Rotational Flow Calculations in Three Dimensional Blade Passages

1982 ◽  
Author(s):  
C. Lacor ◽  
Ch. Hirsch
Keyword(s):  
Experimental Data ◽  
Solution Method ◽  
Three Dimensional ◽  
Rotational Flow ◽  
Calculation Methods ◽  
Three Dimensional Flow ◽  
Additional Function ◽  
Potential Part ◽  
Rotational Part ◽  
Element Technique

A method to calculate the three-dimensional, inviscid, rotational flow in blade passages is described. The three-dimensional flow is separated into a potential part and a rotational part. For a certain class of inlet flows, this rotational part can be described by a single additional function. The solution method can be seen as an extension of the procedure for solving the three-dimensional potential flow. The Finite Element technique is used and the method is illustrated by calculations of the flow in a rectangular elbow with 90 degrees of turning. Comparisons are made with experimental data and other calculation methods.

Simulations of Three-Dimensional Flow and Augmented Heat Transfer in a Symmetrically Grooved Channel

2000 ◽  
Vol 122 (4) ◽  
pp. 653-660 ◽  
Author(s):  
M. Greiner ◽  
R. J. Faulkner ◽  
V. T. Van ◽  
H. M. Tufo ◽  
P. F. Fischer
Keyword(s):  
Three Dimensional ◽  
Spectral Element ◽  
Navier Stokes ◽  
Three Dimensional Flow ◽  
Dimensional Flow ◽  
Two Dimensional Flow ◽  
Transverse Grooves ◽  
Flow Transitions ◽  
Element Technique ◽  
Good Agreement

Navier-Stokes simulations of three-dimensional flow and augmented convection in a channel with symmetric, transverse grooves on two opposite walls were performed for 180⩽Re⩽1600 using the spectral element technique. A series of flow transitions was observed as the Reynolds number was increased, from steady two-dimensional flow, to traveling two and three-dimensional wave structures, and finally to three-dimensional mixing. Three-dimensional simulations exhibited good agreement with local and spatially averaged Nusselt number and friction factor measurements over the range 800⩽Re⩽1600. [S0022-1481(00)00904-X]

Secondary Flow Development In A Cascade Like Passage Of A Turbomachine

1983 ◽  
pp. 11-23
Author(s):  
Amer Nordin Darus
Keyword(s):  
Experimental Data ◽  
Numerical Solution ◽  
Three Dimensional ◽  
Momentum Equation ◽  
Rotational Flow ◽  
Simultaneous Solution ◽  
Analytical Formulation ◽  
Curved Duct ◽  
Flow Development ◽  
Vorticity Equations

Makalah ini memaparkan formulasi analitik dan penyelesaian numerik aliran dimensi tiga yang rotasional di dalam sebuah saluran yang melengkung. Formulasi ini berdasarkan perhitungan halaju aliran dan komponen vortisiti selari axis saluran tersebut. Halaju sekunder ditentukan melalui penyelesaian serentak persamaan-persamaan ke terusan dan vortisiti melalui penggunaan fungsi seperti fungsi arus. Hasil-hasil numerik diberikan dan dibandingkan dengan data-data eksperimen yang ada. This article presents the analytical formulation and numerical solution of the three-dimensional rotational flow in curved duct. The formulation is based on calculating the flow - wise velocity and vorticity. components from the momentum equation. The secondary velocities are determined from the simultaneous solution of the continuity and vorticity equations through the use of a streamlike function. The results presented arc compared with the existing experimental data.

Numerical Investigation of a Centrifugal Compressor for Supercritical CO2 Cycles

2020 ◽  
Author(s):  
Renan Emre Karaefe ◽  
Pascal Post ◽  
Marwick Sembritzky ◽  
Andreas Schramm ◽  
Francesca di Mare ◽  
...  
Keyword(s):  
Experimental Data ◽  
Thermodynamic Properties ◽  
Flow Field ◽  
Numerical Simulations ◽  
Centrifugal Compressor ◽  
Supercritical Co2 ◽  
Solution Method ◽  
Three Dimensional ◽  
Solution Procedure ◽  
Test Loop

Abstract In this work, the performance characteristics and the flow field of a centrifugal compressor operating with supercritical CO2 are investigated by means of three-dimensional CFD. The considered geometry is based on main dimensions of the centrifugal compressor installed in the supercritical CO2 compression test-loop operated by Sandia National Laboratories. All numerical simulations are performed with a recently developed in-house hybrid CPU/GPU compressible CFD solver. Thermodynamic properties are computed through an efficient and accurate tabulation technique, the Spline-Based Table Look-Up Method (SBTL), particularly optimised for the applied density-based solution procedure. Numerical results are compared with available experimental data and accuracy as well as potentials in computational speedup of the solution method in combination with the SBTL are evaluated in the context of supercritical CO2 turbomachinery.

