Radial Turbine Design for Solar Chimney Power Plants

Solar chimney power plants (SCPPs) collect air heated over a large area on the ground and exhaust it through a turbine or turbines located near the base of a tall chimney to produce renewable electricity. SCPP design in practice is likely to be specific to the site and of variable size, both of which require a purpose-built turbine. If SCPP turbines cannot be mass produced, unlike wind turbines, for example, they should be as cheap as possible to manufacture as their design changes. It is argued that a radial inflow turbine with blades made from metal sheets, or similar material, is likely to achieve this objective. This turbine type has not previously been considered for SCPPs. This article presents the design of a radial turbine to be placed hypothetically at the bottom of the Manzanares SCPP, the only large prototype to be built. Three-dimensional computational fluid dynamics (CFD) simulations were used to assess the turbine’s performance when installed in the SCPP. Multiple reference frames with the renormalization group k-ε turbulence model, and a discrete ordinates non-gray radiation model were used in the CFD simulations. Three radial turbines were designed and simulated. The largest power output was 77.7 kW at a shaft speed of 15 rpm for a solar radiation of 850 W/m2 which exceeds by more than 40 kW the original axial turbine used in Manzanares. Further, the efficiency of this turbine matches the highest efficiency of competing turbine designs in the literature.

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Solar Chimney Power Plant Performance for Different Seasons Under Varying Solar Irradiance and Temperature Distribution

Journal of Energy Resources Technology ◽

10.1115/1.4048533 ◽

2020 ◽

Vol 143 (6) ◽

Author(s):

Ulku Ece Ayli ◽

Ekin Özgirgin ◽

Maısarh Tareq

Keyword(s):

Solar Radiation ◽

Solar Energy ◽

Ambient Temperature ◽

Solar Irradiance ◽

Power Plants ◽

Low Cost ◽

Renewable Energy Sources ◽

Three Dimensional ◽

Plant Performance ◽

Solar Chimney

Abstract One of the most promising renewable energy sources is solar energy due to low cost and low harmful emissions, and from the 1980s, one of the most beneficial applications of solar energy is the utilization of solar chimney power plants (SCPP). Recently, with the advancement in computer technology, the use of computational fluid dynamics (CFD) methodology for studying SCPP has become an extensive, robust, and powerful technique. In light of the above, in this study, numerical simulations of an SCPP through three-dimensional axisymmetric modeling is performed. A numerical model is created using CFD software, and the results are verified with an experimental study from the literature. The amount of solar radiation and surrounding weather (ambient temperature) were analyzed, and the effects of the irradiance and air temperature on the output power of the SCPP were studied. Ambient temperature is considered as one of the most important factors that influence collector efficiency in a negative or a positive manner. Solar irradiance is considered to be the most important factor that has an impact on SCPP performance. The investigation includes the study of the relationship between solar insolation and ambient temperatures during the daytime since the difference between the minimum and maximum power values and the performance are very important considering seasonal changes. According to the results, power values are dependent on the amount of solar radiation as well as the ambient temperature, and the importance of selection of location thus climate for an SCPP is found to affect the design of the SCPP.

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Transient CFD Visualization of Fossil Fuel Combustion Simulations

Volume 2: Symposia, Parts A, B, and C ◽

10.1115/fedsm2003-45197 ◽

2003 ◽

Author(s):

Brian Dotson ◽

Kent Eshenberg ◽

Chris Guenther ◽

Thomas O’Brien

Keyword(s):

Power Plants ◽

High Efficiency ◽

Cfd Simulation ◽

Low Cost ◽

Three Dimensional ◽

Cfd Simulations ◽

Projection System ◽

Computational Fluid Dynamics Cfd ◽

High Level ◽

Wall System

The design of high-efficiency lower-emission coal-fed power plants is facilitated by the extensive use of computational fluid dynamics (CFD) simulations. This paper describes work conducted at the National Energy Technology Laboratory (NETL) and Pittsburgh Supercomputing Center (PSC) to provide an environment for the immersive three-dimensional visualization of CFD simulation results. A low-cost high-resolution projection system has been developed in the visualization lab at NETL. This multi-wall system consists of four projection screens, three of which are tiled into four quadrants. The graphics for the multi-wall system are rendered using a cluster of eight personal computers. A high-level visualization interface named Mavis has also been developed to combine the powerful 3D modules of OpenDX with methods developed at NETL for studying multiphase CFD data. With Python, a completely new OpenDX user interface was built that extends and simplifies the features of a basic graphics library.

