A Numerical and Experimental Investigation of Low-conductivity Unglazed, Transpired Solar Air Heaters

2005 ◽  
Vol 127 (1) ◽  
pp. 153-155 ◽  
Author(s):  
Keith Gawlik ◽  
Craig Christensen ◽  
Charles Kutscher
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Experimental Investigation ◽  
Experimental Work ◽  
Experimental Results ◽  
Flow Conditions ◽  
Numerical Work ◽  
Plate Geometry ◽  
Modeling Flow ◽  
Good Agreement

The performance of low-conductivity unglazed, transpired solar collectors was determined numerically and experimentally. The numerical work consisted of modeling flow conditions, plate geometries, and plate conductivities with modified commercial computational fluid dynamics software, and the experimental work compared the performance of two plate geometries made with high and low conductivity materials under a variety of flow conditions. Good agreement was found between the numerical and experimental results. The results showed that for practical low-conductivity materials, performance differed little from the equivalent plate geometry in high-conductivity material.

A Numerical and Experimental Investigation of Low-Conductivity Unglazed, Transpired Solar Air Heaters

Solar Energy ◽  
2002 ◽  
Author(s):  
Keith M. Gawlik ◽  
Charles F. Kutscher
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Experimental Investigation ◽  
Renewable Energy ◽  
Experimental Work ◽  
National Renewable Energy Laboratory ◽  
Laboratory Apparatus ◽  
Flow Conditions ◽  
Numerical Work ◽  
Good Agreement

The performance of low-conductivity unglazed, transpired solar collectors was determined numerically and experimentally. The numerical work consisted of modelling flow conditions and plate geometries with the FLUENT computational fluid dynamics software and the experimental work utilized laboratory apparatus at the National Renewable Energy Laboratory. Good agreement was found between the numerical and experimental results. The results showed that for practical low-conductivity materials, performance differed little from the equivalent geometry in high-conductivity material.

scholarly journals Rotary Wheel Atomizer Study Using Computational Fluid Dynamics and Full-Scale Testing

2018 ◽  
Author(s):  
Frank Vinther ◽  
Tórstein Vincent Joensen ◽  
Maximilian Kuhnhenn ◽  
Mads Reck ◽  
Cameron Tropea
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Fluid Flow ◽  
Drop Size ◽  
Volume Of Fluid ◽  
Experimental Results ◽  
Atomization Process ◽  
Internal Fluid ◽  
Internal Fluid Flow ◽  
Good Agreement

This study models the internal fluid flow from the center to the edge of a rotary atomizer wheel, the flow out of the atomizer, including the film, rivulet and ligament formation, as well as the subsequent atomization process associated with the atomizer outflow using computational fluid dynamics with a volume of fluid approach. The model shows how fluid exits through the overflow and not through the bushing at high inlet fluxes and can reproduce experimental results of power consumption. Furthermore, the drop-size distribution at a given distance from the bushing exit is in good agreement with experimental results. Keywords: Spray drying; Rotary Atomizer; CFD; Droplet size; Volume of Fluid.

scholarly journals Aerodynamic Study of a Tricycle Wheel Subsystem for Drag Reduction

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Thomas Driant ◽  
Lakhdar Remaki ◽  
Hachimi Fellouah ◽  
Stéphane Moreau ◽  
Alain Desrochers
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Tunnel ◽  
Drag Reduction ◽  
Numerical Simulations ◽  
Experimental Results ◽  
Flow Conditions ◽  
Commercial Code ◽  
Computational Fluid Dynamics Cfd ◽  
Drag Analysis

This paper deals with a computational fluid dynamics (CFD) and experimental drag analysis on an isolated rotating wheel subsystem (including its accessories: tire, suspension, A-arms, and fender) of a motor tricycle vehicle with two wheels in front. The main goal of the present work is to study the effect of the fender on the wheel subsystem drag and its optimization. The Star CCM+ commercial code was used for the numerical simulations. Different flow conditions were simulated and some results were validated by comparison to wind tunnel experimental results. To perform drag optimization, several aerodynamic fender shapes were designed and simulated as part of the subsystem. A drastic drag reduction up to 30.6% compared to the original wheel subsystem was achieved through numerical simulations.

