450 kg/hr. The potential and kinetic energies can be neglected. Determine the
During the operation of a steam power plant, the steam flow rate is 227,000 kg/hr with turbine inlet conditions of 4 MPa and 800 K and turbine exhaust (condenser inlet) conditions of 8 kPa and 90%
During the operation of a steam power plant, steam enters the turbine with a flow rate of 230,000 kg/hr at 3.5 MPa and 550° C. The turbine exhaust (condenser inlet) condition is 0.01 MPa with 85%
What is the minimum-power motor (hp) that would be necessary to operate a pump that handles 85 gal/min of city water increasing the water pressure from 15 to 90 psia? The water is at room
A pump is used to remove water after a flood. Estimate the mass-specific work (kJ/kg) required to operate this pump, assuming the process is adiabatic and steady-flow. The water enters the pump at
A pump is used to supply water at a rate of 3 kg/s to a spray cooling system used in a heat-treating operation. Estimate the power required to operate this pump, assuming the process is adiabatic and
Water at 283K and 3.45 MPa enters a steady-flow control volume (open system) at a rate of 0.91 kg/s. Wet steam at 101.325 kPa with a quality of 0.25 also enters the control volume but at a rate of
In certain situations when only superheated steam is available, a need for saturated steam may arise. This need can be met in an adiabatic de super heater, in which liquid water is sprayed into the
A well-insulated, 80-gal (0.3028m3), electric hot-water heater initially contains water at 322 K (120 F). Hot water is withdrawn from the tank at 3 gal/min, while cold water at 283 K (50 F) enters to
A tank having a volume of 5.66 m3 (200 ft3) contains saturated water vapor at 138kPa (20psia). A line is attached to the tank in which vapor flows at 689 kPa (100 psia) and 478 K (400 F). Steam from
Moisture in a steam pipeline can result in corrosion, scaling, and other problems; hence, it is desirable to remove suspended water droplets from the flow. One way to accomplish this is to use a
Wet steam at 380 K enters a cyclonic separator at 0.059 kg/s. The inlet diameter is 62.5 mm. What is the maximum allowable quality such that the inlet velocity does not exceed 25 m/s?
A steam boiler is fed with water at the rate of 1 kg/s. Steam exits the boiler at 100 kPa and 380 K. The average velocity of the steam in the pipe is 10 m/s. What is the pipe diameter?
Water enters a garden-hose nozzle with an average velocity of 1.8 m/s. The diameter at the nozzle entrance is 15 mm. The open nozzle is such that the effective flow area at the exit is an annulus
Air enters a constant-diameter tube with an average velocity of 2 m/s at a temperature of 400 K and a pressure of 0.12MPa. The air exits the tube at a temperature of 350 K and a pressure of 0.10 MPa.
Air is heated as it flows through a constant-diameter tube in steady flow. The air enters the tube at 345 kPa and 300 K and has an average velocity of 3.0 m/s at the entrance. The air leaves at 310
Air is heated as it flows through a 75-mm-diameter pipe at a rate of 0.045 kg/s. At station 1, the air has an average velocity of 5.5 m/s and a temperature of 311 K. Downstream, at station 2, the air
A gas enters a steady-flow system through a 5-cm-diameter tapering duct with an average velocity of 3.5m/s and a density of 1.20kg/m3. It leaves the duct with a specific volume of 0.31m3/kg through a
A saturated liquid–vapor H2O mixture enters a 25-mm-inner-diameter tube at a temperature of 490 K with a quality of 0.95. The mixture is heated at constant pressure as it travels through the tube
The average air velocity in the intake duct of an air conditioner is 3 m/s. The intake air temperature is 35°C. The air comes out of air conditioner at 20°C and flows through a duct, also at
A saturated liquid vapor H2Omixture enters a 30-mm-inner-diameter tube at a temperature of 425 K with a quality of 0.97. The mixture is heated as it travels through the tube and exits at 520 K and
Steam enters a 100-mm-inner-diameter pipe at 760 K and 4.0 MPa. The steam cools as it travels through the pipe and exits at 4 MPa with a quality of 0.93. The average velocity of the fluid exiting the
A saturated liquid–vapor H2O mixture enters a 25-mm-inner-diameter tube at a temperature of 490 K with a quality of 0.95. The mixture is heated as it travels through the tube and exits at 620 K and
Determine the instantaneous kinetic and potential energies (kJ) of a 90-kg object moving at a velocity of 10 m/s, 10 m above the surface of a planet where g = 7m/s2.
