scholarly journals Temporally and Spatially Resolved Flow in a Two-Stage Axial Compressor: Part 2—Computational Assessment

1991 ◽  
Vol 113 (2) ◽  
pp. 227-232 ◽  
Author(s):  
K. L. Gundy-Burlet ◽  
M. M. Rai ◽  
R. C. Stauter ◽  
R. P. Dring
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Thin Layer ◽  
Axial Compressor ◽  
Unsteady Aerodynamics ◽  
Numerical Data ◽  
Navier Stokes ◽  
Grid Refinement ◽  
Spatially Resolved ◽  
Multistage Compressor

Fluid dynamics of turbomachines are complicated because of aerodynamic interactions between rotors and stators. It is necessary to understand the aerodynamics associated with these interactions in order to design turbomachines that are both light and compact as well as reliable and efficient. The current study uses an unsteady, thin-layer Navier–Stokes zonal approach to investigate the unsteady aerodynamics of a multistage compressor. Relative motion between rotors and stators is made possible by the use of systems of patched and overlaid grids. Results have been computed for a 2 1/2-stage compressor configuration. The numerical data compare well with experimental data for surface pressures and wakes. In addition, the effect of grid refinement on the solution is studied.

scholarly journals Temporally and Spatially Resolved Flow in a Two-Stage Axial Compressor: Part 2 — Computational Assessment

1990 ◽  
Author(s):  
Karen L. Gundy-Burlet ◽  
Man Mohan Rai ◽  
R. Charles Stauter ◽  
Robert P. Dring
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Thin Layer ◽  
Axial Compressor ◽  
Unsteady Aerodynamics ◽  
Numerical Data ◽  
Navier Stokes ◽  
Grid Refinement ◽  
Spatially Resolved ◽  
Multistage Compressor

Fluid dynamics of turbomachines are complicated because of aerodynamic interactions between rotors and Stators. It is necessary to understand the aerodynamics associated with these interactions in order to design turbomachines that are both light and compact as well as reliable and efficient. The current study uses an unsteady, thin-layer Navier-Stokes zonal approach to investigate the unsteady aerodynamics of a multistage compressor. Relative motion between rotors and stators is made possible by the use of systems of patched and overlaid grids. Results have been computed for a 2½-stage compressor configuration. The numerical data compare well with experimental data for surface pressures and wakes. In addition, the effect of grid refinement on the solution is studied.

Temporally and Spatially Resolved Flow in a Two-Stage Axial Compressor: Part 1—Experiment

1991 ◽  
Vol 113 (2) ◽  
pp. 219-225 ◽  
Author(s):  
R. C. Stauter ◽  
R. P. Dring ◽  
F. O. Carta
Keyword(s):  
Fluid Dynamics ◽  
Fluid Dynamic ◽  
Axial Compressor ◽  
Spatial Variations ◽  
Navier Stokes ◽  
Dense Matrix ◽  
Two Stage ◽  
Data Set ◽  
Spatially Resolved ◽  
Interactive Nature

The fluid dynamics of turbomachines are extremely complex, due in part to the aerodynamic interactions between rotors and stators. It is necessary to acquire fluid dynamic data that reflect the interactive nature of a turbomachine to correlate with the fluid dynamics predicted from modern analyses. The temporal and spatial variations in the midspan aerodynamics of the second stage of a two-stage compressor have been studied with a two-component LDV system. Spatial variations were examined by traversing the LDV probe volume through a dense matrix of both axial and circumferential positions, while temporal resolution was achieved by acquiring all data as a function of the instantaneous rotor position. Hence, the data set reveals rotor and stator wake structure and decay in both the stationary and rotating frames of reference. The data also compared very favorably with extensive pneumatic measurements previously acquired in this compressor. In Part 2 of the paper, the data are used in the assessment of a prediction of the flow in the compressor using a time-accurate, thin-layer, two-dimensional Navier–Stokes analysis.

scholarly journals Temporally and Spatially Resolved Flow in a Two-Stage Axial Compressor: Part 1 — Experiment

