scholarly journals CFD Models as a Tool to Analyze the Performance of the Hydraulic Agitation System of an Air-Assisted Sprayer

Agronomy ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 769 ◽  
Author(s):  
Jorge Badules ◽  
Mariano Vidal ◽  
Antonio Boné ◽  
Emilio Gil ◽  
F. Javier García-Ramos
Keyword(s):  
Fluid Velocity ◽  
Water Levels ◽  
Correct Prediction ◽  
Cfd Simulations ◽  
Cfd Models ◽  
Fluid Velocities ◽  
Computational Fluid Dynamics Cfd ◽  
Relative Errors ◽  
Setting Parameters ◽  
System Water

A computational fluid dynamics (CFD) model of the fluid velocities generated by the agitation system of an air-assisted sprayer was developed and validated by practical experiments in a laboratory. The model was developed considering different settings of the agitation system: Three water levels in the tank (1000, 2000, and 3000 L); two different numbers of active nozzles (2 or 4); and three working pressures of the agitation circuit (8, 10, or 12 bar). Actual measurements of the fluid velocity into the tank were taken using an acoustic Doppler velocimeter (ADV). CFD simulations made it possible to estimate fluid velocities at 38% of the measuring points with relative errors of less than 30%. Additionally, the CFD models have allowed the correct prediction of the general behavior of the fluid in the tank considering mean velocities depending on the setting parameters of the agitation system (water level in the tank, hydraulic circuit pressure, and number of active nozzles).

Time-Dependent Computational Fluid Dynamics (CFD) Simulations of a Closing Blowout Preventer

2018 ◽  
Author(s):  
Daniel Barreca ◽  
Matthew Franchek ◽  
Mayank Tyagi
Keyword(s):  
Fluid Velocity ◽  
Maximum Pressure ◽  
Cfd Simulations ◽  
Environment Analysis ◽  
Erosion Rates ◽  
Velocity Magnitude ◽  
Blowout Preventer ◽  
Computational Fluid Dynamics Cfd ◽  
Dynamic Meshing ◽  
Water Hammer Effect

Reliability of blowout preventers (BOP) is central for the safety of both rig workers and the surrounding environment. Analysis of dynamic fluid conditions within the wellbore and BOP can provide quantitative data related to this reliability. In cases of a hard shut in, it is suspected that the sudden closure of rams can cause a water hammer effect, creating pressure vibrations within the wellbore. Additionally, as the blowout preventer reaches a fully closed state, fluid velocity can drastically increase. This results in increased erosion rates within the blowout preventer. To investigate fluid movement and pressure vibrations during a well shut-in, CFD simulations will be conducted. Dynamic meshing techniques within ANSYS® FLUENT can be utilized to simulate closing blowout preventer configurations for both 2-D and 3-D geometries. These simulations would deliver information that could lead to a better understanding of certain performance issues during well shut-ins. Such information includes flow velocity magnitude within the BOP and maximum pressure pulse values within the wellbore.

scholarly journals Computational Fluid Dynamics Modeling of Liver Radioembolization: A Review

2021 ◽  
Author(s):  
Jorge Aramburu ◽  
Raúl Antón ◽  
Macarena Rodríguez-Fraile ◽  
Bruno Sangro ◽  
José Ignacio Bilbao
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Point Of View ◽  
Cfd Modeling ◽  
Dynamics Modeling ◽  
Cfd Simulations ◽  
Computational Fluid Dynamics Modeling ◽  
Cfd Models ◽  
Computational Fluid Dynamics Cfd ◽  
Intraarterial Therapy

AbstractYttrium-90 radioembolization (RE) is a widely used transcatheter intraarterial therapy for patients with unresectable liver cancer. In the last decade, computer simulations of hepatic artery hemodynamics during RE have been performed with the aim of better understanding and improving the therapy. In this review, we introduce the concept of computational fluid dynamics (CFD) modeling with a clinical perspective and we review the CFD models used to study RE from the fluid mechanics point of view. Finally, we show what CFD simulations have taught us about the hemodynamics during RE, the current capabilities of CFD simulations of RE, and we suggest some future perspectives.

scholarly journals Fish Upstream Passage through Gauging Stations: Experiences with Iberian Barbel in Flat-V Weirs

