How can the flow rate of tap water be controlled using only pipes and valves? !
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Suppose that X m3/h of tap water is needed now. If no pump is installed in front of the device, the inlet pressure of tap water Y MPa is known. How to choose the diameter of water pipes to ensure that the water flow remains within a certain range? ! What should the flow rate of water be?
The typical design value for flow velocity is 0.5 to 3 meters per second; the pipe diameter can then be calculated based on this value.
“The inlet pressure of tap water, Y in MPa, is known. ”This is not a mathematical concept that remains constant; once pipes are connected to allow water to flow, the pressure starts to drop, and it may drop to such an extent that the desired amount of water cannot be delivered. The flow rate of tap water should be set at 0.5 to 1.5 m/s, and the pipe diameter should be calculated based on the required flow rate. When the diameter of the takeover pipe is close to or larger than that of the water source, the flow rate depends on the diameter of the main water supply pipe and the water pressure
When the main pipe is large enough, the inlet pressure can basically remain constant, right? Pressure P is proportional to flow rate Q. Diameter determined. What is the relationship between P and Q?
When the diameter of the pipe is large enough and the flow rate is low enough, the pressure in the pipe remains essentially constant; P and Q are not in a direct proportional relationship, but rather follow a relationship similar to that of a quadratic equation. According to Bernoulli’s equation, P1/ρg+u2/2g+He=P2/ρg+Hf
The typical design value for the flow velocity is 1.5 to 3 meters per second.
Self-acting valves can be used for control and adjustment; it’s just that the precision isn’t very high