Operation strategies of axial flow fans in a direct dry cooling system under various meteorological conditions

Heat Transfer ◽  
2021 ◽  
Author(s):  
Wenhui Huang ◽  
Lei Chen ◽  
Lijun Yang ◽  
Xiaoze Du
Keyword(s):  
Cooling System ◽  
Axial Flow ◽  
Meteorological Conditions ◽  
Dry Cooling

scholarly journals Cooling Performance Optimization of Direct Dry Cooling System Based on Partition Adjustment of Axial Flow Fans

Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3179
Author(s):  
Wenhui Huang ◽  
Lei Chen ◽  
Weijia Wang ◽  
Lijun Yang ◽  
Xiaoze Du
Keyword(s):  
Wind Direction ◽  
Performance Optimization ◽  
Cooling System ◽  
Axial Flow ◽  
High Wind ◽  
Power Generating Unit ◽  
Wind Speeds ◽  
Mass Flow Rates ◽  
Computational Fluid Dynamics Cfd ◽  
Dry Cooling

Axial flow fans play key roles in the thermo-flow performance of direct dry cooling system under windy conditions, so the energy efficiency of a power generating unit can be improved by optimizing the operation strategies of the axial flow fans. In this work, various measures based on the partition adjustment of axial flow fans with constant power consumption of a 2 × 660 MW power plant are studied by computational fluid dynamics (CFD) methods. The results show that increasing the rotational speed of the windward fans is beneficial to reduce the inlet air temperature and increase the mass flow rates of the fans, which enhance the heat rejections of the air-cooled condensers, especially at high wind speeds. Moreover, the turbine back pressures for the optimal and original cases are achieved by iterative methods, with the largest drop of 2.77 kPa at the wind speed of 12 m/s for 110-case 3 in the wind direction of −90°. It is recommended to adopt 110-case 1 and 110-case 3 at low and high wind speeds, respectively, in the wind directions of 90° and −90°, while 110-case 2 is always the best choice in the 0° wind direction.

scholarly journals Energy-Saving Strategies of Axial Flow Fans for Direct Dry Cooling System

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3176
Author(s):  
Wenhui Huang ◽  
Lei Chen ◽  
Lijun Yang ◽  
Xiaoze Du
Keyword(s):  
Flow Field ◽  
Energy Saving ◽  
Cooling System ◽  
Axial Flow ◽  
Operating Conditions ◽  
Total Power ◽  
Cooling Power ◽  
Prevailing Wind Direction ◽  
Cooling Air ◽  
Dry Cooling

The operating conditions of axial flow fans are closely related to the thermo-flow characteristics of the mechanical draft direct dry cooling system. Moreover, the uneven distribution of cooling air driven by axial flow fans may lead to the deterioration of the heat transfer capacity of air-cooled condensers (ACCs). Therefore, developing energy-saving operating methods for axial flow fans is very meaningful. In this work, two kinds of adjustment strategies to make the flow field more uniform are proposed for a 2 × 300 MW direct dry cooling power-generating unit. The performance of ACCs in the prevailing wind direction is predicted with the help of the macro heat exchanger model. It is found that the inlet air temperatures of fans are significantly reduced by proposed strategies, especially at high wind speeds. Moreover, the minimum cooling air can meet the cooling demand of ACCs for the strategy which made the air flow rates of all fans consistent. Compared with the case without adjustment of fans, the total power consumption of the fan array was cut down effectively, up to 13.94% at the wind speed of 12 m/s. In conclusion, the energy efficiency of ACCs can be improved by the uniform flow field.

Analysis of a Large-Scale Cooling System Fan Gearbox Loads

2017 ◽  
Author(s):  
Charles H. O. Lombard ◽  
Daniel N. J. Els ◽  
Jacques Muiyser ◽  
Albert Zapke
Keyword(s):  
Large Scale ◽  
Cooling System ◽  
Axial Flow ◽  
Output Shaft ◽  
Blade Loading ◽  
Operational Conditions ◽  
Power Stations ◽  
Reverse Loading ◽  
Air Cooled Condensers ◽  
Input Side

South Africa’s coal-fired power stations use super heated steam to drive generator turbines. In arid regions, air-cooled condensers (ACCs) are used to condense the process steam. These ACCs consists of an array of over 200 axial flow fans, each driven by a motor via a reduction gearbox. Distorted fan inlet air flow conditions cause transient blade loading, which results in variations in output shaft bending and torque. A measurement project was conducted where the input and output shaft of such a gearbox were instrumented with strain gauges and wireless bridge amplifiers. Gearbox shaft speed and vibration were also measured. Torsional and bending strains were measured for a variety of operational conditions, where correlations were seen between gearbox loading and wind conditions. The input side experienced no unexpected loads from the motor or changing wind conditions, whereas output shaft loading was influenced by the latter. Digital filters were applied to identify specific bending components, such as the influence of fan hub misalignment and dynamic blade loading. Reverse loading of the gearbox was measured during the fan stop period, and vibration analysis revealed torsional and gearbox vibrations. This investigation documented reliable full scale ACC gearbox loads.

Progress of the 40 MW-Class Advanced Humid Air Turbine Tests

2013 ◽  
Vol 135 (11) ◽  
Author(s):  
Manabu Yagi ◽  
Hidefumi Araki ◽  
Hisato Tagawa ◽  
Tomomi Koganezawa ◽  
Chihiro Myoren ◽  
...  
Keyword(s):  
Metal Surface ◽  
Control Method ◽  
Cooling System ◽  
Pressure Ratio ◽  
Axial Flow ◽  
Test Facility ◽  
Humid Air ◽  
Air Turbine ◽  
Calculation Results ◽  
Flow Compressor

A 40 MW-class test facility has been constructed to verify practicability of applying the advanced humid air turbine (AHAT) system to a heavy-duty gas turbine. Verification tests have been carried out from January 2012, and interaction effects between the key components were established. First, water atomization cooling (WAC) was confirmed to contribute to both increased mass flow rate and pressure ratio for the axial-flow compressor. The good agreement between measured and calculated temperatures at the compressor discharge was also confirmed. These results demonstrated the accuracy of the developed prediction model for the WAC. Second, a control method that realized both flame stability and low nitrogen oxides (NOx) emissions was verified. Although the power output and air humidity were lower than the rated values, NOx concentration was about 10 ppm. Finally, a hybrid nozzle cooling system, which utilized both compressor discharged air and humid air, was developed and tested. The metal surface temperatures of the first stage nozzles were measured, and they were kept under the permissible metal temperature. The measured temperatures on the metal surface reasonably corresponded with calculation results.

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