Turbulent flow simulation of a three-dimensional turbine cascade

1990 ◽  
Author(s):  
D. CHAN ◽  
K. SHEEDY
Keyword(s):  
Turbulent Flow ◽  
Three Dimensional ◽  
Flow Simulation ◽  
Turbine Cascade

Improving a conjugate-heat-transfer immersed-boundary method

2016 ◽  
Vol 26 (3/4) ◽  
pp. 1272-1288 ◽  
Author(s):  
Dario De Marinis ◽  
Marco Donato de Tullio ◽  
Michele Napolitano ◽  
Giuseppe Pascazio
Keyword(s):  
Turbulent Flow ◽  
Immersed Boundary Method ◽  
Conjugate Heat Transfer ◽  
State Of The Art ◽  
Three Dimensional ◽  
Immersed Boundary ◽  
Turbine Cascade ◽  
Wall Functions ◽  
Content Type ◽  
Compressible Turbulent Flow

Purpose – The purpose of this paper is to provide the current state of the art in the development of a computer code combining an immersed boundary method with a conjugate heat transfer (CHT) approach, including some new findings. In particular, various treatments of the fluid-solid-interface conditions are compared in order to determine the most accurate one. Most importantly, the method is capable of computing a challenging three dimensional compressible turbulent flow past an air cooled turbine vane. Design/methodology/approach – The unsteady Reynolds-averaged Navier–Stokes (URANS) equations are solved within the fluid domain, whereas the heat conduction equation is solved within the solid one, using the same spatial discretization and time-marching scheme. At the interface boundary, the temperatures and heat fluxes within the fluid and the solid are set to be equal using three different approximations. Findings – This work provides an accurate and efficient code for solving three dimensional CHT problems, such as the flow through an air cooled gas turbine cascade, using a coupled immersed boundary (IB) CHT methodology. A one-to-one comparison of three different interface-condition approximations has shown that the two multidimensional ones are slightly superior to the early treatment based on a single direction and that the one based on a least square reconstruction of the solution near the IB minimizes the oscillations caused by the Cartesian grid. This last reconstruction is then used to compute a compressible turbulent flow of industrial interest, namely, that through an air cooled gas turbine cascade. Another interesting finding is that the very promising approach based on wall functions does not combine favourably with the interface conditions for the temperature and the heat flux. Therefore, current and future work aims at developing and testing appropriate temperature wall functions, in order to further improve the accuracy – for a given grid – or the efficiency – for a given accuracy – of the proposed methodology. Originality/value – An accurate and efficient IB CHT method, using a state of the art URANS parallel solver, has been developed and tested. In particular, a detailed study has elucidated the influence of different interface treatments of the fluid-solid boundary upon the accuracy of the computations. Last but not least, the method has been applied with success to solve the well-known CHT problem of compressible turbulent flow past the C3X turbine guide vane.

The Characteristics Research of Tube Vortex Based on Large Eddy Simulation

2011 ◽  
Vol 121-126 ◽  
pp. 3657-3661
Author(s):  
Dun Zhang ◽  
Yuan Zheng ◽  
Ying Zhao ◽  
Jian Jun Huang
Keyword(s):  
Large Eddy Simulation ◽  
Turbulent Flow ◽  
Complex Geometry ◽  
Initial Conditions ◽  
Three Dimensional ◽  
Flow Simulation ◽  
Computational Method ◽  
Francis Turbine ◽  
Eddy Simulation ◽  
Large Eddy

Numerical simulation of three-dimensional transient turbulent flow in the whole flow passage of a Francis turbine were based upon the large eddy simulation(LES) technique on Smargorinsky model and sliding mesh technology. The steady flow data simulated with the standard k-εmodel was used as the initial conditions for the unsteady simulation. The results show that LES can do well transient turbulent flow simulation in a Francis turbine with complex geometry. The computational method provides some reference for exploring the mechanism of eddy formation in a complex turbulent of hydraulic machinery.

