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Water substance at 70 bar and 65°C enters a boiler tube of constant inside diameter of 35 mm. The water leaves the boiler tube at 50 bar and 700 K at velocity of 150 m/s. Calculate the inlet volume flow (liters/s). From steam tables: @ 70 bar (7Mpa) and 65°C: υ1 = 0.001017 m3 /kg @ 50 bar (5Mpa) and 700 K (427°C): υ2 = 0.06081 m3 /kg

• A. 0.821

• B. 1.261

• C. 0.344

• D. 1.609

Answer explanation

100 m/s lang dapat yung velocity

A pump in a municipality's water-supply system receives water from the filtration beds and pumps it up to the top of a water tower. The tower's height is 35m, and the inlet piping to the pump is 2m below the pump's intake. The water temperature is 20C, measured at the both the inlet and the discharge from the pump. The mass flow rate through the pump is 100 kg/s, the diameter of the inlet piping is 25cm, and the diameter of the discharge piping is 15cm. Determine the power required by the pump.

• 77.3 kW

• 33.77 kW

• 34.42 kW

• 42.34 kW

The fuel oil has the ff. analysis: C = 89% N2 = 2% H2 = 8% S = 1% With 3% excess air, what is the actual amount of air needed to burn the fuel oil?

• 13.17 kgair/kgfuel

• 13.47 kgair/kgfuel

• 14.47 kgair/kgfuel

• 14.17 kgair/kgfuel

Answer explanation

8% excess air not 3%

Carbon dioxide flows through a nozzle with speed of 380 m/s. The entrance condition of nozzle is 250°C and 1200 kPa. Find the stagnation pressure.

• 2,136.34 kPa

• 2,146.34 kPa

• 2,156.34 kPa

• 2,166.34 kPa

Answer explanation

solution confused with the gas involved

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.

• 233.34

• 973.17

• 198.34

• 204.82

A jet is discharged through a 25mm diameter orifice under a constant head of 0.64m. The total discharge is 103kg in 90 seconds. The jet is observed to pass through a point 60cm downward 1.2m away from the vena contracta. Find the coefficient of discharge

• 0.968

• 0.658

• 0.6795

• 0.743

A jet is discharged through a 25mm diameter orifice under a constant head of 0.64m. The total discharge is 103kg in 90 seconds. The jet is observed to pass through a point 60cm downward 1.2m away from the vena contracta. Find the coefficient of velocity

• 0.968

• 0.658

• 0.6795

• 0.748

Consider 1 kg of air at 32°C that expanded by a reversible polytropic process with n = 1.25 until the pressure is halved. Determine the heat transfer. Specific heat at constant volume for air is 0.1786 kJ/kg-K

• 17.02 kJ heat rejected

• 7.05 kJ heat rejected

• 17.02 kJ heat added

• 7.05 kJ heat added

Answer explanation

Cv should be 0.7186

Consider 4800 lb of steam per hour flowing through a pipe at 100 psia pressure. Assume a velocity of 5280 ft/min. What size of pipe is required? Specific volume of steam at 100 psia υ = 4.432 ft3 /lb.

• 3 in

• . 5 in

• 4 in

• 6 in

With three different quantities x, y, and z of the same kind of liquid of temperatures 9, 21 and 38°C respectively, it is found that when x and y are mixed together the resultant temperature is 17°C and when y and z are mixed together the resultant temperature is 28°C. Find the resultant temperature if x and z were mixed.

• 25.87°C

• 25.92°C

• 20.85°C

• 24.86°C