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A Comparative Study on the Performance of a Horizontal Axis Ocean Current Turbine Considering Deflector and Operating Depths

Sustainability ◽

10.3390/su12083333 ◽

2020 ◽

Vol 12 (8) ◽

pp. 3333

Author(s):

Nauman Riyaz Maldar ◽

Cheng Yee Ng ◽

Lee Woen Ean ◽

Elif Oguz ◽

Ahmad Fitriadhy ◽

...

Keyword(s):

Fluid Pressure ◽

Three Dimensional ◽

Horizontal Axis ◽

Ocean Current ◽

Power Coefficient ◽

Cfd Simulations ◽

Torque Coefficient ◽

Computational Fluid Dynamics Cfd ◽

Turbine Design ◽

Current Turbine

Several different designs and prototypes of ocean current turbines have been tested over recent years. For every design test, emphasis is given to achieving an optimum power output from the flow. In this study, the performance of a Horizontal Axis Ocean Current Turbine (HAOCT) has been investigated using three-dimensional Computational Fluid Dynamics (CFD) simulations for three cases, namely, (1) a turbine without a deflector, (2) a turbine with a deflector, and (3) a turbine with a deflector operating at a higher fluid depth. The turbine design was modeled in DesignModeler software and simulations were carried out in commercial CFD software Flow-3D. The Torque Coefficient (Cm) and Power Coefficient (Cp) for the turbine have been investigated for a certain range of Tip-Speed Ratios (TSRs) in a flow velocity of 0.7 m/s. Furthermore, comparisons have been made to demonstrate the effect of the deflector on the performance of the turbine and the influence of a higher fluid pressure on the same. The results from the simulations indicate that the higher value of Cp was achieved for Case 2 as compared to the other two cases. The findings from the study indicate that the use of the deflector enhances the performance of the turbine. Furthermore, a higher fluid pressure acting on the turbine has a significant effect on its performance.

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Impacts of Ground Slope on Main Performance Figures of Solar Chimney Power Plants: A Comprehensive CFD Research with Experimental Validation

International Journal of Photoenergy ◽

10.1155/2021/6612222 ◽

2021 ◽

Vol 2021 ◽

pp. 1-11

Author(s):

Erdem Cuce ◽

Pinar Mert Cuce ◽

Harun Sen ◽

K. Sudhakar ◽

Umberto Berardi ◽

...

Keyword(s):

Power Output ◽

Pilot Plant ◽

Power Plants ◽

Electrical Power ◽

Maximum Velocity ◽

Discrete Ordinates ◽

Solar Chimney ◽

Reference Case ◽

Sloping Ground ◽

Ground Slope

Geometric parameters in solar chimney power plants are numerically optimised for the purpose of better power output figures. Several parameters have been investigated in the pilot plant such as chimney height and diameter, collector diameter and slope, and slenderness. However, ground slope has not been studied to date despite its perspicuous impact on turbulent flow. In this study, the impacts of the different slope angles of the ground, where the solar radiation is absorbed through the collector, on the main performance parameters of the system are numerically analysed through a reliable CFD software ANSYS FLUENT. By considering the actual geometric figures of the pilot plant, a 3D model is constructed through DO (discrete ordinates) solar ray tracing algorithm and RNG k-ε turbulence model. For the solar intensity of 1000 W/m2, the maximum velocity inside the system is found to be 14.2 m/s, which is in good accordance with the experimental data of 15.0 m/s. Starting from 5 m inside the collector, the chimney inlet heights are reconfigured 0.209, 0.419, 0.625, 0.838, and 1.04 m, respectively, and when the ground slope is 0.1, 0.2, 0.3, 0.4, and 0.5°, the changes in the performance output of the system are investigated. For the reference case which refers to the horizontal ground, the maximum air velocity is determined to be 14.2 m/s and the power output is 54.3 kW. However, when the ground slope is made 0.5°, it is observed that the maximum velocity increases by 37% to 19.51 m/s, and the power output is enhanced to 63.95 kW with a rise of 17.7%. Sloping ground is found a key solution to improve the turbulent effects inside the plant, thus to enhance the electrical power output.

