A mixture with 70% quality at 500 kPa is heated isothermally until its pressure is 300 kPa. Find the heat added during the process. @ 600 kPa: sf = 1.8607 kJ/kg-K sfg = 4.9606 kJ/kg-K @ 300 kPa and 151.86°C: s = 7.0888 kJ/kg-K

Find the enthalpy of water at 212°F and 14.7 psi if the dryness factor is 30%. Use the approximate enthalpy formula of liquid.

Steam at 2 MPa and 250°C in a rigid cylinder is cooled until the quality is 30%. Find the heat rejected from the cylinder. @ 2 Mpa and 250°C: υ = 0.11144 m3/kg u = 2679.6 kJ/kg @ 2 Mpa, (saturated): υf = 0.0011767 m3/kg υg = 0.09963 m3/kg uf = 906.44kJ/kg ug = 1693.8 kJ/kg

A steam generator with economizer and air heater has an overall draft loss of 25.78 cm of water. If the stack gases are at 177°C and if the atmosphere is at 101.3 kPa and 26°C, what theoretical height of stack in meters is needed when no draft fan is used? Assume that the gas constant for the flue gases is the same as that for air.

A Pelton type turbine has 25 m head friction loss of 4.5 m. The coefficient of friction head loss (Morse) is 0.00093 and penstock length of 80 m. What is the penstock diameter?

A tank contains exactly one kilogram of water consisting of liquid and vapor in equilibrium at 1 MPa. If the liquid contains one-third and the remaining is vapor of the volume of the tank, what is the enthalpy of the contents of the tank? @ 1MPa: υf = 0.0011273 m3/kg υfg = 0.19444 m3/kg hf = 762.81 kJ/kg hfg = 2015.3 kJ/kg

A throttling calorimeter is connected to a desuperheated steam line supplying steam to the auxiliary feed pump on a ship. The line pressure measures 2.5 MPa. The calorimeter pressure is 110 kPa at 150°C. Determine the entropy of the steam line. @ 110 kPa and 150°C: h2 = 2775.6 kJ/kg @ 2.5 MPa: hf = 962.11 kJ/kg hfg = 1841 kJ/kg sf = 2.5547 kJ/kg-K sfg = 3.7028 kJ/kg-K

In a gas unit, air enters the combustion chamber at 550 kPa, 227°C and 43 m/s. The products of combustion leave the combustor at 511 kPa, 1004°C and 180 m/s. Liquid fuel enters with a heating value of 43,000 kJ/kg. For fuel-air ratio of 0.0229, what is the combustor efficiency in percent?

A steam pipe having a surface temperature of 250°C passes through a room where the temperature is 27°C. The outside diameter of the pipe is 100 mm and emissivity factor is 0.8. Calculate the radiated heat loss for 3 m pipe length.

Predict the pressure of nitrogen gas at T = 200 K and υ = 0.00385 L/g and b = 0.00141 L/g; a = 0.178 L2-kPa/g2. Use Van der Waals equation.

An insulated rigid tank initially contains 1.5 lb of helium at 80°F and 50 psia. A paddle wheel with power rating of 0.02 hp is operated within the tank for 30 min. Determine the final temperature.

A piston-cylinder device whose piston is resting on top of a set of stops initially contains 0.50 kg of helium gas at 100 kPa and 25°C. The mass of the piston is such that 500 kPa of pressure is required to raise it. How much heat must be transferred to the helium before the piston starts rising?

A Francis turbine is to be operated at a speed of 600 rpm and with discharge of 4 m3/s. If r1= 0.6 m, β = 110°, and the blade height B is 10 cm, what should be the guide vane angle α1 for nonseparating flow condition at the runner entrance?

Compute the amount of condensate formed during a 10 minute warm-up of 180 meter pipe conveys the saturated steam with enthalpy of vaporization, hfg = 1947.8 kJ/kg. The minimum external temperature of pipe is 2°C. The final temperature of pipe is 195°C. The specific heat of pipe material is 0.6 kJ/kg-°C. The specific weight is 28 kg/m.

A single acting compressor has a volumetric efficiency of 89%, operates at 500 rpm. It takes in air at 100 kPa and 30°C and discharges it at 600 kPa. The air handled is 8 m3/min measured at discharged condition. If compression is isentropic, find the effective mean pressure in kPa.

