Computational fluid dynamics analysis of the effect of throat diameter on the fluid flow and performance of ejector

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Mohammadreza Salehi ◽  
Nader Pourmahmoud ◽  
Amir Hassanzadeh ◽  
S. Hoseinzadeh ◽  
P.S. Heyns
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Mach Number ◽  
Content Type ◽  
Standard Code ◽  
Computational Fluid Dynamics Analysis ◽  
Fluent Software ◽  
Computational Fluid Dynamics Cfd ◽  
Throat Diameter ◽  
And Performance

Purpose Using the computational fluid dynamics (CFD) technique, this paper aims to investigate the influence of key parameters such as throat diameter; the suction ratio on the flow field behaviors such as Mach number; pressure; and temperature. Design/methodology/approach To investigate the effect of throat diameter, it is simulated for 4, 6, 8 and 10 mm as throat diameters. The governing equations have been solved by standard code of Fluent Software together with a compressible 2 D symmetric and turbulence model with the standard k–ε model. First, the influence of the throat diameter is investigated by keeping the inlet mass flow constant. Findings The results show that a place of shock wave creation is changed by changing the throat diameter. The obtained results illustrate that the maximum amount of Mach number is dependent on the throat diameter. It is obtained from the results that for smaller throats higher Mach numbers can be obtained. Therefore, for mixing purposes smaller throats and for exhausting bigger throats seems to be appropriate. Originality/value The obtained numerical results are compared to the existing experimental ones which show good agreement.

A 3D Computational Fluid Dynamics Analysis of the Wells Turbine

2002 ◽  
Author(s):  
John Daly ◽  
Ajit Thakker ◽  
Patrick Frawley ◽  
Elvis Sheik Bajeet
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Mach Number ◽  
Computational Model ◽  
Experimental Results ◽  
Dynamics Analysis ◽  
Cfd Model ◽  
Wells Turbine ◽  
Computational Fluid Dynamics Analysis ◽  
Computational Fluid Dynamics Cfd

This paper deals with the application of Computational Fluid Dynamics (CFD) to the turbulent analysis of the Wells Turbine. The objectives of this work were twofold; firstly to develop and benchmark the 3D CFD model and then to use this model to analyse the airflow through the turbine. The model was analysed as fully turbulent compressible flow using the Fluent™ CFD code. The computational model was first benchmarked against previously published experimental and CFD data for two similar turbines. The computational model accurately predicted the non-dimensional torque and non-dimensional pressure drop, while the efficiency predictions were lower than the experimental results. Predicted location of turbine stall also corresponded well with experimental results. Potential causes for differences between the computational and experimental results are suggested. The computational model was then analysed at both high and low tip Mach number settings and also with and without the tip gap, and these results were discussed.

Effect of Cavities in Suddenly Expanded Flow at Supersonic Mach Number

CFD letters ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 57-71
Author(s):  
Atifatul Ismah Ismail
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Mach Number ◽  
Pressure Ratio ◽  
Area Ratio ◽  
Base Pressure ◽  
Sudden Expansion ◽  
Expansion Level ◽  
Computational Fluid Dynamics Cfd ◽  
Base Drag

The contribution from the base drag due to the sub-atmospheric pressure is significant. It can be more than two-thirds of the net drag. There is a need to increase the base pressure and hence decrease the base drag. This research examines the effect of Mach Number on base pressure. To accomplish this objective, it controls the efficacy in an enlarged duct computed by the numerical approach using Computational Fluid Dynamics (CFD) Analysis. This experiment was carried out by considering the expansion level and the aspect cavity ratio. The computational fluid dynamics method is used to model supersonic motion with the sudden expansion, and a convergent-divergent nozzle is used. The Mach number is 1.74 for the present study, and the area ratio is 2.56. The L/D ratio varied from 2, 4, 6, 8, and 10, and the simulated nozzle pressure ratio ranged from 3 to 11. The two-dimensional planar design used commercial software from ANSYS. The airflow from a Mach 1.74 convergent-divergent axi-symmetric nozzle expanded suddenly into circular ducts of diameters 17 and 24.5 mm with and without annular rectangular cavities. The diameter of the duct is taken D=17mm and D=24.5mm. The C-D nozzle was developed and modeled in the present study: K-ε standard wall function turbulence model was used with the commercial computational fluid dynamics (CFD) and validated. The result indicates that the base pressure is impacted by the expansion level, the enlarged duct size, and the passage’s area ratio.

