Performance Analysis of the Small-Scale α-Type Stirling Engine Using Computational Fluid Dynamics Tools

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Zbigniew Buliński ◽  
Ireneusz Szczygieł ◽  
Adam Kabaj ◽  
Tomasz Krysiński ◽  
Paweł Gładysz ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Model ◽  
Stirling Engine ◽  
Coefficient Of Performance ◽  
Navier Stokes ◽  
Small Scale ◽  
Ansys Fluent ◽  
Fluent Software ◽  
Energy Equations

This paper presents the computational fluid dynamics (CFD) model of small-scale α-type Stirling engine. The developed mathematical model comprises of unsteady Reynolds averaged Navier–Stokes set of equations, i.e., continuity, momentum, and energy equations; turbulence was modeled using standard κ–ω model. Moreover, presented numerical model covers all modes of heat transfer inside the engine: conduction, convection, and radiation. The model was built in the framework of the commercial CFD software ANSYS fluent. Piston movements were modeled using dynamic mesh capability in ANSYS fluent; their movement kinematics was described based on the crankshaft geometry and it was implemented in the model using user-defined functions written in C programming language and compiled with a core of the ANSYS fluent software. The developed numerical model was used to assess the performance of the analyzed Stirling engine. For this purpose, different performance measures were defined, including coefficient of performance (COP), exergy efficiency, and irreversibility factor. The proposed measures were applied to evaluate the influence of different heating strategies of the small-scale α-type Stirling engine.

Computational fluid dynamics analysis of a modified Savonius rotor and optimization using response surface methodology

2017 ◽  
Vol 41 (5) ◽  
pp. 285-296 ◽  
Author(s):  
Haris Moazam Sheikh ◽  
Zeeshan Shabbir ◽  
Hassan Ahmed ◽  
Muhammad Hamza Waseem ◽  
Muhammad Zubair Sheikh
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Response Surface Methodology ◽  
Response Surface ◽  
Design Of Experiment ◽  
Coefficient Of Performance ◽  
Speed Ratio ◽  
Ansys Fluent ◽  
Computational Fluid Dynamics Analysis ◽  
Parametric Effects

This article aims to present a two-dimensional parametric analysis of a modified Savonius wind turbine using computational fluid dynamics. The effects of three independent parameters of the rotor, namely, shape factor, overlap ratio, and tip speed ratio on turbine performance were studied and then optimized for maximum coefficient of performance using response surface methodology. The rotor performance was analyzed over specific domains of the parameters under study, and three-variable Box-Behnken design was used for design of experiment. The specific parametric combinations as per design of experiment were simulated using ANSYS Fluent®, and the response variable, coefficient of performance (Cp), was calculated. The sliding mesh model was utilized, and the flow was simulated using Shear Stress Transport (SST) k − ω model. The model was validated using past experimental results and found to predict parametric effects accurately. Minitab® and ReliaSoft DOE++® were used to develop regression equation and find the optimum combination of parameters for coefficient of performance over the specified parametric domains using response surface methodology.

Aerodynamic Analysis of High Energy Efficiency Vehicles by Computational Fluid Dynamics Simulation

2019 ◽  
Vol 32 ◽  
pp. 41-51 ◽  
Author(s):  
Victor Fuerst Pacheco ◽  
Diego Alves de Miranda
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Energy Efficiency ◽  
High Energy ◽  
Dynamics Simulation ◽  
Computational Fluid Dynamics Simulation ◽  
Ansys Fluent ◽  
Fluent Software ◽  
High Energy Efficiency ◽  
Object Of Study

The growing demand for energy efficiency gains in vehicles has led to several advances in more technological and efficient driving units, projects using lighter and more resistant materials and, in particular, a deeper study of aerodynamic studies in order to understand the fluid flow around the object of study. This work presents an aerodynamic study for a vehicle of high-energy efficiency, through computational fluid dynamics simulation in Ansys Fluent software. The main objective is to obtain the traction and drag force vectors acting on the vehicle at different speeds and to better understand the airflow before, during and after contact with the vehicle. With the possession of results, it was facilitated the implementation of improvements that enabled the vehicle to operate even more efficiently.

scholarly journals Minimising exposure to droplet and aerosolised pathogens: a computational fluid dynamics study