A fan draws 1.42 m3 per second of air at a static pressure of 2.54 cm of water through a duct 300 mm diameter and discharges it through a duct of 275 mm diameter. Determine the static fan efficiency if total fan is 75% and air is measured at 25°C and 760 mm Hg.

An air compressor has a suction volume of 0.35 m3/s at 97 kPa and discharges at 650 kPa. How much power is saved by the compressor if there are two stages?

The initial condition of air in an air compressor is 98 kPa and 27 °C and discharges air at 450 kPa. The bore and stroke are 355 mm and 381 mm, respectively with percent clearance of 8% running at 300 rpm. Find the volume of air at suction

An ideal Brayton cycle has a net work output of 150 kJ/kg and backwork ratio of 0.4. if both the turbine and the compressor had an isentropic efficiency of 80%, the net work output of the cycle would be?

To what height will a barometer column rise if the atmospheric conditions are 13.9 psia and 68°F and barometer fluid is ethyl alcohol? Note: @ 68°F; Pv =138.5 lbf/ft^3 and specific gravity of 0.79 for ethyl alcohol:

A model pump delivering water at 180°F (γ = 60.6 lb/ ft^3; pvapor = 7.54 psia) at 900 gpm and 2500 rpm begins to cavitate when the inlet pressure and velocity are 13 psia and 22 fps. Find the required NPSH of a prototype which is 4 times larger and runs at 1100 rpm.

Saturated vapor ammonia at -16°C (hT = 1442.60 kJ/kg) leaves the evaporator and enters the compressor at -6°C (h1 = 1465 kJ/kg). The refrigerant leaves the condenser as saturated liquid at 40°C (h4 = 390.6 kJ/kg) and enters the expansion valve at 35°C (h5 = 366.1 kJ/kg). Heat rejected from the condenser amount to 50 kW. The work to compressor is 208 kJ/kg, while the heat loss from compressor is 33 kJ/kg. If 95 kJ/kg of heat are lost in the piping between the compressor discharge and condenser inlet, determine the refrigerating capacity of the system

A pump will be installed below the reservoir water surface with a required net positive suction head (NPSHR) of 50 ft. The barometric pressure is 14.3 psia, and the vapor pressure is 0.5 psia. Assume friction losses in the intake piping are 5 ft. Find the maximum allowable elevation of the pump relative to the water surface intake to avoid cavitation

A cubical tank of 2 m sides is constructed of metal plate 12 mm and contains water at 75°C. The surrounding air temperature is 16°C. Calculate the overall heat transfer coefficient from water to air. Take the coefficient of thermal conductivity of the metal as 48 W/m-K, the coefficient of heat transfer of water is 2.5 kW/m²-K and the coefficient of heat transfer of the air is 16 W/m²-K

Fuel oil in a day tank for use of an industrial boiler is tested with hydrometer. The hydrometer reading indicates a SG = 0.924 when the temperature of the oil in the tank is 35°C. Calculate the higher heating value of the fuel.

One insulated wall of a cold-storage compartment is 8 m long by 2.5 m high and consists of an outer steel plate 18 mm thick. An inner wood wall is 22.5 m thick. The steel and wood are 90 mm apart to form a cavity which is filled with cork. If the temperature drop across the extreme faces of the composite wall is 15°C. Calculate the heat transfer per hour through the wall and the temperature drop across the thickness of the cork. Take the coefficients of thermal conductivity for steel, cork and wood as 45, 0.045, and 0.18 W/m-K respectively.

In a hydraulic plant the difference in elevation between the surface of the water at intake and the tailrace is 650 ft when the flow is 90 cfs, the friction loss in the penstock is 65 ft and the head utilized by the turbine is 500 ft. The mechanical friction in the turbine is 110 Hp, and the leakage loss is 4 cfs. Find the hydraulic efficiency.

What is the rate of evaporation of a water tube boiler if the factor of evaporation is 1.10, percent rating of 200% and the heating surface area is 250 m²?

A vapor compression refrigeration system is designed to have a capacity of 150 tons of refrigeration. It produces chilled water from 22°C to 2°C. Its actual coefficient of performance is 5.86 and 35% of the power supplied to the compressor is lost in the form of friction and cylinder cooling losses. Determine the condenser cooling water required for a temperature rise of 10°C.