Fishes ◽  
2021 ◽  
Vol 6 (4) ◽  
pp. 81
Author(s):  
Francisco Javier Sanz-Ronda ◽  
Francisco Javier Bravo-Córdoba ◽  
Ana García-Vega ◽  
Jorge Valbuena-Castro ◽  
Andrés Martínez-de-Azagra ◽  
...  
Keyword(s):  
River Discharge ◽  
Water Drop ◽  
Fish Passage ◽  
Water Levels ◽  
Fish Migration ◽  
Target Species ◽  
Flow Conditions ◽  
Cfd Models ◽  
Computational Fluid Dynamics Cfd ◽  
Hydraulic Barriers

The monitoring of river discharge is vital for the correct management of water resources. Flat-V gauging weirs are facilities used worldwide for measuring discharge. These structures consist of a small weir with a triangular cross-section and a flat “V”-shaped notch. Their extensive use is a consequence of their utility in the measurement of both low and high flow conditions. However, depending on their size, local morphology and river discharge can act as full or partial hydraulic barriers to fish migration. To address this concern, the present work studies fish passage performance over flat-V weirs considering their hydraulic performance. For this, radio-tracking and video-monitoring observations were combined with computational fluid dynamics (CFD) models in two flat-V weirs, using Iberian barbel (Luciobarbus bocagei) as the target species. Results showed that fish passage is conditioned by both hydraulic and behavioral processes, providing evidence for scenarios in which flat-V weirs may act as full or partial barriers to upstream movements. For the studied flat-V weirs, a discharge range of 0.27–8 m3/s, with a water drop difference between upstream and downstream water levels lower than 0.7 m and a depth downstream of the weir of higher than 0.3 m can be considered an effective passage situation for barbels. These findings are of interest for quantifying flat-V weir impacts, for engineering applications and for establishing managing or retrofitting actions when required.

Numerical Analysis of Lateral Skirts Performance on Drag Force of a Semi-Trailer Truck

2018 ◽  
Author(s):  
M. Lateb ◽  
H. Fellouah
Keyword(s):  
Drag Force ◽  
Aerodynamic Drag ◽  
Experimental Results ◽  
Navier Stokes ◽  
Force Parameter ◽  
Cfd Simulations ◽  
Total Drag ◽  
Computational Fluid Dynamics Cfd ◽  
Induced Flow ◽  
Relative Errors

This work performs computational fluid dynamics (CFD) simulations using a transient URANS (unsteady Reynolds averaged Navier–Stokes) turbulence model to investigate the influence of lateral skirts — located in the lower part of a semitrailer truck — in terms of reducing the total drag force and fuel consumption savings. The total drag force values are calculated for three semi-trailer trucks speeds (i.e. 60, 70 and 100 km/h), compared, and then validated against experimental results carried out in a wind tunnel reduced model scale (1:28). The relative errors of the aerodynamic drag force parameter are assessed in order to quantify the accuracy and the reliability of the numerical modeling results with regard to the experimental results. In addition, the flow pattern around the semi-trailer truck is then investigated to determine how the induced flow field is channeled, and where the recirculating zones are modified and developed when using the additional skirt device.

Air-Side Performance Characterization of Air-to-Refrigerant Heat Exchangers Using Parallel Parameterized CFD

2013 ◽  
Author(s):  
Khaled Saleh ◽  
Weizhe Han ◽  
Vikrant Aute ◽  
Reinhard Radermacher
Keyword(s):  
Heat Transfer ◽  
Heat Exchangers ◽  
Cfd Simulations ◽  
Cfd Models ◽  
F Factor ◽  
Wide Range ◽  
Different Types ◽  
Computational Fluid Dynamics Cfd ◽  
Friction Performance

The goal of the study presented in this paper is to use Computational Fluid Dynamics (CFD) to characterize the heat transfer and friction performance of fins used in air-to-refrigerant heat exchangers. Five different types of fins used in air-cooled heat exchangers (HXs) are studied using Parallel Parameterized CFD (PPCFD) approach described in this paper. The fin types considered in this paper are; Plain, Wavy, Slit, Super Slit, and Louver. 3-D CFD models are built and tested for these fin types. Based on the CFD results, air side heat transfer coefficient (HTC), Colburn j factor, Fanning f factor, and pressure drop are calculated. The results from CFD simulations are compared against experimental data from the literature for the different fin types and a good agreement is found between the two. In addition, the results from CFD simulations are used to evaluate the thermal and hydraulic performance for a wide range of heat exchanger parameters such as tube diameters, fin pitch, number of rows, and frontal air velocity. The results show the advantages of using PPCFD to efficiently develop correlations for different types of fins used in air-cooled HX, with significant reduction in engineering time. The PPCFD approach can be extended to efficiently optimize novel heat transfer surfaces.