1990 ◽  
Author(s):  
R. Charles Stauter ◽  
Robert P. Dring ◽  
Franklin O. Carta
Keyword(s):  
Fluid Dynamics ◽  
Fluid Dynamic ◽  
Axial Compressor ◽  
Spatial Variations ◽  
Navier Stokes ◽  
Dense Matrix ◽  
Two Stage ◽  
Data Set ◽  
Spatially Resolved ◽  
Interactive Nature

The fluid dynamics of turbomachines are extremely complex, due in part to the aerodynamic interactions between rotors and Stators. It is necessary to acquire fluid dynamic data that reflect the interactive nature of a turbomachine to correlate with the fluid dynamics predicted from modern analyses. The temporal and spatial variations in the midspan aerodynamics of the second stage of a two-stage compressor have been studied with a two-component LDV system. Spatial variations were examined by traversing the LDV probe volume through a dense matrix of both axial and circumferential positions while temporal resolution was achieved by acquiring all data as a function of the instantaneous rotor position. Hence, the data set reveals rotor and Stator wake structure and decay in both the stationary and rotating frames of reference. The data also compared very favorably with extensive pneumatic measurements previously acquired in this compressor. In Part 2 of the paper, the data are used in the assessment of a prediction of the flow in the compressor using a time-accurate, thin-layer, two-dimensional Navier-Stokes analysis.

scholarly journals Computational Analysis to Factor Wind into the Design of an Architectural Environment

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Hassam Nasarullah Chaudhry ◽  
John Kaiser Calautit ◽  
Ben Richard Hughes
Keyword(s):  
Fluid Dynamics ◽  
Power Generation ◽  
Computational Fluid Dynamics ◽  
Three Dimensional ◽  
Numerical Data ◽  
Navier Stokes ◽  
Windward Side ◽  
Average Value ◽  
Continuity Equations ◽  
Prevailing Wind Direction

The effect of wind distribution on the architectural domain of the Bahrain Trade Centre was numerically analysed using computational fluid dynamics (CFD). Using the numerical data, the power generation potential of the building-integrated wind turbines was determined in response to the prevailing wind direction. The three-dimensional Reynolds-averaged Navier-Stokes (RANS) equations along with the momentum and continuity equations were solved for obtaining the velocity and pressure field. Simulating a reference wind speed of 6 m/s, the findings from the study quantified an estimate power generation of 6.4 kW indicating a capacity factor of 2.9% for the benchmark model. At the windward side of the building, it was observed that the layers of turbulence intensified in inverse proportion to the height of the building with an average value of 0.45 J/kg. The air velocity was found to gradually increase in direct proportion to the elevation with the turbine located at higher altitude receiving maximum exposure to incoming wind. This work highlighted the potential of using advanced computational fluid dynamics in order to factor wind into the design of any architectural environment.

The Effect of Turbulence and Real Gas Models on the Two Phase Spontaneously Condensing Flows in Nozzle

2013 ◽  
Author(s):  
Yogini Patel ◽  
Giteshkumar Patel ◽  
Teemu Turunen-Saaresti
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Nucleation Theory ◽  
Classical Nucleation Theory ◽  
Navier Stokes ◽  
Two Phase ◽  
Real Gas ◽  
Spontaneous Condensation ◽  
Condensing Flows ◽  
Computational Fluid Dynamics Cfd

The aim of the paper is to analyse the effect of turbulence and real gas models on the process of spontaneous condensation in converging diverging (CD) nozzle by using commercial Computational Fluid Dynamics (CFD) code. The calculations were based on the 2-D compressible Navier-Stokes (NS) equations coupled with two-equation turbulence model, and the non-equilibrium spontaneous condensing steam flow was solved on the basis of the classical nucleation theory. The results were validated to the available experimental data.

scholarly journals Three-Dimensional Aerodynamic Analysis of a Darrieus Wind Turbine Blade Using Computational Fluid Dynamics and Lifting Line Theory

2017 ◽  
Author(s):  
Francesco Balduzzi ◽  
Alessandro Bianchini ◽  
Giovanni Ferrara ◽  
David Marten ◽  
George Pechlivanoglou ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Performance ◽  
Three Dimensional ◽  
Unsteady Aerodynamics ◽  
Cost Effective ◽  
Navier Stokes ◽  
Line Theory ◽  
Wake Model ◽  
Lifting Line

