Computational Fluid Dynamics Modeling and Experimental Validation of the Thermofluidic Performance of Climatic Chambers

2019 ◽  
Vol 12 (2) ◽  
Author(s):  
R. Silva ◽  
M. Brett ◽  
Almerindo D. Ferreira ◽  
C. Serra ◽  
T. Jesus ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Design Optimization ◽  
International Standards ◽  
Temperature Fields ◽  
Dynamics Modeling ◽  
Model Based ◽  
Computer Fluid Dynamics ◽  
Velocity And Temperature Fields ◽  
Interior Domain

Abstract Climatic chambers are of great importance in research and development to conduct tests of components in closed environmentally controlled conditions. The growing demand from the industry to fulfill stricter international standards creates the necessity to ensure that the thermofluidic behavior of climatic chambers guarantees high-quality consistency in their interior domain. At present, scientific research on climatic chambers available in the literature is scarce and is mostly based on lumped modeling, hence not addressing the heterogeneities that arise in the interior of the chamber. In this work, an in-depth 3D model of the velocity and temperature fields that develops in the interior of climatic chambers was developed in computer fluid dynamics (CFD) and validated with the experimental data from a new prototype. The key objective of this research was to establish a validated framework for model-based design optimization of climatic chambers. The proposed model showed good agreement with the experimental data with a difference of 0.6 m/s and 9.65 °C in the velocity and temperature fields, respectively, thus validating its applicability to perform model-based design optimization of climatic chambers.

Study on the validation of the computer fluid dynamics modeling for a continuously flowing water vessel with the industrial SPECT using a radiotracer

2012 ◽  
Vol 70 (10) ◽  
pp. 2471-2477 ◽  
Author(s):  
Sung-Hee Jung ◽  
Jong-Bum Kim ◽  
Jin-Ho Moon ◽  
Jang-Guen Park ◽  
Chan-Hyeong Kim ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Flowing Water ◽  
Dynamics Modeling ◽  
Computer Fluid Dynamics

Computational Fluid Dynamics Modeling of Gas–Liquid Cylindrical Cyclones, Geometrical Analysis

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Juan Carlos Berrio ◽  
Eduardo Pereyra ◽  
Nicolas Ratkovich
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Cfd Modeling ◽  
Nozzle Geometry ◽  
Geometrical Parameters ◽  
Experimental Setup ◽  
Dynamics Modeling ◽  
Two Phase ◽  
Mean Square Errors

The gas–liquid cylindrical cyclone (GLCC) is a widely used alternative for gas–liquid conventional separation. Besides its maturity, the effect of some geometrical parameters over its performance is not fully understood. The main objective of this study is to use computational fluid dynamics (CFD) modeling in order to evaluate the effect of geometrical modifications in the reduction of liquid carry over (LCO) and gas carry under (GCU). Simulations for two-phase flow were carried out under zero net liquid flow, and the average liquid holdup was compared with Kanshio (Kanshio, S., 2015, “Multiphase Flow in Pipe Cyclonic Separator,” Ph.D. thesis, Cranfield University, Cranfield, UK) obtaining root-mean-square errors around 13% between CFD and experimental data. An experimental setup, in which LCO data were acquired, was built in order to validate a CFD model that includes both phases entering to the GLCC. An average discrepancy below 6% was obtained by comparing simulations with experimental data. Once the model was validated, five geometrical variables were tested with CFD. The considered variables correspond to the inlet configuration (location and inclination angle), the effect of dual inlet, and nozzle geometry (diameter and area reduction). Based on the results, the best configuration corresponds to an angle of 27 deg, inlet location 10 cm above the center, a dual inlet with 20 cm of spacing between both legs, a nozzle of 3.5 cm of diameter, and a volute inlet of 15% of pipe area. The combination of these options in the same geometry reduced LCO by 98% with respect to the original case of the experimental setup. Finally, the swirling decay was studied with CFD showing that liquid has a greater impact than the gas flowrate.

