What range should the pipe diameter change be kept within?
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When the diameter of a pipe is changed, it first results in an increase or decrease in the flow velocity of the fluid within that pipe. Depending on the type of fluid, such an increase or decrease may cause changes in the fluid’s state or have effects on the pipe itself. I’m not sure if there are any regulations regarding the range within which the diameter of pipes should be changed for different types of fluids, in order to avoid other adverse effects
This post was last edited by WSL01218 on 2010-8-25 at 14:10. I think the question you asked is a bit contradictory. In fact, the change in pipe diameter depends on the process system; it is sometimes adopted to achieve certain objectives, such as when there is a two-phase flow of gas and liquid, or when the flow rate or velocity decreases. Meet the requirements for fluid flow velocity.
In fact, the diameter change of pipes depends on the process system; there are no fixed rules, and it depends on the specific circumstances
Technology is the key. . . Coordination among each other is still necessary.
Select the appropriate diameter change based on the flow rate requirements； Actually, as long as you calculate the flow rate and velocity properly, there is no issue with diameter changes. If the velocity is really high, you don’t have to use such a small pipe diameter after all ； The process engineers need to make the judgment
During construction, there was a DN600 water pipe, and the sleeve used to pass it through the wall was too small; it was supposed to be DN600. So the idea was to make the sleeve smaller when the pipe passed through the wall and then restore its original size afterward, as drilling the wall again would pose some risks. After doing the calculations, for DN500 pipes, the flow rate became about 1.5 times higher than before; so I wondered if there were any other requirements. Since it’s a return pipe, I don’t see any problems.
It meets the requirements of process design, such as fluid flow velocity limits; for diameter changes, HG12459 should also be referred to
Make it have a DN550 diameter, and choose a slightly thicker wall thickness.
DN550 may not fit in
There are no specific regulations; requirements can be set according to needs and the supplier’s production capacity.
In principle, the requirements specific to the process system should be met. As for the possible changes in flow velocity within the pipes due to variations in pipe diameter, as well as the occurrence of gas-liquid two-phase flow, it is recommended to refer to the relevant provisions in specification HGT 20570.7 on the calculation of pipe pressure drops.