Anti-freezing of air-cooled heat exchanger by switching off sectors

Wang, Weijia; Kong, Yanqiang; Huang, Xianwei; Yang, Linlin; Du, Xiaoze; Yang, Yongping

doi:10.1016/j.applthermaleng.2017.03.106

Cited by 22 publications

(11 citation statements)

References 19 publications

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“…With no ambient winds, the velocity inlet is assigned for all side surfaces, while the top pressure outlet boundary for the top plane. Figure 3a shows the large-scale numerical domain with a natural draft dry cooling system in center [4,5]. The corresponding grids of the cooling columns as well as the tower shell are described in Figure 3b, where the mesh interval sizes are set as 0.2 m and 2 m for these two sections [11,12,20].…”

Section: Mesh Approach and Boundarymentioning

confidence: 99%

“…Furthermore, the realizable k-ε model is introduced to simulate the turbulent flows. With the closed numerical equations, the flows incorporating boundary layer with high adverse pressure gradient, rotation, flow recirculation and separation, can be predicted accurately [4][5][6][7]13,14,[25][26][27][28]:…”

Section: Numerical Modelmentioning

confidence: 99%

“…What's more, comparing the detailed outlet water temperature of each cooling delta, the water distribution [24][25][26] for air-cooled sectors may be recommended in order to achieve the anti-freezing protection and energetic operation of NDDCS. Figure 1a,b show the geometric schematics of a natural draft dry cooling system and the 11 cooling deltas in each sector [4,5]. The large-scale air-cooled heat exchanger is generally divided into ten sectors, so as to distribute the circulating water flexibly.…”

Section: Introductionmentioning

confidence: 99%

“…By introducing a non-dimensional parameter to present the heat rejection differences of various sectors under ambient winds, Ma et al [9] found performance differences among the sectors, especially for the frontal and Figure 1a,b show the geometric schematics of a natural draft dry cooling system and the 11 cooling deltas in each sector [4,5]. The large-scale air-cooled heat exchanger is generally divided into ten sectors, so as to distribute the circulating water flexibly.…”

Section: Introductionmentioning

confidence: 99%

“…Recently, the anti-freezing water flow rates of sectors [4], switching off sectors [5], louver control [6], as well as simultaneous adjustment principle of circulating water and louver [7] which can all substantially contribute to the preventing freezing of NDDCS, have been numerically investigated. Besides, the pre-heating/peak cooler installation was also proposed for NDDCS [8].…”

Section: Introductionmentioning

confidence: 99%

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Impacts of Water Flow Rate on Freezing Prevention of Air-Cooled Heat Exchangers in Power Plants

et al. 2018

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Under cold ambient conditions, the freezing risk of air-cooled heat exchangers, especially the frontal finned tube bundles, has been a critical concern in power plants. Based on the freezing conditions of the cooling deltas under windy conditions, the flow and heat transfer characteristics of natural draft dry cooling system (NDDCS) with 30%, 40% and 50% increased water flow rates are investigated in this work, and the outlet circulating water temperatures of the easily freezing cooling deltas and sectors are obtained. The results show that the deltas in the middle front and rear sectors become free from freezing at all wind speeds when the circulating water flow rate is increased. For the frontal sector with increased water flow rate, the outlet water temperatures of deltas increase conspicuously at 4 m/s and 8 m/s, while as the wind speed rises to 16 m/s, these deltas still face serious freezing risks due to the huge heat rejection to ambient air. Therefore, freezing prevention of air-cooled NDDCS heat exchangers can be achieved by increasing the water flow rates at small wind speeds, while as the wind speed becomes high, the water flow redistribution is suggested for the frontal and middle sectors due to their big performance difference.

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Section: Mesh Approach and Boundarymentioning

confidence: 99%

Section: Numerical Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Impacts of Water Flow Rate on Freezing Prevention of Air-Cooled Heat Exchangers in Power Plants

et al. 2018

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Energy efficient strategies for anti-freezing of air-cooled heat exchanger

et al. 2020

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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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Anti-freezing of air-cooled heat exchanger by switching off sectors

Cited by 22 publications

References 19 publications

Impacts of Water Flow Rate on Freezing Prevention of Air-Cooled Heat Exchangers in Power Plants

Impacts of Water Flow Rate on Freezing Prevention of Air-Cooled Heat Exchangers in Power Plants

Energy efficient strategies for anti-freezing of air-cooled heat exchanger

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

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