One kilogram of wet steam at a pressure of 8 bar (υg = 0.2404 m³/kg, υf = 0.0011148 m³/kg) and dryness of 0.94 is expanded until the pressure is 4 bar (υg = 0.4625 m³/kg, υf = 0.0010836 m³/kg). If expansion follows the law PVn = C, where n = 1.12, find the dryness fraction of the steam at the lower pressure.

Find the length of a suspension bunker to contain 181 tons of coal without surcharge; width = 4.6 m, depth = 4.3 m. The level capacity of a suspension bunker is 5/8 wdL where: w = width, d = depth and L = length. Density of coal is 800 kg/m³

A diesel power plant uses fuel with heating value of 43,000 kJ/kg. What is the density of the fuel at 25°C?

A diesel power plant consumed 1 m³ of fuel with 30°API at 27°C in 24 hrs. Calculate the fuel rate in kg/hr.

A gas turbine power plant operating on the Brayton cycle delivers 15 MW to a standby electric generator. What are the mass flow rate and the volume flow rate of air if the minimum and maximum pressures are 100 kPa and 500 kPa respectively and temperature of 20°C and 1000°C?

The weight of ammonia circulated in a machine is found to be 21.8 lb/hr. if the vapor enters the compressor with a specific volume of 9.6 ft³/lb, calculate the piston displacement, assuming 80% percent volume efficiency.

The power requirement of a Carnot refrigerator in maintaining a low temperature region at 300 K is 1.5 kW per ton. Find the heat rejected.

A reverse Carnot cycle requires 3 Hp and extracts energy from a lake to heat a house. If the house is kept at 70°F and requires 2000 Btu per minute, what is the temperature of the lake?

A 150 Hp motor is used to drive the compressor. If the heat loss from the compressor is 25 kW and the mass flow rate of the refrigerant entering the compressor is 0.50 kg/s, determine the difference of the enthalpies between the inlet and outlet of the compressor

Two boilers are operating steadily on 91,000 kg of coal contained in a bunker. One boiler is producing 1591 kg of steam per hour at 1.2 factor of evaporation and an efficiency of 65% and another boiler produced 1364 kg of steam per hour at 1.15 factor of evaporation and an efficiency of 60%. How many hrs will the coal in the bunker run the boilers if the heating value of coal is 7,590 kCal/kg?

Five hundred kilograms of poultry enter a chiller at 8°C and are frozen and chilled to a final temperature of 18°C for storage in 15 hours. The specific heat above and below freezing are 3.18 kJ/kg-°C and 1.55 kJ/kg-°C respectively. The latent heat is 246 kJ/kg and the freezing temperature is -5°C. Compute the product load.

A single-stage ammonia compressor is producing 10 tons of refrigeration and the power consumed is 15 Hp. Suction pressure is 25 psi, condensing pressure is 180 psi. Brine temperature is 20°F off brine cooler. Determine the actual coefficient of performance.

Hot gases at 280°C flow on one side of the metal plate 10 mm thickness and air at 35°C flows on the other side. The heat transfer coefficient of the gases is 31.5 W/m²-K and that of the air is 32 W/m²-K. Calculate the over-all heat transfer coefficient.

A single acting, twin cylinder, Ammonia compressor with bore equal to stroke is driven by an engine at 250 rpm. The machine is installed in a chilling plant to produce 700 kW of refrigeration at -18°C evaporating temperature. At this temperature the cooling effect per kg mass is 1160 kJ. The specific volume of vapor entering the compressor is 0.592 m^3 per kilogram. Assume 85% volumetric efficiency, determine the bore in mm.

A furnace wall consists of 35 cm firebrick (k = 1.557 W/m-K), 12 cm insulating refractory (k = 0.346) and 20 cm common brick (k = 0.692) covered with 7 cm steel plate (k = 45). The temperature at the inner surface of the firebrick is 1,230°C and at the outer face of the steel plate is 60°C. Atmosphere is 27°C. What is the value of the combined coefficient for convection and radiation from the outside wall?