scholarly journals CFD & Safety Factors

2013 ◽  
Vol 135 (02) ◽  
pp. 30-35
Author(s):  
Robert A. Leishear
Keyword(s):  
Experimental Validation ◽  
Cfd Modeling ◽  
Correction Factors ◽  
Safety Factors ◽  
Additional Result ◽  
Complex Processes ◽  
Cfd Models ◽  
Fluid Velocities ◽  
Computational Fluid Dynamics Cfd ◽  
The Times

This article presents a research that demonstrates the need for experimental validation of computational fluid dynamics (CFD) models for complex processes, such as blending. An additional result of the study is that it provided researchers a better understanding of how to use CFD models in general. The principle for blending is the same for all blender-pump designs: the business end of a centrifugal pump will be submerged in the salt solutions in the tank. Lab researchers found that, although CFD provided good estimates of an average blending time, experimental blending times varied significantly from the average. The issue of experimental uncertainty is inherent in CFD modeling as well as in many empirical equations used for modeling and design methods. In order to bring all of this research together, the process variables investigated were the fluid velocities in the tanks and the times required to blend the fluids. The large scatter in experimental data shows that large errors can be obtained from CFD models in the absence of experimental correction factors.

Computational Study on Noise of Urban Air Mobility Quadrotor Aircraft

2021 ◽  
Author(s):  
Zhongqi (Henry) Jia ◽  
Seongkyu Lee
Keyword(s):  
Sound Pressure ◽  
Computational Study ◽  
Urban Air ◽  
Noise Levels ◽  
Cfd Simulations ◽  
Community Noise ◽  
Cfd Models ◽  
Quadrotor Aircraft ◽  
Computational Fluid Dynamics Cfd ◽  
The One

This paper investigates the acoustics of a one-passenger and a six-passenger quadrotor urban air mobility (UAM) aircraft in level flight based on a high-fidelity computational fluid dynamics (CFD) approach. The CFD simulations are carried out using the HPCMP CREATETM-AV multidisciplinary rotorcraft analysis and simulation tool Helios. The acoustic simulations are performed using the acoustic prediction tool PSU-WOPWOP. A total of three CFD models are simulated: a one-passenger isolated rotor configuration, a one-passenger full configuration with a fuselage, and a six-passenger isolated rotor configuration. The noise comparison between the one-passenger isolated rotor case and the full configuration case shows that the vehicle fuselage increases the A-weighted sound pressure level (SPL) up to 5 dB. The acoustic comparison between the one-passenger and the six-passenger isolated rotor configuration shows that the maximum overall SPL difference is up to 14 dB. Furthermore, it is shown that the noise of the six-passenger configuration is approximately 11 dB lower than that of a similar-sized conventional helicopter in an overhead scenario. The community noise impact of UAM aircraft is also assessed and compared to various background noise levels. The results show that the one-passenger quadrotor noise can be fully masked by freeway noise at an altitude greater than or equal to 1000 ft, while the six-passenger quadrotor noise can only be partially masked by freeway noise even at an altitude of 1000 ft.

scholarly journals Fish Upstream Passage Through Gauging Stations. Experiences With Iberian Barbel in Flat-V Weirs

2021 ◽  
Author(s):  
Francisco Javier Sanz-Ronda ◽  
Francisco Javier Bravo-Córdoba ◽  
Ana García-Vega ◽  
Jorge Valbuena-Castro ◽  
Andrés Manuel Martínez-de-Azagra ◽  
...  
Keyword(s):  
River Discharge ◽  
Water Drop ◽  
Fish Passage ◽  
Water Levels ◽  
Fish Migration ◽  
Target Species ◽  
Flow Conditions ◽  
Cfd Models ◽  
Computational Fluid Dynamics Cfd ◽  
Hydraulic Barriers

