The number of heat exchange tubes can be determined based on the area of the heat exchanger; then why is it still necessary to determine this number based on the tube arrangement?
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At the beginning of the design, the number of heat exchange tubes was determined based on the heat exchange area. Later, when calculating the tube sheets, it was necessary to arrange the tubes, but the number of tubes required for this arrangement was greater than that determined based on the area of the heat exchanger. How can this problem be solved?
It’s okay; in reality, the heat exchange area resulting from the piping layout isn’t necessarily identical to what’s calculated – a slight deviation is normal!
Just reduce the number of tubes you fabricate – generally, remove some of the tubes around the edges – so that the total number equals the amount determined by the area of the heat exchanger. That’s all there is to it
If the number of pipes is greater than the area specified in the process requirements, there’s no problem at all; it’s sufficient to get confirmation from the process team, as long as they agree. Generally, process calculations include a certain percentage of margin.
First, the number of heat exchange tubes should be determined based on the required heat exchange area; thereafter, the tubes are arranged accordingly. Generally, some space is left in the tube sheet – it’s not necessary to fill it completely; as long as the heat exchange area is sufficient.
Check what percentage more there is. If the difference is significant, one can: 1. Reduce the number of tubes symmetrically, trying to minimize the number of tubes at the edges of the tube sheet and at the gaps in the baffle plates; 2. Increase the center distance between the tube holes appropriately
I share a similar view with the friend above
It’s the issue of theory versus practice; the former refers to the theoretical quantity, while the latter refers to the actual quantity
“The number of heat exchange tubes can be determined based on the area of the heat exchanger; then why is it still necessary to determine this number based on the tube arrangement? ” The calculations done earlier were merely estimates; only in this way could the calculations be carried out (otherwise, it would be impossible to determine the flow area, and thus it would be impossible to calculate the flow velocity and heat transfer coefficient) ； Subsequently, it is necessary to determine the actual structure based on reasonable estimates, as well as the number of heat exchange tubes. This requires deciding on how to arrange the tubes in accordance with the requirements of the equipment design standards, including determining the number of tie rods needed. The tasks ahead relate to the process engineering field, while those behind relate to the equipment engineering field. This post was last edited by lucky1909 on 2009-4-14 11:24.]