Theoretical analysis of effects caused by mixing proportion on plume potential

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Theoretical analysis of effects caused by mixing proportion on plume potential

 

Author: Zhao, Le
Title: Theoretical analysis of effects caused by mixing proportion on plume potential
Degree: M.Eng.
Year: 2011
Subject: Plumes (Fluid dynamics)
Cooling towers -- Environmental aspects.
Atmospheric diffusion.
Hong Kong Polytechnic University -- Dissertations
Department: Dept. of Building Services Engineering
Pages: ix, 74 leaves : ill. (chiefly col.) ; 30 cm.
Language: English
InnoPac Record: http://library.polyu.edu.hk/record=b2451600
URI: http://theses.lib.polyu.edu.hk/handle/200/6398
Abstract: Visible plume from evaporative cooling towers has been a hot spot issue in HVAC (Heating ventilation and air conditioning) field for many years. People show large concern about how to eliminate the plume as it could result in misconception of a fire accident or a hazardous pollutant for local people in highly dense city. Studies conducted on this topic showed different results and many approaches have been proposed to solve this problem. A study by Xinhua Xu et al investigated the reason for plume occurrence and proposed two approaches to control or eliminate it accordingly. This study aimed to investigate this topic by analyzing mixing processes with different mixing proportions and how the mixing proportion could have effects on plume potential. Analysis based on theoretical calculations was applied to analyze the mixing process of ambient air and exhaust air from cooling tower under some typical weather conditions. And the plume potential of those mixing processes is also examined. The result indicates that in general, the plume potential increases with the growth of relative humidity of ambient air. With the increase of mixing proportion of ambient air in mixing process, the increasing degree becomes larger and larger gradually. However, the plume potential decreases with the growth of ambient air temperature, the decreasing degree seems to be almost the same under different mixing proportions. When the relative humidity of ambient air is larger than that of exhaust air from cooling tower; the plume potential increases with the growth of proportion of ambient air in mixing process in general When the relative humidity of ambient air is equal to that of exhaust air from cooling tower, the plume potential generally increases first and then decreases gradually with the increase of proportion of ambient air in mixing process. When the relative humidity of ambient air is smaller than that of exhaust air from cooling tower, the plume potential has a general decrease trend with the growth of proportion of ambient air in mixing process.

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