scholarly journals Application of Computational Fluid Dynamics in Chlorine-Dynamics Modeling of In-Situ Chlorination Systems for Cooling Systems

2020 ◽  
Vol 10 (13) ◽  
pp. 4455
Author(s):  
Jongchan Yi ◽  
Jonghun Lee ◽  
Mohd Amiruddin Fikri ◽  
Byoung-In Sang ◽  
Hyunook Kim
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Power Plant ◽  
Power Plants ◽  
Cooling System ◽  
Low Cost ◽  
Electrochemical Process ◽  
Dynamics Modeling ◽  
Pipe Surface

Chlorination is the preferred method to control biofouling in a power plant cooling system due to its comparative effectiveness and low cost. If a power plant is located in a coastal area, chlorine can be electrochemically generated in-situ using seawater, which is called in-situ electro-chlorination; this approach has several advantages including fewer harmful chlorination byproducts and no need for chlorine storage. Nonetheless, this electrochemical process is still in its infancy in practice. In this study, a parallel first-order kinetics was applied to simulate chlorine decay in a pilot-scale cooling system. Since the decay occurs along the water-intake pipe, the kinetics was incorporated into computational fluid dynamics (CFD) codes, which were subsequently applied to simulate chlorine behavior in the pipe. The experiment and the simulation data indicated that chlorine concentrations along the pipe wall were incremental, even under the condition where a strong turbulent flow was formed. The fact that chlorine remained much more concentrated along the pipe surface than in the middle allowed for the reduction of the overall chlorine demand of the system based on the electro-chlorination. The cooling system, with an in-situ electro-chlorination, consumed only 1/3 of the chlorine dose demanded by the direct injection method. Therefore, it was concluded that in-situ electro-chlorination could serve as a cost-effective and environmentally friendly approach for biofouling control at power plants on coastal areas.

Numerical Investigation of Thermal Flow Field of Air-Cooled Condensers for Yongshou Plant

2012 ◽  
Vol 248 ◽  
pp. 391-394
Author(s):  
Wen Zhou Yan ◽  
Wan Li Zhao ◽  
Qiu Yan Li
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Speed ◽  
Power Plant ◽  
Flow Field ◽  
Wind Direction ◽  
Rotational Speed ◽  
Power Plants ◽  
Thermal Flow ◽  
Air Cooled Condensers

By using the computational fluid dynamics code, FLUENT, Numerically simulation is investigated for Youngshou power plant. Under the constant ambient temperature, the effects of different wind speed and wind direction on the thermal flow field are qualitatively considered. It was found that when considering about the existing and normally operating power plants, the thermal flow field is more sensitive to wind direction and wind speed. Based on the above results, three improved measures such as: increasing the wind-wall height and accelerating the rotational speed of the fans near the edge of the ACC platform and lengthen or widen the platform are developed to effectively improving the thermal flow field, and enhanced the heat dispersal of ACC.

scholarly journals Analysis of the evaporative towers cooling system of a coal-fired power plant

2012 ◽  
Vol 16 (suppl. 2) ◽  
pp. 375-385 ◽  
Author(s):  
Mirjana Lakovic ◽  
Slobodan Lakovic ◽  
Milos Banjac
Keyword(s):  
Energy Efficiency ◽  
Power Plant ◽  
Theoretical Analysis ◽  
Power Plants ◽  
Cooling Tower ◽  
Cooling System ◽  
Low Cost ◽  
Cooling Water ◽  
Energy Efficiency Improvement ◽  
Condensing Pressure

The paper presents a theoretical analysis of the cooling system of a 110 MW coal-fired power plant located in central Serbia, where eight evaporative towers cool down the plant. An updated research on the evaporative tower cooling system has been carried out to show the theoretical analysis of the tower heat and mass balance, taking into account the sensible and latent heat exchanged during the processes which occur inside these towers. Power plants which are using wet cooling towers for cooling condenser cooling water have higher design temperature of cooling water, thus the designed condensing pressure is higher compared to plants with a once-through cooling system. Daily and seasonal changes further deteriorate energy efficiency of these plants, so it can be concluded that these plants have up to 5% less efficiency compared to systems with once-through cooling. The whole analysis permitted to evaluate the optimal conditions, as far as the operation of the towers is concerned, and to suggest an improvement of the plant. Since plant energy efficiency improvement has become a quite common issue today, the evaluation of the cooling system operation was conducted under the hypothesis of an increase in the plant overall energy efficiency due to low cost improvement in cooling tower system.

