Numerical Simulations for Super Large-Scale Natural Draft Cooling Tower With an Optimized Non-Uniform Water Distribution

2017 ◽  
Author(s):  
J. Y. Li ◽  
H. Wang ◽  
W. Sheng
Keyword(s):  
Numerical Simulations ◽  
Water Distribution ◽  
Large Scale ◽  
Cooling Tower ◽  
Water Pressure ◽  
Water Spray ◽  
Natural Draft ◽  
Precise Data ◽  
Spray Density ◽  
Autumn And Winter

The great spray area of a Super Large-Scale Natural Draft Cooling Tower (SLNDWCT) makes it difficult to achieve an uniform wind field, and non-uniform water spray distributions are adopted in engineering. In this paper, to improve the cooling performance, optimized non-uniform water spray distributions are designed by utilizing network hydraulic calculations and numerical simulations. In the network calculations, the node-formula is applied to figure out the water pressure and flow rate of each spray nozzle, providing more precise data in simulations for the heat and mass transfer. Simulations for operating in summer, Spring/Autumn and winter seasons, which are different in water spray density, have been presented. In the operating in summer, the spray zone is divided into two regions (inner and outer regions), and by adjusting the water spray density and areas of the two regions, an improved water distribution is achieved.

Study of operation of natural draft cooling tower, with its hydraulic load reduced

2020 ◽  
Vol 12 (4) ◽  
pp. 268-273
Author(s):  
A. I. Badriev ◽  
V. N. Sharifullin ◽  
S. M. Vlasov ◽  
N. D. Chichirova
Keyword(s):  
Distribution System ◽  
Power Plants ◽  
Water Distribution ◽  
Cooling Tower ◽  
Air Flow ◽  
Thermal Power ◽  
Natural Draft ◽  
Irrigation Density ◽  
Hydraulic Load ◽  
Air Flows

A survey has been held of a BG-2600 natural draft cooling tower of thermal power plants, in the reduced hydraulic load mode. The technical condition of the reinforced concrete tower, the skeleton frame, the irrigation device, the water distribution system and the air duct windows has been inspected. Defects of the cooling tower structural elements have been identified. These include: horizontal sagging of the irrigation device, considerable gaps between its blocks and their partial destruction, problems with nozzles and structures of air duct windows. The identified defects are attributed to the causes of irregular water and air flows. The degree of irregularity of irrigation density and air flow in the tower has been estimated. Over the cross-section of the tower, a significant standard deviation from the average value or irregularity of irrigation density (30%) and irregularity of air flow (23.5%) has been established. The temperature and cooling curves of the cooling tower have been plotted taking into account irregularities of irrigation density and air flow rate. Normal and defective sections of the cooling tower have been identified based on working characteristics. Standard characteristics of the BG-2600 cooling tower have been plotted based on a nomogram. A comparative analysis of the working and standard characteristics has been held. The degree of influence produced by irregularities in water and air flows on the cooling process has been established. It has been found that the established irregularities in water and air flows result in a decrease in the temperature difference on average by 2°C and a decrease of cooling capacity by 7.3 Mcal/m2∙hr with a hydraulic load of 8840 m3/h. The results indicate a significant impact produced by irregularities of flows on cooling effect. The tasks to eliminate irregularities in distribution of flows as well as to increase the tower cooling efficiency have been formulated.

Three-Dimensional Numerical Study on Thermal Performance in a Natural Draft Wet Cooling Tower

2012 ◽  
Vol 614-615 ◽  
pp. 169-173
Author(s):  
Shui Hua Zheng ◽  
Tai Jin ◽  
Jian Ren Fan
Keyword(s):  
Numerical Simulation ◽  
Mass Transfer ◽  
Thermal Performance ◽  
Water Distribution ◽  
Cooling Tower ◽  
Numerical Study ◽  
Three Dimensional ◽  
Cooling Efficiency ◽  
Natural Draft ◽  
Mass Transfer Theory

