Does the pressure gauge measure dynamic pressure, static pressure, or total pressure? What exactly is it?
The pressure gauge shows the static pressure, that is, the pressure in the pipe relative to the outside gauge pressure. The dynamic pressure in the tube cannot be measured by a conventional pressure gauge. The general method of measuring the dynamic pressure is to first measure the average flow rate of the fluid in the tube, and then calculate it according to the formula Pd=1/2 (ρυ^2), this formula fluid There is an introduction in the mechanics book, so you can read it and confirm it.
The resistance loss of the pipeline is actually the static pressure difference, because before and after a straight pipe section, the dynamic pressure is only related to the average flow rate (see the above formula), and the dynamic pressure of each section of the straight pipe section is actually equal , But the pressure before and after the straight pipe section displayed by the pressure gauge is definitely different. This pressure difference is the static pressure difference of the pipe section, which is the resistance loss along the pipe section.
When the air-conditioning box indicates the residual pressure outside the machine, it actually refers to the static pressure outside the machine, not including dynamic pressure, and certainly not full pressure. Since the dynamic pressure of the pipeline is only related to the average flow rate, the dynamic pressure of the pipeline will not be lower and lower like the static pressure. The dynamic pressure of the downstream pipe section may be higher than the dynamic pressure of the upstream pipeline. , As long as the average flow rate in the tube is high. Why is the dynamic pressure of the downstream pipeline higher than the dynamic pressure of the upstream pipeline? There is a technical term called "dynamic pressure recovery". It depends on the loss of a large part of the static pressure, and part of the static pressure is converted into dynamic pressure. But the total total pressure is decreasing.
1. Pressure gauge refers to a gauge that uses elastic elements as sensitive elements to measure and indicate pressure higher than the ambient pressure. The pressure gauge uses the elastic deformation of the sensitive components in the watch, and then the pressure deformation is transmitted to the pointer by the conversion mechanism of the movement in the watch, causing the pointer to rotate to display the pressure.
2. The application of pressure gauges covers almost all industrial processes and scientific research fields, and can be seen everywhere in the fields of heating pipe networks, oil and gas transmission, water and gas supply systems, and vehicle repair and maintenance factories. Especially in the process of industrial process control and technical measurement, because the elastic sensitive element of the mechanical pressure gauge has the characteristics of high mechanical strength and convenient production, the mechanical pressure gauge has been more and more widely used.
