CFD simulation analysis of two-dimensional convergent-divergent nozzle

2018 ◽  
Vol 41 (13) ◽  
pp. 1505-1515 ◽  
Author(s):  
R. Ramesh Kumar ◽  
Yuvarajan Devarajan
Keyword(s):  
Cfd Simulation ◽  
Simulation Analysis ◽  
Two Dimensional

scholarly journals Computational fluid dynamics (CFD) simulation analysis on retinal gas cover rates using computational eye models

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Makoto Gozawa ◽  
Yoshihiro Takamura ◽  
Tomoe Aoki ◽  
Kentaro Iwasaki ◽  
Masaru Inatani
Keyword(s):  
Cfd Simulation ◽  
Simulation Analysis ◽  
Fluid Dynamic ◽  
Fluid Analysis ◽  
Intraocular Gas ◽  
Pars Plana ◽  
Computational Fluid Dynamics Cfd ◽  
Multiple Breaks ◽  
Gas Volume ◽  
Wall Wettability

AbstractWe investigated the change in the retinal gas cover rates due to intraocular gas volume and positions using computational eye models and demonstrated the appropriate position after pars plana vitrectomy (PPV) with gas tamponade for rhegmatogenous retinal detachments (RRDs). Computational fluid dynamic (CFD) software was used to calculate the retinal wall wettability of a computational pseudophakic eye models using fluid analysis. The model utilized different gas volumes from 10 to 90%, in increments of 10% to the vitreous cavity in the supine, sitting, lateral, prone with closed eyes, and prone positions. Then, the gas cover rates of the retina were measured in each quadrant. When breaks are limited to the inferior retina anterior to the equator or multiple breaks are observed in two or more quadrants anterior to the equator, supine position maintained 100% gas cover rates in all breaks for the longest duration compared with other positions. When breaks are limited to either superior, nasal, or temporal retina, sitting, lower temporal, and lower nasal position were maintained at 100% gas cover rates for the longest duration, respectively. Our results may contribute to better surgical outcomes of RRDs and a reduction in the duration of the postoperative prone position.

scholarly journals CFD Simulation of Solid Suspension for a Liquid–Solid Industrial Stirred Reactor

2021 ◽  
Vol 11 (12) ◽  
pp. 5705
Author(s):  
Adrian Stuparu ◽  
Romeo Susan-Resiga ◽  
Alin Bosioc
Keyword(s):  
Chemical Reaction ◽  
Cfd Simulation ◽  
Simulation Analysis ◽  
Solid Phase ◽  
Initial Conditions ◽  
Chemical Reactor ◽  
Liquid Mixtures ◽  
Multiphase Model ◽  
Chemical Product ◽  
Two Phase

The present study examines the possibility of using an industrial stirred chemical reactor, originally employed for liquid–liquid mixtures, for operating with two-phase liquid–solid suspensions. It is critical when obtaining a high-quality chemical product that the solid phase remains suspended in the liquid phase long enough that the chemical reaction takes place. The impeller was designed for the preparation of a chemical product with a prescribed composition. The present study aims at finding, using a numerical simulation analysis, if the performance of the original impeller is suitable for obtaining a new chemical product with a different composition. The Eulerian multiphase model was employed along with the renormalization (RNG) k-ε turbulence model to simulate liquid–solid flow with a free surface in a stirred tank. A sliding-mesh approach was used to model the impeller rotation with the commercial CFD code, FLUENT. The results obtained underline that 25% to 40% of the solid phase is sedimented on the lower part of the reactor, depending on the initial conditions. It results that the impeller does not perform as needed; hence, the suspension time of the solid phase is not long enough for the chemical reaction to be properly completed.

scholarly journals Influence of Lawns on the Summer Thermal Environment and Microclimate of Heritage Sites: A Case Study of Fuling Mausoleum, China

2020 ◽  
Author(s):  
Xiaoyu Wang ◽  
Peng Liu ◽  
Gongwen Xu
Keyword(s):  
Cfd Simulation ◽  
Simulation Analysis ◽  
Thermal Environment ◽  
Measurement Data ◽  
Ground Temperature ◽  
Rapid Urbanization ◽  
Actual Measurement ◽  
Heritage Sites ◽  
Human Thermal Comfort ◽  
The Impact