Theory of Uncertainty Analysis with Application to Naval Hydrodynamics

2021 ◽  
Author(s):  
Joel T. Park
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Uncertainty Analysis ◽  
International Standards ◽  
Verification And Validation ◽  
Random Loading ◽  
History Of ◽  
Force Calibration ◽  
Lower Uncertainty

Abstract The modern methodology for quantifying the quality of experimental data is uncertainty analysis. Current methods are reviewed with some examples primarily from naval hydrodynamics. The methods described are applicable to fluids engineering. The history of uncertainty analysis, US and international standards on uncertainty analysis, verification and validation standards for computational fluid dynamics, and instrument calibration are discussed. One important result is that random loading in force calibration can produce a lower uncertainty estimate than sequential loading. Statistically, the calibration results for the slope and intercept are the same for the two methods in the example thrust calibration, but the uncertainty in random loading is factor of three smaller than sequential loading.

Dynamics Modeling to Inform Design Optimization

2014 ◽  
Author(s):  
Tim Foglesong ◽  
Rob Stone ◽  
John Parmigiani
Keyword(s):  
Design Optimization ◽  
Testing Machine ◽  
Initial Model ◽  
Dynamics Modeling ◽  
Tensile Testing Machine ◽  
Drive Mechanism ◽  
Model Based ◽  
Reinforced Plastic ◽  
Future Work ◽  
Spring Constants

This paper presents the methods employed in modeling a vibratory conveyor for use in model-based design optimization. The conveyor, essentially a large table whose top oscillates at an angle off of horizontal, uses springs between the drive mechanism and the tabletop to directly apply a sinusoidal excitation. These springs prevent the system from losing response amplitude as load is increased. The manufacturer is having difficulty optimizing performance and reliability in newer designs, and has requested a model-based approach to the design optimization. This study discusses the initial steps taken in modeling the original mechanism design, specifically the dynamic model and experimental determination of the necessary spring constants. The first full iteration of the model starts with low detail and simplified geometry, with a plan to add complexity as needed to improve accuracy. In the initial model, the parallel springs in the tabletop suspension are combined, bypassing the spring mounting geometry, and tested as one large spring. The drive mechanism springs, bars of fiber reinforced plastic (FRP), are more meticulously tested in a tensile testing machine. The resulting spring constants are used in the initial model to calculate the sinusoidal response of the tabletop at any given input frequency. The deflection response per time of the tabletop is then measured and compared to the model. Conclusions detail the initial model’s accuracy and Future Work examines how to bring it in closer agreement with the real machine’s sinusoidal response.

Optimization of a Two-Fluid Hydrodynamic Model of Churn-Turbulent Flows

2009 ◽  
Author(s):  
Donna Post Guillen ◽  
Jonathan K. Shelley ◽  
Steven P. Antal ◽  
Elena A. Tselishcheva ◽  
Michael Z. Podowski ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Design Optimization ◽  
Turbulent Flows ◽  
Bubble Size ◽  
Hydrodynamic Model ◽  
Model Parameters ◽  
Interfacial Forces ◽  
Closure Models ◽  
Size Groups

A hydrodynamic model of two-phase, churn-turbulent flows is being developed using the computational multiphase fluid dynamics (CMFD) code, NPHASE-CMFD. The numerical solutions obtained by this model are compared with experimental data obtained at the TOPFLOW facility of the Institute of Safety Research at the Forschungszentrum Dresden-Rossendorf. The TOPFLOW data is a high quality experimental database of upward, co-current air-water flows in a vertical pipe suitable for validation of computational fluid dynamics (CFD) codes. A five-field CMFD model was developed for the continuous liquid phase and four bubble size groups using mechanistic closure models for the ensemble-averaged Navier-Stokes equations. Mechanistic models for the drag and non-drag interfacial forces are implemented to include the governing physics to describe the hydrodynamic forces controlling the gas distribution. The closure models provide the functional form of the interfacial forces, with user defined coefficients to adjust the force magnitude. An optimization strategy was devised for these coefficients using commercial design optimization software. This paper demonstrates an approach to optimizing CMFD model parameters using a design optimization approach. Computed radial void fraction profiles predicted by the NPHASE-CMFD code are compared to experimental data for four bubble size groups.

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