Comparison of Two-Dimensional and Three-Dimensional Turbine Airfoils in Combination With Nonaxisymmetric Endwall Contouring

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Tobias W. Zimmermann ◽  
Oliver Curkovic ◽  
Manfred Wirsum ◽  
Andrew Fowler ◽  
Kush Patel
Keyword(s):  
Three Dimensional ◽  
Cfd Simulations ◽  
Positive Effects ◽  
Beneficial Impact ◽  
Flow Phenomena ◽  
Computational Fluid Dynamics Cfd ◽  
Endwall Contouring ◽  
Turbine Airfoils ◽  
End Wall ◽  
Constant Section

Tangential endwall contouring (TEWC) is intended to improve the turbomachinery blading efficiency. This paper summarizes the experimental and numerical investigation of a test turbine with endwall contoured vanes and blades. Constant section (2D) airfoils as well as optimized compound lean (3D) high pressure steam turbine blading in baseline and endwall contoured configurations have been examined. Brush seals (BSs) are implemented within the casing sided cavities to minimize the leakage flow near the tip endwalls, where the contouring is also applied. The pressure and temperature data that are recorded in three axial measuring planes are plotted to visualize the change in flow structure. This shows that the efficiency is increased for 2D airfoils by means of endwall contouring. However, the efficiency of the first stage suffers, and the endwall contouring is still beneficial for the overall performance of the engine. Both phenomena (an efficiency loss in stage one and an improvement of the performance in stage two) have also been measured for the optimized 3D configurations; thus, it can be expected that the endwall contouring has also a beneficial impact on the performance of multirow turbines. The numerical investigations demonstrate in detail, how the secondary flow phenomena are influenced by end-wall contouring and a description of the changes in vortex formations as well as blade loading are given for the various configurations. It has been found that for steady computational fluid dynamics (CFD) simulations the use of stage interfaces suppresses the positive effects of the endwall contour onto the downstream blade row.

Comparison of 2D and 3D Airfoils in Combination With Non Axisymmetric End Wall Contouring: Part 1 — Experimental Investigations

2016 ◽  
Author(s):  
Tobias W. Zimmermann ◽  
Oliver Curkovic ◽  
Manfred Wirsum ◽  
Andrew Fowler ◽  
Kush Patel
Keyword(s):  
Gas Turbines ◽  
Experimental Investigations ◽  
Test Rig ◽  
Second Stage ◽  
Beneficial Impact ◽  
Flow Phenomena ◽  
2D And 3D ◽  
End Wall ◽  
Constant Section ◽  
Turbine Blading

Tangential end wall contouring is intended to improve turbomachinery blading efficiency. This paper is the first of a series of two papers. It summarizes the experimental investigation of a test turbine with end wall contoured vanes and blades. Constant section airfoils as well as optimized 3D high pressure steam turbine blading in baseline and end wall contoured configurations have been examined in a 2 stage axial turbine test rig at the Institute of Power Plant Technology, Steam and Gas Turbines (IKDG) of RWTH Aachen University. The test rig is driven with air. Brush seals are implemented within the casing sided cavities to minimize the leakage flow near the tip end walls, where the contouring is also applied. The pressure and temperature data that is recorded in three axial measuring planes are plotted to visualize the change in flow structure. This has shown that the efficiency is increased for 2D airfoils by means of end wall contouring, which is caused by a homogenized inflow to the second stage. However the efficiency of the first stage suffers, the end wall contouring is beneficial for the performance of the engine. Both phenomena (an efficiency loss in stage one and an improvement of the performance in stage two) have also been measured for the optimized 3D configurations thus it can be expected that end wall contouring has also a beneficial impact on the performance of multi row turbines. The second part of this paper presents the results of numerical investigations of end-wall contoured blades. It will demonstrate how the secondary flow phenomena are influenced by end-wall contours. The simulations are validated with measured data from the test rig.