COMPUTATIONAL FLUID DYNAMICS ANALYSIS OF FABRICATED MICRONOZZLE FOR SUPERSONIC PARTICLE DEPOSITION

2010 ◽  
Vol 17 (01) ◽  
pp. 45-49
Author(s):  
KYUBONG JUNG ◽  
WOOJIN SONG ◽  
DOO-MAN CHUN ◽  
JUN-CHEOL YEO ◽  
MIN-SAENG KIM ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Particle Deposition ◽  
Room Temperature ◽  
Flow Analysis ◽  
Dynamics Analysis ◽  
Nanoparticle Deposition ◽  
Computational Fluid Dynamics Analysis ◽  
Computational Fluid Dynamics Cfd ◽  
Simulation Results

A micronozzle was applied in nanoparticle deposition system (NPDS) for supersonic deposition. To determine whether suitable behavior of supersonic fluid can be produced or not, computational fluid dynamics (CFD) flow analysis was used. Ni particles were successfully deposited using the fabricated micronozzle in NPDS at room temperature. It was found that shorter micronozzle with larger side profile deposits wide and thick film compared to the deposition using long micronozzle with smaller side profile. These experimental results agree with the simulation results.

scholarly journals Aerodynamic Analysis of Spoiler at Varying Speeds and Angles

2021 ◽  
Vol 9 (11) ◽  
pp. 526-535
Author(s):  
Manas Metar
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Cfd Analysis ◽  
Wake Region ◽  
Aerodynamic Analysis ◽  
Pressure Drag ◽  
High Speeds ◽  
Computational Fluid Dynamics Analysis ◽  
Computational Fluid Dynamics Cfd ◽  
Simulation Results

Abstract: Spoilers have been there in practice since years for the purpose of improving aerodynamics of a car. The pressure drag created at the end of the vehicle, referred to as wake region affects handling of the vehicle. This could be hazardous for the cars at high speeds. By adding a spoiler to the rear of the car reduces that pressure drag and the enhanced downforce helps in better traction. The paper presents aerodynamic analysis of a spoiler through Computational Fluid Dynamics analysis. The spoiler is designed using Onshape software and analyzed through SIMSCALE software. The simulation is carried out by changing angles of attack and velocities. The simulation results of downforce and drag are compared on the basis of analytical method. Keywords: Designing a spoiler, Design and analysis of spoiler, Aerodynamics of spoiler, Aerodynamic analysis of spoiler, Computational fluid dynamics, CFD analysis, CFD analysis of spoiler, Spoiler at variable angles, Types of spoilers, Analytical aerodynamic analysis.

Influence Mechanisms of Manufacture Variations on Supersonic/Transonic Blade Aerodynamic Performances

2020 ◽  
Author(s):  
Baojie Liu ◽  
Jiaxin Liu ◽  
Xianjun Yu ◽  
Dejun Meng ◽  
Wenbin Shi
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Pressure ◽  
Statistical Analysis ◽  
Mach Number ◽  
Systematic Errors ◽  
Aerodynamic Performance ◽  
Aerodynamic Performances ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method

Abstract The results of previous studies have proved that manufacture variations can cause a noticeable influence on compressor aerodynamic performance. The main objective of this paper is to investigate the influence rules and mechanisms of manufacture variations on supersonic/transonic blades aerodynamic performance. The variations used in this study were measured from some newly manufactured high-pressure compressors. In the present study, several blade sections with different design Mach number conditions are selected for further statistical analysis of measured deviation data. Therefore, some systematic errors in the deviation data have been revealed. Based on these data, the computational fluid dynamics (CFD) method has been used to obtain the aerodynamic performances of a large number of the measured blade elements. And then, the analysis of the influence rules of manufacture variations on blade aerodynamic performance in different Mach number conditions has been carried out. The present results indicate that the effects of manufacture variations on blade aerodynamic performance in the lower Mach number (0.8) condition are much more significant comparing to that in the higher Mach number (0.9∼1.2) conditions. Based on this, influence mechanisms of manufacture variations on positive incidence range and negative incidence range have been analyzed. The differences of influence mechanisms in different Mach number conditions are the focus of research.

Analyses of the Compressor Performance Impacts of Centrifugal Compressor Scroll Deformation Due to Installation

2010 ◽  
Author(s):  
C. Xu ◽  
R. S. Amano
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Centrifugal Compressor ◽  
Local Deformation ◽  
Discharge Pipe ◽  
Gas Compression ◽  
Study Results ◽  
Computational Fluid Dynamics Cfd ◽  
Compressor Performance ◽  
And Performance

Centrifugal compressors have widely applications in industrial gas compression processes. Limitations of installation and compressor package always request to modify the compressor geometry to fit certain constrains. Very often, the modifications of the scroll were performed to meet the space constrains. To meet the installation and package requirements, we always modify the scroll and discharge pipe of the compressors. In this study, an original designed scroll and a modified scroll were analyzed by using the Computational Fluid Dynamics (CFD). The study is focused on the performance impacts of the scroll local deformation due to installation constrains. The CFD showed favorable agreements with experiments for original scroll. The detailed flow characters and performance impacts were discussed and results showed that current modifications of the scroll did not have significant impacts to the compressor performance. The study results can be used as a basic guidance for a compressor manufactures.

