scholarly journals Computational Fluid Dynamics Analysis of Alternative Ventilation Schemes in Cage-Free Poultry Housing

Animals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2352
Author(s):  
Long Chen ◽  
Eileen E. Fabian-Wheeler ◽  
John M. Cimbala ◽  
Dan Hofstetter ◽  
Paul Patterson
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Ventilation System ◽  
Airflow Obstruction ◽  
Three Dimensional ◽  
Ventilation Rate ◽  
Full Scale ◽  
Cold Weather ◽  
Cfd Modeling ◽  
Computational Fluid Dynamics Analysis

This work investigated alternative ventilation schemes to help define a proper ventilation system design in cage-free hen houses with the goal of assuring bird welfare through comfortable conditions. Computational fluid dynamics (CFD) modeling was employed to simulate indoor and outdoor airflows to quantify the effectiveness of ventilation systems in maintaining suitable and uniform living conditions at the hen level. Four three-dimensional CFD models were developed based on a full-scale floor-raised layer house, corresponding to ventilation schemes of the standard top-wall inlet, sidewall exhaust, and three alternatives: mid-wall inlet, ceiling exhaust; mid-wall inlet, ridge exhaust; and mid-wall inlet, attic exhaust with potential for pre-treatment of exhaust air. In a sophisticated and powerful achievement of the analysis, 2365 birds were individually modeled with simplified bird-shapes to represent a realistic number, body heat, and airflow obstruction of hens housed. The simulated ventilation rate for the layer house models was 1.9–2.0 m3/s (4100 ft3/min) in the desired range for cold weather (0 °C). Simulation results and subsequent analyses demonstrated that these alternative models had the capacity to create satisfactory comfortable temperature and air velocity at the hen level. A full-scale CFD model with individual hen models presented robustness in evaluating bird welfare conditions.

scholarly journals Computational Fluid Dynamics Modeling of Ventilation and Hen Environment in Cage-Free Egg Facility

Animals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1067
Author(s):  
Long Chen ◽  
Eileen E. Fabian-Wheeler ◽  
John M. Cimbala ◽  
Daniel Hofstetter ◽  
Paul Patterson
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Indoor Environment ◽  
Ventilation System ◽  
Side Wall ◽  
Cold Weather ◽  
Cfd Modeling ◽  
Dynamics Modeling ◽  
Poultry Facilities ◽  
Method Of Evaluation

Poultry facilities are going through an evolution in design due to growing demands for cage-free eggs and egg products without unified guidelines to accommodate these transitions. The goal of this study was to help builders and egg producers assess current ventilation design within cage-free production facilities for conditions that impact hen comfort and welfare. The method of evaluation was simulation of the indoor environment of a hen house via computational fluid dynamics (CFD) modeling with individual hens modeled at a typical stocking density. This paper describes the development of a three-dimensional model of a commercial floor-raised cage-free hen house that is cross-ventilated to document current environmental conditions. A one-eighth section of the barn was modeled at full-scale using existing ventilation schemes with each bird represented by a hen-shaped, heated, solid body. A conventional top-wall inlet, side-wall exhaust (TISE) ventilation configuration was modeled for this study. The simulated ventilation rate for the hen house was approximately 3 m3/h (1.77 ft3/min) per hen resulting in 7092 m3/h (4174 ft3/min) for the 2365 birds, which falls at the higher end of the desired cold weather (0 °C) ventilation range. Contours of airflow, temperature, and pressure were generated to visualize results. Three two-dimensional planes were created at representative cross-sections to evaluate the contours inside and outside the barn. Five animal-occupied zones within each of the model planes were evaluated for practical hen comfort attributes. The simulation output suggested the TISE standard ventilation system could limit air speed to a comfortable average of 0.26 m/s (51 ft/min) and the temperature could be maintained between 18 and 24 °C on average at the bird level. Additionally, the indoor static pressure difference was very uniform averaging −25 Pascal (0.1 inches of water), which falls in the normal range for a floor-raised hen house with negative-pressure ventilation during cold weather conditions. Findings confirmed that CFD modeling can be a powerful tool for studying ventilation system performance at the bird level, particularly when individual animals are modeled, to assure a comfortable indoor environment for animal welfare in poultry facilities.

