Solved examples of fluid flow
Explanation
Fluid Fluid name and type
U Values that you want to calculate
Example #1
Task: Calculate the pipe diameter if the water flow velocity is 1 m/s and the flow rate is 5 lit/min.
Solution: Pipe diameter is 10.3 mm
Example #2
Task: Calculate the airflow velocity if the inner diameter of the pipe is 50 mm and the flow rate is 100 m3/h at a pressure of 3 bar absolute and a temperature of 15 °C
Solution: Flow velocity is 14.15 m/s
Example #3
Task: Calculate the diameter of the carbon dioxide pipe with a flow rate of 10 kg/h and a velocity 2 m/s at a pressure of 7 bar absolute and a temperature of 20 °C.
Solution: Pipe diameter is 11.8 mm
Example #4
Task: Calculate the pressure drop generated by the air at a flow rate of 500 m3 / h through a pipe with an inside diameter of 60 mm and a length of 100 m. The air temperature is 5 C, the roughness of the pipeline is 0.02 mm, and the coefficient of local resistances is equal to zero - there are no local resistances in the pipeline. Pressure on the pipeline start is 4 bar gauge.
Solution: Pressure drop is: 95.67 mbar
Example #5
Task: Calculate the air flow through a pipe with an inside diameter of 1 inch and a length of 200 m. The available pressure in the air tank from which the pipeline starts is 2 bar gauge. At the end of the pipeline, the air flows out into the atmosphere. The internal roughness of the pipe wall is 0.1 mm. The pipeline has 6 pipe elbows 90 degrees and a radius of 1.5 D. The air temperature is 15 C.
Solution: Flow rate is: 90.713 m3/h
Example #6
Task: Calculate the pressure drop that creates air at a flow rate of 1000 cfh through a pipeline with an inside diameter of ½“, and a length of 1000 ft, with an internal roughness of the pipe wall of 0.012 in. The pipeline has 4 elbows 90 degrees and one reduction at the end of the pipeline to ¼“, after which the air flows into the open atmosphere.
Solution: Pressure drop is: 7.287 bar
Example #7
Task: Calculate flow rate of air through the orifice plate. Orifice internal diameter is 100mm, and tube where orifice is inserted, internal diameter is 200mm. Pressure in front of the orifice is 104000 Pa, and pressure after the orifice is 100000 Pa absolute. Pressures are measured on the corner taps. Temperature of air is 15 C.
Solution: Flow rate is: 1374.5 m3/h
Example #8
Task: Calculate flow rate of water flowing through orifice plate with external diameter of 120 mm and internal diameter of 80 mm. Measured pressures in front and after the orifice is 11000 mm H2O and 10000 mm H2O. Pressure is measured on 1 inch taps.
Solution: Flow rate is: 54.674 m3/h
Example #9
Task: Calculate flow rate of water through the orifice with external diameter of 200 mm, internal diameter of 160 mm. Measured pressure drop in front of the orifice is 10729 mm H2O and measured pressure drop is 400 mm H2O. Pressures are measured at corner taps
Solution: Flow rate is: 155.94 m3/h
Example #10
Task: Calculate pressure drop in round pipe with flow of 5 m3/h, pipe length 100 m, internal pipe diameter of 25 mm and pipe roughness of 0.1 mm. Flowing fluid is water with density of 1000 kg/m3. Local resistance can be negligible K = 0.
Solution: Pressure drop is: 4.78 bar
Example #11
Task: Calculate flow rate of water through closed round pipe with internal diameter of 25 mm, pipe length of 100 m. Pipe line connecting reservoir on the elevation of 20 m above the pipe exit with water flowing to open atmosphere. Reservoir is under atmospheric pressure. Pipe roughness is 0.1 mm.
Solution: Flow rate is: 3.16 m3/h
Example #12
Task: Calculate pressure drop of 2000 m3/h of air flowing through closed rectangle chanel to open atmosphere. Chanel width is 400 mm and height is 250 mm. Chanel is with surface roughness of 0.01 mm. Local resistance coefficient is line is 3.5. Chanel length is 85 m.
Solution: Pressure drop is: 298.96 Pa
Example #13
Task: Calculate the heat output of the heat exchanger if the water flow is 2 l/s, the temperature in front of the exchanger is 25 C, and behind the exchanger is 60 C. The diameter of the connecting pipes is 60 mm.
Solution: Heat output: 292.43 kW
Example #14
Task: Calculate the flow of water through the heat exchanger if the heat output of the exchanger is 2000 kW. The temperature in front and behind the exchanger is 70 C and 90 C. The diameter of the connecting pipes is 150 mm.
Solution: Flow rate: 86.173 m3/h
Example #15
Task: Calculate the flow of water through the chiller if the output of the chiller is 2000 kW. The temperature in front and behind the chiller is 12 C and 7 C. Calculate also the diameter of the connecting pipes for a known water flow rate of 1 m/s.
Solution: Flow rate: 344.96 m3/h
Example #16
Task: Calculate the pressure drop generated by the natural gas at a flow rate of 200 Sm3/h through a pipe with nominal diameter of 2 inch and a length of 200 m. The gas temperature is 5 C, the surface roughness of the pipeline is 0.02 mm. Along the pipeline are 5 elbows R=1.5D, 90 deg. Pressure on the pipeline start is 2 bar gauge.
Solution: Pressure drop is: 59.6 mbar
Example #17
Task: Calculate the maximum natural gas flow through a pipe with nominal diameter of 3/4 inch and a length of 200 m. The available pressure from pipeline from which the pipeline starts is 500 mbar gauge. Pipeline is connected with the gas train that requires 200 mbar gauge pressure for operation. The internal roughness of the pipe surface is 0.01 mm. The pipeline has 6 pipe elbows 90 degrees and a radius of 1.5 D. The natural gas temperature is 15 C.
Solution: Flow rate is: 27 Sm3/h
Example #18
Task: Calculate the pressure drop that creates natural gas at a flow rate of 500 MMSCFD through a pipeline with the nominal diameter of 36", and the length of 4 miles, with an internal roughness of the pipe wall of 0.0005 in. Gas temperature 40 F and the pressure at the pipeline start is 700 psi.
Solution: Pressure drop is: 3.89 psi
Example #19
Task:
Calculate the minimum wall thickness of the pipe if the internal pressure in the pipe is 300 psi,
the nominal diameter of the pipe is 4", pipe material - carbon steel according to ASTM A53, Grade A.
The pipe is electric resistance welded - ERW.
The pipeline location class is 2, ambient temperature is 30 C.
Anticipate corrosion allowance CA=1 mm.
Factory tolerance of pipe wall thickness 12.5%.
Solution: Pipe wall thickness t = 2.07 mm
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