A Hybrid Flow Network-CFD Method for Achieving Any Desired Flow Partitioning Through Floor Tiles of a Raised-Floor Data Center

2003 ◽  
Author(s):  
James W. VanGilder ◽  
Ted Lee
Keyword(s):  
Data Center ◽  
Flow Resistance ◽  
Cfd Simulation ◽  
Floor Tile ◽  
Electrical Circuit ◽  
Trial And Error ◽  
Flow Network ◽  
Floor Tiles ◽  
Circuit Analogy ◽  
Cfd Method

A technique is presented which allows a data center designer or operator to achieve any desired partitioning of available airflow among the floor tiles of a raised-floor data center without resorting to trial-and-error. The output from the analysis is a tile-by-tile prescription of flow resistance characteristics (e.g., damper settings), which accomplishes the desired partitioning. The technique is derived from an electrical-circuit analogy of the airflow in the data. Each circuit branch represents one path that air may follow from the CRAC unit supply, through a particular floor tile, and ultimately back to the CRAC return. Any desired flow partitioning through tiles can be achieved by proper adjustment of tile resistances in each circuit; however, by itself, the flow network has too many unknowns to be solvable. A CFD simulation of the entire data center, in which the desired flow partitioning is specified, provides the pressure distribution above (in the room) and below (in the plenum) the floor tiles. The method is illustrated in step-by-step fashion with a simple example case.

scholarly journals Two-phase CFD simulation of the monodyspersed suspension hydraulic behaviour in the tank apparatus from a circulatory pipe

2008 ◽  
Vol 10 (1) ◽  
pp. 22-27 ◽  
Author(s):  
Roch Plewik ◽  
Piotr Synowiec ◽  
Janusz Wójcik
Keyword(s):  
Cfd Simulation ◽  
Fluidised Bed ◽  
Cfd Simulations ◽  
Two Phase ◽  
Hydraulic Behaviour ◽  
Hydraulic Conditions ◽  
The One ◽  
Cfd Method ◽  
Multi Phase ◽  
The Ideal

Two-phase CFD simulation of the monodyspersed suspension hydraulic behaviour in the tank apparatus from a circulatory pipe The hydrodynamics in fluidized-bed crystallizers is studied by CFD method. The simulations were performed by a commercial packet of computational fluid dynamics Fluent 6.x. For the one-phase modelling (15), a standard k-ε model was applied. In the case of the two-phase flows the Eulerian multi-phase model with a standard k-ε method, aided by the k-ε dispersed model for viscosity, has been used respectively. The collected data put a new light on the suspension flow behaviour in the annular zone of the fluidised bed crystallizer. From the presented here CFD simulations, it clearly issues that the real hydraulic conditions in the fluidised bed crystallizers are far from the ideal ones.

Optimization of Data Center Room Layout to Minimize Rack Inlet Air Temperature

2005 ◽  
Author(s):  
Siddharth Bhopte ◽  
Dereje Agonafer ◽  
Roger Schmidt ◽  
Bahgat Sammakia
Keyword(s):  
Design Optimization ◽  
Air Temperature ◽  
Data Center ◽  
Floor Tile ◽  
Optimization Approach ◽  
Wrong Decision ◽  
Air Temperatures ◽  
Variable Approach ◽  
Entire Height ◽  
Facility Manager

In a typical raised floor data center with alternating hot and cold aisles, air enters the front of each rack over the entire height of the rack. Since the heat loads of data processing equipment continues to increase at a rapid rate, it is a challenge to maintain the temperature within the requirements as stated for all the racks within the data center. A facility manager has discretion in deciding the data center room layout, but a wrong decision will eventually lead to equipment failure. There are many complex decisions to be made early in the design as the data center evolves. Challenges occur such as optimizing the raised floor plenum, floor tile placement, minimizing the data center local hot spots etc. These adjustments in configuration affects rack inlet air temperatures which is one of the important key to effective thermal management. In this paper, a raised floor data center with 4.5 kW racks is considered. There are four rows of racks with alternating hot and cold aisle arrangement. Each row has six racks installed. Two CRAC units supply chilled air to the data center through the pressurized plenum. Effect of plenum depth, floor tile placement and ceiling height on the rack inlet air temperature is discussed. Plots will be presented over the defined range. Now a multi-variable approach to optimize data center room layout to minimize the rack inlet air temperature is proposed. Significant improvement over the initial model is shown by using multi-variable design optimization approach. The results of multi-variable design optimization are used to present guidelines for optimal data center performance.

