THERMAL-CONTACT RESISTANCE IN FINNED TUBING
Interference-fit finned tubes depend for their heattransfer capability upon a contact pressure between fin and tube. The bond resistance under such conditions is relatively small compared to the other resistances in the heatflow path. At elevated temperatures, however, differential thermal expansion between fins and tubes completely relaxes the contact pressure and introduces an additional gap resistance; this may become a significant part of the total resistance to heat transfer. A theoretical method for predicting the gap resistance is derived in terms of the fin and tube dimensions, their physical properties, the fluid temperatures and heat-transfer coefficients, and the initial contact pressure. Test data on five finned-tube units representing embedded, tension-wound, and muff-type fins are given in graphical and tabular form. Very good agreement is found between theory and test in two of the interferencefit units. The other two show only fair agreement. (auth)
- Research Organization:
- Griscom-Russell Co., Massillon, Ohio
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-15-002744
- OSTI ID:
- 4148967
- Journal Information:
- Journal of Heat Transfer (U.S.), Journal Name: Journal of Heat Transfer (U.S.) Vol. Vol: 82; ISSN JHTRA
- Country of Publication:
- Country unknown/Code not available
- Language:
- English
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