S-SS-3-7 Heat Transfer Performance of Integral Low-Finned Tube Bundles; Liquid Application

A. Salehpour and J. W. Palen

New HTRI data for two low-finned tube bundles have been analyzed. One of these bundles has 30 fins/in. (1,181 fins/m) tubes with segmental baffles and the other one has 19 fins/in. (748 fins/m) tubes with double-segmental baffles. The analysis also includes the original finned-tube data in the HTRI data bank. The geometries of previous HTRI bundles have been described in Supplements 1 and 2 to HTRI Data Book 1.

Based on this analysis, it has been observed that with finned tubes the shellside heat transfer j-factor for liquids is less than for gases. The j-factor correlation for finned-tube bundles was originally developed based on the air data, as discussed in HTRI Report STG-3. Further adjustments have been necessary in order to predict the new data. A new correlation is used to calculate j-factors for Reynolds numbers greater than 800. For Reynolds numbers less than 400, the heat transfer j-factor is evaluated from the previous HTRI method. By this method the j-factor is obtained by multiplying the plain tube j-factor by a boundary layer overlap correction factor. Between Reynolds numbers of 400 and 800 a linear proration is used to obtain the heat transfer coefficient.

With the new correlation 98.8 percent of 600 data point included in this analysis are predicted within ± 30 percent of the measured values. A selection of the representative data is provided in Appendix A. Supplement 3 to HTRI Data Book 1 will be issued later which will include all the data.