Determine the instantaneous kinetic and potential energies (kJ) of a 860-kg automobile crossing the Rocky Mountains on Trail Ridge Road traveling at 35 mph at an elevation of 9700 feet above sea
Air at 100 °C and 0.2 MPa flows at an average velocity of 30 m/s through a pipe whose cross-sectional flow area is 0.2m2. Determine the mass flow rate of the air in kg/s.
Compressed air is introduced into the ballast tank of a submarine and drives the water out of the tank at the rate of 2m3/s when the submarine is at a depth of 10 m. The pressure at this depth is
Steam at 580 K and 0.70 MPa flows through a 3-in-diameter pipe at 15 m/s. Determine the mass flow rate in kg/hr.
A feedwater pump for a 30-MW steam power plant pumps water, which enters as a saturated liquid at 0.78 MPa with a flow rate of 40.0 kg/s. Determine the minimum inlet pipe diameter required if the
Water exits a nozzle into the atmosphere at 0.1 MPa. The flow has an essentially uniform velocity of 0.7 m/s. The nozzle outlet diameter is 15mm, and the temperature of the water is 305 K. Determine
Water with a density of 990 kg/m3 is discharged by a pump at a rate of 3 × 105 cm3/min from a pipe. Determine the mass flow rate in units of kg/min and lbm/hr.
Natural gas enters a 150-km-long pipeline (0.30-m inner diameter) at 6.5 MPa (gage) and exits at 3.0 MPa (gage). The natural gas flow rate is 24.06 kg/s. The temperature of the natural gas is 17° C
Liquid water at 380 K and 5 MPa flows at a rate of 1 gal/min in a nominal 1-in, schedule-40 pipe (of 1.049-in inside diameter). Determine the average velocity (m/s) of the water.
A small pipe with a valve connects two rigid tanks, as shown in the sketch. The volume of tank A is 0.6m3 and it initially contains 0.03m3 of liquid water and 0.57m3 of water vapor in equilibrium at
Superheated steam initially at 420 K and 0.3MPa (state 1) is held in the device shown in the sketch. At state 1, the plunger is 0.6m away from the cylinder, and the piston is 0.25m above the bottom
Air is contained in a vertical cylinder fitted with a frictionless piston and a set of stops, as shown in the sketch. The cross-sectional area of the piston is 0.05m2. The air is initially at 400 °C
An uninsulated rigid 0.8-m3 tank initially contains steam at 860 K and 0.9 MPa. The tank then cools until equilibrium is established at a final temperature of 40 °C.A. Determine the pressure
Initially, a rigid 6-m3 tank contains helium (assumed to be an ideal gas) at 300 K and 0.10 MPa. The tank is then heated until the temperature reaches 400 K. A pressure-relief valve at the top
A 18-cm-diameter spherical balloon contains air at 1.2 atm and 25 °C. Determine the mass of the air in the balloon.
With the valves open, the radiator of a steam heating system has a volume of 0.06m3 and contains dry saturated vapor (x = 1.0) at 0.14MPa. After the valves are closed on the radiator, the pressure
A vertical, closed, cylindrical tank 0.4m high with 0.3 m diameter contains a saturated mixture of water and steam at 400 K. The depth of the liquid is 25 mm. Determine the mass and quality of the
Initially, a rigid 0.00246-m3 tank is filled with saturated liquid water at 100 kPa. A cover is placed on the tank, and the water then cools to 294 K. The diameter of the opening underneath the cover
A rigid 0.0283-m3 tank initially containing water at 380 K and 0.070 MPa cools until it reaches 294 K.A. Determine the final pressure (MPa) in the tank.B. Determine the final liquid mass (kg) and
During the expansion process at a crank angle θ = 400°, the temperature and pressure in the cylinder of a spark-ignition engine are 2400 K and 1.8 MPa, respectively. (Note: Top center is 360.) The
A gas is confined in a 0.057-m3 rigid tank at 57 °C and 690 kPa. The mass of the gas is 0.23 kg.A. Determine the apparent molecular weight (mass) of this gas in kg/kmol.B. After a heating process,
A rigid tank initially contains a mixture of liquid water and water vapor at a pressure of 100 kPa. Determine the proportions by volume of liquid and vapor necessary to make the mixture pass through
Consider a steam turbine in which steam enters at 1500 psia and 900 F with a flow rate of 85.4 lbm/s. As shown in the sketch for Problem 3.55, a portion of the steam is extracted from the turbine
Consider a steam turbine in which steam enters at 10.45 MPa and 780 K with a flow rate of 38.739 kg/s. As shown in the sketch for Problem 3.55, a portion of the steam is extracted from the turbine
Consider the mixing chamber shown in the sketch. Two streams of fluid enter the chamber and two streams exit. Determine whether the system is in steady state, and, if not, determine the magnitude