Due to the rapid progress in high-performance computing and the availability of increasingly large computational resources, Navier-Stokes computational fluid dynamics (CFD) now offers a cost-effective, versatile and accurate means to improve the understanding of the unsteady aerodynamics of Darrieus wind turbines and deliver more efficient designs. In particular, the possibility of determining a fully resolved flow field past the blades by means of CFD offers the opportunity to both further understand the physics underlying the turbine fluid dynamics and to use this knowledge to validate lower-order models, which can have a wider diffusion in the wind energy sector, particularly for industrial use, in the light of their lower computational burden. In this context, highly spatially and temporally refined time-dependent three-dimensional Navier-Stokes simulations were carried out using more than 16,000 processor cores per simulation on an IBM BG/Q cluster in order to investigate thoroughly the three-dimensional unsteady aerodynamics of a single blade in Darrieus-like motion. Particular attention was payed to tip losses, dynamic stall, and blade/wake interaction. CFD results are compared with those obtained with an open-source code based on the Lifting Line Free Vortex Wake Model (LLFVW). At present, this approach is the most refined method among the “lower-fidelity” models and, as the wake is explicitly resolved in contrast to BEM-based methods, LLFVW analyses provide three-dimensional flow solutions. Extended comparisons between the two approaches are presented and a critical analysis is carried out to identify the benefits and drawbacks of the two approaches.

scholarly journals Three-Dimensional Aerodynamic Analysis of a Darrieus Wind Turbine Blade Using Computational Fluid Dynamics and Lifting Line Theory

2017 ◽  
Vol 140 (2) ◽  
Author(s):  
Francesco Balduzzi ◽  
David Marten ◽  
Alessandro Bianchini ◽  
Jernej Drofelnik ◽  
Lorenzo Ferrari ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Performance ◽  
Three Dimensional ◽  
Unsteady Aerodynamics ◽  
Cost Effective ◽  
Navier Stokes ◽  
Line Theory ◽  
Wake Model ◽  
Lifting Line

Due to the rapid progress in high-performance computing and the availability of increasingly large computational resources, Navier–Stokes (NS) computational fluid dynamics (CFD) now offers a cost-effective, versatile, and accurate means to improve the understanding of the unsteady aerodynamics of Darrieus wind turbines and deliver more efficient designs. In particular, the possibility of determining a fully resolved flow field past the blades by means of CFD offers the opportunity to both further understand the physics underlying the turbine fluid dynamics and to use this knowledge to validate lower-order models, which can have a wider diffusion in the wind energy sector, particularly for industrial use, in the light of their lower computational burden. In this context, highly spatially and temporally refined time-dependent three-dimensional (3D) NS simulations were carried out using more than 16,000 processor cores per simulation on an IBM BG/Q cluster in order to investigate thoroughly the 3D unsteady aerodynamics of a single blade in Darrieus-like motion. Particular attention was paid to tip losses, dynamic stall, and blade/wake interaction. CFD results are compared with those obtained with an open-source code based on the lifting line free vortex wake model (LLFVW). At present, this approach is the most refined method among the “lower-fidelity” models, and as the wake is explicitly resolved in contrast to blade element momentum (BEM)-based methods, LLFVW analyses provide 3D flow solutions. Extended comparisons between the two approaches are presented and a critical analysis is carried out to identify the benefits and drawbacks of the two approaches.

