Theoretical Study and CFD Simulation of Airflow Distribution through a Cold Store

2012 ◽  
Vol 170-173 ◽  
pp. 3543-3549 ◽  
Author(s):  
Yi Tang ◽  
Jing Xie ◽  
Chen Miao ◽  
Jin Feng Wang ◽  
Yi Zheng
Keyword(s):  
Cfd Simulation ◽  
Vertical Plane ◽  
Simple Algorithm ◽  
Three Dimension ◽  
Wall Function ◽  
3D Technology ◽  
Airflow Distribution ◽  
Cold Store ◽  
Airflow Field ◽  
Computational Fluid Dynamics Cfd

Recently, the quantity of the cold store has been increased quickly. It is a key point to improve the uniformity of airflow field to the cold store. In this paper, a model of simulating cold store by computational fluid dynamics (CFD) was introduced. Simple algorithm combined with Boussineq assumption was used and turbulent equation combined with standard wall function was applied to define the flow of air in the cold store. Both the structured mesh and unstructured mesh to cold store model were simulated. The simulation methods of airflow in a cold store between three-dimension (3D) technology and two-dimension (2D) technology were also discussed. The experiment was validated and proved that unstructured grid was in better agreement with the result of experiments and it was gotten that the three-dimension (3D) technology had a higher accuracy in simulation of airflow distribution. The airflow distribution in the vertical plane and horizontal plane in cold store were gotten, respectively.

Numerical Simulation on Comparison of Air Flow Distribution with Different Algorithms

2012 ◽  
Vol 220-223 ◽  
pp. 2716-2720
Author(s):  
Jing Xie ◽  
Yi Tang ◽  
Jin Feng Wang ◽  
Chen Miao ◽  
Yue Zhao
Keyword(s):  
Numerical Simulation ◽  
Cfd Simulation ◽  
Air Flow ◽  
Vertical Plane ◽  
Simple Algorithm ◽  
Mesh Size ◽  
Dimensional Accuracy ◽  
Flow Speed ◽  
Simulation Accuracy ◽  
Cold Store

To get the air distribution in a small cold store, a mini type cold store ( 4. 5 m ( l)×3. 3 m (w )×2. 5 m (h) ) was referenced. The model of the small cold store was established in the software named GAMBIT and after this the three-dimensional numerical simulation was used. The different simulation result was verified by the experiments. The accuracy of simulation in airflow field in cold stores was studied by comparison of various mesh rezoning, various decoupling methods for airflow speed and pressure. The results showed that 10cm dimensional accuracy was the suitable mesh size for the calculation speed without affecting the simulation accuracy, and the SIMPLE algorithm was better for the PISQ algorithms to simulate steady air flow of the cooling process in a cold store without products. It was concluded that there was a large circumfluence in the flow field, the speeds in the center and corner were lower than those in other places. The distribution of flow speed in the horizontal plane had a good symmetrical, however that in the vertical plane was lower than that in the center, but higher upwards and downwards. The study validated 3D CFD simulation technology for the small cold store. The results of the research offered the optimized methods of using CFD and acted as the reference of the simulation model in the cold store.

Computational Fluid Dynamics Simulation about the Impact of Products on a Cold Store

2012 ◽  
Vol 170-173 ◽  
pp. 3550-3554
Author(s):  
Jing Xie ◽  
Yi Tang ◽  
Jin Feng Wang ◽  
Chen Miao ◽  
Yi Zheng
Keyword(s):  
Simple Calculation ◽  
Dynamics Simulation ◽  
Wall Function ◽  
Computational Fluid Dynamics Simulation ◽  
Lower Margin ◽  
Airflow Distribution ◽  
Cold Store ◽  
Main Steam ◽  
Volume Method ◽  
The Impact

The unreasonable airflow distribution often occurs in the cold store. Some specific parameters of airflow in the cold store are difficult to obtain in the practical experiments. The unreasonable airflow causes quality decline and large energy consumption. In this paper, the airflow distributions in an empty commercial cold store and the cold store filled with products were studied by CFD and investigated using the 3D modeling method which combined SIMPLE calculation method and finite-volume method. Meshes of the fan were refined locally with the airflow near the walls was modified by applying the non-wall function. Through comparing the airflow distributions in the empty cold store and in the cold store filled with products, differences such as the lower margin velocity, the smaller width and the deviation of the main steam in the cold store filled with products were found.

Incorporating Fluid Dynamics Considerations into Olfactory Displays

2012 ◽  
pp. 415-428 ◽  
Author(s):  
Haruka Matsukura ◽  
Hiroshi Ishida
Keyword(s):  
Fluid Dynamics ◽  
Cfd Simulation ◽  
Indoor Environments ◽  
Odor Concentration ◽  
Turbulent Airflow ◽  
Airflow Field ◽  
Computational Fluid Dynamics Cfd ◽  
Sensory Tests ◽  
Body Heat ◽  
Olfactory Display

In this chapter, the authors describe fluid dynamics considerations regarding odor dispersal in real environments and their relationship with realistic odor presentation using an olfactory display. The authors propose the use of a Computational Fluid Dynamics (CFD) simulation in conjunction with the olfactory display. A CFD solver is employed to calculate the turbulent airflow field in a given environment and the dispersal of odor molecules from their source. The simulation result is used to reproduce realistic changes in the odor concentration with time and space at the nose. The results of sensory tests are presented as a demonstration of CFD-based odor presentation. The effect of body heat on odor dispersal in indoor environments and how it affects odor perception is also discussed.