scholarly journals Computational fluid dynamics analysis of the hydraulic (filtration) efficiency of a residential swimming pool

2018 ◽  
Vol 16 (5) ◽  
pp. 750-761 ◽  
Author(s):  
J. Zhang ◽  
N. Sinha ◽  
M. Ross ◽  
A. E. Tejada-Martínez
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Residence Time ◽  
Dead Zone ◽  
Three Dimensional ◽  
Circulation Pattern ◽  
Filtration Efficiency ◽  
Swimming Pools ◽  
Hydraulic Efficiency ◽  
Computational Fluid Dynamics Analysis

Abstract Hydraulic or filtration efficiency of residential swimming pools, quantified in terms of residence time characteristics, is critical to disinfection and thus important to public health. In this study, a three-dimensional computational fluid dynamics model together with Eulerian and Lagrangian-based techniques are used for investigating the residence time characteristics of a passive tracer and particles in the water, representative of chemicals and pathogens, respectively. The flow pattern in the pool is found to be characterized by dead zone regions where water constituents may be retained for extended periods of times, thereby potentially decreasing the pool hydraulic efficiency. Two return-jet configurations are studied in order to understand the effect of return-jet location and intensity on the hydraulic efficiency of the pool. A two-jet configuration is found to perform on par with a three-jet configuration in removing dissolved constituents but the former is more efficient than the latter in removing or flushing particles. The latter result suggests that return-jet location and associated flow circulation pattern have an important impact on hydraulic efficiency. Thus return-jet configuration should be incorporated as a key parameter in the design of swimming pools complementing current design standards.

Computational Fluid Dynamics Based Mixing Prediction for Tilt Pad Journal Bearing TEHD Modeling—Part II: Implementation With Machine Learning

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Jongin Yang ◽  
Alan Palazzolo
Keyword(s):  
Machine Learning ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Three Dimensional ◽  
Leading Edge ◽  
Cfd Modeling ◽  
Inlet Temperature ◽  
Training Set ◽  
Simplified Approach ◽  
Flow Mixing

Abstract Reynolds based thermo-elasto-hydrodynamic (TEHD) simulations of tilting pad journal bearings (TPJBs) generally provide accurate results; however, the uncertainty of the pad’s leading edge thermal boundary conditions causes uncertainty of the results. The highly complex thermal-flow mixing action between pads (BPs) results from the oil supply nozzle jets and geometric features. The conventional Reynolds approach employs mixing coefficients (MCs), estimated from experience, to approximate a uniform inlet temperature for each pad. Part I utilized complex computational fluid dynamics (CFD) flow modeling to illustrate that temperature distributions at the pad inlets may deviate strongly from being uniform. The present work retains the uniform MC model but obtains the MC from detailed three-dimensional CFD modeling and machine learning, which could be extended to the radially and axially varying MC case. The steps for implementing an artificial neural network (ANN) approach for MC regression are provided as follows: (1) utilize a design of experiment step for obtaining an adaptable training set, (2) conduct CFD simulations on the BP to obtain the outputs of the training set, (3) apply an ANN learning process by Levenverg–Mardquart backpropagation with the Bayesian regularization, and (4) couple the ANN MC results with conventional TEHD Reynolds models. An approximate log fitting method provides a simplified approach for MC regression. The effectiveness of the Reynolds TEHD TPJB model with ANN regression-based MC distributions is confirmed by comparison with CFD based TEHD TPJB model results. The method obtains an accuracy nearly the same as the complete CFD model, but with the computational economy of a Reynolds approach.

Extent, capacity and possibilities of computational fluid dynamics as a design tool for pump intakes: a review

2018 ◽  
Vol 18 (5) ◽  
pp. 1518-1530 ◽  
Author(s):  
Jie Zhang ◽  
Tien Yee
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Three Dimensional ◽  
Design Tool ◽  
Cfd Modeling ◽  
Cfd Simulations ◽  
Pump Station ◽  
Computational Fluid Dynamics Cfd ◽  
Future Direction ◽  
Computational Resources

