Three Dimensional Simulation of the Effect of Windcatcher’s Inlet Shape

2019 ◽  
Author(s):  
Peter Abdo ◽  
Rahil Taghipour ◽  
B. P. Huynh
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Indoor Environment ◽  
Natural Ventilation ◽  
Air Flow ◽  
Three Dimensional ◽  
Sectional Area ◽  
Cross Sectional ◽  
Dimensional Simulation ◽  
Convergent Inlet

Abstract Windcatcher has been used over centuries for providing natural ventilation using wind power, it is an effective passive method to provide healthy and comfortable indoor environment. The windcatcher’s function is based on the wind and on the stack effect resulting from temperature differences. Generally, it is difficult for wind to change its direction, and enter a room through usual openings, the windcatcher is designed to overcome such problems since they have vertical columns to help channel wind down to the inside of a building. The efficiency of a windcatcher is maximized by applying special forms of opening and exit. The openings depend on the windcatcher’s location and on its cross sectional area and shape such as square, rectangular, hexagonal or circular. In this study the effect of the inlet design is investigated to achieve better air flow and increase the efficiency of windcatchers. To achieve this, CFD (computational fluid dynamics) tool is used to simulate the air flow in a three dimensional room fitted with a windcatcher based on the different inlet designs. The divergent inlet has captured the highest air flow with a difference of approximately 3% compared to the uniform inlet and 5% difference compared to the bulging-convergent inlet.

Effect of Windcatcher’s Inlet Shape on Ventilation Flow Through a Two Dimensional Room

2018 ◽  
Author(s):  
Peter Abdo ◽  
Rahil Taghipour ◽  
B. P. Huynh
Keyword(s):  
Indoor Environment ◽  
Natural Ventilation ◽  
Air Flow ◽  
Two Dimensional ◽  
Sectional Area ◽  
Cross Sectional ◽  
Indoor Space ◽  
Flow Through ◽  
Convergent Inlet ◽  
Natural Means

Natural ventilation is the process of supplying and removing air through an indoor space by natural means. Windcatcher has been used over centuries for providing natural ventilation using wind power, it is an effective passive method to provide healthy and comfortable indoor environment by decreasing moisture content in the air and reducing pollutants concentration. The windcatcher’s function is based on the wind and on the stack effect resulting from temperature differences. Generally, it is difficult for wind to change its direction, and enter a room through usual openings, the windcatcher is designed to overcome such problems since they have vertical columns aimed at helping wind to channel down to the inside of a building. The efficiency of a windcatcher is maximized by applying special forms of opening and exit. The openings depend on the windcatcher’s location and on its cross sectional area and shape such as square, rectangular, hexagonal or circular. In this study the effect of the inlet design is investigated to achieve better air flow and increase the efficiency of windcatchers. To achieve this, CFD (computational fluid dynamics) tool is used to simulate the air flow in a two dimensional room fitted with a windcatcher based on different inlet designs such as a uniform inlet, a divergent inlet and a bulging-convergent inlet.

Effect of Wind Speed on Ventilation Flow Through a Two Dimensional Room Fitted With a Windcatcher

2018 ◽  
Author(s):  
Rahil Taghipour ◽  
Peter Abdo ◽  
B. P. Huynh
Keyword(s):  
Indoor Environment ◽  
Natural Ventilation ◽  
Air Flow ◽  
Two Dimensional ◽  
Cross Sectional ◽  
Indoor Space ◽  
Wind Speeds ◽  
Flow Through ◽  
Convergent Inlet ◽  
Natural Means

Natural ventilation is the process of supplying and removing air through an indoor space by natural means. Windcatcher has been used over centuries for providing natural ventilation using wind power, it is an effective passive method to provide healthy and comfortable indoor environment by decreasing moisture content in the air and reducing pollutants concentration. The windcatcher’s function is based on the wind and on the stack effect resulting from temperature differences. Generally, it is difficult for wind to change its direction, and enter a room through usual openings, the windcatcher is designed to overcome such problems since they have vertical columns aimed at helping wind to channel down to the inside of a building. The efficiency of a windcatcher is maximized by applying special forms of opening and exit. The openings depend on the windcatcher’s location and on its cross sectional area and shape such as square, rectangular, hexagonal or circular. In this study the effect of different wind speeds on the total air flow captured by different inlet designs is investigated. To achieve this, CFD (computational fluid dynamics) tool is used to simulate the air flow in a two dimensional room fitted with a windcatcher applying wind speeds from 1 m/s up to 14 m/s and based on different inlet designs such as a uniform inlet, a divergent inlet and a bulging-convergent inlet.

scholarly journals Three-Dimensional Simulation of Wind-Driven Ventilation Through a Windcatcher With Different Inlet Designs