Three-dimensional compressible–incompressible turbulent flow simulation using a pressure-based algorithm

2008 ◽  
Vol 37 (6) ◽  
pp. 747-766 ◽  
Author(s):  
Khodayar Javadi ◽  
Masoud Darbandi ◽  
Mohammad Taeibi-Rahni
Keyword(s):  
Turbulent Flow ◽  
Three Dimensional ◽  
Flow Simulation

Turbulence Measurements Downstream of a Turbine Cascade at Different Incidence Angles and Pitch-Chord Ratios

1993 ◽  
Author(s):  
Vincenzo Dossena ◽  
Antonio Perdichizzi ◽  
Marina Ubaldi ◽  
Pietro Zunino
Keyword(s):  
Turbulent Flow ◽  
Reynolds Stress ◽  
Incidence Angle ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Turbine Cascade ◽  
Mean Flow ◽  
Flow Measurements ◽  
Flow Features ◽  
Turbulent Flow Structure

An experimental investigation on a linear turbine cascade has been carried out to study the effects induced by incidence angle and pitch-chord ratio variations on the three-dimensional turbulent flow downstream of the cascade. Previous mean flow measurements have shown how these parameters influence the energy losses and the secondary velocity field. Now detailed hot wire measurements have been performed on a plane located at 22 per cent of an axial chord downstream of the trailing edge, in order to determine the distribution of all the six Reynolds stress tensor components, for three incidence conditions (i = −30, 0, +30 deg) and for three pitch-chord ratios (s/c = 0.58, 0.72, 0.87). Significant changes of the turbulent flow structure, interesting magnitude and distribution of the Reynolds stress components, have been observed for all the considered test conditions. The analysis of the results shows the correlation between the mean flow features and the turbulent quantities and the relationship between the energy loss production and the blade loading variation. The presented data are also suitable for assessing the behaviour of turbulence models in complex 3D flows, on design and off-design conditions.

Experimental Research and Turbulent Flow Simulation of the Updraft Free-Exit-Flow Hydropower Turbine System

2002 ◽  
Author(s):  
Haifeng Li ◽  
Yulin Wu ◽  
David T. Kao
Keyword(s):  
Turbulent Flow ◽  
Experimental Research ◽  
Production Efficiency ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Flow Simulation ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Predicting Performance ◽  
Optimizing Design

During development of the updraft free-exit-flow hydropower turbine system, serious attention was paid to impact of the traditional turbine system to environment. The paper presents results of experimental research and three-dimensional turbulent flow simulation of the runner. The experiment demonstrated that, on one hand, the system can enhance exit flow aeration and downstream water quality; on the other hand, it gives good results in terms of its power production efficiency, about 85%. Based on the time-averaged Navier-Stokes equations and standard k-ε model, the SIMPLEC algorithm was applied for the numerical analysis. To guarantee credibility of the calculation, FLUENT5.5 code was used, which can provide distribution of pressure and velocity respectively. With comparison between the experimental data and calculating results, it can be concluded that flow simulation can be an effective tool for predicting performance and optimizing design of new turbine runner.

Large-Eddy Turbulent Flow Simulation of an Industrial Helical Static Mixer

Volume 4 ◽  
2004 ◽  
Author(s):  
Ramin K. Rahmani ◽  
Theo G. Keith ◽  
Anahita Ayasoufi
Keyword(s):  
Turbulent Flow ◽  
Critical Role ◽  
Three Dimensional ◽  
Flow Simulation ◽  
Reynolds Numbers ◽  
Static Mixer ◽  
Static Mixers ◽  
Large Eddy ◽  
Turbulent Models ◽  
Les Model

Viscous liquids have to be homogenized in continuous operations in many branches of processing industries; and therefore, fluid mixing plays a critical role in the success or failure of many industrial processes. Consequences of improper mixing include non-reproducible processing conditions and lowered product quality, resulting in the need for more elaborate downstream purification processes and increased waste disposal costs. The range of practical flow Reynolds numbers for helical static mixers in industry is usually from very small (Re ≈ 0) to moderate values (e.g. Re = 5,000). However, it has been found that the flow regime within helical static mixers is turbulent for relatively low Reynolds numbers, compared to the flow inside a pipe with no mixing elements present. This paper extends previous studies by the authors on the industrial helical static mixer. Its purpose is to present an improved understanding of the turbulent flow pattern for single-phase liquids through the mixer. Three-dimensional finite volume simulations are used to study the performance of the mixer using different turbulent models. Large-Eddy Simulation (LES) model is applied to the flow in an industrial helical static mixer to calculate the flow velocities, pressure drops, etc. Using a variety of predictive tools, the mixing results are obtained. Also, the accuracy and global performance of several different turbulent models are compared against the LES model.

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