Computational Study of Single-Sided Ventilation Through a 3-Dimensional Room

Author(s):  
A. Idris ◽  
B. P. Huynh

Ventilation flow through a 3-dimensional rectangular-box room is investigated numerically, by using a commercial Computational Fluid Dynamics (CFD) software package. The room has all its window openings located on one wall, and the wind is assumed to blow parallel to this wall. The standard K-epsilon turbulence model is used. Air’s flow rate and flow pattern are considered in terms of wind speed and the openings’ characteristics, such as their number, location, size and shape. For a constant total area of the openings, it is found that ventilation rate increases with more openings, especially when they are widely separated or positioned at different heights.

Author(s):  
A. Idris ◽  
B. P. Huynh

A commercial Computational Fluid Dynamics (CFD) software package is used to investigate numerically a 3-dimensional rectangular-box room with rounded edges. The room has all its window openings located on one wall only. The standard K-ε turbulence model is used. Air’s flow rate and flow pattern are considered in terms of wind speed and the openings’ characteristics, such as their number, location, size and shape. Especially, comparison with ventilation rate corresponding to when the room edges are sharp is made; and thereby the effects of the edges being rounded are examined.


2020 ◽  
Vol 44 (2) ◽  
pp. 189-201 ◽  
Author(s):  
Mahmoud Elhalwagy ◽  
Anthony Straatman ◽  
Bernard Goyette ◽  
Gideon Avigad

Simulations were conducted to study the airflow across skids of grapes in a horticultural grape drying chamber for the purpose of balancing the airflow to produce a uniform drying environment. The focus of the study was on the approach taken to provide balanced airflow using a computational fluid dynamics (CFD) tool combined with experimental data. The process was to first characterize the crate stacks by comparison of airflow simulations across a single crate stack to experimental data to establish resistance coefficients. The next step was to use these coefficients to simulate a row of stacked skids to establish corrections in terms of additional (variable) resistance that would result in balanced airflow. The corrected model was then used to simulate flow through the entire horticultural chamber to confirm that under the conditions of fan operation, the balance of airflow persists. The study shows that while the unmodified stacks had nearly 20% imbalance from the first to the last stack, the stack with resistance modifiers corrected this imbalance to within 5%, which is considered suitable for operation of the chamber.


RBRH ◽  
2021 ◽  
Vol 26 ◽  
Author(s):  
Mayara Francisca da Silva ◽  
Fábio Veríssimo Gonçalves ◽  
Johannes Gérson Janzen

ABSTRACT Computational Fluid Dynamics (CFD) simulations of a leakage in a pressurized pipe were undertaken to determine the empirical effects of hydraulic and geometric factors on the leakage flow rate. The results showed that pressure, leakage area and leakage form, influenced the leakage flow rate significantly, while pipe thickness and mean velocity did not influence the leakage flow rate. With relation to the interactions, the effect of pressure upon leakage flow rate depends on leakage area, being stronger for great leakage areas; the effects of leakage area and pressure on leakage flow rate is more pronounced for longitudinal leakages than for circular leakages. Finally, our results suggest that the equations that predict leakage flow rate in pressurized pipes may need a revision.


2021 ◽  
Author(s):  
Sanaz Dianat

The research paper investigates the impact of a window’s exterior air film on the assembly temperature. The exterior air film constitutes a vital portion of a window’s insulating values. The air film increases the temperature of the window exterior pane to a temperature above ambient temperature. The air film also rises the interior glass temperature and reduces the heat transfer from the interior surface. According to computational fluid dynamics (CFD), the air film is removed in windy conditions, decreasing the window temperature on the outside as well as on the inside. The idea behind the project is to carry out an experimental procedure on three different windows to validate the CFD results, which indicates the effect of various wind speeds. Keyword: Exterior air film, computational fluid dynamics, window assembly, wind speed


2021 ◽  
Author(s):  
Sanaz Dianat

The research paper investigates the impact of a window’s exterior air film on the assembly temperature. The exterior air film constitutes a vital portion of a window’s insulating values. The air film increases the temperature of the window exterior pane to a temperature above ambient temperature. The air film also rises the interior glass temperature and reduces the heat transfer from the interior surface. According to computational fluid dynamics (CFD), the air film is removed in windy conditions, decreasing the window temperature on the outside as well as on the inside. The idea behind the project is to carry out an experimental procedure on three different windows to validate the CFD results, which indicates the effect of various wind speeds. Keyword: Exterior air film, computational fluid dynamics, window assembly, wind speed