The monitoring of river discharge is vital for the correct management of water resources. A worldwide facility used for measuring discharge are flat-V gauging weirs. These structures consist of a small weir, with a triangular cross-section and a flat “V”-shaped notch. Their extensive use is a consequence of their utility in the measurement of both low and high flow conditions. However, depending on their size, local morphology and river discharge can act as full or partial hydraulic barriers to fish migration. To give answer to this question, the present work studies fish passage performance over flat-V weirs considering their hydraulic performance. For this, radio-tracking and video monitoring observations were combined with computational fluid dynamics (CFD) models in two flat-V weirs, using Iberian barbel (Luciobarbus bocagei) as target species. Results show that fish passage is conditioned by both hydraulic and behavioral processes, providing evidences about the scenarios where flat-V weirs may act as full or partial barriers to upstream movements. For the studied flat-V weirs, a discharge range of 0.27-8 m3/s, with a water drop difference between upstream and downstream water levels lower than 0.7 m and a depth downstream the weir higher than 0.30 m can be considered as an effective passage situation for barbels. These findings are of interest to quantify flat-V weir impacts, for engineering applications and to establish managing or retrofitting actions when required.

scholarly journals Using CFD to Evaluate Natural Ventilation through a 3D Parametric Modeling Approach

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2197
Author(s):  
Nayara Rodrigues Marques Sakiyama ◽  
Jurgen Frick ◽  
Timea Bejat ◽  
Harald Garrecht
Keyword(s):  
Natural Ventilation ◽  
Parametric Modeling ◽  
Cfd Simulations ◽  
3D Design ◽  
Post Process ◽  
Test House ◽  
Model Set ◽  
Computational Fluid Dynamics Cfd ◽  
Set Up ◽  
Passive Strategy

Predicting building air change rates is a challenge for designers seeking to deal with natural ventilation, a more and more popular passive strategy. Among the methods available for this task, computational fluid dynamics (CFD) appears the most compelling, in ascending use. However, CFD simulations require a range of settings and skills that inhibit its wide application. With the primary goal of providing a pragmatic CFD application to promote wind-driven ventilation assessments at the design phase, this paper presents a study that investigates natural ventilation integrating 3D parametric modeling and CFD. From pre- to post-processing, the workflow addresses all simulation steps: geometry and weather definition, including incident wind directions, a model set up, control, results’ edition, and visualization. Both indoor air velocities and air change rates (ACH) were calculated within the procedure, which used a test house and air measurements as a reference. The study explores alternatives in the 3D design platform’s frame to display and compute ACH and parametrically generate surfaces where air velocities are computed. The paper also discusses the effectiveness of the reference building’s natural ventilation by analyzing the CFD outputs. The proposed approach assists the practical use of CFD by designers, providing detailed information about the numerical model, as well as enabling the means to generate the cases, visualize, and post-process the results.

scholarly journals Dependence of the Flue Gas Flow on the Setting of the Separation Baffle in the Flue Gas Tract

2021 ◽  
Vol 11 (7) ◽  
pp. 2961
Author(s):  
Nikola Čajová Kantová ◽  
Alexander Čaja ◽  
Marek Patsch ◽  
Michal Holubčík ◽  
Peter Ďurčanský
Keyword(s):  
Particulate Matter ◽  
Flue Gas ◽  
Gas Flow ◽  
Negative Impact ◽  
Combustion Process ◽  
Cfd Simulations ◽  
Piv Measurements ◽  
Computational Fluid Dynamics Cfd ◽  
Particle Imaging ◽  
Combustion Of Solid Fuels

With the combustion of solid fuels, emissions such as particulate matter are also formed, which have a negative impact on human health. Reducing their amount in the air can be achieved by optimizing the combustion process as well as the flue gas flow. This article aims to optimize the flue gas tract using separation baffles. This design can make it possible to capture particulate matter by using three baffles and prevent it from escaping into the air in the flue gas. The geometric parameters of the first baffle were changed twice more. The dependence of the flue gas flow on the baffles was first observed by computational fluid dynamics (CFD) simulations and subsequently verified by the particle imaging velocimetry (PIV) method. Based on the CFD results, the most effective is setting 1 with the same boundary conditions as those during experimental PIV measurements. Setting 2 can capture 1.8% less particles and setting 3 can capture 0.6% less particles than setting 1. Based on the stoichiometric calculations, it would be possible to capture up to 62.3% of the particles in setting 1. The velocities comparison obtained from CFD and PIV confirmed the supposed character of the turbulent flow with vortexes appearing in the flue gas tract, despite some inaccuracies.

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