Turbine Airfoil Heat Transfer Predictions Using CFD

2005 ◽  
Author(s):  
Anil K. Tolpadi ◽  
James A. Tallman ◽  
Lamyaa El-Gabry
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Turbulence Modeling ◽  
Three Dimensional ◽  
Numerical Approach ◽  
Navier Stokes ◽  
Design System ◽  
Computational Fluid Dynamics Cfd ◽  
Turbine Airfoils ◽  
Typical Design

Conventional heat transfer design methods for turbine airfoils use 2-D boundary layer codes (BLC) combined with empiricism. While such methods may be applicable in the mid span of an airfoil, they would not be very accurate near the end-walls and airfoil tip where the flow is very three-dimensional (3-D) and complex. In order to obtain accurate heat transfer predictions along the entire span of a turbine airfoil, 3-D computational fluid dynamics (CFD) must be used. This paper describes the development of a CFD based design system to make heat transfer predictions. A 3-D, compressible, Reynolds-averaged Navier-Stokes CFD solver with k-ω turbulence modeling was used. A wall integration approach was used for boundary layer prediction. First, the numerical approach was validated against a series of fundamental airfoil cases with available data. The comparisons were very favorable. Subsequently, it was applied to a real engine airfoil at typical design conditions. A discussion of the features of the airfoil heat transfer distribution is included.

A Systematical Study of the Influence of Blade Number on the Performance of a Side Channel Pump

2019 ◽  
Vol 141 (11) ◽  
Author(s):  
Annika Fleder ◽  
Martin Böhle
Keyword(s):  
Experimental Studies ◽  
Numerical Results ◽  
Channel Height ◽  
Side Channel ◽  
Outer Diameter ◽  
Cfd Simulations ◽  
Blade Number ◽  
Performance Curves ◽  
Flow Phenomena ◽  
Computational Fluid Dynamics Cfd

For side channel machines, distinction is made between side channel pumps and peripheral pumps. The blade number of side channel machines has a large influence on the performance of the pump. This is known from several experimental studies. For industrial side channel pumps, the blade number is between 20 and 26, whereas for industrial peripheral pumps, the blade number is much larger (between 36 and 90). In this paper, the influence of the blade number on the performance and the inner flow phenomena of different pumps will be investigated experimentally and numerically. The inner flow of the pump is examined in detail by computational fluid dynamics (CFD) simulations. Flow angles and velocities of the circulation flow between side channel and impeller are considered for different blade numbers. To explain the influences of the blade number, numerical results and theoretical formulas are combined. The experiments are carried out for two different modular side channel pump units, which differ in the side channel height h, the outer impeller diameter da, and the length of the blades l. So, the influence of the blade number can be studied in the context of other parameters like, for example, the relation between blade length and outer diameter of the pump. The obtained numerical results are compared with experimental data. Effects of the blade number on the performance curves of the pumps are shown by experimental and numerical results.

Transient CFD Visualization of Fossil Fuel Combustion Simulations

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.

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

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.

Design of Curved Annular Diffusers

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
Vinayender Kuchana ◽  
N. Balakrishnan ◽  
Balamurugan Srinivasan
Keyword(s):  
Design Space ◽  
Pressure Gradients ◽  
Cfd Simulations ◽  
Maximum Slope ◽  
Pressure Fields ◽  
Annular Diffuser ◽  
Computational Fluid Dynamics Cfd ◽  
Curvature Distribution ◽  
Automated Optimization ◽  
End Wall

Abstract Influence of curvature distribution and area-ratio (AR) distribution on the pressure fields within the curved annular diffuser are discussed. General guidelines for end-wall contouring to control the pressure gradients on the diffuser walls are evolved and further demonstrated through computational fluid dynamics (CFD) simulations. Also, detailed guidelines for controlling the adverse pressure gradients (APG) on duct walls are presented. A geometry generation methodology (GGM) which enables both design and evaluation of curved annular diffusers based on the guidelines evolved is presented. The approach presented deals with the sensitivity of the duct performance parameters to duct wall modifications. In that sense, the work per se is not a description of an automated optimization process, but rather about the physical principles that can guide such an optimization. An aggressive diffuser design space is identified with ducts of maximum slope of 50 deg and maximum divergence angle between the outer and inner walls of 10 deg for length to inlet height ratio ranging from 1.25 to 2.5. Part of the identified design space for which the flow separation can be eliminated based on the guidelines evolved is demarcated. The need for flow control, possibly passive, is established for more aggressive designs.

Simulation of Spray Cooling in a Desublimer

2000 ◽  
Author(s):  
Malcolm J. Andrews ◽  
David Zwick
Keyword(s):  
Drop Size ◽  
Three Dimensional ◽  
Spray Cooling ◽  
Cfd Modeling ◽  
Lagrangian Description ◽  
Water Spray ◽  
Cfd Simulations ◽  
Computational Fluid Dynamics Cfd ◽  
Fully Coupled ◽  
Water Spray Cooling

Abstract Three-dimensional Computational Fluid Dynamics (CFD) simulations are presented for water spray cooling of a Phthalic Anhydride desublimer. The multiphase CFD modeling includes a fully coupled Eulerian/Lagrangian formulation for the carrier gas and water spray, and a quasi-steady model for the desublimation process. The use of a Lagrangian description for the spray enables a drop size distribution, but also necessitates running the simulation through the transient to obtain a steady operation result. The simulation has been used to study effect of drop size, spray dispersion and spray location/orientation.

