PRE BOARD PIPE 2

50問 • 1年前

問題一覧

During a reversible process there are abstracted 317 kJ/s from 1.134 kg/s from 1.134 kg/s of a certain gas while the temperature remains constant at 26.7C. For this gas Co=2.232 and Cv=1.713 kJ/ kgK. The initial pressure is 586 kPa. Determine the final volume flow rate.

0.05 m3/s

A tank contains 20 kg of air at 200 kPa (gage) and 23C. During heating g process the temperature of air rises. For safety purposes a technician installed a relief-cycle type valve so that pressure of air inside the tank never exceed 260 kPa (gage). At wht air temperature the relief valve will start releasing air?

82 C

A motorcycle uses nitrogen (k=1.399) as the working substance. The heat supplied is 54 kJ and the adiabatic expansion ratio is 10. Determine the heat rejected.

21.6 kJ

Consider 1kg of air at 32C that expanded by a reversible polytropic process with n=1.23 until the pressure is lived. Determine the heat transfer if the Sp.heat at constant volume of air is 0.1786 kJ/kgK.

17.02 kJ heat added

A pump discharges 550 pm of water to a height of 35 ft. With an efficiency of 80%. What is the power input?

6.09 HP

The fuel has the following analysis: C=89%, N2=2%, H2=8%, S=1% with excess air, what is the actual amount air needed to burn the fuel oil?

14.17 kgair/kgfuel

A reciprocating compressor handles 1,400 fm of air measures at intake where p1-18 psia ant TI=90F. The discharged pressure is 92 psia. Calculate the work if the process of the compression is isothermal.

-179.5 HP

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/m?. At B, the pipe diameter is 30cm, and the pressure is 330 kN / m3, Point B is 1.0m lower than A. Find the flow rate if the pump puts 16kW into the flow. Neglect head loss.

0.42 m3/s

Find the thrust and efficiency of two 2- m diameter propellers through which flows a total of 600m3/s of air 11.3 N/m3. The propellers are attached to an airplane moving at 250 kph through still air. Neglect eddy losses.

36,077 N, 73%

A turbine receives 150 Ibm/sec of air 63 psia and 2450R and expands it polytropically to 14.7 psia. The exponent "n" is equal to 1.45 for the process. Determine the power.

52,343.16 BTU/sec

A boiler plant generates 224,000 lb of steam and burns 13,9 tons of coal per hour. The coal has a heating value of 11400 BTU/b. A test of a particulates leaving the boiler shows that 3804 lb of particulate is being discharged per hour. What is the particulate discharged per million BTU heat input to the furnace?

12 lb/106 BTU

Consider 4800 lb of steam per hour flowing through a pipe at 100 psia pressure. Ssume a velocity of 5280 ft/min. What size of pipe is required? Specific volume of steam at 100 psia v=4.432 ft/1b.

4 in

A 2-stage double-acting compressor is to deliver 90 lb/min of air from 14.3 psia and 90F to a final pressure of 185 psia. The normal barometer is 29.8 in- Hg and the temperature is 80F. The pressure drop in the inter cooler is 3psia and the speed is 210 rpm and pV1.34=C during compression and expansion. The clearance is 5% for both cylinders. The temperature of the cooling water increased by 18F. Find the volume of free air.

1230 CFM

A nozzle receives 0.5 ks/s of air pressure of 2700 kPa and a velocity of 30 m/s and enthalpy of 923 kJ/kg and the air leaves at a pressure of 700 kPa and with enthalpy of 660 kJ/kg. Determine the exit velocity from the nozzle.

726 m/s

What is the mass of acetylene gas, V=0.94 ft3, R=59.35 ftlb/lbR, T=90F, P=200psi. A. B. C. D.

0.829 lb

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

2.67 lbs

What is the absolute pressure if the gauge pressure is reading 9 bar and the atmospheric pressure is 0.9 bar?

9.9 bar

Find the density of oil with a specific gravity of 1.6 in g/cm3.

1.6 g/cm3

During an experiment on Charles Law, the volume of gas trapped in the apparatus was 10000mm3 when the temperature was 18C. The temperature of the gas was then raised to 85C. Determine the new volume of gas trapped in the apparatus if the pressure exerted on the gas remained constant.

12302.41 mm3

During the working stroke of an engine the heat transferred out of the system was 150 KJ/kg of working substance. The internal energy also decreased by 400 kJ/kg of work done.