2020 ◽  
Author(s):  
Paolo Perella ◽  
Mohammad Tabarra ◽  
Ertan Hataysal ◽  
Amir Pournasr ◽  
Ian Renfrew
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Suction Catheter ◽  
Particle Removal ◽  
Ansys Fluent ◽  
Protective Shield ◽  
Pragmatic Clinical Trials ◽  
Fluent Software ◽  
Dynamics Modelling ◽  
Suction Flow

BackgroundHazardous pathogens are spread in either droplets or aerosols produced during aerosol generating procedures (AGP). Adjuncts minimising exposure of healthcare workers to hazardous pathogens released during AGP may be beneficial. We used state-of-the-art Computational Fluid Dynamics modelling to optimise the performance of a custom-designed shield.MethodsWe modelled airflow patterns and trajectories of particles (size range 1–500µm) emitted during a typical cough using Computational Fluid Dynamics (ANSYS Fluent software), in the presence and absence of a protective shield enclosing the head of a patient. We modelled the effect of different shield designs, suction tube position, and suction flow rate on particle escape from the shield.ResultsUse of the shield prevented escape of 99.1–100% of particles, which were either trapped on the shield walls (16–21%) or extracted via suction (79–82%). At most, 0.9% particles remained floating inside the shield. Suction flow rates (40–160L min−1) had no effect on the final location of particles in a closed system. Particle removal from within the shield was optimal when a suction catheter was placed vertically next to the head of the patient. Addition of multiple openings in the shield reduced the purging performance from 99% at 160 L min−1 to 67% at 40 L min−1.ConclusionComputational fluid dynamics modelling provides information to guide optimisation of the efficient removal of hazardous pathogens released during AGP from a custom-designed shield. These data are essential to establish before clinical use and/or pragmatic clinical trials.

scholarly journals CFD Analysis of Hybrid Solar Chimney Power Plant

2018 ◽  
Vol 225 ◽  
pp. 04011
Author(s):  
Mohammed A. Aurybi ◽  
Hussain H. Al-Kayiem ◽  
Syed I.U. Gilani ◽  
Ali A. Ismaeel
Keyword(s):  
Flue Gas ◽  
Navier Stokes ◽  
Discrete Ordinates ◽  
Hybrid Mode ◽  
Solar Chimney ◽  
Ansys Fluent ◽  
Novel Approach ◽  
Fluent Software ◽  
Solar Chimney Power Plant ◽  
Energy Equations

In this study, a novel approach has been proposed as a solar chimney integrated with an external heat source to extend the system operation during the absence of solar energy. Flue gas channels have been utilized to exchange heat with the air inside the collector of the solar chimney. The hybrid solar chimney has been investigated numerically by ANSYS-Fluent software, using discrete ordinates radiation model. The hybrid system was simulated in 3D, steady-state by solving Navier-Stokes and energy equations. The numerical results have been validated using experimental measurements of a conventional solar chimney. The influence of flue channels on the system performance was predicted and analyzed in hybrid mode. With 0.002 kg/s of flue gas at 100°C injected in flue channels during the daytime; hybrid mode results demonstrated enhancement of 24% and 9 % for velocity and temperature, respectively. The power generation was enhanced by 56%. It has been proved that the proposed technique is able to resolve the set back of night operation problem of the solar chimney plants.

scholarly journals Mixing Performance of Counter-Axial Flow Impeller using Computational Fluid Dynamics

2018 ◽  
Vol 8 (02) ◽  
Author(s):  
Ian Torotwa ◽  
Changying Ji
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Axial Flow ◽  
Turbulence Models ◽  
Navier Stokes ◽  
Navier Stokes Equation ◽  
Ansys Fluent ◽  
Rushton Turbine ◽  
Mixing Performance ◽  
Computational Fluid Dynamics Cfd

In this study, turbulent flow fields in a baffled vessel stirred by counter-axial flow impeller have been investigated in comparison to the Rushton turbine. The resultant turbulence was numerically predicted using computational fluid dynamics (CFD). Turbulence models were developed in ANSYS Fluent 18.1 solver using the Navier-Stokes equation with the standard k-ε turbulence model. The Multiple Reference Frame (MRF) approach was used to simulate the impeller action in the vertical and horizontal planes of the stirred fluid volume. Velocity profiles generated from the simulations were used to predict and compare the performance of the two designs. To validate the CFD model, the simulation results were compared with experimental results from existing work and a satisfactory agreement was established. It was concluded that the counter-axial flow impeller could provide better turbulence characteristics that would improve the quality of mixing systems.

