Steam at 285psia (tsat=413F, hg=1202.45Btu/lb) enters a convective superheater in a saturated state and leaves at 600F(h=1316.4). The hot gas (cp=0.241Btu/lb-F) leave the superheater at 1150F. There are 1.6 lbg/lbsteam and the total steam flow is 17,580lb/hr. If the transmittance is U=4Btu/hr-ft2-F, find the temperature of gas entering the superheater and the heating surface area.

An open vessel 30cm in diameter and 90cm high is filled with water to a depth of 45cm. Find the magnitude of the velocity in rad/s such that the vortex is just at the bottom.

In a food processing plant a brine solution is heated from 6c   to 12C in a double- pipe heat exchanger by water entering at 50 C and  leaving at 40c at the rate of 0.166 kg/s. If the overall heat  transfer coefficient is 850 W/m, what heat exchanger area  is required for counter flow ?

•An auditorium seating 1500 people is to be maintained at 80°F dry bulb and 60°F wet bulb temperature when outdoor air is at 91°F dry bulb and 75°F wet bulb. Solar heat load is 110,000 Btu/hr and supply air is at 60°F, determine the amount of supply air

An open tank 1.82m square, weighs 3,425N and contains 0.91m of water. It is acted upon by an unbalanced force of 10,400N parallel to the pair of sides. What must be the height in m of the sides of the tank so that no water will be spilled?

What is the discharge capacity if a concrete pipe culvert 4ft in diameter and 10m long if the difference in water level at the outlet is 1.52m. Assume coefficient of discharge of 0.74

The weight of a certain crown in air was found to be 15N and its weight in water is 12N. Compute its specific gravity.

The constituents of a fuel are 85% carbon, 13% hydrogen, and 2% oxygen. When burning this fuel in a boiler  furnace the air supply is 50% in excess of the theoretical minimum required for complete combustion, the inlet temperature of the air being 31°C and exit gas  temperature of 280°C. Calculate the heat energy carried away to waste in the flue gases expressed as a percentage of the heat energy supplied, taking the specific heat of the flue gases as 1.005 kJ/kgK

Gate AB is vertical and 5 ft wide by 3ft high hinged at point A and restrained by a stop at point B. If stop B will break if the force on it reached 9000lb, find the critical water depth.

Horizontal orifice under a constant head of 1.3m issues a jet which hits a point 5m below the centerline of the orifice and 5m horizontally from the vena contracta. What is the coefficient of velocity?

If the velocity of water is 8m/s and the pressure is 140kPa on the discharge side of a pump.      What is the head of the pump if the velocity is 4m/s and pressure is 90kpa before the pump?

Which of the following refrigerant does not belong to A1 Safety group classification?

An insulated steam pipe passes through a room in which the air and walls are at 250 C. The outside diameter of the pipe is 70mm, and its surface temperature and emissivity are 2000 C and 0.8 respectively. If the coefficient associated with free convection heat transfer from the surface to the air is 15W/m2-K, what is the rate of heat transfer loss from the surface per unit length of pipe

A 16cm diameter pipe of length 200m and surface elevation of 50m from the discharge of the pipe with f=0.03 and loss of head due to entrance coefficient k=0.5 what is the velocity of flow in m/s?

Water flows at 0.2m3/s through a 300mm diameter, 120m long pipe under a pressure difference of 280mm Hg. Compute the friction factor

•A small pump serving as model, when tested in laboratory using water at 3600 rpm, delivered 30 cfs at a head of 125 ft. If the efficiency of this model pump is 84%, predict the 76 horsepower input to the prototype pump if it is to develop the same head as model pump and the model pump has a scale ratio of 1:10. Assume the efficiency of the prototype pump is 90%. 

The charge in a Diesel engine consists of 18.34 grams of fuel, with lower heating value of 42,571 kJ/kg, and 409 grams of fuel and products of combustion. At the beginning of compression, T1 = 60°C. Let rk = 14. For constant cp = 1.11 kJ/kg-°C, what should be the cut-off ratio in the corresponding ideal cycle?

