May I ask whether compressed air or nitrogen with the same mass flow rate can use the same pipe diameter even if their pressures are different?
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Given the same mass flow rate of compressed air or nitrogen, can the pipe diameter remain the same when the pressure differs (such as 0.3 MPa, 0.6 MPa, and 2 MPa)? Can the flow rate be higher as the pressure of compressed air or nitrogen increases? ? Or smaller? Why? ?
Gas flow rate is closely related to pressure
When the mass flow rate of compressed air or nitrogen is the same and their molecular weights are similar, a lower pressure corresponds to a larger volume. With the same pipe diameter, the flow velocity at lower pressures is higher, resulting in greater pressure drops and resistance losses; therefore, it is recommended to use a larger pipe diameter.
Given the same mass flow rate of compressed air or nitrogen, can the pipe diameter remain the same when the pressure differs (such as 0.3 MPa, 0.6 MPa, and 2 MPa)? If the pressures are different but the pipe diameters are the same, there should be a difference in wall thickness. Can the flow rate be higher as the pressure of compressed air or nitrogen increases? ? Or smaller? Why? ? Flow rate is the relationship between flow volume and pipe diameter; flow volume is related to volume, and volume is related to pressure. It is necessary to determine these factors first before analyzing whether they have an impact
What I’m referring to is when the volumetric flow rate remains constant
With a constant volumetric flow rate, does the flow velocity increase as the pressure rises? ? ?
The gas flow rate varies depending on the pressure; the pipe diameter must be determined based on the flow rate and volume flow. Theoretically, the higher the pressure, the lower the flow rate, or it may increase first and then decrease – the specifics vary depending on the type of medium used. For reference, the recommended range of flow velocities for various media can be found in the table included in the \"Chemical Process Piping Design Manual\".
Theoretically, the greater the pressure, the lower the flow velocity? ? Sir, could you explain in more detail? It’s not clearly stated, but the greater the pressure, the greater the energy available to overcome resistance. It seems that a higher value for flow rate should be applicable, right? ? Looking forward to your advice
From an engineering perspective, aside from what you mentioned, safety considerations are also important. The higher the pressure, the greater the risk; once the critical point is exceeded, it is not advisable to use high flow rates. High flow speeds increase friction and erosion on the pipe walls, leading to thinning of those walls as well as of the elbows. In the case of flammable or explosive fluids, static electricity is more likely to be generated, which can trigger fires.
For compressed air or nitrogen under different pressures, the nominal diameter of the pipeline required will be different when the mass flow rate is the same. Different pressures correspond to different densities of compressed air or nitrogen. Mass flow rate is related to the medium density, flow velocity, and flow cross-sectional area. When the flow rate is the same, it is also related to the medium density and the flow cross-sectional area. When the mass flow rate is constant, density is inversely proportional to the flow cross-sectional area (which can be converted to the pipe diameter). For higher densities, a smaller pipe diameter is required.
In engineering, the margin for pipe diameter is generally quite large; it may be one size larger than the optimal diameter, mainly to reduce the number of pipe specifications and thereby lessen the workload