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The Radial Turbine, for Low Specific Speeds and Low Velocity Factors

Journal of Engineering for Power ◽

10.1115/1.3673108 ◽

1961 ◽

Vol 83 (1) ◽

pp. 1-8 ◽

Cited By ~ 3

Author(s):

E. M. Knoernschild

Keyword(s):

Three Dimensional ◽

Efficiency Improvement ◽

Low Velocity ◽

Blade Loading ◽

Turbine Performance ◽

Radial Turbine ◽

Low Specific Speed ◽

Specific Speed ◽

Turbine Design ◽

Radial Turbines

The main factors which influence radial-turbine performance are discussed. After a short description of the losses in radial turbines, the concept of the diffusion parameter is introduced. It is shown how the turbine geometry influences performance and, in particular, the reaction. The influence of a variation of the reaction on performance of radial turbines with high and low specific speed is discussed. Three-dimensional effects appear especially in the exducer region of the turbine. They may contribute to backflow and to a distorted distribution of the meridional velocity. The basic approach to improving turbines in the range of low-velocity factors and low specific speed is indicated. It appears that an attempt to reach impulse conditions in radial turbines is difficult, and only a rather small efficiency improvement can be expected. The approach to be taken in adapting a turbine design to low-specific-speed operation is pointed out, and the deterioration of the blade loading pattern due to such a reduction of the specific speed is shown.

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Three-dimensional CFD analysis for simulating the greenhouse effect in solar chimney power plants using a two-band radiation model

Renewable Energy ◽

10.1016/j.renene.2013.10.011 ◽

2014 ◽

Vol 63 ◽

pp. 498-506 ◽

Cited By ~ 52

Author(s):

Ehsan Gholamalizadeh ◽

Man-Hoe Kim

Keyword(s):

Greenhouse Effect ◽

Power Plants ◽

Three Dimensional ◽

Cfd Analysis ◽

Solar Chimney ◽

Radiation Model

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Mastering of NIL Stamps with Undercut T-Shaped Features from Single Layer to Multilayer Stamps

Nanomaterials ◽

10.3390/nano11040956 ◽

2021 ◽

Vol 11 (4) ◽

pp. 956

Author(s):

Philipp Taus ◽

Adrian Prinz ◽

Heinz D. Wanzenboeck ◽

Patrick Schuller ◽

Anton Tsenov ◽

...

Keyword(s):

Electron Beam Lithography ◽

Nanoimprint Lithography ◽

Silicon Oxide ◽

Three Dimensional ◽

Single Layer ◽

Fabrication Technology ◽

Large Area ◽

Structural Colors ◽

Biomimetic Structures ◽

Morpho Butterfly

Biomimetic structures such as structural colors demand a fabrication technology of complex three-dimensional nanostructures on large areas. Nanoimprint lithography (NIL) is capable of large area replication of three-dimensional structures, but the master stamp fabrication is often a bottleneck. We have demonstrated different approaches allowing for the generation of sophisticated undercut T-shaped masters for NIL replication. With a layer-stack of phase transition material (PTM) on poly-Si, we have demonstrated the successful fabrication of a single layer undercut T-shaped structure. With a multilayer-stack of silicon oxide on silicon, we have shown the successful fabrication of a multilayer undercut T-shaped structures. For patterning optical lithography, electron beam lithography and nanoimprint lithography have been compared and have yielded structures from 10 µm down to 300 nm. The multilayer undercut T-shaped structures closely resemble the geometry of the surface of a Morpho butterfly, and may be used in future to replicate structural colors on artificial surfaces.

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Performance enhancement of Savonius wind turbine by blade shape and twisted angle modifications

Proceedings of the Institution of Mechanical Engineers Part A Journal of Power and Energy ◽

10.1177/0957650920987942 ◽

2021 ◽

pp. 095765092098794

Author(s):

Ahmed M Nagib Elmekawy ◽

Hassan A Hassan Saeed ◽

Sadek Z Kassab

Keyword(s):

Wind Turbine ◽

Performance Enhancement ◽

Three Dimensional ◽

Turbulence Models ◽

Vertical Axis ◽

Cfd Simulations ◽

Sliding Mesh ◽

Blade Shape ◽

Rotor Shape ◽

Twisting Angle

Three-dimensional CFD simulations are carried out to study the increase of power generated from Savonius vertical axis wind turbines by modifying the blade shape and blade angel of twist. Twisting angle of the classical blade are varied and several proposed novel blade shapes are introduced to enhance the performance of the wind turbine. CFD simulations have been performed using sliding mesh technique of ANSYS software. Four turbulence models; realizable k -[Formula: see text], standard k - [Formula: see text], SST transition and SST k -[Formula: see text] are utilized in the simulations. The blade twisting angle has been modified for the proposed dimensions and wind speed. The introduced novel blade increased the power generated compared to the classical shapes. The two proposed novel blades achieved better power coefficients. One of the proposed models achieved an increase of 31% and the other one achieved 32.2% when compared to the classical rotor shape. The optimum twist angel for the two proposed models achieved 5.66% and 5.69% when compared with zero angle of twist.

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