Computational Fluid Dynamics Modeling of Mixed Convection Flows in Building Enclosures

2013 ◽  
Author(s):  
Alexander Kayne ◽  
Ramesh Agarwal
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Mixed Convection ◽  
Turbulence Model ◽  
Numerical Algorithm ◽  
Navier Stokes ◽  
Cfd Simulations ◽  
Flow And Heat Transfer

In recent years Computational Fluid Dynamics (CFD) simulations are increasingly used to model the air circulation and temperature environment inside the rooms of residential and office buildings to gain insight into the relative energy consumptions of various HVAC systems for cooling/heating for climate control and thermal comfort. This requires accurate simulation of turbulent flow and heat transfer for various types of ventilation systems using the Reynolds-Averaged Navier-Stokes (RANS) equations of fluid dynamics. Large Eddy Simulation (LES) or Direct Numerical Simulation (DNS) of Navier-Stokes equations is computationally intensive and expensive for simulations of this kind. As a result, vast majority of CFD simulations employ RANS equations in conjunction with a turbulence model. In order to assess the modeling requirements (mesh, numerical algorithm, turbulence model etc.) for accurate simulations, it is critical to validate the calculations against the experimental data. For this purpose, we use three well known benchmark validation cases, one for natural convection in 2D closed vertical cavity, second for forced convection in a 2D rectangular cavity and the third for mixed convection in a 2D square cavity. The simulations are performed on a number of meshes of different density using a number of turbulence models. It is found that k-epsilon two-equation turbulence model with a second-order algorithm on a reasonable mesh gives the best results. This information is then used to determine the modeling requirements (mesh, numerical algorithm, turbulence model etc.) for flows in 3D enclosures with different ventilation systems. In particular two cases are considered for which the experimental data is available. These cases are (1) air flow and heat transfer in a naturally ventilated room and (2) airflow and temperature distribution in an atrium. Good agreement with the experimental data and computations of other investigators is obtained.

scholarly journals A Comparison of Experimental and Computational Heat Transfer Results for a Leading Edge Impingement System

2018 ◽  
Vol 3 (4) ◽  
pp. 23
Author(s):  
Robert Pearce ◽  
Peter Ireland ◽  
Ed Dane ◽  
Janendra Telisinghe
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Turbine Blades ◽  
Leading Edge ◽  
Reynolds Numbers ◽  
High Heat ◽  
Navier Stokes ◽  
Spatially Resolved ◽  
Computational Fluid Dynamics Simulations ◽  
Dynamics Simulations

Leading edge impingement systems are increasingly being used for high pressure turbine blades in gas turbine engines, in regions where very high heat loads are encountered. The flow structure in such systems can be very complex and high resolution experimental data is required for engine-realistic systems to enable code validation and optimal design. This paper presents spatially resolved heat transfer distributions for an engine-realistic impingement system for multiple different hole geometries, with jet Reynolds numbers in the range of 13,000–22,000. Following this, Reynolds-averaged Navier-Stokes computational fluid dynamics simulations are compared to the experimental data. The experimental results show variation in heat transfer distributions for different geometries, however average levels are primarily dependent on jet Reynolds number. The computational simulations match the shape of the distributions well however with a consistent over-prediction of around 10% in heat transfer levels.

Design of a rotor blade tip for the investigation of dynamic stall in the transonic wind-tunnel Göttingen

2016 ◽  
Vol 120 (1232) ◽  
pp. 1509-1533 ◽  
Author(s):  
B. Lütke ◽  
J. Nuhn ◽  
Y. Govers ◽  
M. Schmidt
Keyword(s):  
Experimental Data ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Numerical Data ◽  
Dynamic Stall ◽  
Navier Stokes ◽  
Fe Model ◽  
Stress Distributions ◽  
Cfd Simulations ◽  
Blade Tip

ABSTRACTThe aerodynamic and structural design of a pitching blade tip with a double-swept planform is presented. The authors demonstrate how high-fidelity finite element (FE) and computational fluid dynamic (CFD) simulations are successfully used in the design phase. Eigenfrequencies, deformation, and stress distributions are evaluated by means of a three-dimensional (3D) FE model. Unsteady Reynolds-averaged Navier-Stokes (RANS) simulations are compared to experimental data for a light dynamic stall case atMa= 0.5,Re= 1.2 × 106. The results show a very good agreement as long as the flow stays attached. Tendencies for the span-wise location of separation are captured. As soon as separation sets in, discrepancies between experimental and numerical data are observed. The experimental data show that for light dynamic stall cases atMa= 0.5, a factor of safety ofFoS= 2.0 is sufficient if the presented simulation methods are used.

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