The air flow passes through 2 heaters, and its volume decreases. Let’s analyze this in detail; are there any professionals available?
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This post was last edited by batawfn on 2022-2-26 at 17:29. The air flow decreases after passing through the 2 heaters; could someone provide a detailed analysis? Is there anyone with expertise who can explain this? I can only roughly say that there is a pressure loss, which causes the flow rate to decrease. The traffic has decreased. Is there anyone professional who can analyze it? Diameter: DN1200; pressure air flow rate: 0–5000 Nm3/H; pressure: 20 KPa. The normal operating flow rate is 20,000 Nm3/H. After passing through 2 heaters, the flow rate drops to 7000 Nm3/H, with a temperature of 180 degrees. The pressure value has not been determined yet; it will be provided upon arrival at the site.
It’s best to refine the question and make it more comprehensive. The previous diagram, or a clear explanation of what the device is used for, would help with the discussion. It is speculated that there might be a leak inside the valves of the air purification system.
Actually, by asking this question, you are aware that there is a possibility of inaccurate measurement – the air flow rate needs to be converted to standard conditions. What type of flow meters are these two? Is there thermal and pressure compensation? How is temperature and pressure compensation achieved? Does it come with a temperature and pressure compensation module? Should it still be done in the DCS system? Is there a calculation sheet for the flow meter, and are the parameters of the temperature and pressure compensation formulas consistent with those given in the calculation sheet? These are all factors that affect measurement accuracy, and they need to be addressed one by one
Is it that only this much flow can be generated after heating, or is only this much flow detected? There is still a change in flow rate before and after heating. Is the temperature control of the heater regulating the flow rate?
Only this much traffic was tested.
I calculated the temperature compensation; with constant pressure, the flow rate doesn’t change much. It’s very different from reality
The temperature changes relatively little, because as you can think, in the ideal gas law, Kelvin temperature is proportional to it; a difference of 20°C and 30°C corresponds to a change of (273+30)/(273+20) = 1.03, which is a very small increase. However, pressure has a greater impact, so compressed air systems generally incorporate pressure compensation. It depends on how much the design pressure and design temperature of your flow meter differ from your actual operating conditions – if the difference is large, compensation is necessary.
The flow rate, as indicated by the value written, is already in cubic meters per second. For these issues, it depends on what exactly the problem is It would be best to have a flowchart.
The difference is too large. Is it always like this? The process should be able to determine the actual flow rate; we need to check the flow meter as well as the temperature and pressure compensation formulas in the DCS. Here, we have had cases where the units in those formulas were incorrect
Find the opening on the pipe and insert the anemometer for testing; be sure to wrap it in a cloth when inserting to prevent air leakage, as otherwise the Venturi effect could draw in outside air and affect the measurements. Subsequently, the current flow rate can be calculated based on the flow velocity. Compare the measured flow rate with the flow meter reading.