Effect of Baffle Openings to the Flow Distribution in a SERVCO Fume Cupboard

2014 ◽  
Vol 660 ◽  
pp. 719-723
Author(s):  
Mohd Amal Asrol Omar ◽  
Wirachman Wisnoe ◽  
Azman Bakri
Keyword(s):  
Fluid Dynamics ◽  
Cross Sections ◽  
Recirculation Zone ◽  
Cfd Simulation ◽  
Flow Distribution ◽  
Recirculation Region ◽  
Large Size ◽  
Airflow Distribution ◽  
Potential Contributor ◽  
Computational Fluid Dynamics Cfd

Recirculation region behind a fume cupboard sash is the potential contributor to the leakage of the contaminants due to its large size. This is found from the computational fluid dynamics (CFD) simulation of SERVCO fume cupboard using κ-ω turbulence model. For a good fume cupboard, the recirculation zone needs to be minimized while maintaining the flow distribution to all area in the fume cupboard. The opening on the baffle may reduce the recirculation zone which in turn may reduce back flow that is the cause of leakage. In this paper, the effect of shape of baffle openings on flow distributions of a SERVCO fume cupboard will be presented as a result of CFD. The results are presented in terms of velocity vectors Vy (in the direction towards the sash opening) at different cross sections for 4 opening shapes. The opening is found to improve the airflow distribution.

scholarly journals CFD Simulation of the Airflow Distribution Inside Cube-Grow

CFD Letters ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 81-89
Author(s):  
Arina Mohd Noh ◽  
Hamdan Mohd Noor ◽  
Fauzan Ahmad
Keyword(s):  
Plant Growth ◽  
Urban Agriculture ◽  
Cfd Simulation ◽  
Measurement Data ◽  
Actual Measurement ◽  
Airflow Distribution ◽  
Computational Fluid Dynamics Cfd ◽  
Simulation Results ◽  
Urban People ◽  
Air Hole

Cube-Grow was developed by MARDI to promote urban agriculture to the urban population. The product enables urban people to grow their vegetables with limited space. The initial test run of the system shows that the plant growth inside the structure was below expectation. The problem arises due to a lack of airflow or improper ventilation inside the structure. Optimum ventilation or airflow is crucial for plant growth as it enhances evapotranspiration at the leaf area to promote optimum plant growth. Therefore, this study aims to increase the airflow inside the Cube-Grow and find the best location for the air hole. Computational fluid dynamics (CFD) simulation was used in this study the analyse the effect of adding an air hole to the airflow characteristic inside the Cube-Grow. CFD also was used to select the best location to place the air hole. 3 option of air hole location was analysed and the results were compared with the existing design. The initial CFD simulation results were compared with the actual measurement data before it was used for further analysis. The result shows that adding an air hole increases overall airflow inside the Cube-Grow. Option 3 was chosen as the best location for the air hole as it produces a uniform and higher airflow inside the Cube-Grow. The study proved that CFD was able to be used to optimize the design of Cube-Grow before the actual prototype was built.

scholarly journals Energy-Efficient Improvement Approaches through Numerical Simulation and Field Measurement for a Data Center

Energies ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2757 ◽  
Author(s):  
Fujen Wang ◽  
Yishun Huang ◽  
BowoYuli Prasetyo
Keyword(s):  
Numerical Simulation ◽  
Data Center ◽  
Cfd Simulation ◽  
Field Measurements ◽  
Heat Index ◽  
Temperature Index ◽  
Performance Indexes ◽  
Airflow Distribution ◽  
Computational Fluid Dynamics Cfd ◽  
Simulation Results

The power density of electronic equipment increased dramatically recently. Data center and data processing and telecommunication facilities are facing the exceptionally high sensible heat loads which result in a large amount of energy consumption. In this study, a numerical simulation using computational fluid dynamics (CFD) was conducted to investigate the influence of alternative approaches to avoid bypassing and recirculation for air distribution in a full-scale data center. Field measurements were extensively conducted to validate the simulation results. Various performance indexes were adopted to enhance the evaluation of the thermal performance of the data center. The simulation results revealed that the practice with hot aisle enclosure and the installation of blocking panels for the unoccupied racks can provide satisfactory airflow distribution and thermal management under low load conditions. The return temperature index (RTI) can be improved by 3% through CFD simulation through installation of the blank panels, which reveals the reduction of recirculation airflow. The return heat index (RHI) increases by 8%, which presents a reduction of bypass airflow. A practical experiment using physical air curtains was conducted to enclose the hot aisle in the data center, which also reveals an 8% improvement for bypass airflow. Higher cooling performance can be achieved via reduction of recirculation and bypass airflow in the data center. Through the simulation of different improvement approaches in the data center, the optimum practice for cooling airflow arrangement can be identified accordingly.