Polymer Electrolyte Fuel Cell Design Based on Three-Dimensional Computational Fluid Dynamics Modeling

2009 ◽  
Vol 6 (2) ◽  
Author(s):  
Stefano Cordiner ◽  
Simon Pietro Lanzani ◽  
Vincenzo Mulone ◽  
Marco Chiapparini ◽  
Angelo D’Anzi ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Fuel Cell ◽  
Polymer Electrolyte ◽  
Cooling System ◽  
Three Dimensional ◽  
Design Procedure ◽  
Operating Conditions ◽  
Polymer Electrolyte Fuel Cell ◽  
Dynamics Modeling

An entirely numerical design procedure, based on computational fluid dynamics, is introduced to evaluate the performance of different polymer electrolyte fuel cell layouts and sets of operating conditions for assigned target parameters in terms of performance. The design procedure has been applied to a coflow design, characterized by large active area (500 cm2), moderate temperature (70°C), liquid cooling, and metal supporting. The role of heat transfer between the cell and the cooling system is analyzed to properly address the influence of operating conditions on power density and flooding via a comprehensive parametric analysis.

Numerical Investigation of Recirculation of Air-Cooled Condensers for a Large Power Plant

2012 ◽  
Vol 516-517 ◽  
pp. 355-359
Author(s):  
Wan Li Zhao ◽  
Wen Zhou Yan ◽  
Can Bing Xu
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Speed ◽  
Power Plant ◽  
Wind Direction ◽  
Rotational Speed ◽  
Power Plants ◽  
Normal Operation ◽  
Large Power ◽  
Air Cooled Condensers

In order to minimize the recirculation to ensure normal operation of the air-cooled condensers (ACC) system, the recirculation phenomenon and its dependence on ambient winds are numerically simulated by using the computational fluid dynamics code, FLUENT. Under the constant ambient temperature, the effects of different wind speed and wind direction on the recirculation are qualitatively considered by applying the concept of the recirculation rate. The mechanism of occurrence of recirculation are presented and analyzed. It was found that when considering about the existing and normally operating power plants, the recirculation is more sensitive to wind direction and wind speed. Based on the above results, three improved measures increasing the wind-wall height and accelerating the rotational speed of the fans near the edge of the ACC platform and lengthen or widen the platform are developed to effectively reduce the recirculation.

scholarly journals Computational Fluid Dynamics Model of Air Velocity through a Poultry Transport Trailer in a Holding Shed

2020 ◽  
Vol 36 (6) ◽  
pp. 963-973
Author(s):  
Christian L. Heymsfield ◽  
Yi Liang ◽  
Thomas A. Costello
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Cooling System ◽  
Model Simulation ◽  
List Type ◽  
Cfd Model ◽  
Dynamics Modeling ◽  
Air Velocity ◽  
Space Module ◽  
Alternative Design

HighlightsComputational fluid dynamics modeling was an effective tool to simulate conditions on transport trailers in holding broilers for slaughter, to understand the performance of existing and alternative system configurations;Model simulation and measurements indicated that less than 32% of airflow generated by the cooling fans in the existing fan configuration in this study actually penetrated through the bird-occupied spaces;Simulations suggest that higher air velocity in the bird occupied zone within the modules can be achieved by alternative fan configurations at the holding shed, such as employing one fan per module, or with the addition of a transition enclosures from each fan outlet to the face of the receiving module. Abstract. The configuration of cooling systems in commercial holding sheds, where live broilers wait in cage modules for slaughter, varies between processing plants, with cooling system efficacies largely unknown. A computational fluid dynamics (CFD) model was developed to simulate airflow through cage modules in a poultry trailer in a typical holding shed configuration. Three alternative design configurations were simulated in order to better understand the air velocity profiles and to explore potential improvements for better cooling performance. Experimental data were collected within modules in a poultry trailer, parked in an existing commercial holding shed during warm summer conditions. Results from the CFD model had reasonable agreement with measured field data. Simulated air velocities were mostly within one standard deviation of measured values. Simulation of airflow through modules in the base configuration showed that less than 32% of airflow from the fans actually penetrated through the bird-occupied space. Module tiers experienced different airflow penetration due to the ad hoc positioning/alignment of the fans relative to the modules. In the base industry configuration, fans were in fixed positions and the number of fans and their centerline discharge axes did not align with the modules on the trailer. Regions not aligned with the faces of the fans, such as the uppermost and bottommost tiers, and horizontal locations offset from the fans, received the least airflow through the modules. Sections of modules experienced lower air velocity with increasing distance from the fans. Simulation of Design Alternative 2 (which added additional fans so that a fan was centered on each row) predicted an improved fan airflow of 3.08 and 3.05 kg s-1 through the cages in two adjacent rows, compared to 1.52 and 2.15 kg s-1 predicted for the original configuration. The increased air velocity using the alternative design illustrates the potential improvement and need to further optimize the design of these holding sheds. This research showed that a CFD model is an effective tool to simulate airflow conditions on poultry trailers in holding sheds to explore various holding shed cooling configurations and strategies. Keywords: Air velocity, CFD, Poultry Transportation, Poultry welfare.

