Survey of Steady-Steady RANS CFD Modeling Techniques for Prediction Passive Device Flow Control in External Compression Inlets

2012 ◽  
Author(s):  
Trajaen Troia ◽  
Amish Patel ◽  
Michelle Bright ◽  
Dick Crouse
Keyword(s):  
Flow Control ◽  
Cfd Modeling ◽  
External Compression ◽  
Passive Device ◽  
Modeling Techniques

scholarly journals Computational investigation of cavity flow control using a passive device

2012 ◽  
Vol 116 (1176) ◽  
pp. 153-174 ◽  
Author(s):  
B. Khanal ◽  
K. Knowles ◽  
A. J. Saddington
Keyword(s):  
Flow Control ◽  
Near Field ◽  
Flow Analysis ◽  
Flow Visualisation ◽  
Complete Suppression ◽  
Detached Eddy Simulation ◽  
Mean Flow ◽  
Passive Device ◽  
Unsteady Pressure ◽  
Empty Cavity

Abstract In this paper, flow control effectiveness of a passive device in relation to open cavity flowfield is investigated computationally and compared with experimental work. Specifically the modification in the cavity flowfield due to the presence of a spoiler is studied in details to explain the physics behind the flow control effects. A combination of 2D and 3D flow visualisation tools are used to understand the flow behaviour inside the cavity and the quantitative analysis of the unsteady pressure fluctuations is also performed to assess the unsteady effects. Flow simulations with a turbulence model based on a hybrid RANS/LES (commonly known as Detached-Eddy Simulation (DES)) are used in this study. The time-mean flow visualisation clearly showed the presence of three dimensional effects inside the empty cavity whereas the 3D effects were found to diminish in the presence of a spoiler. In the unsteady flow analysis, near-field acoustic spectra were computed for empty cavity as well as cavity-with-spoiler cases. Study of unsteady pressure spectra for the cavity-with-spoiler case was found to record the complete suppression of the dominant tones in the presence of the spoiler. The analysis has indicated that the main reason behind this suppression is due to the inability of faintly energised vortical structures (faintly energised as a result of the extraction of turbulent kinetic energy by the spoiler) to maintain the unsteady flapping of the separated shear layer.

Creating a Calibrated CFD Model of a Midsize Data Center

2015 ◽  
Author(s):  
Zachary M. Pardey ◽  
James W. VanGilder ◽  
Christopher M. Healey ◽  
David W. Plamondon
Keyword(s):  
Data Center ◽  
Real Data ◽  
Measured Data ◽  
Cfd Modeling ◽  
Design Stage ◽  
Cfd Model ◽  
Modeling Techniques ◽  
Room Model ◽  
Tile Flow ◽  
Level Of Agreement

Calibrating a CFD model against measured data is the first step to successfully utilizing this technology for change-management and the optimization of an existing data center. To date, there has been very little published on this calibration process; more focus has been placed on the use of CFD at the design stage and the development of modeling techniques and solvers. Further, few studies which feature comprehensive comparisons of CFD-predicted and measured data have been published for real data centers, and many that have, demonstrated only modest agreement at best. This study provides another such comparison — for a 7,400 ft2 (687 m2), 138-rack, raised-floor facility. The goals of the study are to benchmark the level of agreement that can be practically obtained and also to investigate the level of modeling detail required. Additionally, specific practical advice covering both CFD modeling and experimental measurements is provided. A plenum-only CFD model is compared to measured tile airflow rates and a room-model, which uses measured tile flow rates as boundary conditions, is compared to temperatures measured at each rack inlet. The level of agreement is among the best published to date and demonstrates that a CFD model can be adequately calibrated against measured data and is of value for ongoing data center operation.

Improving the Performance of a Two Way Flow Control Valve, Using a 3D CFD Modeling

2014 ◽  
Author(s):  
Emma Frosina ◽  
Adolfo Senatore ◽  
Dario Buono ◽  
Michele Pavanetto ◽  
Micaela Olivetti ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Flow Control ◽  
Fluid Dynamic ◽  
Control Valve ◽  
Operating Conditions ◽  
Cfd Modeling ◽  
Flow Control Valve ◽  
Development Costs ◽  
Definition Of ◽  
The Mathematical Model

The paper introduces a methodology aimed to optimize the performance of hydraulic components; in particular the design of a new two way flow control valve studying the valve internal fluid-dynamic behavior will be introduced. The methodology is based on the definition of a CFD tridimensional fluid-dynamic model. In fact, the model can help engineers to develop the best geometry, to optimize the valve performance, reducing the prototyping requirement and finally the time-to-market and, consequently, the development costs. At first, the original spool internal geometry has been evaluated and studied to tune the mathematical model and to validate it comparing its results with the data obtained through an experimental campaign. Then, the same approach has been applied to investigate several different internal spool geometries to define the best one in all operating conditions. A limited number of solutions have been prototyped and tested to verify the mathematical model predictions, in order to find the best configuration whose performances are consistent with the assigned objective for the component.

A Modeling Approach to Study the Fluid-Dynamic Forces Acting on the Spool of a Flow Control Valve

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Emma Frosina ◽  
Adolfo Senatore ◽  
Dario Buono ◽  
Kim A. Stelson
Keyword(s):  
Flow Control ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Control Valve ◽  
Maximum Error ◽  
Cfd Modeling ◽  
Flow Control Valve ◽  
Pressure Force ◽  
Modeling Approach ◽  
Balance Of Forces

This paper introduces an approach to study a valve's internal fluid dynamics. During operation, the flow causes forces on the spool. These forces must be correctly balanced. Since these forces cannot be measured, a three-dimensional (3D) computational fluid dynamic (CFD) modeling approach is needed. A case study has been undertaken to verify the approach on a two-way pressure compensated flow control valve. Since forces vary during operation, the analysis must be transient. From the initial zero spool position, the flow goes through the valve causing a spool shift inside the valve's housing until the spool stops at its final position. Forces depend on the spring reaction, the inlet pressure force, the pressure force of the fluid inside the spool, and the spring holder volumes, and the balance of forces influences the outlet flow rate at the final spool position. First, the initial case geometry was modeled, prototyped, and tested, and this geometry was studied to verify the model accuracy compared to experimental data. The comparison shows good agreement with a maximum error of 3%. With the same approach, several other geometries were designed, but only the best geometry was prototyped and tested. The model was adopted to make several analyses of velocity contouring, streamlines trends, and pressure distribution in the fluid volume. The modeled and tested results achieved the expected performance confirming the effectiveness of the methodology.

Aerated Grit Tank Improved Using CFD Modeling Techniques

2013 ◽  
Vol 2013 (16) ◽  
pp. 2400-2418 ◽  
Author(s):  
Carl Seifried ◽  
Michael Showalter ◽  
Mark Goodin
Keyword(s):  
Cfd Modeling ◽  
Modeling Techniques
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