The Effect of Different Turbulence Models on the Emitter Discharge by Using Computational Fluid Dynamics

2013 ◽  
Vol 662 ◽  
pp. 586-590
Author(s):  
Gang Lu ◽  
Qing Song Yan ◽  
Bai Ping Lu ◽  
Shuai Xu ◽  
Kang Li
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Field ◽  
Turbulence Models ◽  
Experimental Results ◽  
Turbulent Model ◽  
Simulation Results ◽  
Rsm Model ◽  
Dynamics Method ◽  
Emitter Discharge

Four types of Super Typhoon drip emitter with trapezoidal channel were selected out for the investigation of the flow field of the channel, and the CFD (Computational Fluid Dynamics) method was applied to simulate the micro-field inside the channel. The simulation results showed that the emitter discharge of different turbulent model is 4%-14% bigger than that of the experimental results, the average discharge deviation of κ-ω and RSM model is 5, 4.5 respectively, but the solving efficiency of the κ-ω model is obviously higher than that of the RSM model.

scholarly journals Theoretical Analysis of Brush Seals Leakage Using Local Computational Fluid Dynamics Estimated Permeability Laws

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
Lilas Deville ◽  
Mihai Arghir
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Reynolds Number ◽  
Principal Direction ◽  
Experimental Results ◽  
Leakage Flow ◽  
Cfd Analysis ◽  
Brush Seal ◽  
Brush Seals ◽  
Local Reynolds Number

Brush seals are a mature technology that has generated extensive experimental and theoretical work. Theoretical models range from simple correlations with experimental results to advanced numerical approaches coupling the bristles deformation with the flow in the brush. The present work follows this latter path. The bristles of the brush are deformed by the pressure applied by the flow, by the interference with the rotor and with the back plate. The bristles are modeled as linear beams but a nonlinear numerical algorithm deals with the interferences. The brush with its deformed bristles is then considered as an anisotropic porous medium for the leakage flow. Taking into account, the variation of the permeability with the local geometric and flow conditions represents the originality of the present work. The permeability following the principal directions of the bristles is estimated from computational fluid dynamics (CFD) calculations. A representative number of bristles are selected for each principal direction and the CFD analysis domain is delimited by periodicity and symmetry boundary conditions. The parameters of the CFD analysis are the local Reynolds number and the local porosity estimated from the distance between the bristles. The variations of the permeability are thus deduced for each principal direction and for Reynolds numbers and porosities characteristic for brush seal. The leakage flow rates predicted by the present approach are compared with experimental results from the literature. The results depict also the variations of the pressures, of the local Reynolds number, of the permeability, and of the porosity through the entire brush seal.

scholarly journals CFD Study on Impeller Effect on Mixing in Miniature Stirred Tank Reactor

CFD letters ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 15-26
Author(s):  
Adnan Ghulam Mustafa ◽  
Mohd Fadhil Majnis ◽  
Nor Azyati Abdul Muttalib
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Calcium Alginate ◽  
Alginate Beads ◽  
Experimental Results ◽  
Stirred Tank ◽  
Stirred Tank Reactor ◽  
Calcium Alginate Beads ◽  
Tank Reactor ◽  
Simulation Results

