TE-2 Heat Transfer and Pressure Drop Characteristics of Flow Inside Spirally Grooved Tubes in the Turbulent Regime
This report presents the results of two studies:
Pressure drop and heat transfer data have been obtained on Phelps Dodge-type spirally grooved 1-in. diameter tubes of various configurations with respect to groove pitch and groove depth. Generalized correlations were developed for prediction of intube DP and convective heat transfer coefficient as function of the groove geometry.
Both pressure drop and heat transfer increase with greater density and depth of grooving. Beyond a certain groove depth (function of the groove density) the increase of heat transfer diminishes, but pressure drop keeps increasing. Comparison criteria are presented for performance evaluation of the grooved tubes relative to a plain tube. For the same pumping horsepower, some of the grooved tubes produced up to 35 percent better overall coefficient U with condensing steam as heating medium. Based on the tubeside alone, heat transfer coefficient h increased on some of the tubes up to 100 percent over plain tube (at constant flow rate), but the pressure drop for these cases was approximately 8 times that of the plain tube.
Pressure drop and heat transfer data have been obtained on Turbotec spirally grooved tubes of various configurations and tube diameters.
This report contains an analysis of the effects of geometry and tubeside Reynolds and Prandtl numbers on the performance of the tested tubes in the turbulent region, methods to extrapolate the data to other conditions and criteria for selection of the optimum configuration.