Does a change in the temperature of the gas in the pipeline affect the pipeline pressure?
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A stable gas supply pipeline, with a cold water bath jacket installed at a certain section of the pipeline to lower the temperature of the gas inside; no liquefaction occurs during this process. Does the pressure in the pipeline change after the temperature is reduced?
The operating condition is equivalent to flow in a heat exchange tube with a constant cross-section; at low flow rates, the temperature decreases while the pressure inside the tube increases. . . Textbooks on engineering fluid mechanics cover this, but it’s unknown in actual operating conditions.
Given that it is a continuous gas supply and not a confined space.
In our everyday pipelines, the gas flow velocity is not high, so the Mach number is low; as a result, the pressure changes follow a quadratic relationship, which is even smaller and not noticeable.
Assuming that your supply pressure and flow rate, as well as the pressure and flow rate at which the gas is used, remain constant, then after heat exchange, the internal energy of the gas decreases, resulting in a drop in gas pressure~~
1. The gas equation is PV/T = C; where V remains constant, and P changes with T. Theoretically, as the temperature decreases, the pressure also decreases. 2. The gas supply pipeline is part of a gas supply system, and the extent to which cooling can be achieved using jackets is limited. Whether a visible decrease in pressure can be observed depends on the size of the system. 3. Obviously, small gas supply systems (with low flow rates) are more likely to show changes in pressure
How do you determine that V remains constant? This isn’t a closed container either; it’s an open system.
When discussing this issue, gas should no longer be considered an incompressible fluid.
You mentioned the Mach number; how is this value obtained in practical operations?
You can search on Baidu for the definition of Mach number; it is the ratio of the gas flow velocity to the local speed of sound.