Knowing the pressure difference and pipe diameter, how to calculate flow velocity and flow rate
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For liquid oxygen pipelines, with a density of 1.14, a pipe diameter of DN65, and a liquid level difference of 2 meters, what formula should be used to calculate the flow velocity or flow rate?
There are two formulas for calculating velocity and flow rate: 1. Velocity formula: Velocity = Pressure difference / (Pipe length x Fluid density x Pressure retention coefficient). The pressure retention coefficient is usually set at 0.6, while the pipe length can be determined based on actual conditions. 2. Flow formula: Flow = Diameter squared x π/4 x Flow rate, where the diameter must be converted to meters. Taking the liquid oxygen pipeline as an example, the flow velocity is calculated using the flow velocity formula: Flow velocity = (2 m x 9.8 m/s² x 1.14 kg/m³) / (65 mm x 0.6) ≈ 1.22 m/s. The flow rate is calculated using the flow rate formula: Flow rate = (0.065 m³) x π/4 x 1.22 m/s ≈ 0.002 m³/s. Therefore, the flow velocity in the liquid oxygen pipeline is approximately 1.22 m/s, and the flow rate is approximately 0.002 m³/s. .
The flow velocity values are set at 1-2 m/s
Your question is good – isn’t that exactly what a differential pressure flow meter is used for? Chapter 1 of Principles of Chemical Engineering is about this
Hello, I have a question: Flow rate = Pressure difference / (Pipe length × Fluid density × Pressure retention coefficient). I don’t understand this formula; could you please explain the derivation process or its origin? Thank you
Using this formula, the calculation above is also incorrect. You didn’t even mention how long the pipe is – how is it possible to calculate anything like that? I searched for it, but it seems there’s no such formula available
Hello, may I ask what Q=AV... means? Could you explain it a bit more in detail? Thank you.