Tube pitch in most shell-and-tube exchangers is typically ______________ tube outer diameter?
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Answer: B. 1.25-1.50 times
Explanation
Tube pitch is selected between 1.25 and 1.50 times the outer tube diameter standardly. This ratio provides sufficient metal ligament width in the tube sheet for structural strength. It balances shell-side pressure drop against required heat transfer surface area density. Shell-and-tube heat exchangers require careful spacing of tubes to optimize fluid performance. Tighter pitches increase heat transfer but raise shell-side pressure drop significantly. Wider pitches reduce pressure drop but require larger shell diameters for the same surface area.
Mechanical design engineers specify this pitch ratio during the initial sizing of exchangers. Proper spacing ensures adequate structural integrity of the tube sheet under operating loads. Adhering to standard pitch ratios prevents excessive manufacturing costs and operational issues. Option A would place tubes too close together, destroying tube sheet structural integrity. Option C represents an excessively wide spacing that wastes valuable shell volume. Option D describes tube clearance rather than center-to-center tube pitch dimensions.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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