Synthetic air is made by blending pure O2 and pure N2. All streams are at 100 kPa and 298 K. The synthetic air has a composition of 79% N2 and 21% O2 by volume with an apparent molecular weight of
While preparing a bath you have both the hot- and cold-water faucets on. The ambient pressure is 100 kPa. This pressure can also be assumed to be the pressure associated with each stream. The cold-
While preparing a bath you have both the hot- and cold-water faucets on. A steady state has been reached with the water level in the tub constant. The ambient pressure is 100 kPa. This pressure can
While preparing a bath you have both the hot-and cold-water faucets turned on. For the conditions indicated, what is the necessary volume flow rate at the exit for the total mass in the tub to remain
Hot water at 120 F (48.9 °C) from a water heater is used to supply simultaneously a shower with 2.5 gal/ min, an automatic dishwasher with 6.5 gal/ min, and a washing machine with 9.4 gal/min. Cold
Consider a steam turbine in which steam enters at 10.0 MPa and 780 K with a flow rate of 39.0 kg/s. As shown in the sketch, a portion of the steam is extracted from the turbine after partial
Consider the stepped cylindrical tank shown in the sketch below. The tank is initially filled with water (ρ = 997 kg/m3) to a height of 0.7 m. A plug in the bottom of the tank is quickly removed and
Consider a cylindrical tank with a diameter D of 1.0m and a height H of 1.5m as shown in the sketch below. Water (ρ = 1000 kg/m3 enters the tank at the bottom through a tube with diameter d of 5mm
To fill an initially empty 275-gal tank with fuel oil requires 12 min. If the flow from the filling nozzle is steady, estimate the velocity of the fuel oil exiting the 20-mm-diameter filling nozzle.
At steady state, fuel oil is supplied at 0.50 cm3/s to an oil furnace for home heating. The fuel oil density is 877 kg/m3. Combustion air at 19 °C and 100 kPa enters the furnace with a mass flow
The water faucet on a stoppered kitchen sink was accidentally left slightly open. The faucet volumetric flow rate is 0.12 gal/min. The ambient pressure is 100 kPa. Formally apply the principle of the
Consider a rectangular sheet-metal duct carrying air at 60 F at 100 kPa. The volume flow rate at the entrance to the duct is 1200 ft3/min. A portion of the air exits through a grille, as shown in the
At steady state, fuel oil is supplied at 0.01 gal/min to an oil furnace for home heating. (1 gal = 3.785 10–3m3.) The fuel oil density is 870 kg/m3. Combustion air at 65 F and 1 atm enters the
Geothermal power plants utilize steam produced at locations where the hot core of the earth is quite close to the surface Yellowstone National Park is such a location, with many hot springs and
Process steam is extracted from a turbine in a paper mill power plant. Moisture is removed from the extracted steam using a cyclonic separator before it enters a distribution line. The steam enters
Process steam is extracted from a turbine in a paper mill power plant. Moisture is removed from the extracted steam using a cyclonic separator before it enters a distribution line. The steam enters
Moisture in a steam pipeline can result in corrosion, scaling, and other problems; hence, it is desirable to remove suspended water droplets from the flow. One way to accomplish this is to use a
An automobile is cruising along a level highway steadily at 62 miles/hr. The onboard computer indicates a fuel economy of 26 miles/gal. The engine is operating at an air fuel ratio of 14.7 (mass
Oil enters an open system (control volume) at a rate of 100 kg/s through pipe 1. Oil leaves the open system (control volume, through pipe 2 at 50 kg/s and through pipe 3 at 70 kg/s. Determine the
A 1-m-diameter tank (empty at time zero) is being filled by liquid water flowing through a 0.025-m-diameter pipe at an average velocity of 30 m/s with a temperature of 100C. Evaporation is
A rigid tank (volume V) containing an ideal gas is initially at T1 and P1. At time zero, an exit pipe (area A) is opened and gas flows out of the tank at velocity V = K(P – Patm)1/2, where P is the
Search online for the following information and convert it to each of the units requested. Set up a spreadsheet to show your results and to the speeds. You will find conversion factors in the
You must time the filling of four cups or more. A calibrated milk jug with the top cut off works well. Do not use a one- or two- cup measurement. Use a spreadsheet for the calculations below and
Water with a density of 990 kg/m3 is discharged from a pipe with a volume flow rate of 0.4m3/min. Determine the mass flow rate in units of kg/s.a. 396 kg/s, b. 6.6 kg/s, c. 0.4
Water is flowing through a 4-cm diameter pipe at a volume flow rate of 0.3m3/min. What is the flow velocity in the pipe? a. 12.5 m/s, b. 24.0 m/s, c. 1.0m/s, d. 4.0m/s.
