Three-Dimensional CFD Simulations of Hydrodynamics for the Lowland Dam Reservoir

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.

Radial Turbine Design for Solar Chimney Power Plants

Energies ◽

10.3390/en14030674 ◽

2021 ◽

Vol 14 (3) ◽

pp. 674

Author(s):

Paul Caicedo ◽

David Wood ◽

Craig Johansen

Keyword(s):

Power Plants ◽

Reference Frames ◽

Three Dimensional ◽

Discrete Ordinates ◽

Large Area ◽

Solar Chimney ◽

Cfd Simulations ◽

Radial Turbine ◽

Design Changes ◽

Turbine Design

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.

Particle diameter prediction in supercritical nanoparticle synthesis using three-dimensional CFD simulations. Validation for anatase titanium dioxide production

Chemical Engineering Science ◽

10.1016/j.ces.2009.03.032 ◽

2009 ◽

Vol 64 (13) ◽

pp. 3051-3059 ◽

Cited By ~ 25

Author(s):

J. Sierra-Pallares ◽

E. Alonso ◽

I. Montequi ◽

M.J. Cocero

Keyword(s):

Titanium Dioxide ◽

Three Dimensional ◽

Particle Diameter ◽

Nanoparticle Synthesis ◽

Cfd Simulations

Contribution of upper airway geometry to convective mixing

Journal of Applied Physiology ◽

10.1152/japplphysiol.90764.2008 ◽

2008 ◽

Vol 105 (6) ◽

pp. 1733-1740 ◽

Cited By ~ 8

Author(s):

Santhosh T. Jayaraju ◽

Manuel Paiva ◽

Mark Brouns ◽

Chris Lacor ◽

Sylvia Verbanck

Keyword(s):

Three Dimensional ◽

Upper Airway ◽

Axial Dispersion ◽

Half Width ◽

Experimental Results ◽

Cfd Simulations ◽

Flow Rates ◽

Axial Dispersion Coefficient ◽

Dispersive Effect ◽

Flow Directions

We investigated the axial dispersive effect of the upper airway structure (comprising mouth cavity, oropharynx, and trachea) on a traversing aerosol bolus. This was done by means of aerosol bolus experiments on a hollow cast of a realistic upper airway model (UAM) and three-dimensional computational fluid dynamics (CFD) simulations in the same UAM geometry. The experiments showed that 50-ml boluses injected into the UAM dispersed to boluses with a half-width ranging from 80 to 90 ml at the UAM exit, across both flow rates (250, 500 ml/s) and both flow directions (inspiration, expiration). These experimental results imply that the net half-width induced by the UAM typically was 69 ml. Comparison of experimental bolus traces with a one-dimensional Gaussian-derived analytical solution resulted in an axial dispersion coefficient of 200–250 cm2/s, depending on whether the bolus peak and its half-width or the bolus tail needed to be fully accounted for. CFD simulations agreed well with experimental results for inspiratory boluses and were compatible with an axial dispersion of 200 cm2/s. However, for expiratory boluses the CFD simulations showed a very tight bolus peak followed by an elongated tail, in sharp contrast to the expiratory bolus experiments. This indicates that CFD methods that are widely used to predict the fate of aerosols in the human upper airway, where flow is transitional, need to be critically assessed, possibly via aerosol bolus simulations. We conclude that, with all its geometric complexity, the upper airway introduces a relatively mild dispersion on a traversing aerosol bolus for normal breathing flow rates in inspiratory and expiratory flow directions.

Numerical Simulation of Emergency Release of Liquid Petroleum Gas on a Car Gas Station

Rocznik Ochrona Środowiska ◽

10.54740/ros.2021.004 ◽

2021 ◽

Vol 23 ◽

pp. 65-77

Author(s):

Zdzislaw Salamonowicz ◽

Malgorzata Majder-Lopatka ◽

Anna Dmochowska ◽

Aleksandra Piechota-Polanczyk ◽

Andrzej Polanczyk

Keyword(s):

