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

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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Numerical simulation of heat transfer process in solar enhanced natural draft dry cooling tower with radiation model

Applied Thermal Engineering ◽

10.1016/j.applthermaleng.2016.11.155 ◽

2017 ◽

Vol 114 ◽

pp. 977-983 ◽

Cited By ~ 5

Author(s):

Qiuhuan Wang ◽

Jialing Zhu ◽

Xinli Lu

Keyword(s):

Heat Transfer ◽

Numerical Simulation ◽

Transfer Process ◽

Cooling Tower ◽

Heat Transfer Process ◽

Radiation Model ◽

Natural Draft ◽

Dry Cooling Tower ◽

Dry Cooling

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Utilization of the lateral accelerated cross-wind to improve the cooling performance of a natural draft dry cooling tower

Thermal Science ◽

10.2298/tsci19s4013w ◽

2019 ◽

Vol 23 (Suppl. 4) ◽

pp. 1013-1024 ◽

Cited By ~ 1

Author(s):

Weiliang Wang ◽

Junfu Lyu ◽

Hai Zhang ◽

Qing Liu ◽

Guangxi Yue ◽

...

Keyword(s):

Cooling Tower ◽

Collecting Duct ◽

Ventilation Rate ◽

Lateral Flow ◽

Wind Condition ◽

Coal Consumption ◽

Flow Acceleration ◽

Natural Draft ◽

Dry Cooling Tower ◽

Dry Cooling

Cross-wind degrades the performance of a natural draft dry cooling tower (NDDCT). Based on the basic affecting mechanism, this paper introduces a wind collecting approach. By using a wind collecting duct, the lateral flow acceleration of cross-wind is broken up, and the lateral flow kinetic energy is utilized to increase the lateral and rearward static pressure outside the radiator inlet. By adoption of a CFD model, the effect of the wind collecting approach is investigated comprehensively. It is found that the wind collecting ducts could improve the pressure distribution around the radiator bundle, reinforce the lateral air intake, and reduce the intensity of mainstream vortices, so as to enhance the ventilation rate of a NDDCT. For an outstanding performance, the two-duct wind collecting scheme is suggested, which may assure a NDDCT working in an approximately wind free manner in all investigated cross-wind range, and increase the ventilation rate by ~63% under the high cross-wind condition, which may reduce the overall coal consumption by 23500~33500 tons annually for a 660 MW coal-fired unit. The numerical results are confirmed by a hot state modelling experiment conducted in a wind tunnel.

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