Abstract The thermal environment and microclimate of heritage sites has been severely impacted by rapid urbanization. This study collected various meteorological measurement data as a reference for computational fluid dynamics (CFD) simulation settings. Then CFD was applied to simulate the impact of lawns on the thermal environment and microclimate of Fuling Mausoleum. We found that lawns and soil can cool the air through evaporation, and thus have a specific cooling effect on the bricked ground. After lawns were planted, the bricked ground temperature decreased by 1.56–17.54°C than that before lawns were planted at 14:00, a decrease of 2.68%–24.20%. Under normal circumstances, when the wind speed or relative humidity increased, the ground temperature dropped. Greenbelt vegetation can adjust the microclimate and human thermal comfort indicators. The consistency of the difference between the actual measurement and the CFD simulation results shows that CFD simulation can thus accurately reflect the internal temperature field distribution if the selection of simulation parameters is reasonable. Theoretical calculation and analysis, experimental measurement research, and modern computer simulation analysis methods applied together constitute a complete system for studying modern physical environmental problems and can provide reliable and economic results.

scholarly journals Two-dimensional CFD simulation and pilot-scale experimental verification of a downdraft gasifier: effect of reactor aspect ratios on temperature and syngas composition during gasification

2020 ◽  
Vol 7 (3) ◽  
pp. 536-550
Author(s):  
Chootrakul Siripaiboon ◽  
Prysathyrd Sarabhorn ◽  
Chinnathan Areeprasert
Keyword(s):  
Steady State ◽  
Temperature Profile ◽  
Fuel Consumption ◽  
Cfd Simulation ◽  
Pilot Scale ◽  
Reactor Wall ◽  
Two Dimensional ◽  
High Concentration ◽  
Downdraft Gasifier ◽  
Aspect Ratios

Abstract This paper focuses on a two-dimensional CFD simulation of a downdraft gasifier and a pilot-scale experiment for verification using wood pellet fuel. The simulation work was carried out via the ANSYS-Fluent CFD software package with in-house coding via User Defined Function. Three gasification parameters were taken into account in the simulation and validation to achieve highly accurate results; namely, fuel consumption, temperature profile, and syngas composition. After verification of the developed model, the effects of aspect ratios on temperature and syngas composition were investigated. Results from simulation and experimental work indicated that the fuel consumption rate during the steady state gasification experiment was 1.750 ± 0.048 g/s. The average steady state temperature of the experiment was 1240.32 ± 14.20 K. In sum, the fuel consumption and temperature profile during gasification from modeling and experimentation show an error lower than 1.3%. Concentrations of CO, CO2, H2, and CH4 were 20.42 vol%, 15.09 vol%, 8.02 vol%, and 2.6 vol%, respectively, which are comparable to those of the experiment: 20.00 vol%, 15.48 vol%, 8.00 vol%, and 2.65 vol%. A high concentration of syngas is observed in the outer radial part of the reactor because of the resistive flow of the air inlet and the synthesis gas produced. The average temperatures during the steady state of the gasifier with aspect ratios (H/D) of 1.00, 1.38 (experiment), and 1.82 were 978.77 ± 11.60, 1256.46 ± 9.90, and 1368.94 ± 9.20 K, respectively. The 1.82 aspect ratio reactor has the smallest diameter, therefore the radiative heat transferred from the reactor wall affects the temperature in the reactor. Syngas compositions are comparable. Inverse relationships between the aspect ratios and the syngas LHV, (4.29–4.49 MJ/N m3), cold gas efficiency (29.66% to 31.00%), and carbon conversion (79.59% to 80.87%) are observed.

scholarly journals Quantification of denitrification in permeable sediments: Insights from a two-dimensional simulation analysis and experimental data

2006 ◽  
Vol 4 (9) ◽  
pp. 294-307 ◽  
Author(s):  
Perran L. M. Cook ◽  
Frank Wenzhöfer ◽  
Søren Rysgaard ◽  
Oleksiy S. Galaktionov ◽  
Filip J. R. Meysman ◽  
...  
Keyword(s):  
Experimental Data ◽  
Simulation Analysis ◽  
Two Dimensional ◽  
Permeable Sediments ◽  
Dimensional Simulation

