Does a water pressure gauge measure static pressure, dynamic pressure, or total pressure?
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If it’s only dynamic pressure, why doesn’t the reading on the water gauge change after the valve is closed? If it’s just static pressure, then what’s the point of a gauge? Because what matters to me is the magnitude of flow, that is, the flow rate, which is also the dynamic pressure. If it’s full pressure, then~~~ I don’t know what use this reading has. Thank you all for your advice. Thank you so much.
My personal understanding is that it should be the full pressure. The valve is closed tightly; I’m not sure if both the inlet and outlet are shut off If only the inlet is closed while the outlet remains open, the pressure will drop (unless there is pressure at the outlet), but since the liquid in the pipeline has not been completely drained, the pressure gauge will not return to zero. If everything is turned off, pressure will build up in the system pipelines.
I think it measures the total pressure. Suppose there is a trough 1 meter high, with water flowing out from the bottom. A net pressure of 1 meter of water column was measured when the valve was closed. When the valve is open and the flow rate of water is u=1 m/s, using Bernoulli’s equation, it is possible to estimate that p=(9.8*1 m – 0.5*(1 m/s)^2)*1000 kg/m^3=9300 Pa, which is equivalent to a pressure of about 0.95 meters of water column. It can be seen that the pressure change before and after valve operation is only 5%, so the change in the pressure gauge is not significant. It’s just my guess; I’m not sure if it’s correct.
In other words, generally speaking the dynamic pressure is very low; as a result, the pressure gauge can only indicate the magnitude of the static pressure roughly. It is not possible to determine how fast the flow rate is or what the flow volume is So what’s the use of this table? :o
It measures pressure. The flow rate can be estimated using a formula. Even after the valve was closed, the pressure of the liquid remained, and the gauge pressure stayed the same.
A pressure gauge measures gauge pressure; it should be static pressure, as learned when calculating in chemical engineering principles.
The pressure gauge measures the (total potential energy difference).
It’s similar to doing experiments on the principles of chemical engineering in university—like the Bernoulli equation. A water pressure gauge measures the dynamic head and static head of the water flow, that is, the total pressure.
The pressure gauge measures gauge pressure; this should be static pressure
According to ** in the chemical formula, it should be the total pressure. Therefore, the conveying height and distance of the fluid can be determined based on the readings of the pressure gauge.
It must be the static head; if the flow velocity is not high (2 m/s) and the outlet valve is closed, the dynamic head converts to a very small static head, estimated to be around 400 Pa. Compared to the water pressure, which is assumed to be 200,000 Pa gauge pressure, this value is so small that the pressure gauge shows little change.