Flow rate issues in steam delivery pipes

It is recommended to pick up a book on Principles of Chemical Engineering; at the macro level, comparisons are needed under certain conditions, such as the relationship between flow rate, pressure, the cross-sectional area of the pipe (diameter), and flow velocity. At the microscopic level, factors such as the viscosity of the fluid and the resistance of the pipes, along with their relationship to the flow velocity, also need to be considered. For reference.

In a situation like this, you can think about it from an extreme perspective: if there is no pressure on the steam, what would be its flow rate?

The concepts are unclear, and the questions lack logic. Concepts such as pressure, pressure difference, pressure drop, flow velocity, and flow rate can be understood by looking them up on Baidu. The economic flow velocity adopted in design: for many gases, the higher the pressure, the lower the flow velocity; however, this is not the case for steam, and the reason for this is unclear. Gas flow operates on principles similar to electric current – those who have studied Ohm’s law in middle school should be aware that a circuit consists of three parameters: voltage, current, and resistance. In university, this knowledge is refined to more accurate terms: voltage is replaced by potential difference, and circuits are limited to purely resistive circuits. By analogy with this principle, it is not pressure that affects the flow rate, but rather the pressure difference. Components such as pressure relief valves and flow control orifices have a very small effective flow area; the flow velocity within these small openings can reach hundreds of meters per second. In actual calculations, only the flow velocity within the pipeline is taken into account – for gases, this is around 10 m/s, while for steam it is around 20–60 m/s

What affects the flow rate should be the pressure difference between the two ends; I’ve forgotten the specific calculation formula.

““It is the pressure difference at both ends that affects the flow rate” – this statement is correct, but there can be significant differences in how it is understood and applied. Using the analogy of electric current and fluid flow, the statement that \"the current is the same everywhere in a series circuit\" would be incorrect if compared to \"the flow velocity is the same everywhere in a fluid circulation system where there is no exchange of material\"; it is the flow rate that is the same, not the flow velocity. If there is a valve between two sections of a pipe in a system, the pressure difference before and after the valve can only be used to calculate the flow velocity within the valve; the pressure difference between two points in the pipe determines the flow velocity between those two points

This is related to the size of your pipeline, the pressure, and the flow rate; given a certain amount of flow and a constant pipeline diameter, the flow speed remains the same； The greater the pressure, the higher the flow velocity per unit diameter; this can be seen from Bernoulli’s equation

For the same gas pipeline, what you say is correct; during flow, there is a pressure drop which causes the gas pressure to decrease and its volume to expand, resulting in an increase in flow velocity

Be mindful of the scope of application; the Bernoulli equation is only applicable to incompressible fluids