The annual peak load on a 15,000kW power plant is 10,500kW. Two substations are supplied by this plant. Annual energy dispatched through substation A is 27,500,000 kW-hr with a peak at 8900kW, while 16, 500,000 are sent through B with a peak 6650kW. Neglect line losses. Find the diversity factor between substations and the capacity factor of the plant

A shell-and-tube heat exchanger must transfer 205 kW to a solution  with a specific heat of 3.26 kJ/kg-K and change its temperature from  65c to 93C Steam is available at 250 kPa (tsat=127.35C). The unit convective  coefficient is 3400 W/m  for the inside and 7300 W/m -K for the  outside. The thermal conductivity for the tubes is 111 W/m-K, and the tubes have 4.0 cm O.D. and 3.0 cm I.D. and are 3 m long.   Determine the number of tubes required

A furnace burns coal with the ff. ultimate analysis:     C=80.17%,  H=4.34%,  O=2.69%,  N=1.45%,  S=0.84%,  A=7.09%  W=3.42%   For 15% excess air and complete combustion. Determine the actual air needed per kg  if water is to be included and air is at 28C and  0%RH(w=0.0143kgv/kgda).

•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 certain gas at 101.325 kPa and 10°C whose volume is 2.83 m3 capacity. Before admission, the storage vessel contained gas at a pressure and temperature of 137.8 kPa and 26°C; after admission, the pressure increased to 1171.8 kPa. What should be the final temperature of the gas in the vessel in Kelvin?  

Two large plane surfaces are 1 in apart, and the space between them  is filled with a liquid of absolute viscosity 0.02000 lb-sec/ft2. Assuming the velocity gradient to be a straight line, what force is required to pull a very thin plate of 4 ft2 area at a constant speed of 1 ft/sec if the plate is 1/3 in from one of the surfaces

Two pipes with the same friction factor and length are parallel. If the first pipe has twice the diameter of the second, what must be the ratio of their flow

Steam at 30 bar, 375°C, is generated in a boiler at the rate of 30000 kg/h from feed water at 130°C. The fuel has a calorific value of 42 MJ/kg and the daily consumption is 53 tonne. Calculate  the equivalent engine power if the overall efficiency of the plant is 0.13

If the center of gravity of a ship in the upright position is 10m above the center of gravity of the portion under water, the displacement being 1000 metric tons, and the ship is tipped 300 causing the center of buoyancy to shift sidewise 8m. What is the value of the moment in kg-m

A balloon weighs 300 lb and has a volume of 15,000ft3. It is filled with helium, which weighs 0.0112pcf at the temperature and pressure of the air, which weighs 0.0807 pcf. What load will the balloon support

•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.

A 6 in thick concrete wall, having thermal conductivity  k=0.50 Btu/h , is  exposed to air at 70 F on one side and air at 20 F on the opposite side. The heat transfer coefficients are  hi=2.0 Btu/h on the 70F side and ho=10 Btu/h  on the 20F side. Determine the heat transfer rate

A logging firm in Isabella operates a Diesel Electric Plant to supply its electric energy requirements. During a 2 hour period, the plant consumed 250 gallons of fuel at 80°F and produced 2900 kW-hrs. Industrial fuel is used at 30°API and was purchased at P30/li at 60°F. Determine the overall thermal efficiency of the plant.  

If a triangle of height d and base b is vertical and submerged in a liquid with its vertex at the liquid surface, compute the depth to its center of pressure

A vertical jet of water supports a load of 200N at a constant vertical height of  2m  from the tip of the nozzle. The diameter of the jet is 25mm. Find the velocity of the jet at the nozzle  tip.

A 300mmx75mm venture meter is inserted in a 300mm diameter pipeline where water flows at 55L/s. Neglecting losses, compute the drop in pressure head from the inlet to the throat

Determine the monochromatic emissive power at 1.30  m of a  blackbody at a temperature of 1500 F .

