A Discussion of the Mean S2 Stream Surfaces Applied to Quasi-Three-Dimensional Calculation Programs for Turbomachinery Design

1987 ◽  
Author(s):  
Zhu Xujin ◽  
Wang Zhongqi
Keyword(s):  
Three Dimensional ◽  
Inviscid Flow ◽  
Curvilinear Coordinate System ◽  
Governing Equations ◽  
Flow Properties ◽  
Stream Surface ◽  
Curvilinear Coordinate ◽  
Orthogonal Curvilinear Coordinate System ◽  
The Mean ◽  
Turbomachinery Design

This paper attempts to clarify the various definitions of the “S2m” surfaces applied to quasi-3-d inviscid flow computation in turbomachinery by adopting an extended concept of true S2 stream surface (PAG S2) in the discussion. It is indicated that PAG S2 gives a more universal and applicable model to solve the pitch -averaged flow properties through turbine blade passages, especially when a non-orthogonal curvilinear coordinate system is introduced into its governing equations in the present paper.

A Method for Calculating Axial Turbomachine End Wall Turbulent Boundary Layers

1989 ◽  
Author(s):  
Kang Shun ◽  
Liu Fengjun ◽  
Wang Zhongqi
Keyword(s):  
Boundary Layer ◽  
Iterative Solution ◽  
Stream Surface ◽  
Wall Boundary Layer ◽  
Wall Boundary ◽  
Curvilinear Coordinate ◽  
Orthogonal Curvilinear Coordinate System ◽  
Layer Flow ◽  
End Wall ◽  
Differential And Integral Equations

Based on two families of relative stream-surface theory, the differential and integral equations of the endwall boundary layer in the S2 stream surface (hub to tip stream surface) have been established in the orthogonal curvilinear coordinate system in the present paper. By directly associating the blade force defects with the warping of S2 stream surface near the endwall, we have proposed a new method for predicting the endwall boundary layer. This method can be used to conduct the interactions of the end wall boundary layer with the S2 stream surface potentisl flow, in order to get the iterative solution of the end wall boundary layer flow with the potential flow in S2 stream surface. The predicted results have shown that the present method is acceptable.

Influence of Blade Aerodynamic Loading on Efficiency of Radial-Inflow Turbines

1992 ◽  
Author(s):  
T. Takamura ◽  
F. Nishiguchi
Keyword(s):  
Shape Factor ◽  
Rotor Blade ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Blade Loading ◽  
Stream Surface ◽  
Turbine Efficiency ◽  
Blade Shape ◽  
Velocity Triangle ◽  
The Mean

This paper describes the relation between turbine efficiency and rotor blade loading parameters. Tests were carried out on 12 kinds of rotors, which had the same inlet velocity triangle and meridional contour, but different blade numbers (8–11) and blade lengths. The momentum thickness and shape factor of the boundary layers obtained from the results of a quasi-three dimensional flow analysis were used as the rotor blade loading parameters. It was found that blade loading could be evaluated by the shape factor at the mean stream surface and that turbine efficiency was affected by the blade shape of the exducer.

scholarly journals General Curved Surface Fitting and Calculation of Flow Along Arbitrarily Twisted Stream Surface

1985 ◽  
Author(s):  
Wu Wenquan ◽  
Yu Haoyu
Keyword(s):  
Stream Function ◽  
Engineering Application ◽  
Small Deformation ◽  
Surface Fitting ◽  
Curved Surface ◽  
Coordinate Surface ◽  
Stream Surface ◽  
Curvilinear Coordinate ◽  
Orthogonal Curvilinear Coordinate System ◽  
Stream Lines

This paper consists of two parts. (1) General curved surface fitting and grid refining. A method of fitting a set of given discrete points on several stream lines to give a smooth and arbitraily twisted stream surface was developed. Based upon the small deformation theory for thin plate, the Kirchhoff’s Equation was solved and twofold transformations were incorporated. The first step is the transformation from physical surface into computational surface and the second is affine transformation. The accuracy of the result is about 0.004% and the CPU time needed is reasonable for engineering application. Then the refined computational grid and the calculation for the geometrical quantities of the grid are carried out on the fitted surface. (2) Calculation of the flow along the fitted stream surface. Employing non-orthogonal curvilinear coordinate system, the fitted stream surface is selected as a coordinate surface, so that there are only two velocity components even when the stream surface is arbitrarily twisted, and it is very convenient to define the stream function. The general equation for the quasi-linear stream function governing the flow along the fitted stream surface was employed. This was solved with the method of direct decomposition of matrix. The numerical examples are also included in this paper. The present method can be used for S1 and S2 stream surfaces and other engineering calculations.

