Selection of pipe diameter and flow rate for cooling water pumps and chiller water pumps in air separation units
Thread Content
Hello everyone. I read in books that the flow velocity at the pump inlet should be between 0.5 and 1 m/s, while it should be between 1.5 and 2 m/s at the outlet. But in our factory, we use 2 m/s as the value for the diameter of the inlet and outlet pipes. Why is that? This post was last edited by chc1125 on 2008-10-30 at 15:56
If the pump’s capacity is sufficient, there’s no problem. If, one day, it’s desired to upgrade the pump’s capacity, considering thickening the inlet pipe could be an option.
Oh, thank you. Is your surname Yang? Haha, if so, just one surname
I remember that the petrochemical design manual specifies that the inlet flow velocity for water pumps should be between 1.2 (it might also be 1.0; I can’t remember exactly) and 2.0 M/S. The outlet velocity could be higher, ranging from 1.5 to 3.0 M/S. It is correct to use 2 M/S as the design value; or, if one considers a lower value for the inlet, 1.5 M/S is also acceptable
Currently, the value in this regard is generally below 3 m/s; values above 1 m/s are too slow, as it leads to the accumulation of large amounts of sludge and other sedimentary deposits
Oh, cicadas. Thank you all
Relationship between water pump flow rate and pipe diameter (reference values): Diameter: 200mm (8")----Flow rate: 4 m³/min. Diameter: 150mm (6")----Flow rate: 2.5 m³/min. Diameter: 125mm (5")----Flow rate: 1.5 m³/min. Diameter: 100mm (4")----Flow rate: 1 m³/min. Diameter: 80mm (3")----Flow rate: 0.6 m³/min. Diameter: 65mm (2-1/2")----Flow rate: 0.4 m³/min. Diameter: 50mm (2")----Flow rate: 0.2 m³/min. Diameter: 40mm (1-1/2")----Flow rate: 0.15 m³/min. Diameter: 32mm (1-1/4")----Flow rate: 0.08 m³/min. Diameter: 25mm (1")----Flow rate: 0.05 m³/min. Diameter: 20mm (3/4")----Flow rate: 0.025 m³/min
Requirements for the diameter of water pump piping: Based on the standard flow rate of the water pump, the following formula is used: Flow rate (Q) = Pipe cross-sectional area (A) × Flow velocity (V). The flow velocity at the outlet of the water pump is approximately 2.5 M/sec; if the inlet side of the water pump is under negative pressure (suction type), the flow velocity is approximately 2 M/sec. The flow rate can be found on the nameplate of the water pump. Pipe cross-sectional area: A=πD²/4 (the only unknown, D, is the pipe diameter)