Calculate the drive horsepower for pumping 1703 L/min cold water to a tank suction at 127 mmHg vacuum, delivery at 5.3 kg/cm² ga., both measured close to pump, ep = 0.65.

The journals of a shaft are 380 mm diameter, it runs at 105 rpm and the coefficient of friction between journals and bearings is 0.02. If the average load on the bearings is 200 kN, find the heat generated per minute at the bearings.

If the load on water-cooled condenser is 150,000 Btu/hr and the temperature rise of the water in the condenser is 10°F, what is the quantity of water circulated in gpm?

An insulated steam pipe located where the ambient temperature is 32°C, has an inside diameter of 50 mm with 10 mm thick wall. The outside diameter of corrugated asbestos insulation is 125 mm and the surface coefficient of still air, ho = 12 W/m²-K. Inside the pipe is steam having a temperature of 150°C with film coefficient hi = 6000 W/m²-K. Thermal conductivity of pipe and asbestos insulation are 45 and 0.12 W/m-K respectively. Determine the heat loss per unit length of pipe.

A composite wall is made up of an external thickness of brickwork 110 mm thick inside which is a layer of fiberglass 75 mm thick. The fiberglass is faced internally by an insulating board 25 mm thick. The coefficients of thermal conductivity are as follow: Brickwork-1.5 W/m-K Fiberglass-0.04 W/m-K Insulating board-0.06 W/m-K The surface transfer coefficients of the inside wall is 3.1 W/m²-K while that of the outside wall is 2.5 W/m²-K. Take the internal ambient temperature as 10°C and the external temperature is 27°C. Determine the heat loss through such wall 6m high and 10 m long.

A cylindrical flash tank mounted with its axis horizontal is used to separate liquid ammonia from ammonia vapor. The ammonia bubbles through the liquid with 70 m³/min leaving the disengaging surface. The disengaging rate is limited to 60 m/min and the liquid level is to operate with the liquid level one-third to the diameter from the top. Determine the diameter if the tank is 1.5 m long.

A wall with an area of 10 m2 is made of a 2 cm thickness of white pine (k = 0.133 W/m-°C) followed by a 10 cm of brick (k = 0.649 W/m-°C). The pine is on the inside where the temperature is 30°C while the outside temperature is 10°C. Assuming equilibrium conditions exist, what is the temperature at the interface between the two metals?

How many watts will be radiated from a spherical black body 15 cm in diameter at a temperature of 800°C?

An ideal gas turbine operates with a pressure ratio of 10 and the energy input in the high temperature heat exchanger is 300 kW. Calculate the air flow for temperature limits of 30°C and 1200°C.

A water tube boiler has a capacity of 1000 kg/hr of steam. The factor of evaporation is 1.3, boiler rating is 200%, boiler efficiency is 65% and heating surface area is 0.91 m² per bo.Hp. And the heating value of fuel is 18,400 kCal/kg. The total coal available in the bunker is 50,000 kg. Determine the no. of hrs. to consume the available fuel.

A cold storage compartment is 4.5 m long by 4 m wide by 2.5 m high. The four walls, ceiling and floor are covered to a thickness of 150 mm with insulating material which has a coefficient of thermal conductivity of 5.8x10-2W/m-K. Calculate the quantity of heat leaking through the insulation per hour when the outside and inside face temperature of the material is 15°C and -5°C respectively.

To cool farm products, 300 kg of ice at -4.4°C are placed in bunker. Twenty four hours later the ice has melted into water at 7.2°C. What is the average rate of cooling provided by the ice in kJ/hr?

Kerosene is the fuel of a gas turbine plant: fuel-air ratio, mf = 0.012, T3 = 972 K, pressure ratio, rp = 4.5, exhaust to atmosphere. Find the available energy in kJ per kg air flow. Assume k = 1.34 and Cp = 1.13.