CFD-Based Throughflow Solver in a Turbomachinery Design System

2007 ◽  
Author(s):  
Fahua Gu ◽  
Mark R. Anderson
Keyword(s):  
Three Dimensional ◽  
Design System ◽  
Flow Angle ◽  
Stream Surface ◽  
Streamline Curvature ◽  
Machine Performance ◽  
Multi Stage ◽  
Pros And Cons ◽  
Turbomachinery Design ◽  
Different Levels

Throughflow analysis is a critical component for the multi-stage axial turbomachine design. The Euler throughflow approach has been developed over the last couple of decades, but has been less successful than its early peer, the streamline curvature approach. In this paper an Euler throughflow approach is described for engineering applications. It includes the steps needed to construct the stream surface, such as modifications for the incidence and deviation, and the throat area correction. The flow angle difference at the trailing edge and in the downstream non-bladed gap stations is resolved, and the numerical loss from solving the Euler equation is removed as well. This solver has been integrated into a comprehensive turbomachinery design system. It creates and modifies the machine geometries and predicts the machine performance at different levels of approximation, including one-dimensional design and analysis, quasi-three-dimensional methods (blade-to-blade and throughflow) and full-three-dimensional steady-state CFD analysis. The flow injection and extraction functions are described, as is the implementation of the radial mass distribution. Some discussion is dedicated to the shock calculation. Finally, examples are provided to demonstrate the pros and cons of the Euler throughflow approach and also to demonstrate the potential to solve for a wider range of flow conditions, particularly choked and transonic flows that limit stream function based solvers.

Prediction of Compressible Subsonic Flow through an Axisymmetric Exhaust Valve-port Assembly

1995 ◽  
Vol 209 (4) ◽  
pp. 289-295 ◽  
Author(s):  
J A Naser ◽  
A D Gosman
Keyword(s):  
Field Data ◽  
Subsonic Flow ◽  
Numerical Procedure ◽  
Simple Algorithm ◽  
Exhaust Valve ◽  
Curvilinear Coordinate System ◽  
Governing Equations ◽  
Curvilinear Coordinate ◽  
Flow Through ◽  
Good Agreement

Flow details through an axisymmetric exhaust valve-port assembly have been investigated numerically. Computations were performed for steady compressible subsonic air flow at different valve lifts. The numerical procedure used for this purpose solves the governing equations using the SIMPLE algorithm. The governing equations are expressed in a general curvilinear coordinate system and are discretized in a finite volume fashion. The time-averaged governing equations are closed using the k–e. turbulence model. The predictions are assessed by comparing with the available experimental flow field data. Good agreement is observed between the predictions and the experiment.

Multall—An Open Source, Computational Fluid Dynamics Based, Turbomachinery Design System

2017 ◽  
Vol 139 (12) ◽  
Author(s):  
John D. Denton
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Three Dimensional ◽  
Design System ◽  
Input File ◽  
Stream Surface ◽  
Source Codes ◽  
Overall Performance ◽  
Complex Features ◽  
Turbomachinery Design

Turbomachinery design systems are usually the jealously guarded property of large companies, and the author is not aware of any for which the source code is freely available. This paper is aimed providing a freely available system that can be used by individuals or small companies who do not have access to an in-house system. The design system is based on the three-dimensional (3D) computational fluid dynamics (CFD) solver Multall, which has been developed over many years. Multall can obtain solutions for individual blade rows or for multistage machines, and it can also perform quasi-3D (Q3D) blade-to-blade calculations on a prescribed stream surface and axisymmetric throughflow calculations. Multall is combined with a one-dimensional (1D) mean-line program, Meangen, which predicts the blading parameters on a mean stream surface and writes an input file for Stagen. Stagen is a blade geometry generation and manipulation program which generates and stacks the blading, combines it into stages, and writes an input file for Multall. The system can be used to design the main blade path of all types of turbomachines. Although it cannot design complex features such as shroud seals and individual cooling holes, these features can be modeled, and their effect on overall performance predicted. The system is intended to be as simple and easy to use as possible, and the solver is also very fast compared to most CFD codes. A great deal of user experience ensures that the overall performance is reasonably well predicted for a wide variety of machines. This paper describes the system in outline and gives an example of its use. The source codes are written in FORTRAN77 and are freely available for other users to try.

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