Alternative Layouts for Air Distribution Improvement of a Computing Data Center

2013 ◽  
Vol 677 ◽  
pp. 282-285
Author(s):  
F.J. Wang ◽  
C.M. Lai ◽  
Y.S. Huang ◽  
J.S. Huang
Keyword(s):  
Data Center ◽  
Best Practice ◽  
Cfd Simulation ◽  
Numerical Study ◽  
Cost Effective ◽  
Distribution Patterns ◽  
Air Distribution ◽  
Cooling Performance ◽  
Airflow Distribution ◽  
Computational Fluid Dynamics Cfd

In this study, numerical simulation by using computational fluid dynamics (CFD) codes were conducted to investigate the influence of alternative layouts for air distribution in a full scale newly constructed data center. Through the simulation of different airflow distribution patterns in the data center, the optimum practice for cooling airflow arrangement can be identified easily. The simulation results also revealed that the best practice with a vertical under floor cooling architecture can provide satisfactory airflow distribution and thermal management. Higher cooling performance can be achieved by providing better separation of cold and hot aisle stream. Rack cooling index (RCI) has been used to evaluate the cooling performance of environmental conditions for the data center facility. Numerical study through CFD simulation can not only identify the best practice for airflow distribution, but also provide the energy-efficient and cost-effective HVAC system specific for data center facility.

scholarly journals Computational fluid dynamics (CFD) simulation analysis on retinal gas cover rates using computational eye models

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Makoto Gozawa ◽  
Yoshihiro Takamura ◽  
Tomoe Aoki ◽  
Kentaro Iwasaki ◽  
Masaru Inatani
Keyword(s):  
Cfd Simulation ◽  
Simulation Analysis ◽  
Fluid Dynamic ◽  
Fluid Analysis ◽  
Intraocular Gas ◽  
Pars Plana ◽  
Computational Fluid Dynamics Cfd ◽  
Multiple Breaks ◽  
Gas Volume ◽  
Wall Wettability

AbstractWe investigated the change in the retinal gas cover rates due to intraocular gas volume and positions using computational eye models and demonstrated the appropriate position after pars plana vitrectomy (PPV) with gas tamponade for rhegmatogenous retinal detachments (RRDs). Computational fluid dynamic (CFD) software was used to calculate the retinal wall wettability of a computational pseudophakic eye models using fluid analysis. The model utilized different gas volumes from 10 to 90%, in increments of 10% to the vitreous cavity in the supine, sitting, lateral, prone with closed eyes, and prone positions. Then, the gas cover rates of the retina were measured in each quadrant. When breaks are limited to the inferior retina anterior to the equator or multiple breaks are observed in two or more quadrants anterior to the equator, supine position maintained 100% gas cover rates in all breaks for the longest duration compared with other positions. When breaks are limited to either superior, nasal, or temporal retina, sitting, lower temporal, and lower nasal position were maintained at 100% gas cover rates for the longest duration, respectively. Our results may contribute to better surgical outcomes of RRDs and a reduction in the duration of the postoperative prone position.

scholarly journals Numerical Investigation for the Resin Filling Behavior during Ultraviolet Nanoimprint Lithography of Subwavelength Moth-Eye Nanostructure

Coatings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 799
Author(s):  
Yuanchi Cui ◽  
Xuewen Wang ◽  
Chengpeng Zhang ◽  
Jilai Wang ◽  
Zhenyu Shi
Keyword(s):  
Simulation Model ◽  
Nanoimprint Lithography ◽  
Cfd Simulation ◽  
Boundary Slip ◽  
Accurate Analysis ◽  
Inlet Velocity ◽  
Filling Height ◽  
Proposed Model ◽  
Good Consistency ◽  
Computational Fluid Dynamics Cfd

Accurate analysis of the resin filling process into the mold cavity is necessary for the high-precision fabrication of moth-eye nanostructure using the ultraviolet nanoimprint lithography (UV-NIL) technique. In this research, a computational fluid dynamics (CFD) simulation model was proposed to reveal resin filling behavior, in which the effect of boundary slip was considered. By comparison with the experimental results, a good consistency was found, indicating that the simulation model could be used to analyze the resin filling behavior. Based on the proposed model, the effects of process parameters on resin filling behavior were analyzed, including resin viscosity, inlet velocity and resin thickness. It was found that the inlet velocity showed a more significant effect on filling height than the resin viscosity and thickness. Besides, the effects of boundary conditions on resin filling behavior were investigated, and it was found the boundary slip had a significant influence on resin filling behavior, and excellent filling results were obtained with a larger slip velocity on the mold side. This research could provide guidance for a more comprehensive understanding of the resin filling behavior during UV-NIL of subwavelength moth-eye nanostructure.

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