S-SS-3-9 Improvements to the Stream Analysis Method for Prediction of Shellside Pressure Drop

A. Salehpour

Pressure drop data, obtained in the HTRI single-phase research facility with four new bundles, have been analyzed in conjunction with the previous data in the HTRI data bank. The bundles used in the new experiments were a finned-tube bundle with 30 fins/in. tubes and segmental baffles; a finned-tube bundle with 19 fins/in. tube and double-segmental baffles; a plain tube bundle with a 90° layout angle; and a plain tube bundle with a 45 percent baffle cut and a large baffle spacing-to-shell diameter ratio.

The analysis has resulted in improvements to the correlations in the Stream Analysis Method for the prediction of shellside pressure drop. The data from the bundle with the large baffle cut and wide baffle spacing, have shown that the longitudinal flow calculation model described in HTRI Report S-SS-3-4 should be used at values of baffle spacing-to-shell diameter ratios of 0.8 and higher. The data have also shown that the window nonideality correction factor (FR) for units with a tube-to-baffle leakage stream is less than recommended in HTRI Report S-SS-3-1. Another observation from the finned tube data is that the turbulent flow friction factor should actually be lower than the calculated quantities based on the method of HTRI Report STG-3.

The improvements to the Stream Analysis Method have been implemented in the HTRI ST Computer Program and applied to the data. Both bundle and total (nozzle-to-nozzle) pressure drop data have been analyzed. Predictions of 93 percent of the data fall within ± 30 percent of the measured values for the Reynolds numbers in the range of 2.1 to 24,700. Almost all of the heat transfer data are predicted to within ± 30 percent of the measured values.