Computational Fluid Dynamics Modeling of Fabric Systems for Intelligent Garment Design

MRS Bulletin ◽  
2003 ◽  
Vol 28 (8) ◽  
pp. 568-573 ◽  
Author(s):  
Jim Barry ◽  
Roger Hill ◽  
Paul Brasser ◽  
Michal Sobera ◽  
Chris Kleijn ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Protective Clothing ◽  
High Performance ◽  
Low Cost ◽  
Dynamics Modeling ◽  
Textile Materials ◽  
Property Data ◽  
Materials Used ◽  
Garment Design

AbstractProtective clothing provides laboratory and hazardous-materials workers, firefighters, military personnel, and others with the means to control their exposure to chemicals, biological materials, and heat sources. Depending on the specific application, the textile materials used in protective clothing must provide high performance in a number of areas, for example, impermeability to hazardous chemicals, breathability, light weight, low cost, and durability. Models based on computational fluid dynamics have been developed to predict the performance of protective clothing materials. Such models complement testing by enabling property data from laboratory materials tests to be used in predictions of the performance of integrated multilayer garments under varying environmental conditions.

Three-Dimensional Computational Fluid Dynamics Modeling and Validation of Ion Current Sensor in a Gen-Set Diesel Engine Using Chemical Kinetic Mechanism

2017 ◽  
Vol 139 (10) ◽  
Author(s):  
Tamer Badawy ◽  
Naeim Henein
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Low Cost ◽  
Combustion Process ◽  
Chemical Kinetic ◽  
Operating Conditions ◽  
Ion Current ◽  
Design Parameters ◽  
Current Signal ◽  
Dynamics Modeling

Ion current sensing is a low-cost technology that can provide a real-time feedback for the in-cylinder combustion process. The ion current signal depends on several design parameters of the sensing probe in addition to the operating conditions of the engine. To experimentally determine the effect of each of these parameters on the ion current signal, it requires modifications in the engine which would be costly and time consuming. A 3D computational fluid dynamics (CFD) model, coupled with a chemical kinetic solver, was developed to calculate the mole fraction of the ionized species formed in different zones in the fuel spray. A new approach of defining a number of virtual ion sensing probes was introduced to the model to determine the influence of sensor design and location relative to the spray axis on the signal characteristics. The contribution of the premixed and the mixing-diffusion controlled combustion was investigated. In addition, the crank angle resolved evolution of key ionization species produced during the combustion process was also compared at different engine operating conditions.

Human reliability in non-destructive inspections of nuclear power plant components: modeling and analysis

2019 ◽  
Vol 7 (2B) ◽  
Author(s):  
Vanderley Vasconcelos ◽  
Wellington Antonio Soares ◽  
Raissa Oliveira Marques ◽  
Silvério Ferreira Silva Jr ◽  
Amanda Laureano Raso
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Human Factors ◽  
Nuclear Power ◽  
Power Plants ◽  
Failure Modes ◽  
Cooling System ◽  
Human Reliability ◽  
Non Destructive ◽  
Plant Components

Non-destructive inspection (NDI) is one of the key elements in ensuring quality of engineering systems and their safe use. This inspection is a very complex task, during which the inspectors have to rely on their sensory, perceptual, cognitive, and motor skills. It requires high vigilance once it is often carried out on large components, over a long period of time, and in hostile environments and restriction of workplace. A successful NDI requires careful planning, choice of appropriate NDI methods and inspection procedures, as well as qualified and trained inspection personnel. A failure of NDI to detect critical defects in safety-related components of nuclear power plants, for instance, may lead to catastrophic consequences for workers, public and environment. Therefore, ensuring that NDI is reliable and capable of detecting all critical defects is of utmost importance. Despite increased use of automation in NDI, human inspectors, and thus human factors, still play an important role in NDI reliability. Human reliability is the probability of humans conducting specific tasks with satisfactory performance. Many techniques are suitable for modeling and analyzing human reliability in NDI of nuclear power plant components, such as FMEA (Failure Modes and Effects Analysis) and THERP (Technique for Human Error Rate Prediction). An example by using qualitative and quantitative assessesments with these two techniques to improve typical NDI of pipe segments of a core cooling system of a nuclear power plant, through acting on human factors issues, is presented.

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