Liquid Surface ◽

Atmospheric Stability ◽

Three Dimensional ◽

Three Dimensional Model ◽

Liquid Form ◽

Cfd Simulations ◽

Danger Zone ◽

Liquid Petroleum Gas ◽

Gas Station ◽

Hazardous Zone

LPG storage tanks may be seriously threatened by a fire coming from nearby fuels or by leakage appearance. The aim of the study was to prepare a three-dimensional model of LPG release on a car gas station under different environmental conditions. CFD simulations of liquid and gas phase release from a tank localized on a car gas station was performed. First, ALOHA software was applied to determine mass flow rate, while Ansys software was used to determine the shape and size of hazardous zone. To reflect real condition atmospheric stability classes were applied. It was observed that for classes A-D the hazardous zone was decreasing. While, for E and F class the range was increased. It was noticed that the location of the leakage affects the extent of the danger zone. For the leaking below the liquid surface analyzed LPG has liquid form. While, for the leaking above the liquid surface analyzed LPG has gas form. Furthermore, for liquid leakage the largest hazard zone of release was observed.

Effect of Temperature Nonuniformity on Heat Transfer in an Unshrouded Transonic HP Turbine: An Experimental and Computational Investigation

Volume 4: Heat Transfer, Parts A and B ◽

10.1115/gt2010-22700 ◽

2010 ◽

Cited By ~ 1

Author(s):

Imran Qureshi ◽

Andy D. Smith ◽

Kam S. Chana ◽

Thomas Povey

Keyword(s):

Heat Transfer ◽

Three Dimensional ◽

Aerodynamic Characteristics ◽

Test Facility ◽

Effect Of Temperature ◽

Inlet Temperature ◽

Experimental Measurements ◽

Turbine Stage ◽

Cfd Simulations ◽

Turbine Inlet

Detailed experimental measurements have been performed to understand the effects of turbine inlet temperature distortion (hot-streaks) on the heat transfer and aerodynamic characteristics of a full-scale unshrouded high pressure turbine stage at flow conditions that are representative of those found in a modern gas turbine engine. To investigate hot-streak migration, the experimental measurements are complemented by three-dimensional steady and unsteady CFD simulations of the turbine stage. This paper presents the time-averaged measurements and computational predictions of rotor blade surface and rotor casing heat transfer. Experimental measurements obtained with and without inlet temperature distortion are compared. Time-mean experimental measurements of rotor casing static pressure are also presented. CFD simulations have been conducted using the Rolls-Royce code Hydra, and are compared to the experimental results. The test turbine was the unshrouded MT1 turbine, installed in the Turbine Test Facility (previously called Isentropic Light Piston Facility) at QinetiQ, Farnborough UK. This is a short duration transonic facility, which simulates engine representative M, Re, Tu, N/T and Tg /Tw at the turbine inlet. The facility has recently been upgraded to incorporate an advanced second-generation temperature distortion generator, capable of simulating well-defined, aggressive temperature distortion both in the radial and circumferential directions, at the turbine inlet.

Three-dimensional seismic analysis of concrete gravity dams considering foundation flexibility

Mechanics and Mechanical Engineering ◽

10.2478/mme-2021-0012 ◽

2021 ◽

Vol 25 (1) ◽

pp. 88-98

Author(s):

Mokhtar Messaad ◽

Messoud Bourezane ◽

Mohamed Latrache ◽

Amina Tahar Berrabah ◽

Djamel Ouzendja

Keyword(s):

Young’S Modulus ◽

Seismic Analysis ◽

Young's Modulus ◽

Three Dimensional ◽

Shear Stresses ◽

Total System ◽

Dam Reservoir ◽

Principal Stresses ◽

Foundation Soil ◽

North West

Abstract Concrete dams are considered as complex construction systems that play a major role in the context of both economic and strategic utilities. Taking into account reservoir and foundation presence in modeling the dam-reservoir-foundation interaction phenomenon leads to a more realistic evaluation of the total system behavior. The article discusses the dynamic behavior of dam-reservoir-foundation system under seismic loading using Ansys finite element code. Oued Fodda concrete dam, situated at Chlef, in North-West of Algeria, was chosen as a case study. Parametric study was also performed for different ratios between foundation Young's modulus and dam Young's modulus E f /E d (which varies from 0.5 to 4). Added mass approach was used to model the fluid reservoir. The obtained results indicate that when dam Young's modulus and foundation Young's modulus are equal, the foundation soil leads to less displacements in the dam body and decreases the principal stresses as well as shear stresses.

