A new theoretical method for predicating the part-load performance of natural draft dry cooling towers

Ma, Huan; Si, Fengqi; Kong, Yu; Zhu, Kangping; Yan, Wensheng

doi:10.1016/j.applthermaleng.2015.08.104

Cited by 32 publications

(9 citation statements)

References 16 publications

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“…B sed n H n's t e y M et l [92,93] proposed a theoretical model to consider both the impacts of ambient temperature and crosswind. They also considered the initial temperature difference since this parameter have a significant effect on the vertical air velocity of the cooling tower under windless condition.…”

Section: Dimensionless Studymentioning

confidence: 99%

A review of the crosswind effect on the natural draft cooling towers

Gurgenci

Guan

et al. 2019

Applied Thermal Engineering

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Crosswind is a significant concern for the design and operation of a natural draft cooling tower. The negative effects of crosswind on the thermal performance of natural draft cooling towers have been shown in many cases, for a variety of tower types. This paper presents a comprehensive review to synthesize the current research status in this field. At first, three common cooling tower research methods used to quantify the crosswind effect: full-scale/field measurements, lab-scale tests and CFD modelling, are reviewed and discussed. Then, based on the existing literature, the crosswind effect and its working mechanism on different types of natural draft cooling towers are summarized and discussed. Finally, the most current findings and solutions to address the crosswind issue are reported. The main advantages and disadvantages of each solution are presented and discussed. The information collected in this review paper could be a useful guidance for the design and optimization of natural draft cooling tower.

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Section: Dimensionless Studymentioning

confidence: 99%

A review of the crosswind effect on the natural draft cooling towers

Gurgenci

Guan

et al. 2019

Applied Thermal Engineering

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“…With the vertically arranged heat exchanger bundles of the dry-cooling system, Zhao et al [5,6] numerically presented detailed aerodynamic fields around the cooling deltas in the absence of winds, and at wind speeds of 4 m/s and 12 m/s. Ma et al [7] proposed a new theoretical model for the CFD process, to predict dry-cooling system performance, by using the power function of the initial temperature difference for the evaluation of ambient temperature effects and the outlet air velocity for the calculation of heat rejection.…”

Section: Introductionmentioning

confidence: 99%

Influencing Mechanisms of a Crosswind on the Thermo-Hydraulic Characteristics of a Large-Scale Air-Cooled Heat Exchanger

et al. 2019

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For the large scale air-cooled heat exchanger of a natural draft dry cooling system (NDDCS) in power plants, its thermo-flow characteristics are basically dominated by crosswinds. Unfortunately however, the detailed mechanisms of the crosswind effects have yet to be fully uncovered. Therefore, in this research, the local flow and heat transfer performances of the cooling deltas, which are also termed as the fundamental cells of the large-scale air-cooled heat exchanger, are specifically investigated with full consideration for the cell structure and the water-side temperature distribution at various wind speeds. A 3D CFD method with a realizable k-ε turbulence model, heat exchanger model, and porous media model is developed, and the accuracy and credibility of the numerical model are experimentally validated. With the numerical simulation, the overall 3D outlet air temperature of the large-scale air-cooled heat exchanger, and the corresponding local air velocity and temperature fields of the cooling deltas are qualitatively analyzed. Furthermore, the air-mass flow rate and heat rejection are also quantitatively studied at both the global and local views. The results depict that with an increase in the wind speed, the air mass flow rate and heat rejection will increase greatly for the frontal deltas; however, they will drop dramatically for the middle-front deltas. As for the middle- as well as the middle-rear deltas, the thermo-flow performances vary markedly at various wind speeds, which behave in the most deteriorated manner at a wind speed of 12 m/s. The rear deltas show the best thermo-flow performances at a wind speed of 12 m/s, but the worst at 16 m/s. A detailed analysis of the variable fields for each cooling delta may contribute to the performance improvement of the large-scale air-cooled heat exchanger of NDDCS.

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“…Compared with wet cooling tower, dry cooling tower reduces the loss of steam and water caused by evaporation and blow-down, and has been widely applied in the regions with rich coal and lack of water [1] . When passing across heat exchanger, the entering air will be heated by hot circulating water inside the heat exchanger bundles of the tower by convective heat transfer.…”

Section: Introductionmentioning

confidence: 99%

The Effects of Windbreak Walls with Various Widths on Thermal Performance Enhancements of the Dry Cooling Tower under Crosswind

Ma¹,

Si²,

Li³

et al. 2018

dtetr

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A numerical model of the dry cooling tower is established, considering the detailed structures of the delta-type radiators. Heat transfer characteristics of the radiators, along with cooling water temperature drop of the whole tower are obtained, and the impacts of windbreak walls with various widths on thermal performance enhancement of the tower are analyzed and compared. It's found that the effects caused by windbreak walls are not always positive, walls with small width would lead to performance deterioration of the tower. As wall width increases, the walls would enhance thermal performance of the tower gradually, and the optimal benefit brought by windbreak walls appears at the width between radiator height and 5/4 radiator height. Moreover, at large wall width, the positive effect brought by the walls is decreasing, but thermal performance of the tower in this condition is still superior to that at no-wall condition. This study provides guidance for the design, manufacture and practical application of windbreak walls in the dry cooling towers.

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A new theoretical method for predicating the part-load performance of natural draft dry cooling towers

Abstract: 14temperature difference, the tower has larger resistance to crosswindand cooling 15 efficiency declines more slowly, Moreover, heat rejection of the tower increases more 16 rapidly with initial temperature difference under a smaller crosswind velocity. 17

Cited by 32 publications

References 16 publications

A review of the crosswind effect on the natural draft cooling towers

A review of the crosswind effect on the natural draft cooling towers

Influencing Mechanisms of a Crosswind on the Thermo-Hydraulic Characteristics of a Large-Scale Air-Cooled Heat Exchanger

The Effects of Windbreak Walls with Various Widths on Thermal Performance Enhancements of the Dry Cooling Tower under Crosswind

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