Computational fluid dynamics (CFD) for “typical Dutch” houses failure: experiments and numerical modelling comparison.

2020 ◽  
Author(s):  
Manuel Andrés Díaz Loaiza ◽  
Benedikt Bratz ◽  
Jeremy Bricker ◽  
PAul Korswagen
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Model ◽  
Numerical Modelling ◽  
Flow Direction ◽  
Orientation Angle ◽  
Small Scale ◽  
Flow Conditions ◽  
Computational Fluid Dynamics Cfd ◽  
Multiple Variables

<p><strong>Computational fluid dynamics (CFD)  for “typical Dutch” houses failure: experiments and numerical modelling comparison.</strong></p><p>Authors: Andres Diaz Loaiza<sup>1</sup>, Benedikt Bratz<sup>1,2</sup>, Jeremy Bricker<sup>1</sup> and Paul Korswagen<sup>1</sup></p><p>1- Hydraulic Structures and Flood Risk, Technical University of Delft, 1- Technische Universität Braunschweig</p><p> </p><p>Coastal and riverine floods can be a catastrophic natural hazard with importance consequences. Many of the casualties occurring during these events can be attributed to the collapse of residential houses, and it is thus required to gain knowledge about the failure mechanism of these structures. Multiple variables can lead to various flow conditions that will in turn represent different load pressures over the house; among these, the type of the material (used in the construction), the orientation angle in respect to the main flow direction, the shape of the structure, and the urban density (blockage ratio), are relevant. In the present paper, small scale experiments are compared with CFD simulations performed with openFOAM in order to obtain a numerical model than can predict different combinations of load pressures for various flood events.</p><p> </p><p>The present study aims to represent different “typical Dutch” houses near or close to a dam break in which rapid high flow velocities and depths can be presented. The flow conditions and load pressures outputs are compared to physical results in order to validate the numerical model.</p>

scholarly journals From numerical prototypes to real models: a progressive study of aerodynamic parameters of nonconventional concrete structures with Computational Fluid Dynamics

2020 ◽  
Vol 13 (3) ◽  
pp. 628-643
Author(s):  
C. V. S. SARMENTO ◽  
A. O. C. FONTE ◽  
L. J. PEDROSO ◽  
P. M. V. RIBEIRO
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Performance ◽  
Large Scale ◽  
Computational Models ◽  
Computational Cost ◽  
Concrete Structures ◽  
Navier Stokes ◽  
Small Scale ◽  
Aerodynamic Parameters

Abstract The practical evaluation of aerodynamic coefficients in unconventional concrete structures requires specific studies, which are small-scale models evaluated in wind tunnels. Sophisticated facilities and special sensors are needed, and the tendency is for modern and slender constructions to arise with specific demands on their interaction with the wind. On the other hand, the advances obtained in modern multi-core processors emerge as an alternative for the construction of sophisticated computational models, where the Navier-Stokes differential equations are solved for fluid flow using numerical methods. Computations of this kind require specialized theoretical knowledge, efficient computer programs, and high-performance computers for large-scale calculations. This paper presents recent results involving two real-world applications in concrete structures, where the aerodynamic parameters were estimated with the aid of computational fluid dynamics. Conventional quad-core computers were applied in simulations with the Finite Volume Method and a progressive methodology is presented, highlighting the main aspects of the simulation and allowing its generalization to other types of problems. The results confirm that the proposed methodology is promising in terms of computational cost, drag coefficient estimation and versatility of simulation parameters. These results also indicate that mid-performance computers can be applied for preliminary studies of aerodynamic parameters in design offices.