Determine the critical radius in cm for an asbestos-cement covered pipe. Kasb=0.208 W/m .The external heat-transfer coefficient is 1.5 Btu/h

A classroom that normally contains 40 people is to be air-conditioned with window air-conditioning units of 5 kW cooling capacity. A person at rest may be assumed to dissipate heat at a rate about 360 kJ/hr. There are 10 light bulbs in the room, each with a rating of 100 watts. The rate of heat transfer to the classroom through the walls and the windows is estimated to be 15,000 kJ/hr. If the room is to be maintained at a constant temperature of 21°C, determine the number of window air-conditioning units required.

C8H18  fuel is burned with 25% excess. Calculate the weight of air needed including moisture if air is at 25C and 60% RH.(w=0.012)

A waste heat recovery boiler produces 4.8Mpa (dry saturated) steam from 104C feedwater. The boiler receives energy from 5kg/s of 954C dry air. After passing through the waste heat boiler, the temperature of the air has been reduced to 343C. How much steam in kg is produced per second? At 4.8mPa dry saturated, h=2796kJ/kg

A certain coal has the following ultimate analysis: C = 70.5% H = 4.5% O2 = 6% N2 = 1.0% S = 3.0% Ash = 11% Moisture = 4% A stoker fired boiler of 175,000 kg/hr steaming capacity uses this coal as fuel. Calculate the volume of air in m3 /hr with air at 60°F (15.6°F) and 14.7 psia (101.325 kPa) the coal is burned with 30% excess air. Boiler efficiency is 70% and factor of evaporation of 1.10.  

A 22.7kg/s flow of air enters a preheater at 28C and leaves at 150C; 23.7kg/s of exhaust gases, cp=1.09kJ/kg-K, enters at 315C. The overall coefficient of heat transfer is 710 W/m2-C. Determine the surface area for counterflow

A cubical tank of 2 m sides is constructed of metal plate 12 mm thick contains water at 75°C. The surrounding air temperature is 16°C. Calculate  the heat loss through each side of tank per minute. Take the coefficient of thermal conductivity of the metal as 48 W/mK, the coefficient of heat transfer of the water 2.5 kW/m²K, and the coefficient of heat transfer of the air 16 W/m²K.

A steel pipe (having a 5.0 cm OD is covered with a 4.2 cm thick layer of magnesia ( which is in turn covered with a 3.4 cm layer of fiberglass insulation( k=0.048 W/m-K). The pipe wall outside temperature is 370 K and the outside surface temperature of the fiberglass is 305 K. What is the interfacial temperature between the magnesia and the fiberglass?

Saturated steam at 500K flows in a 20cm-ID, 21cm-OD, pipe. The pipe is covered with 8cm of insulation that has a thermal conductivity of 0.1W/mK. The pipe’s conductivity is 52W/m-K. The ambient temperature is 300K. The unit convective coefficient on the inside is 18,000W/m2-K and on the outside is 12W/m2-K. Determine the heat loss from 4m of pipe.

Determine the ASHRAE number designation for dichlorotetraflouroethane, CClF2CClF2

The equivalent evaporation of a boiler, from and at 100C, is 15kgsteam/kg fuel, and the calorific value of the fuel burned is 41.9MJ/kg. Find the efficiency of the boiler.

The hot combustion gases of a furnace are separated from the ambient air and its surrounding, which are at 250 C, by a brick wall 0.15m thick. The brick has a thermal conductivity of 1.2W/m-K and a surface emissivity of 0.8. Under steady state conditions and outer surface temperature of 1000 C is measured. Free convection heat transfer to the air adjoining this surface is characterized by a convection coefficient of 20W/m2-K. What is the brick inner surface temperature in C

A cylinder of 0.122-m radius rotates concentrically inside a fixed cylinder of 0.128-m radius. Both cylinders are 0.305 m long. Determine the viscosity of the liquid that fills the space between the cylinders if a torque of 0.881N-m is required to maintain an angular velocity of 60 revolutions per minute

A natural gas has the following percentage volumetric composition. CH4=59.8%,  C2H6=37.6%,  N2=2.2%, CO2=0.4%.  Calculate for complete, the weight of air supplied including moisture if air is in excess of 25% and at 28C and 50% RH(0.012kgv/kgda)

•A 75 hp motor that has an efficiency of 91% is worn out and is replaced by a high-efficiency motor that has an efficiency of 95.4%. Determine the reduction in heat gain of the room due to higher efficiency under full-load conditions.