Abstract Flow near pump intakes is three-dimensional in nature, and is affected by many factors such as the geometry of the intake bay, uniformity of approach flow, critical submergence, placements and operation combinations of pumps and so on. In the last three decades, advancement of numerical techniques coupled with the increase in computational resources made it possible to conduct computational fluid dynamics (CFD) simulations on pump intakes. This article reviews different aspects involved in CFD modeling of pump station intakes, outlines the challenges faced by current CFD modelers, and provides an attempt to forecast future direction of CFD modeling of pump intakes.

scholarly journals Feasibility of Computational Fluid Dynamics for Evaluating the Intraventricular Hemodynamics in Single Right Ventricle Based on Echocardiographic Images

2018 ◽  
Vol 2018 ◽  
pp. 1-11
Author(s):  
Li-Jun Chen ◽  
Zhi-Rong Tong ◽  
Qian Wang ◽  
Yu-Qi Zhang ◽  
Jin-Long Liu
Keyword(s):  
Fluid Dynamics ◽  
Heart Failure ◽  
Computational Fluid Dynamics ◽  
Right Ventricle ◽  
Three Dimensional ◽  
Cfd Modeling ◽  
Flow Models ◽  
Echocardiographic Image ◽  
Intraventricular Flow ◽  
And Function

This study introduced a combined computational fluid dynamics (CFD) and echocardiography methodology to simulate blood flow in the single right ventricle (SRV) and normal ventricles to study the intraventricular flow. Derived from echocardiographic image loops, CFD-based three-dimensional (3D) flow models of normal subject’s left ventricle (LV) and right ventricle (RV) and SRV with and without heart failure at three characteristic diastolic statuses were reconstructed. The CFD derived morphological and functional measurements in normal ventricles and the SRV were validated with echocardiography. The vortex in the normal ventricles and the SRV were studied. The morphological and functional measurements derived from CFD modeling and echocardiography were comparable, and both methods demonstrated the larger volume and higher spherical index in the SRV, in particular the SRV with heart failure. All the vortices in the SRV were smaller than those in the normal control subject’s LV and RV, notably with heart failure. Unlike normal LV and RV, no vortex ring was observed in the SRV. Echocardiography-based CFD demonstrated the feasibility of quantifying ventricular morphology and function; in addition, CFD can detect the abnormal flow pattern (smaller or obliterated vortices) in the SRV when compared with normal ventricles.

Modelling of wastewater treatment plants – how far shall we go with sophisticated modelling tools?

2006 ◽  
Vol 53 (3) ◽  
pp. 79-89 ◽  
Author(s):  
G.C. Glover ◽  
C. Printemps ◽  
K. Essemiani ◽  
J. Meinhold
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plants ◽  
Pilot Scale ◽  
Full Scale ◽  
Structure Identification ◽  
Oxidation Ditch ◽  
Computational Fluid Dynamics Analysis

Several levels of complexity are available for modelling of wastewater treatment plants. Modelling local effects rely on computational fluid dynamics (CFD) approaches whereas activated sludge models (ASM) represent the global methodology. By applying both modelling approaches to pilot plant and full scale systems, this paper evaluates the value of each method and especially their potential combination. Model structure identification for ASM is discussed based on a full-scale closed loop oxidation ditch modelling. It is illustrated how and for what circumstances information obtained via CFD (computational fluid dynamics) analysis, residence time distribution (RTD) and other experimental means can be used. Furthermore, CFD analysis of the multiphase flow mechanisms is employed to obtain a correct description of the oxygenation capacity of the system studied, including an easy implementation of this information in the classical ASM modelling (e.g. oxygen transfer). The combination of CFD and activated sludge modelling of wastewater treatment processes is applied to three reactor configurations, a perfectly mixed reactor, a pilot scale activated sludge basin (ASB) and a real scale ASB. The application of the biological models to the CFD model is validated against experimentation for the pilot scale ASB and against a classical global ASM model response. A first step in the evaluation of the potential of the combined CFD-ASM model is performed using a full scale oxidation ditch system as testing scenario.