Modelling the effect of computation sampling on insight error in computational fluid dynamics scientific simulation

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Moeti Masiane ◽  
Eric Jacques ◽  
Wuchun Feng ◽  
Chris North
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Design Methodology ◽  
Cfd Simulation ◽  
Grid Resolution ◽  
Content Type ◽  
Computational Fluid Dynamics Cfd ◽  
Independent Variable ◽  
Cfd Applications ◽  
The Ideal

Purpose The purpose of this paper is to collect data from humans as they generate insights from the visualised results of computational fluid dynamics (CFD) scientific simulation. The authors hypothesise the behaviour of their insight errors (IEs) and proceed to quantify the IEs provided by the crowd participants. They then use the insight framework to model the behaviours of the errors. Using the crowd responses and models from the framework, they test the hypotheses and use the results to validate the framework for the speedup of CFD applications. Design/methodology/approach The authors use a randomised between-subjects experiment with blocking. CFD grid resolution is the independent variable while IE is the dependent variable. The experiment has one treatment factor with five levels. In case varying timestamps has an effect on insight variance levels, the authors block the responses by timestep. In total, 150 participants are randomly assigned to one of five groups and also randomly assigned to one of five blocks within a treatment. Participants are asked to complete a benchmark and open-ended task. Findings The authors find that the variances of insight and perception errors have a U-shaped relationship with grid resolution, that similar to the previously studied visualisation applications, the IE framework is valid for insights generated from CFD results and grid resolution can be used to predict the variance of IE resulting from observing CFD post-processing results. Originality/value To the best of the authors’ knowledge, no other work has measured IE variance to present it to simulation users so that they can use it as a feedback metric for selecting the ideal grid resolution when using grid resolution to speedup CFD simulation.

scholarly journals Correlation between LAA Morphological Features and Computational Fluid Dynamics Analysis for Non-Valvular Atrial Fibrillation Patients

2020 ◽  
Vol 10 (4) ◽  
pp. 1448 ◽  
Author(s):  
Benigno Marco Fanni ◽  
Katia Capellini ◽  
Mario Di Leonardo ◽  
Alberto Clemente ◽  
Elisa Cerone ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Atrial Fibrillation ◽  
Computational Fluid Dynamics ◽  
Morphological Features ◽  
Imaging Data ◽  
Lower Velocity ◽  
Computational Fluid Dynamics Analysis ◽  
Coupling Dynamics ◽  
Computational Fluid Dynamics Cfd ◽  
Cardiovascular Structure

The left atrial appendage (LAA) is a complex cardiovascular structure which can yield to thrombi formation in patients with non-valvular atrial fibrillation (AF). The study of LAA fluid dynamics together with morphological features should be investigated in order to evaluate the possible connection of geometrical and hemodynamics indices with the stroke risk. To reach this goal, we conducted a morphological analysis of four different LAA shapes considering their variation during the cardiac cycle and computational fluid dynamics (CFD) simulations in AF conditions were carried out. The analysis of main geometrical LAA parameters showed a huger ostium and a reduced motility for the cauliflower and cactus shapes, as well as a lower velocity values from the CFD analysis. Such findings are in line with literature and highlight the importance of coupling dynamics imaging data with CFD calculations for providing information not available at clinical level.

Computational Fluid Dynamics Analysis of Early Embryonic Aortic Arch-Ligation

2013 ◽  
Author(s):  
Prahlad G. Menon ◽  
William Kowalski ◽  
Kerem Pekkan
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
In Silico ◽  
Great Artery ◽  
Short Term ◽  
Vascular Morphogenesis ◽  
Computational Fluid Dynamics Analysis ◽  
The Us ◽  
Computational Fluid Dynamics Cfd ◽  
Biomechanical Forces

Congenital heart disease occurs in 8 out of every 1000 live births in the US and more than half of this population is associated with great artery lesions. Selective remodeling of the paired, bilaterally symmetric embryonic aortic arches (AA) is a crucial stage in vascular morphogenesis and has known association with biomechanical forces [1]. Fetal cardiac interventions are currently explored clinically as an alternative repair technique for congenital anomalies, in-utero [2]. Several computational fluid dynamics (CFD) studies have been performed focusing on subject specific embryonic cardiovascular anatomies [3–5]. These developments could benefit fetal interventions that are planned in-silico before execution. To demonstrate this possibility, we computed the hemodynamic variation and wall shear stress (WSS) patterns resulting from systematic in-silico AA ligation intervention performed on normal chick AA models viz. Hamburger Hamilton (HH) stage 18 and 24 (3 and 4 days, respectively). A unique methodology employing CFD-computed WSS for modeling short-term biological growth response on AA morphogenesis is also presented.

scholarly journals An investigation into contracted loaded tip propellers using computational fluid dynamics (CFD)

2018 ◽  
Author(s):  
N R J Williams
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Test Data ◽  
Experimental Test ◽  
Performance Improvements ◽  
Computational Fluid Dynamics Cfd ◽  
And Performance ◽  
Cfd Method ◽  
Developed Pressure

This paper investigates the potential performance improvements of adding contracted loaded tips to propellers. A Wageningen B5-75 Series propeller has been simulated and verified against published experimental test data. Contracted tips have then been added to a Wageningen propeller and the modified propeller then simulated. A CFD method and model has been developed. Pressure, velocity and vector plots have all been analysed detailing the mechanism behind the contracted tips. Limitations behind this method have been explored and explained, and recommendations for further studies made. The development of a database of propeller characteristics and performance chart data to allow quick evaluation of designs has also been proposed. 

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