A deaerating heater operates at 26.7psia(tsat=242.95F) and receives water at 181.6F. Drains from higher-pressure heaters enter in the amount of 168,000 lb/hr at 303.7F. The feedwater flow from the heater is 673,000lb/hr. Calculate the steam flow for an enthalpy of 1237.2Btu/lb.

A centrifugal pump is at best efficiency point (BEP). Assume the pump characteristic are head, h = 7 m, flow rate, Q = 19 liters/s, and rotative speed n = 1170 rpm. Find the specific speed in SI units.

What type of turbine delivers 25,000 bhp at 500 rpm under a net head of 5350 ft?

•In an actual refrigeration cycle using R12 as working fluid, the refrigerant flow rate is 0.05 kg/s. Vapor enters the expansion valve at 1.15 MPa, 40°C (h = 238.5 kJ/kg) and leaves the evaporator at 175 kPa, -15°C (h = 345 kJ/kg). The electric input to motor driving the compressor is measured and found 3.0 kW. Motor efficiency at this load 92% and mechanical efficiency 82%. Determine the actual coefficient of performance for this cycle.

A square concrete conduit having a side of 0.788m carries water at a rate of 4m3/s. Using Hazen William formula with C=120, compute the head loss if the length of the conduit is 45m

A 35,000 kW plant has a utilization factor of 71 % and a load factor of 39.6 %. What is the average load in the plant?

A liquid of specific gravity 1.75 flows in a 6cm horizontal pipe. The total energy at a certain point in the flow is 80m. The elevation of the pipe above a fixed datum is 2.6m. If the pressure at the specified point is 75kpa, determine the velocity of flow and the power available at that point.

Water enters a 3cm diameter tube with a velocity of 50m/s and a temperature of 20C and is heated. Calculate the average unit convective coefficient. For water, kinematic viscosity= 1.006x10-6m2/s; prandtL number=7; and thermal conductivity=0.597W/m-K.

The steam drum of a water- tube boiler has hemispherical ends, the diameter is 1.22 m and the overall length is 6 m. Under steaming conditions the temperature of the shell before lagging was 230°C and the temperature of the surrounds was 51°C. The temperature of the cladding after lagging was 69°C and the surrounds 27°C. Assuming 75% of the total shell area to be lagged and taking the radiation constant as 5.67 X 10- 11kW/ m2 -K4, estimate the saving in heat energy per hour due to lagging.

What surface area must be provided by the filament of a 100W evacuated light globe where t=2482C and emissivity= 0.38 for the filament? Assume the ambient temperature to be 25.6C.

In an experiment to determine the calorific value of an oil fuel by means of a bomb calorimeter, the mass of the sample of fuel was 0.75 gram, mass of water surrounding the bomb 1.8 kg, water equivalent of bomb and fittings 470 grams, and the rise in temperature was 3.3°C. Calculate the calorific value of this oil in MJ/kg. Take specific heat of water= 4.2 kJ/kgK.

A hollow steel sphere contains a 100-watt electrical filament, and these data are known; r =9 in., r =12 in. The film coefficient for the inner and outer surfaces are   hi= 2, ho = 6 Btu hr-ft2 -F ; the environmental temperature is 80 F. Assuming the steady state, compute the temperature inside air

A flat circular plate is 500 mm diameter. Calculate the theoretical quantity of heat radiated per hour when its temperature is 215°C and the temperature of its surrounds is 45°C. Take the value of the radiation constant as 5.67 X 10-11 kJ/ m2 s K4. 

A cylindrical tank (10m in diameter and 5m in depth) contains water at 20C (9.789kN/m3)and  is brimful. If the water is heated to 50C (9.689kN/m3), how much water will spill over the edge of the tank?