Reconstruction Strategy of a Data Center based on CFD Simulation of outdoor wind environment

2021 ◽  
Author(s):  
Gao Meng ◽  
Zhang Lubingbing ◽  
Lu Dongmei ◽  
Zhang Qingke ◽  
Wang Wanjiang
Keyword(s):  
Data Center ◽  
Cfd Simulation ◽  
Wind Environment ◽  
Reconstruction Strategy

Hydraulic Characteristics of the New Type Bulb Turbine With Micro-Head

2013 ◽  
Author(s):  
Lingyu Li ◽  
Yuan Zheng ◽  
Daqing Zhou ◽  
Zihao Mi
Keyword(s):  
Numerical Simulation ◽  
Cfd Simulation ◽  
Guide Vane ◽  
Three Dimensional ◽  
Flow Distribution ◽  
Three Dimensions ◽  
Guide Vanes ◽  
Runner Blade ◽  
Cfd Method ◽  
Bulb Turbine

The head of low-head hydropower stations is generally higher than 2.5m in the world, while micro-head hydropower resources which head is less than 2.5m are also very rich. In the paper, three-dimensional CFD method has been used to simulate flow passage of the micro-head bulb turbine. The design head and unit flow of the turbine was 1m and 3m3/s respectively. With the numerical simulation, the bulb turbine is researched by analyzing external characteristics of the bulb turbine, flow distribution before the runner, pressure distribution of the runner blade surface, and flow distribution of the outlet conduit under three different schemes. The turbine in second scheme was test by manufactured into a physical model. According to the results of numerical simulation and model test, bulb turbine with no guide vane in second scheme has simpler structure, lower cost, and better flow capacity than first scheme, which has traditional multi-guide vanes. Meanwhile, efficiency of second scheme has just little decrease. The results of three dimensions CFD simulation and test results agree well in second scheme, and higher efficiency is up to 77% which has a wider area with the head of 1m. The curved supports in third scheme are combined guide vanes to the fixed supports based on 2nd scheme. By the water circulations flowing along the curved supports which improve energy transformation ability of the runner, the efficiency of the turbine in third scheme is up to 82.6%. Third scheme, which has simpler structure and best performance, is appropriate for the development and utilization of micro-head hydropower resources in plains and oceans.

scholarly journals Computational Fluid Dynamics Model of Wells Turbine for Oscillating Water Column System: A Review

2021 ◽  
Vol 2053 (1) ◽  
pp. 012013
Author(s):  
N. Abdul Settar ◽  
S. Sarip ◽  
H.M. Kaidi
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Water Column ◽  
Cfd Simulation ◽  
Oscillating Water Column ◽  
Wells Turbine ◽  
Flow Problems ◽  
Cfd Models ◽  
Column System ◽  
Cfd Method

Abstract Wells turbine is an important component in the oscillating water column (OWC) system. Thus, many researchers tend to improve the performance via experiment or computational fluid dynamics (CFD) simulation, which is cheaper. As the CFD method becomes more popular, the lack of evidence to support the parameters used during the CFD simulation becomes a big issue. This paper aims to review the CFD models applied to the Wells turbine for the OWC system. Journal papers from the past ten years were summarized in brief critique. As a summary, the FLUENT and CFX software are mostly used to simulate the Wells turbine flow problems while SST k-ω turbulence model is the widely used model. A grid independence test is essential when doing CFD simulation. In conclusion, this review paper can show the research gap for CFD simulation and can reduce the time in selecting suitable parameters when involving simulation in the Wells turbine.

scholarly journals Effect of Slit Channel Width of a Shim Embedded in Slot-Die Head on High-Density Stripe Coating for OLEDs