ANÁLISE NUMÉRICA DO ESCOAMENTO E DOS COEFICIENTES AERODINÂMICOS EM AEROFÓLIOS SEM E COM A UTILIZAÇÃO DE FLAPS PLAIN

2018 ◽  
Vol 12 (1) ◽  
pp. 45
Author(s):  
William Denner Pires Fonseca ◽  
Lourival Matos de Sousa Filho ◽  
Genilson Vieira Martins
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Navier Stokes ◽  
Ansys Fluent ◽  
Naca 0012

<p class="04CorpodoTexto">Este trabalho apresenta o estudo numérico do escoamento e das características aerodinâmicas em aerofólios simétrico e assimétrico sem e com flap. Um modelo bidimensional, permanente e viscoso é adotado no problema. As equações da conservação de massa (Continuidade) e da conservação de movimento (Navier-Stokes) são diferenciadas pelo método dos volumes finitos através do software CFD (<em>Computational Fluid Dynamics</em>) ANSYS/Fluent™. Inicialmente o código numérico é validado com a comparação dos resultados obtidos numa simulação para um aerofólio da série NACA 4 dígitos sem flap com os resultados apresentados na literatura. Em seguida buscou-se averiguar como se comporta os campos de pressão e velocidade, as linhas de corrente, os coeficientes de sustentação e arrasto para os aerofólios simétrico (NACA 0012) e assimétrico (EPLLER 423) sem e com flap. Por fim é verificado qual aerofólio é mais eficiente aerodinamicamente.</p>

scholarly journals A Computational Fluid Dynamics Study on Shearing Mechanisms in Thermal Elastohydrodynamic Line Contacts

Lubricants ◽  
2019 ◽  
Vol 7 (8) ◽  
pp. 69 ◽  
Author(s):  
Marko Tošić ◽  
Roland Larsson ◽  
Janko Jovanović ◽  
Thomas Lohner ◽  
Marcus Björling ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Stokes Equations ◽  
Plug Flow ◽  
Fluid Pressure ◽  
Navier Stokes ◽  
Shear Strain Rate ◽  
Mixture Flow ◽  
Ansys Fluent ◽  
Line Contacts

A computational fluid dynamics (CFD) model of the thermal elastohydrodynamically lubricated (EHL) line contact problem has been developed for the purpose of exploring the physical processes that occur inside a thin EHL film subjected to shearing motion. The Navier–Stokes equations are solved by using the finite volume method (FVM) in a commercial CFD software, ANSYS Fluent. A set of user-defined functions (UDF) are used for computing viscosity, density, heat source, temperature of moving surfaces and elastic deformation of the top roller according to well-established equations commonly used in the EHL theory. The cavitation problem is solved by taking into account multiphase mixture flow. The model combinations of Houpert and Ree–Eyring and of Tait and Carreau were used for modeling the non-Newtonian behavior of Squalane and the results were compared. Both rheological models suggest the existence of shear-band and plug-flow at high fluid pressure. Due to the differences in viscosity at GPa-level pressure, the chosen model has substantial influence on the computed shear stress and temperature distributions in the high-pressure region. This shows the importance of using correct rheology information in the whole range of pressure, temperature, and shear strain rate.

scholarly journals CFD (Computational Fluid Dynamics) Modeling on Narasena Bengawan UV Team Quickster UAV Wings with Addition of Vortex Generator to Aerodynamic Performance

2021 ◽  
Vol 20 (2) ◽  
pp. 77
Author(s):  
Mohammad Fahmi Luthfi ◽  
Dominicus Danardono ◽  
Eko Budi Prasetya ◽  
Yudi Kurniawan
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Speed ◽  
Lift Coefficient ◽  
Vortex Generator ◽  
Aerodynamic Performance ◽  
Navier Stokes ◽  
Dynamics Modeling ◽  
Ansys Fluent ◽  
Computational Fluid Dynamics Modeling

This research is based on obtaining the best possible aerodynamic performance for the Quickster Narasena Bengawan UV Team UAV aircraft wing design. One of the factors that greatly affects the flying performance of a UAV is the wing. The wing on the Quickster Narasena UAV aircraft uses an MH33 airfoil, because MH33 is specifically for high-speed UAV aircraft. This research will discuss the comparison of the performance of a wing without a vortex generator with a wing with a vortex generator. Variations in the positioning of the vortex generator on the wing of the Quickster Narasena UAV will also be discussed in this study. The method used in this research is the CFD (Computational Fluid Dynamics) method. The simulation process will use the ANSYS Fluent 19.0 application with the K-Omega SST method with the Reynolds-Averaged-Navier-Stokes (RANS) equation as the basis. The purpose of this study is to obtain the results of the coefficient of drag, lift, and the contour of the turbulence that will occur. The simulation results that have been done are the geometry of the wing with the addition of a vortex generator can reduce the drag coefficient and can increase the lift coefficient.

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