scholarly journals A Design Study of Radial Inflow Turbines With Splitter Blades in Three-Dimensional Flow

1996 ◽  
Vol 118 (2) ◽  
pp. 353-361 ◽  
Author(s):  
W. D. Tjokroaminata ◽  
C. S. Tan ◽  
W. R. Hawthorne
Keyword(s):  
Reverse Flow ◽  
Three Dimensional ◽  
Flow Region ◽  
Inverse Design ◽  
Design Technique ◽  
Design Study ◽  
Three Dimensional Flow ◽  
Dimensional Flow ◽  
Rotational Part ◽  
Blade Geometry

An inverse design technique to design turbomachinery blading with splitter blades in three-dimensional flow is developed. It is based on the use of Clebsch transformation, which allows the velocity field to be written as a potential part and a rotational part. It is shown that the rotational part can be expressed in terms of the mean swirl schedule (the circumferential average of the product of radius and tangential velocity) and the blade geometry that includes the main blade as well as the splitter blade. This results in an inverse design approach, in which both the main and the splitter blade geometry are determined from a specification of the swirl schedule. Previous design study of a heavily loaded radial inflow turbine, without splitter blades, for a rather wide variety of specified mean swirl schedules results in a blade shape with unacceptable nonradial blade filament; the resulting reduced static pressure distribution yields an “inviscid reverse flow region” covering almost the first half of the blade pressure surface. When the inverse design technique is applied to the design study of the turbine wheel with splitter blades, the results indicate that the use of splitter blades is an effective means for making the blade filament at an axial location more radial as well as a potential means for eliminating any “inviscid reverse flow” region that may exist on the pressure side of the blades.

Numerical Simulation of Three-Dimensional Cavitation Around a Hydrofoil

2011 ◽  
Vol 133 (8) ◽  
Author(s):  
Jing Yang ◽  
Lingjiu Zhou ◽  
Zhengwei Wang
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Flow Field ◽  
Pressure Gradient ◽  
Three Dimensional ◽  
Side Wall ◽  
Viscosity Coefficient ◽  
Cavitation Model ◽  
Three Dimensional Flow ◽  
Shedding Frequency

Cavitation around a hydrofoil has significant three-dimensional features. The full cavitation model and a RNG k−ɛ turbulence model with a modified turbulence viscosity coefficient and which related to the vapor and liquid densities in the cavitating region were used to simulate cavitation around a hydrofoil, with emphasizing on cavity’s three-dimensional features. Computations were made on the three-dimensional flow field around a NACA66 hydrofoil at a 6 deg angle of attack. The results show that the shedding frequency on the 3D hydrofoil agrees well with the experimental data. The computed results also capture the main feature of the 3D cavitation, which had a crescent shaped cavity because of the span wise velocity. This span wise velocity is due to the span wise pressure gradient caused by the lateral vortex near the side wall of the tunnel.

scholarly journals The shape and motion of gas bubbles in a liquid flowing through a thin annulus

2018 ◽  
Vol 855 ◽  
pp. 1017-1039 ◽  
Author(s):  
Q. Lei ◽  
Z. Xie ◽  
D. Pavlidis ◽  
P. Salinas ◽  
J. Veltin ◽  
...  
Keyword(s):  
Experimental Data ◽  
Flow Direction ◽  
Three Dimensional ◽  
Gas Bubbles ◽  
Bubble Velocity ◽  
Bubble Motion ◽  
Three Dimensional Flow ◽  
Close Match ◽  
Bubble Length ◽  
Component Parallel

We study the shape and motion of gas bubbles in a liquid flowing through a horizontal or slightly inclined thin annulus. Experimental data show that in the horizontal annulus, bubbles develop a unique ‘tadpole-like’ shape with a semi-circular cap and a highly stretched tail. As the annulus is inclined, the bubble tail tends to vanish, resulting in a significant decrease of bubble length. To model the bubble evolution, the thin annulus is conceptualised as a ‘Hele-Shaw’ cell in a curvilinear space. The three-dimensional flow within the cell is represented by a gap-averaged, two-dimensional model, which achieved a close match to the experimental data. The numerical model is further used to investigate the effects of gap thickness and pipe diameter on the bubble behaviour. The mechanism for the semi-circular cap formation is interpreted based on an analogous irrotational flow field around a circular cylinder, based on which a theoretical solution to the bubble velocity is derived. The bubble motion and cap geometry is mainly controlled by the gravitational component perpendicular to the flow direction. The bubble elongation in the horizontal annulus is caused by the buoyancy that moves the bubble to the top of the annulus. However, as the annulus is inclined, the gravitational component parallel to the flow direction becomes important, causing bubble separation at the tail and reduction in bubble length.