Flow field prediction in full-scale Carrousel oxidation ditch by using computational fluid dynamics

2010 ◽  
Vol 62 (2) ◽  
pp. 256-265 ◽  
Author(s):  
Yin Yang ◽  
Yingying Wu ◽  
Xiao Yang ◽  
Kai Zhang ◽  
Jiakuan Yang
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Field ◽  
Full Scale ◽  
Hydrodynamic Performance ◽  
Cfd Modeling ◽  
Oxidation Ditch ◽  
Wall Model ◽  
Moving Wall ◽  
Carrousel Oxidation Ditch

In order to optimize the flow field in a full-scale Carrousel oxidation ditch with many sets of disc aerators operating simultaneously, an experimentally validated numerical tool, based on computational fluid dynamics (CFD), was proposed. A full-scale, closed-loop bioreactor (Carrousel oxidation ditch) in Ping Dingshan Sewage Treatment Plant in Ping Dingshan City, a medium-sized city in Henan Province of China, was evaluated using CFD. Moving wall model was created to simulate many sets of disc aerators which created fluid motion in the ditch. The simulated results were acceptable compared with the experimental data and the following results were obtained: (1) a new method called moving wall model could simulate the flow field in Carrousel oxidation ditch with many sets of disc aerators operating simultaneously. The whole number of cells of grids decreased significantly, thus the calculation amount decreased, and (2) CFD modeling generally characterized the flow pattern in the full-scale tank. 3D simulation could be a good supplement for improving the hydrodynamic performance in oxidation ditch designs.

scholarly journals Three-dimensional computational fluid dynamics analysis of an electric submerged arc furnace

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
K. Karalis ◽  
N. Karalis ◽  
N. Karkalos ◽  
Ν. Ntallis ◽  
G. S. E. Antipas ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Electrical Conductivity ◽  
Computational Fluid Dynamics ◽  
Three Dimensional ◽  
Decisive Role ◽  
Arc Furnace ◽  
Computational Fluid Dynamics Analysis ◽  
Cfd Method ◽  
Submerged Arc Furnace

AbstractA computational fluid dynamics (CFD) method is proposed to analyze the operation of a submerged electric arc furnace (SAF) used in ferronickel production. A three-dimensional mathematical model was used for the time-dependent solution of the fluid flow, heat transfer and electromagnetic phenomena. The slag's physical properties, which play a crucial role in the SAF operation, were previously determined using classical molecular dynamics simulations and empirical relationships. The analysis revealed that the main slag properties affecting SAF operation are density, viscosity and electrical conductivity—the latter two being mutually dependent. The high electrical conductivity values of the slag favor melting via the high Joule heat produced within the slag region. Calculation of the dimensionless Péclet and Reynolds numbers revealed that the slag velocities play a decisive role in heat transfer and further indicate that the slag flow is laminar. The average slag velocity calculated 0.0001 m/s with maxima in the vicinity of the electrodes.

Development and Validation of a Three-Dimensional Multiphase Flow Computational Fluid Dynamics Analysis for Journal Bearings in Steam and Heavy Duty Gas Turbines

2012 ◽  
Vol 134 (10) ◽  
Author(s):  
Stephan Uhkoetter ◽  
Stefan aus der Wiesche ◽  
Michael Kursch ◽  
Christian Beck
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Multiphase Flow ◽  
Gas Turbines ◽  
Three Dimensional ◽  
Air Entrainment ◽  
Journal Bearings ◽  
Heavy Duty ◽  
Computational Fluid Dynamics Analysis

The traditional method for hydrodynamic journal bearing analysis usually applies the lubrication theory based on the Reynolds equation and suitable empirical modifications to cover turbulence, heat transfer, and cavitation. In cases of complex bearing geometries for steam and heavy-duty gas turbines, this approach has its obvious restrictions in regard to detail flow recirculation, mixing, mass balance, and filling level phenomena. These limitations could be circumvented by applying a computational fluid dynamics (CFD) approach, resting closer to the fundamental physical laws. The present contribution reports about the state of the art of such a fully three-dimensional multiphase-flow CFD approach, including cavitation and air entrainment for high-speed turbomachinery journal bearings. It has been developed and validated using experimental data. Due to the high ambient shear rates in bearings, the multiphase-flow model for journal bearings requires substantial modifications in comparison to common two-phase flow simulations. Based on experimental data, it is found, that particular cavitation phenomena are essential for the understanding of steam and heavy-duty-type gas turbine journal bearings.

Sign in / Sign up

Export Citation Format

Share Document