Mixing of fluid can happen in existence or absence of impeller which will affect the mixing performance. The hydrodynamics behavior of fluid has a strong effect on the mixing. The design of mixing systems and operation using the agitated tanks is complicated because it is difficult to obtain accurate information for turbulence’s impeller induced. Computational Fluid Dynamics can be used to provide a detailed comprehension of those systems. This paper describes the effect of various designs of impeller in miniature stirred tank reactor towards the mixing of the calcium alginate beads with the milk using Computational Fluid Dynamics (CFD) software, ANSYS Fluent 19.2. The four different type of impellers are edge beater, 5-turbine blade, t-shape, and paddle. The impeller was simulated at different speeds of 150 rpm, 250 rpm, and 300 rpm. K-epsilon turbulence model was employed to simulate the flow distribution pattern of calcium alginate beads and the Multiple Reference Frame approach was used for the impeller rotation’s simulation. The simulation results obtained have a good agreement with the experimental results in term of vortex formation. The simulation results obtained for contour plots were fitted well with the experimental results as well as with pattern of impeller flow which was also studied. As a result, an optimal design of the impeller that is able to produce good mixing can be achieved using CFD analysis. The results obtained after performing the simulation proved that edge beater blade outperformed the other impellers and took the least time to fully distribute the calcium alginate beads in the tank at 250 rpm compared to 150 and 300 rpm. It can also be concluded that the edge beater blade is the best for the mixing of two-phase fluid and also produces mixed pattern flow. The obtained results from CFD can also be used to scale up the mixing process in larger systems.

scholarly journals Comparison of Blade Element Method and CFD Simulations of a 10 MW Wind Turbine

Fluids ◽  
2018 ◽  
Vol 3 (4) ◽  
pp. 73 ◽  
Author(s):  
Galih Bangga
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Separation ◽  
Spatial Interpolation ◽  
Flow Conditions ◽  
Cfd Simulations ◽  
Computational Fluid Dynamics Cfd ◽  
Correction Terms ◽  
Selection Of ◽  
Blade Element

The present studies deliver the computational investigations of a 10 MW turbine with a diameter of 205.8 m developed within the framework of the AVATAR (Advanced Aerodynamic Tools for Large Rotors) project. The simulations were carried out using two methods with different fidelity levels, namely the computational fluid dynamics (CFD) and blade element and momentum (BEM) approaches. For this purpose, a new BEM code namely B-GO was developed employing several correction terms and three different polar and spatial interpolation options. Several flow conditions were considered in the simulations, ranging from the design condition to the off-design condition where massive flow separation takes place, challenging the validity of the BEM approach. An excellent agreement is obtained between the BEM computations and the 3D CFD results for all blade regions, even when massive flow separation occurs on the blade inboard area. The results demonstrate that the selection of the polar data can influence the accuracy of the BEM results significantly, where the 3D polar datasets extracted from the CFD simulations are considered the best. The BEM prediction depends on the interpolation order and the blade segment discretization.

scholarly journals Performance prediction of loop-type wind turbine

2020 ◽  
Vol 12 (2) ◽  
pp. 168781401984047
Author(s):  
Wonyoung Jeon ◽  
Jeanho Park ◽  
Seungro Lee ◽  
Youngguan Jung ◽  
Yeesock Kim ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Tunnel ◽  
Wind Turbine ◽  
Experimental Results ◽  
Scale Model ◽  
Dynamics Analysis ◽  
Blockage Ratio ◽  
Horizontal Axis Wind Turbine ◽  
Computational Fluid Dynamics Analysis

An experimental and analytical method to evaluate the performance of a loop-type wind turbine generator is presented. The loop-type wind turbine is a horizontal axis wind turbine with a different shaped blade. A computational fluid dynamics analysis and experimental studies were conducted in this study to validate the performance of the computational fluid dynamics method, when compared with the experimental results obtained for a 1/15 scale model of a 3 kW wind turbine. Furthermore, the performance of a full sized wind turbine is predicted. The computational fluid dynamics analysis revealed a sufficiently large magnitude of external flow field, indicating that no factor influences the flow other than the turbine. However, the experimental results indicated that the wall surface of the wind tunnel significantly affects the flow, due to the limited cross-sectional size of the wind tunnel used in the tunnel test. The turbine power is overestimated when the blockage ratio is high; thus, the results must be corrected by defining the appropriate blockage factor (the factor that corrects the blockage ratio). The turbine performance was corrected using the Bahaj method. The simulation results showed good agreement with the experimental results. The performance of an actual 3 kW wind turbine was also predicted by computational fluid dynamics.

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