Extent, capacity and possibilities of computational fluid dynamics as a design tool for pump intakes: a review

2018 ◽  
Vol 18 (5) ◽  
pp. 1518-1530 ◽  
Author(s):  
Jie Zhang ◽  
Tien Yee
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Three Dimensional ◽  
Design Tool ◽  
Cfd Modeling ◽  
Cfd Simulations ◽  
Pump Station ◽  
Computational Fluid Dynamics Cfd ◽  
Future Direction ◽  
Computational Resources

Abstract Flow near pump intakes is three-dimensional in nature, and is affected by many factors such as the geometry of the intake bay, uniformity of approach flow, critical submergence, placements and operation combinations of pumps and so on. In the last three decades, advancement of numerical techniques coupled with the increase in computational resources made it possible to conduct computational fluid dynamics (CFD) simulations on pump intakes. This article reviews different aspects involved in CFD modeling of pump station intakes, outlines the challenges faced by current CFD modelers, and provides an attempt to forecast future direction of CFD modeling of pump intakes.

Three-Dimensional Fluid Flow Phenomena in the Blade End Wall Corner Region

1986 ◽  
Author(s):  
B. K. Hazarika ◽  
R. Raj ◽  
D. R. Boldman
Keyword(s):  
Flow Visualization ◽  
Relative Size ◽  
Three Dimensional ◽  
Leading Edge ◽  
Horseshoe Vortex ◽  
Mean Velocity ◽  
Corner Region ◽  
Rate Of Spread ◽  
Flow Phenomena ◽  
End Wall

The three-dimensional flow in the blade end wall corner region was investigated. The techniques used in the investigation included flow visualization, static and total pressure measurements with conventional probes, and mean volocity profile measurements with a single sensor inclined hot-wire probe. Six critical axial stations along the blade chord were chosen for detailed measurements based on the flow visualization results. A large number of data points were obtained very close to the corner walls at each axial location including all the components of the mean velocity. Based on the measurements, three vortices were identified. A horseshoe vortex started near the leading edge. A corner eddy was formed between the horseshoe vortex and the corner. Another vortex was formed at the rear portion of the corner due to the secondary flow of the second kind. The relative size and the rate of spread of the vortices in the streamwise direction are discussed.

A Hybrid Particle-Continuum Framework

2008 ◽  
Author(s):  
Matthew K. Borg ◽  
Jason M. Reese
Keyword(s):  
Three Dimensional ◽  
Computational Modelling ◽  
Numerical Code ◽  
Test Cases ◽  
Cfd Simulations ◽  
Hybrid Particle ◽  
Hybrid Framework ◽  
Computational Fluid Dynamics Cfd ◽  
Polyhedral Cells ◽  
The Individual

A new hybrid particle-continuum numerical code is currently being developed as an engineering tool for accurate and fast computational modelling of nanoflows. Molecular Dynamics (MD) and Computational Fluid Dynamics (CFD) are the components/solvers used within the particle and continuum zones respectively. In this paper the development of a two-component hybrid framework, based on domain-decomposition, is described. The main objective of the framework is to facilitate hybrid MD-CFD simulations within complex geometries, using a mesh of structured/unstructured arbitrary polyhedral cells, identical to that used in engineering CFD. This requires complex three-dimensional (3D) interfaces and overlap regions (comprising user-defined sub-regions) to be constructed between adjacent zones. The individual sub-regions serve as an appropriate means of exchanging information between components (i.e. coupling or boundary condition imposition), in 3D, during the hybrid simulation. The global domain is decomposed appropriately into MD and CFD sub-domains such that internal boundaries within the overlap regions become the external boundaries on the separate meshes, prior to commencing the hybrid simulations. The hybrid framework is implemented in OpenFOAM [1], an open source C++ CFD toolbox, using a general, case-independent approach and is parallelised. Two nanochannel test cases are investigated to show that the hybrid environment is flexible and well-suited for engineering design applications as well for the development of new hybrid codes and coupling models.

Sign in / Sign up

Export Citation Format

Share Document