CFD Simulations of Three-Dimensional Flow in Turbomachinery Applications

Proceedings of the Third International Conference on Engineering Computational Technology ◽

10.4203/ccp.76.35 ◽

2009 ◽

Author(s):

J. Yan ◽

D. Gregory-Smith ◽

A. Karanjkar

Keyword(s):

Three Dimensional ◽

Cfd Simulations ◽

Three Dimensional Flow ◽

Dimensional Flow

Numerical 3-D Conjugated Heat Transfer Simulation of a First Inter-Stage Internal Cooled Thermal Barrier Coated Gas Turbine Bucket

ASME 2007 Power Conference ◽

10.1115/power2007-22041 ◽

2007 ◽

Cited By ~ 1

Author(s):

Alejandro Herna´ndez Rossette ◽

Zdzislaw Mazur C. ◽

Jesu´s Cordero Guridi ◽

Eric Chumacero Polanco

Keyword(s):

Heat Transfer ◽

Gas Turbine ◽

Thermal Loading ◽

Three Dimensional ◽

Navier Stokes ◽

Thermal Barrier ◽

Cfd Simulations ◽

Temperature Changes ◽

Heat Transfer Simulation ◽

Conjugated Heat Transfer

As a gas turbine entry temperature (TET) increases, thermal loading on first stage blades increases too and therefore, a variety of cooling techniques and thermal barrier coatings (TBCs) are used to maintain the blade temperature within the acceptable limits. In this work a multi-block three dimensional Navier-Stokes commercial turbomachinery oriented CFD-code has been used to compute steady state conjugated heat transfer (CHT) on the blade suction and pressure coated sides of a rotating first inter-stage (nozzle and bucket) with cooling holes of a 60 MW Gas turbine. A Spallart Allmaras model was used for modeling the turbulence. Convection and radiation were modeled for a super alloy blade with and without TBC. The CFD simulations were configured with a mesh domain of nozzle and bucket inter-stage in order to predict the fluid parameters at inlet and outlet of bucket for validate with turbine inter-stage parameter data test of gas turbine manufacturer. The effects of blade surface temperature changes were simulated with both configurations coated and uncoated blades.

Transient Air-Water Flow and Air Demand following an Opening Outlet Gate

Modelling and Simulation in Engineering ◽

10.1155/2018/3194935 ◽

2018 ◽

Vol 2018 ◽

pp. 1-12 ◽

Cited By ~ 2

Author(s):

James Yang ◽

Ting Liu ◽

Wenhong Dai ◽

Penghua Teng

Keyword(s):

Water Flow ◽

Hydraulic Jump ◽

Three Dimensional ◽

Cfd Simulations ◽

Wire Ropes ◽

Air Supply ◽

Flow Features ◽

Demand Rate ◽

Air Pockets ◽

Bottom Outlets

In Sweden, the dam-safety guidelines call for an overhaul of many existing bottom outlets. During the opening of an outlet gate, understanding the transient air-water flow is essential for its safe operation, especially under submerged tailwater conditions. Three-dimensional CFD simulations are undertaken to examine air-water flow behaviors at both free and submerged outflows. The gate, hoisted by wire ropes and powered by AC, opens at a constant speed. A mesh is adapted to follow the gate movement. At the free outflow, the CFD simulations and model tests agree well in terms of outlet discharge capacity. Larger air vents lead to more air supply; the increment becomes, however, limited if the vent area is larger than 10 m2. At the submerged outflow, a hydraulic jump builds up in the conduit when the gate reaches approximately 45% of its full opening. The discharge is affected by the tailwater and slightly by the flow with the hydraulic jump. The flow features strong turbulent mixing of air and water, with build-up and break-up of air pockets and collisions of defragmented water bodies. The air demand rate is several times as much as required by steady-state hydraulic jump with free surface.