Two-Dimensional Computational Fluid Dynamics Study on the Performance of Twin Vertical Axis Wind Turbine With Deflector

2020 ◽  
Vol 142 (8) ◽  
Author(s):  
Yichen Jiang ◽  
Peidong Zhao ◽  
Li Zou ◽  
Zhi Zong ◽  
Kun Wang
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Turbine ◽  
Cfd Simulation ◽  
Vertical Axis ◽  
Energy Utilization ◽  
Offshore Wind ◽  
Two Dimensional ◽  
Vertical Axis Wind Turbine ◽  
Local Flow

Abstract The offshore wind industry is undergoing a rapid development due to its advantage over the onshore wind farm. The vertical axis wind turbine (VAWT) is deemed to be potential in offshore wind energy utilization. A design of the offshore vertical axis wind turbine with a deflector is proposed and studied in this paper. Two-dimensional computational fluid dynamics (CFD) simulation is employed to investigate the aerodynamic performance of wind turbine. An effective method of obtaining the blade’s angle of attack (AoA) is introduced in CFD simulation to help analyze the blade aerodynamic torque variation. The numerical simulations are validated against the measured torque and wake velocity, and the results show a good agreement with the experiment. It is found that the blade instantaneous torque is correlated with the local AoA. Among the three deflector configurations, the front deflector leads to favorable local flow for the blade, which is responsible for the improved performance.

Two-Dimensional Numerical Simulations of a Biphasic Representation of Human Tibia in Car-Pedestrian Accidents

2008 ◽  
Author(s):  
Haibin Chen ◽  
Xuemei Cheng ◽  
King H. Yang
Keyword(s):  
Simulation Analysis ◽  
Fluid Phase ◽  
Material Model ◽  
Injury Mechanism ◽  
Two Dimensional ◽  
Governing Equations ◽  
Human Tibia ◽  
Pedestrian Accidents ◽  
Poroelastic Material ◽  
Poroelastic Model

A two-dimensional poroelastic model of the tibia was developed to improve the understanding of injury mechanism of tibia during car-to-pedestrian impacts. A “poroelastic” approach was utilized to establish the governing equations of human tibia, and the finite element method was applied to solve these governing equations. Both the cortical and cancellous components of tibia were represented using a poroelastic material model consisted of a solid and a fluid phase. The geometry of the model was reconstructed from CT scans of the left tibia of a living human volunteer. A lateral-medial impact direction was selected in the simulation analysis. Correspondingly, the tibia poroelastic model was validated against published shearing experiments with the whole PMHS tibia. The model predictions showed good agreement against the PMHS test data. The developed poroelastic model can be used as a helpful tool to investigate injury mechanism of the tibia in car-to-pedestrian accidents.

A Study on the Aerodynamic Characteristics for a Two-Dimensional Trajectory Correction Fuze

2014 ◽  
Vol 703 ◽  
pp. 370-375 ◽  
Author(s):  
Jie Min Li ◽  
Guang Lin He ◽  
Hao Yang Guo
Keyword(s):  
Cfd Simulation ◽  
Fluid Dynamic ◽  
Aerodynamic Characteristics ◽  
Two Dimensional ◽  
Roll Control ◽  
Speed Range ◽  
The Common ◽  
Trajectory Correction ◽  
Control Forces ◽  
Targeting Accuracy

This study researched the aerodynamic characteristics of a two-dimensional trajectory correction fuze used for the common artillery ammunition, which increases the targeting accuracy by decreasing the circular error probability. The correction fuze has a pair of fixed canard and a pair of steering canards for roll control and guidance. In this study, computational fluid dynamic (CFD) simulation is performed to study the aerodynamic characteristics of the trajectory correction fuze. The primary purpose of this performance was to predict the aerodynamic coefficients and flow field over a spin-stabilized projectile with the correction fuze. Calculation covered from-10 degrees to 10 degrees steering canards deflection over speed range from Mach 0.6 to 3. The results showed the variation law in the rotary moment of correction module and the control forces of the steering canards with the Mach varying, providing aerodynamic reference for the research of trajectory correction projectiles in the future.

Sign in / Sign up

Export Citation Format

Share Document