Mathematical Model and Experimental Data for Water Cooling in Counterflow Film Cooling Towers

Abstract

The article considers the research methods, mathematical simulation, and calculation of heat-and-mass-transfer characteristics of film-type fills (packings) of cooling towers. The basic research approaches include experimental, numerical, and approximate methods. It is noted that the experimental and approximate methods are the most applicable for practical purposes when calculating cooling towers. One of the approximate methods consists in the application of flow structure models, namely, diffusion or cellular models. The authors consider the application of the cellular model for the gas and liquid phases in the form of an analytical solution with the thermal number of transfer units to calculate the thermal efficiency of the gas phase (air heating) and determine further the efficiency of the cooling water based on the thermal balance equation. The main parameters of the model, namely the number of cells for the gas and liquid phases, are calculated using the presented expressions. The article presents experimental data on hydraulic resistance, the volumetric coefficient of mass transfer, and thermal efficiency in the gas and liquid phases, obtained using the experimental model of a cooling tower with a bank of tubes (fill pack) with a discrete-regular rough surface. The calculation results by the cellular model are shown to agree with the experimental data. In addition, the calculation is performed for mini cooling towers with regular fills, used in rectification and absorption columns.