Some Turbulence and Diffusion Parameter Estimates within Cooling Tower Plumes Derived from Sodar Data

Abstract

Temperature and velocity fluctuations within a cooling tower plume in stable conditions at the Keystone power plant in Pennsylvania have been measured by use of a calibrated sodar. Monostatic and bistatic systems probed the plume at several positions 40 to 300 m downwind of the cooling tower. Comparison of the sodar estimates of the temperature and velocity structure parameters (CT2 and CV2) with those derived from measurements taken by aircraft at the same location shows acceptable agreement. Alternate methods of averaging profiles of CT2 through the plume are used to investigate single and relative dispersion coefficients. Both methods describe a linear increase of plume width with distance from the cooling tower. Combining values of temperature and velocity structure parameters leads to estimates of turbulence kinetic energy dissipation rate ? near 0.3 m2 s?3 and temperature fluctuation destruction rate N of 0.01?0.21 K2 s?1. The decrease in CT2 and CV2 is found to be exponential with horizontal distance from the tower; CT2 decreases more rapidly than CV2. Time-lapse photography used simultaneously with the sodar measurements indicates that the thermal turbulence plume is larger than the condensation plume by a factor of 2?5.