Evaluation of Mathematical Models for Characterizing Plume Behavior from Cooling Towers. Volume 1. Dispersion from Single and Multiple Source Natural Draft Cooling Towers

摘要

Fifteen mathematical models for visible plume prediction from natural draft cooling towers are evaluated theoretically and tested with 39 sets of single-tower visible plume field data from three sites. Seven of these models with the capability of treating plumes from multiple towers are further tested with 26 sets of multiple tower data from two sites. The visible plume outlines provided by these data give information on the trajectory of the plume as well as dilution. The model/data comparisons prepared in this study revealed systematic behaviors in the predictions of most models which were able to be traced back to model assumptions. A wide range of predictions was found to occur among the models. No one model performed consistently well for all data sets. Theoretical analysis of the model formulations revealed that models which correctly predict the plume trajectory due to the entrainment mechanism alone will overpredict dilution. The more successful models employ an additional mechanism to provide additional bending without additional mixing. The correctness of any of the additional bending mechanisms remains to be determined. The model/data discrepancies are partly due to model errors and partly due to data measurement errors. The accuracy of the data makes it unlikely for a model to predict better than a factor of 1 1/2-2 in most, perhaps 90%, of all data cases.