Coatings ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 772
Author(s):  
Dongkyun Shin ◽  
Jinyoung Lee ◽  
Jongwoon Park
Keyword(s):  
Electric Circuit ◽  
Electrical Circuit ◽  
High Density ◽  
Voltage Source ◽  
Light Emitting ◽  
Slot Die ◽  
Potential Applications ◽  
Circuit Analogy ◽  
Wide Slit ◽  
Fine Organic

With an attempt to achieve high-density fine organic stripes for potential applications in solution-processable organic light-emitting diodes (OLEDs), we have performed slot-die coatings using a shim with slit channels in various shapes (rectangular-shaped narrow, rectangular-shaped wide, and reversely tapered channels) in the presence of narrow µ-tips. Based on hydraulic-electric circuit analogy, we have analyzed the fluid dynamics of an aqueous poly (3,4-ethylenedioxythiophene): poly (4-styrenesulfonate) (PEDOT:PSS). It is observed that the coating speed can be increased and the stripe width can be reduced using a shim with rectangular-shaped wide slit channels. It is attributed that the hydraulic resistance is decreased and thus more fluid can reach a substrate through µ-tips. This behavior is consistent with the simulation result of the equivalent electrical circuit with a DC voltage source representing a pressure source. Using the shim with 150-µm-wide slit channels, we have successfully fabricated 200 PEDOT:PSS stripes within the effective coating width (150 mm) and 160 OLED stripes (34 stripes per inch) with the luminance of 325 cd/m2 at 5 V.

Precision Compound Sand Control Screen Internal Flow Field of the CFD Simulation

2014 ◽  
Vol 644-650 ◽  
pp. 4682-4685
Author(s):  
Zhi Jian Wang ◽  
Tian Zhu Zhang ◽  
Jin Shang ◽  
Metsakeu Kong Evariste
Keyword(s):  
Flow Field ◽  
Cfd Simulation ◽  
Internal Flow ◽  
Screen Effect ◽  
Theoretical Support ◽  
Sand Control ◽  
Porous Media Model ◽  
Speed Change ◽  
Cfd Method ◽  
Production Losses

In this paper, calculating fluid dynamics (CFD) method is utilized for analyzing the precision compound sand control screen internal flow field so as to establish appropriate models. During this numerical calculation, by using the - turbulence model is used to simulate the resistance characteristics under different working conditions when crude oil flows through precision compound sand control screen, analyze its speed change rule, flow path and pressure distribution, etc. The use of porous media model to simulate the resistance of the oil screen effect, the oil screen is replaced by the porous jump surface to simulate the strainer of pressure drop. To screen sand control performance and reduce the flow resistance to provide theoretical support, make the reservoir production losses to a minimum.

A Transonic Compressor Stage: Part 2 — CFD Simulation

2004 ◽  
Author(s):  
G. V. Hobson ◽  
A. J. Gannon ◽  
R. P. Shreeve
Keyword(s):  
Cfd Simulation ◽  
Pressure Ratio ◽  
Internal Flow ◽  
Design Tool ◽  
Experimental Results ◽  
Navier Stokes ◽  
Experimental Program ◽  
Compressor Stage ◽  
Transonic Compressor ◽  
Cfd Method

The simulation of a transonic compressor stage is presented. This stage was designed using an Euler CFD code with the intent of minimizing the use of empirical design techniques. The stage has subsequently been built and tested. More recently an existing multi-block Navier-Stokes code with a steady averaging-plane to pass information between the blade rows was used to simulate the flow through the machine. Performance maps of stage pressure ratio and efficiency at 70, 80, 90 and 100% speeds from both the Euler and Navier-Stokes CFD codes are compared with the experimental results. Details of the internal flow from the Navier-Stokes code are presented. Comparison of the design Euler CFD and experimental results showed reasonable agreement and validated its use as a design tool. Agreement between experimental and the current Navier-Stokes CFD results was good, allowing the code to be used in the viewing of the internal flow field. Improvements to the initial design CFD method are discussed in light of the experimental program and more recent simulations.

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