The air flow velocity u is determined by the fan Velocity u is considered constant over the height and In a one-dimensional approximation, the average air Relaxation time of droplet temperature (s)ĭroplet velocity in z direction in stagnant airĭroplet velocity in z direction in upward air Thermal efficiency of a cooling tower, dimensionless Intensity of heat and mass transfer of droplets during With increase in the velocity ofĭroplets, the time of interaction with a ‘‘fresh’’, colderĪir is reduced. The water evaporates and convective heat transfer with aĬolder air occurs. The opposite directions gives a complete description ofĮvaporative cooling of droplets. Of a boundary-value problem for two phases moving in Mechanical draft cooling tower, we use the results obtained for a natural draft cooling tower. įor simulation of evaporative cooling of water in the Pilot model of the microcooling tower with monodisperseĭroplet distribution has recently been created. The number of droplets per unit volume (m3 ) International Journal of Heat and Mass Transfer 47 (2004) 165–177Ĭoefficient of aerodynamic drag, dimensionlessĭiffusion coefficient for water vapor (m2 /s) It is worth to note, that theĠ017-9310/$ - see front matter Ó 2003 Elsevier Ltd. Limits of applicability of this approximation for the problems of evaporative cooling. Our new approach allows one to determine the Majority of simulations of evaporative cooling the approximation of monodisperse ensemble of droplets is Wide distribution of droplet radii are used, in the vast The modern level of the description of these processes isĪlthough in industry the cooling towers with rather Phase transition during evaporative cooling is simplified. However, the description of the kinetics of The two-dimensional internal aerodynamics of the cooling tower. Performance is presented, which allows calculation of In, a mathematical model of the cooling tower In this work, the size distribution of droplets and elements of two-dimensionalĪerodynamics of a mechanical draft cooling tower are Tower a polydisperse ensemble of droplets is formed by In our previous publication, we considered only Only a water droplet flow takes place, and there are no Processes in a mechanical draft cooling tower, where In this paper we consider the heat and mass transfer Water-collecting pond and the fan to create an artificial Basic elements of such cooling towersĪre shown in Fig. Height of the mechanical draft cooling towers can va ryįrom 2 to 12 m. Industry for deep cooling of circulating water. Mechanical draft cooling towers are widely used in This control system permits one to optimize the performance of the mechanical draft cooling tower under Mathematical model of a control system of the mechanical draft cooling tower is suggested and numerically investigated. The relativeĪccuracy of well-defined monodisperse approximation is about several percent of heat efficiency of the cooling tower. It was shown that the average cube of the droplet radius practically determines thermal efficiency. The explanation of the influence of atmospheric pressure on the cooling tower performance has been obtained for the first time. Of heat and mass transfer between water droplets and damp air, to take into account the cooling tower design parameters and the influence of atmospheric conditions on the thermal efficiency of the tower. Simulation based on our model allows one to calculate contributions of various physical parameters on the processes Mathematical model takes into account the radii distribution function of water droplets. The model describes available experimental data with an accuracy of about 3%. Velocity, its radii and temperature, and also a change in the temperature and density of the water vapor in a mist air in aĬooling tower. Represents a boundary-value problem for a system of ordinary differential equations, describing a change in the droplets Brovka St., Minsk 220072, BelarusĪ new mathematical model of a mechanical draft cooling tower performance has been developed. Luikov Heat and Mass Transfer Institute, National Academy of Sciences of Belarus, 15, P. International Journal of Heat and Mass Transfer 47 (2004) 165–177Įvaporative cooling of water in a mechanical draft
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