2019 ◽  
Vol 12 (4) ◽  
Author(s):  
Peter Abdo ◽  
Rahil Taghipour ◽  
B. Phuoc Huynh
Keyword(s):  
Wind Speed ◽  
Average Velocity ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Three Dimensional ◽  
Cfd Modeling ◽  
Ansys Fluent ◽  
Wind Velocities ◽  
Dimensional Simulation ◽  
Convergent Inlet

Abstract Windcatcher is an effective natural ventilation system, and its performance depends on several factors including wind speed and wind direction. It provides a comfortable and healthy indoor environment since the introduced fresh air decreases the moisture content and reduces the pollutant concentration. Since the wind speed and its direction are generally unpredictable, it is important to use special inlet forms and exits to increase the efficiency of a windcatcher. In this study, computational fluid dynamics (CFD) modeling is implemented using ansys fluent to investigate the airflow entering a three-dimensional room through a windcatcher with different inlet designs. Three designs are studied which are a uniform inlet, a divergent inlet, and a bulging-convergent inlet. The airflow pattern with all inlets provided adequate ventilation through the room. With all the applied wind velocities (1, 2, 3, and 6 m/s) at the domain's inlet, the divergent inlet shape has captured the highest airflow through the room and provided higher average velocity at 1.2 m high enhancing the thermal comfort where most of the human occupancy occurs. With 6 m/s wind velocity, the divergent inlet has captured 2.55% more flow rate compared to the uniform inlet and 4.70% compared to the bulging-convergent inlet, and it has also provided an average velocity at 1.2 m high in the room of 7.16% higher than the uniform inlet and 8.44% higher than the bulging-convergent inlet.

scholarly journals Influence of air velocity on indoor environment quality in unidirectional flow operating theatres: A study based on Computational Fluid Dynamics

2019 ◽  
Vol 85 ◽  
pp. 02003
Author(s):  
Gonzalo Sánchez-Barroso Moreno ◽  
Justo García Sanz-Calcedo ◽  
Alfonso C. Marcos Romero
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Performance ◽  
Indoor Environment ◽  
Air Flow ◽  
Environment Quality ◽  
Hospital Facility ◽  
Unidirectional Flow ◽  
Indoor Environment Quality ◽  
Operating Theatres

It is necessary to characterise air-conditioning airflow in omanuscriprder to optimize hospital Indoor Environment Quality in high-performance operating theatres, and also reduce the risk of nosocomial infection due to pathogen contamination. The aim of this article is to study the prevalence of optimal healthy conditions from controlled air flow quality in hospital facilities, and to minimize energy consumption. To this purpose, the indoor air movement was modelled by Computational Fluid Dynamics technology. The optimal results showed that it is necessary to drive ultra-clean air ranging between 0.25 m/s and 0.40 m/s, values which are adequate to perform efficient sweeping and cleaning of the air near the patient, maintaining unidirectional air flow permanently as the air passes through the surgical field. These speeds must be taken into account as calculation parameters in new hospital facility projects, and as control parameters for the existing operating theatres.

scholarly journals Analysis of a Converging, Annular, Isothermal Melt Blowing Jet Using Computational Fluid Dynamics

2005 ◽  
Vol os-14 (3) ◽  
pp. 1558925005os-14
Author(s):  
Eric M. Moore ◽  
Dimitrios V. Papavassiliou ◽  
Robert L. Shambaugh
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Kinetic Energy ◽  
Near Field ◽  
Flow Characteristics ◽  
Sectional Area ◽  
Melt Blowing ◽  
Mean Velocity ◽  
Cross Sectional ◽  
Computational Fluid Dynamics Cfd

An unconventional melt blowing die was analyzed using computational fluid dynamics (CFD). This die has an annular configuration wherein the jet inlet is tapered (the cross-sectional area decreases) as the air approaches the die face. It was found that the flow characteristics of this die are different from conventional slot and annular dies. In particular, for the tapered die the near-field normalized turbulent kinetic energy was found to be lower at shallow die angles. Also, it was found that the peak mean velocity behavior was intermediate between that of conventional annular and slot dies. The centerline turbulence profiles were found to be qualitatively similar to those of annular dies; quantitatively, higher values were present for tapered dies.

A NEW METHOD TO STUDY ATHEROSCLEROSIS AND ASSESS THE EFFECTIVENESS OF PERCUTANEOUS CORONARY INTERVENTION BY COMPUTATIONAL FLUID DYNAMICS SIMULATION

2017 ◽  
Vol 17 (02) ◽  
pp. 1750035
Author(s):  
CHANGNONG PENG ◽  
PENGCHENG XU ◽  
ZHANCHAO XIAN ◽  
XIAOQING WANG ◽  
WENHUA HUANG ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Percutaneous Coronary Intervention ◽  
Coronary Intervention ◽  
Functional Evaluation ◽  
Sectional Area ◽  
Area Formula ◽  
High Quality ◽  
Cross Sectional ◽  
Percutaneous Coronary