A 305 mm x 457 mm four stroke single acting diesel engine is rated at 150 kW at 260 rpm. Fuel consumption at rated load is 0.26 kg/kW-hr with a heating value of 43,912 kJ/kg. Calculate the brake thermal efficiency

Steam is expanded through a nozzle and the enthalpy drop per kg of steam from the initial pressure to the final pressure of 60 kJ. Neglecting friction, find the velocity of discharge and the exit area of the nozzle to pass 0.20 kg/s if the specific volume of the steam at exit is 1.5 m³/kg

The surface temperature of the hot side of the furnace wall is 1200°C. It is desired to maintain the outside of the wall at 38°C. A 152 mm of refractory silica is used adjacent to the combustion chamber and 10 mm of steel covers the outside. What thickness of insulating bricks is necessary between refractory and steel, if the heat loss should be kept at 788 W/m²? Use k = 13.84 W/m-K for refractory silica; 0.15 for insulating brick, and 45 for steel

2.5 liters of superheated steam at 25 bar and 400 C (υ = 0.1252 m³/kg) is expanded in an engine to a pressure of 0.1 bar (υg = 14.674 m³/kg, υf = 0.0010102 m³/kg) when its dryness fraction is 0.9. Find the final volume of the steam.

Steam with an enthalpy of 800 kCal/kg enters a nozzle at a velocity of 80 m/s. Find the velocity of the steam at the exit of the nozzle if its enthalpy is reduced to 750 kCal/kg, assuming the nozzle is horizontal and disregarding heat losses. Take g = 9.81 m/s² and J constant = 427 kg-m/kCal.

In a hydro-electric plant, water flows at 10 m/s in a penstock of 1 m³ cross-sectional area. If the net head of the plant is 30 m and the turbine efficiency is 85%, what is the turbine output?

A liquid with a specific gravity of 1.26 is being pumped in a pipeline from A to B. At A, the pipe diameter is 60 cm and the pressure is 300 kN/m². At B, the pipe diameter is 30 cm and the pressure is 330 kN/m². Point B is 1.0 m lower than A. Find the flow rate if the pump puts 16kW into the flow. Neglect head loss

Calculate the air power of a fan that delivers 1200 m³/min of air through a 1 m x 1.5 m outlet. Static pressure is 120 mm WG and density of air is 1.18.

An air compressor takes in 9 kg/min of air at 98 kPa; υ1 = 0.125 m³/kg and discharges it at 680 kPa; υ2 = 0.03 m³/kg. The increase of internal energy is 93 kJ/kg and the work done on air is 163 kJ/kg; the change in potential and kinetic energy are neglected. How much heat is transferred per kg of air?

If the air required for combustion is 20 kg per kg of coal and the boiler uses 3000 kg of coal per hr, determine the mass of gas entering the chimney. Assume an ash loss of 15%.

A centrifugal pump discharged 20 L/s against a head of 17 m when the speed is 1500 rpm. The diameter of the impeller was 30 cm and the brake horsepower was 6.0. A geometrically similar pump 40 cm in diameter is to run at 1750 rpm. Assuming equal efficiencies, what brake horsepower is required?

The tank of an air compressor has a volume of 3 ft³ and is filled with air at a temperature of 40°F. If a gage on the tank reads 150 psig, what is the mass of the air in the tank?

A pump delivers 20 cfm of water having a density of 62 lb/ft³. The suction and discharge gage reads 5 in. Hg vacuum and 30 psi respectively. The discharge gage is 5 ft above the suction gage. If pump efficiency is 70%, what is the motor power?

A two-stage compressor receives 0.35 kg/s of air at 100 kPa and 269 K and delivers it at 5000 kPa. Find the heat transferred in the intercooler.

Specific volume is the number of cubic meters of mixture per kilogram of dry air. If dry air has these following properties: Ra = 287 J/kg-K, T = 303 K, Pa = 99.604 kPa. Solve for the specific volume

A hydro-electric impulse turbine is directly coupled to a 24 pole, 60 Hz alternator. It has a specific speed of 60 rpm and develops 3000 Hp. What is the required diameter assuming a peripheral speed ratio of 0.45?

A reciprocating compressor handles 1,400 cfm of air measured at intake where P1 = 18 psia and T1 = 90°F. The discharge pressure is 92 psia. Calculate the work if the process of the compression is isothermal.

A centrifugal pump with a 3 ft impeller diameter operates at 800 rpm. If the speed is to be increased to 1200 rpm, determine the impeller diameter that should be used so that the same shaft input power would be required.

The tailwater and headwater of a hydro-electric plant are 150 m and 200 m respectively. What is the water power if the flow is 15 m³/s and a head loss of 10% of the gross head?