Author(s):  
Fuping Qian ◽  
Xingwei Huang ◽  
Mingyao Zhang

Numerical simulations of cyclones with various vortex finder dimensions and inlet section angles were performed to study the gas shortcut flow rate. The numerical solutions were carried out using commercial computational fluid dynamics (CFD) code Fluent 6.1. A prediction model of the gas shortcut flow rate was obtained based on response surface methodology by means of the statistical software program (Minitab V14). The results show that the length of the vortex finder insertion, the vortex finder diameter and the inlet section angle play an important role in influencing the gas shortcut flow rate. The gas shortcut flow rate decreases when increasing the inlet section angle, and increases when increasing the vortex finder diameter and decreasing the length of the vortex finder insertion. Compared with the effect of the length of the vortex finder insertion on the shortcut flow rate, the effect of the vortex finder diameter on the gas shortcut flow rate seems more pronounced. The effect of the vortex finder dimension on the gas shortcut flow rate is changed with the different inlet section angles, i.e., the effects of the vortex finder dimension of the conventional cyclone (the inlet section angle is 0º) on the gas shortcut flow rate is stronger than the cyclone with 30º and 45º inlet section angles.


Author(s):  
Richard J. S. Whitehouse ◽  
Carlos Lam ◽  
Stephen Richardson ◽  
Peter Keel

Results from an advanced 3-dimensional Computational Fluid Dynamics (CFD) model have proven to form an effective basis on which to design stable and scour resistant subsea structures in areas of seabed which are prone to scouring. A case study application from the UK sector of the southern North Sea is presented to demonstrate the benefits of the CFD analysis.


2015 ◽  
Vol 137 (7) ◽  
Author(s):  
Georgios N. Lygidakis ◽  
Ioannis K. Nikolos

A recently developed academic computational fluid dynamics (CFD) code, named Galatea, is used for the computational study of fully turbulent flow over the NASA common research model (CRM) in a wing-body configuration with and without horizontal tail. A brief description of code's methodology is included, while attention is mainly directed toward the accurate and efficient prediction of pressure distribution on wings' surfaces as well as of computation of lift and drag forces against different angles of attack, using an h-refinement approach and a parallel agglomeration multigrid scheme. The obtained numerical results compare close with both the experimental wind tunnel data and those of reference solvers.


Author(s):  
Shoab Ahmed Talukder ◽  
B. Phuoc Huynh

Torque converter (TC) is a totally enclosed hydrodynamic turbomachine, used most often in automobiles for the smooth transfer of power and speed change from the engine to the transmission, and torque magnification. A typical TC has 3 major components: a pump that is attached directly to the TC cover and connected to the engine shaft, a turbine connected to the transmission shaft, and a stator connected to the transmission housing via a one-way clutch and providing guidance for the fluid flow. In this work, effects of the number of stator blades on the performance of a TC are investigated numerically, using a commercial Computational Fluid Dynamics (CFD) software package. The standard k-epsilon turbulence model was used. A Newtonian fluid whose properties correspond to industrial oil was used for the working fluid. The range of speed ratio (between turbine’s speed and pump’s) of 0.2–0.8 was considered. It was found that as the stator blades’ number increases (here from 13 to 19), the TC’s efficiency and torque ratio vary significantly, passing through minimum and generally also reaching a maximum.


Ocean Science ◽  
2013 ◽  
Vol 9 (5) ◽  
pp. 855-866 ◽  
Author(s):  
N. O'Sullivan ◽  
S. Landwehr ◽  
B. Ward

Abstract. Wind speed measurements over the ocean on ships or buoys are affected by flow distortion from the platform and by the anemometer itself. This can lead to errors in direct measurements and the derived parametrisations. Here we computational fluid dynamics (CFD) to simulate the errors in wind speed measurements caused by flow distortion on the RV Celtic Explorer. Numerical measurements were obtained from the finite-volume CFD code OpenFOAM, which was used to simulate the velocity fields. This was done over a range of orientations in the test domain from −60 to +60° in increments of 10°. The simulation was also set up for a range of velocities, ranging from 5 to 25 m s−1 in increments of 0.5 m s−1. The numerical analysis showed close agreement to experimental measurements.


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