Problem_Solving_02

20問 • 1年前

問題一覧

Nitrogen (k = 1.4) is expanded isentropically, its temperature changes from 620°F to 60°F. Find the pressure ratio (P1/P2).

B. 12.91

What is the temperature in °C of 2 liters of water at 30°C after 500 Calories of heat have been added?

B. 30.25

Calculate the mass of a 2 m³ propane at 280 kPa and 40°C.

D. 9.47 kg

Compute the approximate value of temperature of water having enthalpy of 208 BTU/lb.

B. 115.55°C

What is the approximate enthalpy of water at 90°C?

C. 376.83 kJ/kg

Find the heat transfer required to convert 5 kg of water at a pressure of 20 bar and temperature of 21°C into steam of dryness fraction 0.90 at the same pressure. Properties of Steam: • P = 20 bar • hf = 909 kJ/kg • hfg = 1890 kJ/kg Note: for water at 21°C, h = 88 kJ/kg

C. 12 610 kJ

If 6 liters of a gas at a pressure of 100 kPa are compressed reversibly according to PV² = C, until the volume becomes 2 liters. Find the final pressure.

C. 900 kPa

Determine the quality of steam in a vessel containing 2 kg of saturated vapor and 8 kg of saturated liquid.

C. 20 %

An adiabatic tank containing air is used to power an air turbine during times of peak power demand. The tank has a volume of 500 m³ and contains air at 1000 kPa and 500°K. Calculate the temperature at an instant where the pressure is 100 kPa

A. -14.03°C

Steam at a pressure of 9 bar (hf = 743 kJ/kg, hfg = 2031 kJ/kg) is generated in an exhaust gas boiler from feedwater at 80°C (h = 334.9 kJ/kg). If the dryness fraction of the steam is 0.96, determine the heat transfer per kilogram of steam.

A. 2357.86

Calculate the entropy of steam at 60 psia with a quality of 0.60. Properties of steam at 60 psia: Sf = 0.4274 Btu/lb°R Sfg = 1.2172 Btu/lb°R

B. 1.1577 Btu/lb°R

One kilogram of water ( Cv = 4.2 kJ/kg-K ) is heated by 300 BTU of energy. What is the change in temperature in K ?

A. 75.36 K

A 35.0 mL sample of gas is enclosed in a flask at 22°C. If the flask was placed in an ice bath at 0°C, then calculate the new gas volume be if the pressure is held constant.

B. 32.39 mL

A device produce 37.5 joules per cycle. There is one power stroke per cycle. What is the power output if the device is run at 45 rpm.

B. 28.125 W

Gas is enclosed in a cylinder with a weighted piston as the top boundary. The gas is heated and expands from a volume of 0.04 m³ to 0.10 m³ at a constant pressure of 200 kPa. Calculate the work done by the system.

C. 12 kJ

Aluminum has a specific heat of 0.902 J/gm°-C. Determine how much is the heat lost when a piece of aluminum with a mass of 23.984 g cools from a temperature of 415.0°C to a temperature of 22.0°C.

C. 8500 J

Air enters a nozzle steadily at 2.21 kg/m³ and 30 m/s. Calculate the mass flow rate through the nozzle if the inlet area of the nozzle is 80 cm².

D. 0.53 kg/s

Water is boiling at 1 atm pressure in a stainless pan on an electric range. It is observed that 2 kg of liquid water evaporates in 30 min. The rate of heat transfer to the water is:

C. 2.51 kW

Steam enters the superheaters of a boiler at a pressure of 25 bar and dryness of 0.98 and leaves at the same pressure at a temperature of 370°C. Calculate the heat energy supplied in the superheaters. Properties of steam: At 25 bar and 370°C ( h = 3171.8 kJ/kg ) and at 25 bar and 0.98 dryness ( hf = 962.11 kJ/kg, hfg = 1841.01 kJ/kg ).

C. 405.51

If 10 lbs of water evaporated at atmospheric pressure until a volume of 288.5 ft³ is occupied, how much work is done?

A. 610,358 ft-lb

Machine Design ( 1st Set )

Jacky Shane Luyas Buhia · 20問 · 2年前

Machine Design ( 1st Set )