Compute the volume of expansion tank for a chilled water system that contains 2000gal of water. The system is regulated to 10psig at the tank with an operating temperature of 45F. It is estimated that the maximum water temperature during extended shutdown would be 100F and a safety relief valve in the system is set for 35psig. Assume standard barometric pressure and steel pipe. Take specific volume at 100F as 0.01613ft3/lb and at 45F as 0.01602ft3/lb

An empty, open can is 30 cm high with a 15 cm diameter. The can, with the open end down, is pushed under water with a density of 1000 kg/m3 . Find the water level in the can when the top of the can is 50 cm below the surface.

An economizer receives hot gas (cp=0.27Btu/lb-R) and water in the ratio 1.56lbg/lbw. The gas enters at 850F and   leaves at 355F; the water enters at 120F. Find the exit temperature of the water and the LMTD for parallel flow

A boiler fuel contains 86.1% carbon, 12.5% hydrogen, 0.4% oxygen and 1% sulphur. 40% excess air is supplied to the furnace and the fuel rate is 400 kg/h. Calculate  the quantity of heat energy transferred to the air per hour if it enters the air heater at 18C and leaves at 130°C. Take Cp for air as 1.005 kJ/kgK and humidity ratio of 0.013kgv/kgda.

The mass analysis of a fuel is 84% carbon, 14% hydrogen and 2% ash. It is burnt with 20% excess air relative to stoichiometric requirement. If 100 kg/h of this fuel is burnt in a boiler determine  the volumetric flow rate of the gas if its temperature and pressure are 250°C and 1 bar respectively. Note: Air contains 23.1% oxygen by mass. Ro= 8.3143 kJ/kg mol K and atomic mass relationships are: oxygen 16, carbon 12, hydrogen 1. 

A small drop of water at 80 0F is in contact with the air and has diameter 0.02 in. If the pressure within the droplet is 0.082 psi greater than the atmosphere, what is the value of the surface tension?

Estimate the exit temperature of 1000cfm of air at 120F flowing in a 16in round duct 24ft in length. The duct has 1in of fibrous glass insulation, and the overall heat transfer coefficient based on outside surface is 0.2Btu/(hrft2-F). The environment temperature is 12F. Take average density of air as 0.067ft3/lb.

The total incident radiant energy upon a body which partially reflects absorbs, and transmits radiant energy is 2200 W/m .  Of this amount, 450 W/  is reflected and   900 W/m  is absorbed by the body. Find the transmissivity

Two hundred metric tons per hour of coal are burned in 125% stoichiometric air; the as fired ultimate analysis is 75%C, 4%H, 0.5%S, 6%O, 1.5%N, 8%W, 5% Ash. Find the mass of air needed to burn the fuel.

A steam boiler generating 25,560 kg/hr of steam at 4.137Mpa and  426.7C an enthalpy of 3274.1 kJ/kg is continuously blown at the rate of 1116kg/hr with an enthalpy of 1055kJ/kg.. Feedwater enters the economizer at 148.9C with an enthalpy of 629.87kJ/kg. the furnace burns 2700kg/hr of coal with a higher heating value of 30,470.6kJ/kg. Calculate the overall efficiency of the steam boiler

A water cooler uses 50 lb/hr of melting ice to cool running water from 80°F to 42°F. Based on the inside coil area, Ui = 110 Btu/hr-ft2 -°F. Find the gpm of water cooled

A closed feedwater heater, with a transmittance of U=350Btu/hr-ft2-F, uses condensing steam at 20 psia (tsat=227.96F) for heating 85,000lb/hr of water from 60F to 215F. What is the transmitting area?

A strainer has a coefficient Cv rating of 60. It is to be used in a system to filter 50gpm of water. What pressure loss  expressed in feet of water can be expected?

Find the equivalent length of 167mm diameter pipe, f=0.024 for a reentrant pipe entrance with k=1.

The head loss in 50m of 12cm diameter pipe is known to be 6m when liquid of specific gravity of 0.9 and viscosity of 0.04pa-s at the rate 0.06m3/s. Find the shear stress at the wall of the pipe

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 5.8 X 10-2  W/ m K. Calculate the quantity of heat leaking through the insulation per hour when the outside and inside face temperatures of the material is 15°C and    -5°C respectively.