Flow in a centrifugal spectrometer

1992 ◽  
Vol 238 ◽  
pp. 221-250 ◽  
Author(s):  
A. A. Dahlkild ◽  
G. Amberg ◽  
H. P. Greenspan
Keyword(s):  
Vertical Wall ◽  
Axisymmetric Flow ◽  
Three Dimensional ◽  
Shear Layers ◽  
Vertical Shear ◽  
Rotational Flow ◽  
Basic Process ◽  
Three Dimensional Flow ◽  
Exploratory Experiment ◽  
Flow Through

Rotational flow through narrow axial channels is considered in connection with a proposed technique to sort and separate particles according to sedimentation velocities. Nonlinear and linear axisymmetric flow through two channels connected by a slot in the vertical wall is studied numerically. A linearized formulation for the three-dimensional flow through a circumferentially blocked channel, with arbitrary positioning of the inlets and outlets, is examined analytically. Both approaches indicate that to have a sharp criteria for fractionation, the vertical shear layers on the channel walls must overlap. Otherwise, Coriolis effects, accompanying a strong azimuthal motion, make the sorting less precise. Results of an exploratory experiment with a simple two-stage machine demonstrate the feasibility of the basic process for simultaneous and continuous separation and fractionation.

scholarly journals A Design Study of Radial Inflow Turbines With Splitter Blades in Three-Dimensional Flow

1994 ◽  
Author(s):  
W. D. Tjokroamlnata ◽  
C. S. Tan ◽  
W. R. Hawthorne
Keyword(s):  
Reverse Flow ◽  
Three Dimensional ◽  
Flow Region ◽  
Inverse Design ◽  
Design Technique ◽  
Design Study ◽  
Three Dimensional Flow ◽  
Dimensional Flow ◽  
Rotational Part ◽  
Blade Geometry

An inverse design technique to design turbomachinery blading with splitter blades in three-dimensional flow is developed. It is based on the use of Clebsch transformation which allows the velocity field to be written as a potential part and a rotational part. It is shown that the rotational part can be expressed in terms of the mean swirl schedule (the circumferential average of the product of radius and tangential velocity) and the blade geometry that includes the main blade as well as the splitter blade. This results in an inverse design approach in which both the main and the splitter blade geometry are determined from a specification of the swirl schedule. Previous design study of a heavily-loaded radial inflow turbine, without splitter blades, for a rather wide variety of specified mean swirl schedules result in a blade shape with unacceptable non-radial blade filament; the resulting reduced static pressure distribution yields an “inviscid reverse flow region”1 covering almost the first half of the blade pressure surface. When the inverse design technique is applied to the design study of the turbine wheel with splitter blades, the results indicate that the use of splitter blades is an effective means for making the blade filament at an axial location more radial as well as a potential means for eliminating any “inviscid reverse flow” region that may exist on the pressure side of the blades.

An Euler correction method for computing two-dimensional unsteady transonic flows

1999 ◽  
Vol 103 (1020) ◽  
pp. 85-94
Author(s):  
D. Das ◽  
S. Santhakumar
Keyword(s):  
Flow Field ◽  
Correction Method ◽  
Momentum Equation ◽  
Present Calculation ◽  
Full Potential ◽  
Rotational Flow ◽  
Potential Equation ◽  
Irrotational Flow ◽  
Potential Part ◽  
Rotational Part

AbstractAn Euler correction method is developed for unsteady, transonic inviscid flows. The strategy of this method is to treat the flow-field behind the shock as rotational flow and elsewhere as irrotational flow. The solution for the irrotational flow is obtained by solving the unsteady full-potential equation using Jameson's rotated time-marching finite-difference scheme. Clebsch's representation of velocity is followed for rotational flow. In this representation the velocities are decomposed into a potential part and a rotational part written in terms of scalar functions. The potential part is computed from the unsteady full potential equation with appropriate modification based on Clebsch's representation of velocity. The rotational part is obtained analytically from the unsteady momentum equation written in terms of Clebsch variables. This method is applied to compute the unsteady flow-field characteristics for an oscillating NACA 64A010 aerofoil. The results of the present calculation are found to be in good agreement with both Euler solution and experimental results.

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