Based on the heat and mass transfer theory and characteristics of the CFD software, a three-dimensional numerical simulation platform had been developed to study the thermal performance in a natural draft wet cooling tower. This platform was validated using the measured results of a running cooling tower. The flow and temperature field in the cooling tower were investigated. It is found that the water temperature and flow field can be correctly calculated using this platform. The cooling efficiency could be improved due to non-uniform fill and water distribution methods.

scholarly journals A CFD MODEL BASED ON WET DEPOSITION OF LARGE-SCALE NATURAL DRAFT COOLING TOWER

2019 ◽  
Vol 35 (esp01) ◽  
pp. 23-32
Author(s):  
Xuan Wang ◽  
◽  
Wenjie Bao ◽  
Xiaodong Huang ◽  
Xue Wang ◽  
...  
Keyword(s):  
Wet Deposition ◽  
Large Scale ◽  
Cooling Tower ◽  
Cfd Model ◽  
Natural Draft ◽  
Model Based

Investigating the Effects of Flue Gas Injection and Hot Water Distribution and Their Interaction on Natural Draft Wet Cooling Tower Performance

2019 ◽  
Author(s):  
Tom V. Eldredge ◽  
John M. Stapleton
Keyword(s):  
Water Temperature ◽  
Flue Gas ◽  
Water Distribution ◽  
Cooling Tower ◽  
Cold Water ◽  
Gas Injection ◽  
Hot Water ◽  
Moist Air ◽  
Cooling Performance ◽  
Natural Draft

Abstract This paper utilizes numerical modeling to address the effects of two parameters on natural draft cooling tower performance, namely the radial hot water distribution and flue gas injection. Predictions show that cold water temperature leaving the tower can be slightly decreased by increasing the weighting of the radial hot water distribution towards the tower periphery. The injection of scrubbed flue gas into the tower chimney can have either a positive or a negative effect on tower cooling performance, depending on the temperature of the flue gas relative to the temperature of moist air in the chimney. The temperature of the scrubbed flue gas is the primary variable affecting cooling tower performance, associated with flue gas injection. This paper investigates using the radial distribution of hot water to optimize the tower cooling performance when injecting scrubbed flue gas into the chimney, both for conditions when the flue gas is warmer and cooler than the temperature of moist air in the chimney. Predictions with no flue gas injection show that optimizing hot water distribution produced 0.4 °C reduction in cooled water temperature. With relatively cold (32.2 °C) and relatively hot (65.6 °C) flue gas injection, optimizing hot water distribution produced slightly more than 0.2 °C reduction in cooled water temperature.

scholarly journals Simultaneous effects of water spray and crosswind on performance of natural draft dry cooling tower

2013 ◽  
Vol 17 (2) ◽  
pp. 443-455 ◽  
Author(s):  
Hossein Ahmadikia ◽  
Mohsen Soleimani ◽  
Ehsan Gholami
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Rate ◽  
Transfer Rate ◽  
Cooling Tower ◽  
Wind Condition ◽  
Water Spray ◽  
Natural Draft ◽  
Spray System ◽  
Dry Cooling Tower ◽  
Dry Cooling

To investigate the effect of water spray and crosswind on the effectiveness of the natural draft dry cooling tower (NDDCT), a three-dimensional model has been developed. Efficiency of NDDCT is improved by water spray system at the cooling tower entrance for high ambient temperature condition with and without crosswind. The natural and forced heat convection flow inside and around the NDDCT is simulated numerically by solving the full Navier-Stokes equations in both air and water droplet phases. Comparison of the numerical results with one-dimensional analytical model and the experimental data illustrates a well-predicted heat transfer rate in the cooling tower. Applying water spray system on the cooling tower radiators enhances the cooling tower efficiency at both no wind and windy conditions. For all values of water spraying rate, NDDCTs operate most effectively at the crosswind velocity of 3m/s and as the wind speed continues to rise to more than 3 m/s up to 12 m/s, the tower efficiency will decrease by approximately 18%, based on no-wind condition. The heat transfer rate of radiator at wind velocity 10 m/s is 11.5% lower than that of the no wind condition. This value is 7.5% for water spray rate of 50kg/s.

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