The issue of the difference between the recommended steam flow rate and the recommended air flow rate
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I would like to invite everyone here to discuss the recommended flow rates for steam and air. General manuals recommend a relatively high flow rate for steam, which ranges from about 20 to 40 m/s depending on the pressure. For the air ducts at the outlet of ordinary fans, it is recommended that the flow velocity be less than 15 m/s. Question 1: If the pressure drop permits, can the flow velocity in the air ducts be increased appropriately? What consequences would that have? Question 2: If high flow velocities in air ducts lead to high noise levels, can it be assumed that steam pipelines also generate significant noise? Is there any empirical formula that can be used to quantitatively calculate the noise produced by fluid flow within pipes? Thank you.
With high steam pressure and high flow velocity, it can withstand pressure losses; the fan has low air pressure and cannot tolerate high pressure drops. Since the steam flows only within the pipes without interacting with air vibrations, the noise level is low. The air from the fan comes from or is discharged into the air; it is in frequent contact with air, which can cause air vibrations and thus results in high noise levels
If the wind speed of the air inside the duct is too high, it will cause vibration in the duct； If the steam flow rate increases, as long as it is not discharged directly into the atmosphere, the noise inside the pipeline should not change significantly ；
The air flow has a high velocity, resulting in high energy loss and noise. As for the steam flow, it also has high energy loss; moreover, steam basically produces no noise
Thank you. Can it be understood then that noise is mostly caused by the exchange of air inside the pipes with the outside environment? Moreover, the noise caused by the impact vibrations of the flow velocity within the pipe on the pipe walls or other components is relatively low.
More or less, most of the noise comes from the interface rather than the interior; the interior is relatively steady-state