The performance of a group of bent-strip inserts used for enhancement of convective heat transfer coefficients in tubes carrying hot gases is studied and an evaluation of relative performance is made.
The relative performances are compared by use of performance evaluation criteria (PEC) developed to determine the performance improvement of a given insert over that of a smooth tube. The PEC used were based on increase in heat duty for fixed geometry under either a fixed pressure drop constraint or a constant pumping power constraint. The effects of insert width, pitch and Reynolds number are presented for both constraints.
New data are given for two configurations of a bent-tab insert and the same PEC are applied to determine their relative performance.
The PEC comparisons show that improvements in convective heat transfer coefficients both types of inserts are strongly dependent on Reynolds number over the test range of 3000 to 30,000. Under the constant pressure drop constraint, both types of inserts showed improvements over a smooth tube only at lower Reynolds numbers. Under the constant pumping power constraint, larger improvements were found and for a wider range of Reynolds numbers.
Units: Dual
Citation: Symposium, ASHRAE Transactions, 1988, vol. 94, pt. 2, Ottawa
Product Details
- Published:
- 1988
- Number of Pages:
- 18
- File Size:
- 1 file , 1.1 MB
- Product Code(s):
- D-OT-88-05-5