High-pitch spiral computed tomography coronary angiography (CTCA) is able to perform a whole-heart scan within one heartbeat, resulting in high-quality images with high spatial and temporal resolution. To investigate the performance of high-quality CTCA images, an anatomic stenosis evaluation by digital subtracted angiography (DSA) was compared to a functional stenosis evaluation by CTCA-derived fraction flow reserve (FFR). A total of 54 arterial segments with stenosis were collected from 23 patients, and three-dimensional (3D) geometrical models were reconstructed. The computational fluid dynamics (CFDs) analysis was used to calculate the pressure distributions and FFR values. The correlation between anatomic and functional evaluation factors was assessed with either the ratio of anatomic reduction or CTCA-derived FFR values at the corresponding anatomic locations. Pearson correlation analysis was performed, and a significant correlation was found relating to the diameter ([Formula: see text]) and the cross-sectional area ([Formula: see text]). A significant correlation was also found in the functional evaluation relating to the diameter ([Formula: see text]) and the cross-sectional area ([Formula: see text]). High-quality CT images greatly reduce the time needed for geometric reconstruction. Significant advances in the accuracy of the reconstruction have resulted in more accurate CFD analysis, which can help to improve clinical diagnoses. The results of this study show that the CFD method can be a feasible tool for the clinic diagnosis of stenosis and for determining whether a patient requires percutaneous coronary intervention (PCI).

Effects of Volute Cross-Sectional Area Distribution on Performance of Double-Suction Volute Pump

2019 ◽  
Author(s):  
Szu Yung Chen ◽  
Lu Zhang ◽  
Yumiko Sekino ◽  
Hiroyoshi Watanabe
Keyword(s):  
Fluid Dynamics ◽  
Genetic Algorithm ◽  
Computational Fluid Dynamics ◽  
Secondary Flow ◽  
Cross Sections ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Suction Pump ◽  
Computational Fluid Dynamics Cfd

Abstract The following study describes the optimization design procedure of a double-suction pump. BASELINE pump is designed as inlet nozzle diameter 800 mm and impeller outlet diameter 740 mm. Each component of a BASELINE pump, impeller configurations, discharge volute, and the suction casing were determined by DOE (Design of Experiments) and sensitivity analysis. However, finite selected design parameters for each component are mostly restricted to the free surface design of the pump casing. In this study, the optimization method approach along with steady Computational Fluid Dynamics (CFD) is introduced to achieve the high efficiency request of a double-suction pump. To investigate the matching optimization of the impeller and discharge volute at design point, the full parametric geometry of discharge volute was developed referred to the BASELINE shape and Multi-Objective Genetic Algorithm NSGA-II (Non-dominated Sorting Genetic Algorithm II) was used. Optimization result shows that by increasing the volute cross-sectional area from the volute tongue till the circumferential angle 180 deg. provides lower loss. This is due to the improvement achieved for the better distribution of the velocity gradient within the volute. A validated unsteady computational fluid dynamics (CFD) was also employed to investigate the performance difference between optimized volute design and the BASELINE which correlated to the pressure fluctuation and secondary flow behavior inside the cross-sections from 80% to 120% of nominal flow rate. The result shows that the flow distortion in the streamwise direction is stronger with the BASELINE and sensitively affects the operation stability. This is due to the different secondary flow pattern in the cross-sections, hence demonstrating a design direction of desired volute cross-sectional shape for high-performance can be used in a double-suction volute pump.

scholarly journals Computational Fluid Dynamics Approach for Performance Prediction in a Zinc–Air Fuel Cell

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2185 ◽  
Author(s):  
K. Huang ◽  
Thangavel Sangeetha ◽  
Wu-Fu Cheng ◽  
Chunyo Lin ◽  
Po-Tuan Chen
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Fuel Cell ◽  
Three Dimensional ◽  
Current Data ◽  
Numerical Results ◽  
Porous Electrodes ◽  
Cross Sectional ◽  
Anode Electrode ◽  
Experimental Values

In this study, we investigated the development of a computational fluid dynamics (CFD) model for simulating the physical and chemical processes in a zinc (Zn)–air fuel cell. Theoretically, the model was based on time-dependent, three-dimensional conservation equations of mass, momentum, and species concentration. The complex electrochemical reactions occurring within the porous electrodes were described by the Butler–Volmer equation with velocity, pressure, current density, and electronic and ionic phase potentials computed in electrodes. The Zn–air fuel cell for the present study comprised of four major components, such as a porous Zn anode electrode, air cathode electrode, liquid potassium hydroxide (KOH) electrolyte, and air flow channels. The numerical results were first compared with the experiments, showing close agreement with the predicted and experimental values of the measured voltage–current data of a single Zn–air fuel cell. Numerical results also exhibited mass fraction contours of oxygen (O2) and zinc oxide (ZnO) in the mid-cross-sectional plane. A parametric study was extended to assess the performance of a Zn–air fuel cell at various cathode and electrolyte parameters.

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