Air at 200 kPa and 50C flows through a 9-cm diameter pipe at a mass flow rate of 0.15 kg/s. What is the flow velocity? a. 12.7 m/s, b. 10.9 m/s, c. 15.7 m/s,d. 7.8 m/s.
Water at 300 kPa and 440 K flows through a 12-cm diameter pipe at a velocity of 16 m/s. What is the mass flow rate? a. 0.273 kg/s.b. 0.12 kg/s.c. 1.09 kg/s.d. 0.09 kg/s.
Air at 150 kPa and 350 K enters a compressor with a velocity of 30 m/s. If the air exits the compressor at 2 MPa and 600 K, what is the outflow velocity when the inflow and outflow duct diameters are
Water enters a nozzle with a velocity of 0.4 m/s. If the nozzle inflow diameter is 2 cm and the outflow diameter is 0.7 cm, what is the outflow velocity?Assume that the water is
Water at 500 kPa and 600 K flows through a 15-cm-diameter pipe at a mass flow rate of velocity of 0.2 m3/s. What is the flow velocity? a. 1.5 m/s.b. 6.2 m/s.c. 19.5 m/s.d. 12.4 m/s.
Water at 6.90 MPa and 95 °C enters the steam-generating unit of a power plant and leaves the unit as steam at 6.90MPa and 850 °C. Determine the following properties in SI units using the NIST
How to Use the NIST Software. Given the following property data for H2O, designate the region, line, or point in T–v or P–v space (i.e., compressed liquid, liquid–vapor mixture, superheated
What is the temperature or quality of H2O in the following states? A: ننا ت ت ق ة B: C: D: E: 20 °C, 2000 kJ/kg (u) 2 MPa, 0.1 m3/kg 140 °C, 0.5089 m/kg 4 MPa, 25 kg/m 3 2 MPa, 0.111m3/kg
Steam is condensing in the shell of a heat exchanger at 305 K under steady conditions. The volume of the shell is 2.75m3. Determine the mass of the liquid in the shell if the specific enthalpy of the
A 0.6-m3 tank contains 0.2 kg of H2O at 350 K. Determine the pressure in the tank and the enthalpy of the H2O. H₂O M = 0.2 kg T= 350 K Of Rigid tank V = 0.6 m³
Wet steam exits a turbine at 50 kPa with quality 0.83. Determine the following properties of the wet steam: T, v, h, u, and s. Give the units. Steam in Steam turbine Steam out Pexit = 50 kPa Xexit =
In a proposed automotive steam engine, the steam after expansion would reach a state at which the pressure is 200 kPa (gage) and the specific volume is 0.2997 m3/kg. Atmospheric pressure is 100 kPa.
How to Interpolate. Apply interpolation to the property data in Table B.1 to determine the following properties of saturated liquid H2O:A. The specific volume at 300.7 KB. The saturation pressure at
Steam expands is entropically (i.e., at constant entropy s) from 2MPa and 500 K to a final state in which the quality is 0.90. Determine the final-state temperature, pressure, and specific volume.
Consider 0.25 kg of steam contained in a rigid container at 600 K and 4MPa. The steam is cooled to 300 K. Determine the entropy change of the H2O associated with this cooling process. Note: Find S2
How to Interpolate. Apply interpolation to the property data in Table B.2 to determine the following properties of saturated vapor H2O:A. The specific volume at 50.8 kPa.B. The saturation temperature
Apply interpolation to the property data in Table B.3 to determine the following properties of superheated steam:A. The specific volume at 637 K and 700 kPaB. The mass-specific enthalpy at 752 K and
A water heater operating under steady-flow conditions delivers 10 liters/min at 75 °C and 370 kPa. The input conditions are 10 °C and 379 kPa. What are the corresponding changes in internal energy

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