250 kJ/kg

Kerosene is pumped into an aircraft fuel tank through a hose that has an inside diameter of 4cm. If the velocity of a kerosene is 8 m/s through the hose, determine the mass flow rate. Assume that kerosene has a density of 800 kg/m3.

8.06 kg/m3

What is the power of the pump, HP, if it delivers 925 gal/min of water against a head of 15m?

P=11.5 HP

Determine the mass of water vapour contained in a 150m3 room at 100 kPa, 23C and 40% relative humidity. From steam tables: Psat @ 23C=2.810 kPA.

1.2342 kg

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.

2.35 ft

A piston moves inside a cylinder at a velocity of 6.0m/s. The 160mm diameter piston is currently located within the 160.2mm inside diameter cylinder. The film of oil is separating the piston from the cylinder has an absolute viscosity of 0.4 N-s/m2. Assuming a linear velocity profile, find the shear stresses in the oil. (T= μV/H).

24,000 N/m2

A room contains air at 20C and 96 kPA at a relative humidity of 75%. Determine the enthalpy of moist air.

49.515 KJ/kgda

50 kg of cooling water per second enter the condenser at 25C and leaves at 50C. Find the heat carried away by water.

5233.75 kW

A carnot cycle has a sink temperature of 100F and cycle eff of 70%. Find the temperature of the heat source.

1406.70F

A carnot cycle has a temperature of 550F and minimum temperature of 100F. If the heat added is 4200 BTU/min, find HP output of the engine.

44.13

A carnot cycle operates between 30C and 350C. Find the cycle efficiency.

51.36%

Calculate approximate enthalpy of water at 90C.

376.83 kJ/kg

Determine the degrees of superheat of steam at 101.325 kPa and 170C.

70 C

What is the resulting pressure when one kg of air at 104 kPa and 98C is heated at constant volume to 450C?

202.67 kPa

Water flows in a pipe at the rate of 10 kg/s. If the velocity of the flow is 10 m/s, find the pipe diameter

35.68 mm

An automobile vacuum gauge reads 600 mmHg when the barometer reads 760 mmHg. What is the absolute condenser pressure in bar?

0.213

An air compressor has an inlet enthalpy of 35 BTU/lb and an exit enthalpy of 70 BTU/lb. The mass flow rate of air is 3 lb/s. If the heat loss is 466.62 BTU/min, find the work input to the compressor.

159.59 HP

Determine the pressure exerted on a diver at 30m below the free surface of the sea. Assume a barometric pressure of 101 kPa and specific gravity of sea water is 1.03.

404 kPa

Calculate the heat transfer per hour through a solid bricks wall 6m long, 1.9m high, and 225 mm thick, when the outer surface is at 5 degC and the inner surface 17 degC, the coefficient of thermal conductivity o the bricks being 0.6 W/m-K.

2,004.48 kJ

Determine the coil face area required to maintain a face velocity of 400 ft/min. if the air flow rate over the coil is 2100 ft3/min.

5.25 ft2

How much refrigeration capacity is required to cool 2000 cfm of air from 85 degF to 70 degF ?

2.7 TOR

In an ammonia condensing machine (compressor plus condenser) the water used for condensing is 55 degF and the evaporator is at 15 degF. Calculate the ideal COP.

11.875

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

13.14

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 9.4 ft3/ld, calculate the piston displacement ,assuming 80% volume efficiency.

261.6 ft3/hr

The load on a water-cooled is 90,000 Btu/hr. if the quantity of water circulated through the condenser is 15gpm, determine the temperature rise of the water in the condense.

12 degF

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

30 GPM

Determine the estimated condenser load for an open type compressor having a cooling capacity of 16,500 Btu/hr and a heat rejection factor of 1.32.

21,780 Btu/hr

To cool farm products, 300 kg of ice at - 4.4 degC are placed in bunker. Twenty four hours late the ice have melted into water at 7.2 degC. what is the average rate of cooling provided by the ice in kj/kh?

4679.28 kj/hr

A 150 HP motor is used to drive a 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.

173.80 kj/kg

A cylindrical flash tank mounted with its axis horizontal is used to separate liquid ammonia from ammonia vapor. The ammonia vapor 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 of the diameter from the top. Determine the diameter if the tank is 1.5 m long.

830 mm

A fluid with a kinetic viscosity of 2.5x10^-5 ft2/sec is flowing at 0.1 ft/sec from an orifice 3” in diameter. How can a fluid be described ?

The fluid is laminar

machine design 2

ユーザ名非公開 · 5問 · 2年前

machine design 2