A Blade Theory of an Impeller With an Arbitrary Surface of Revolution

1971 ◽  
Vol 93 (4) ◽  
pp. 454-460 ◽  
Author(s):  
Yasutoshi Senoo ◽  
Yoshiyuki Nakase
Keyword(s):  
Flow Direction ◽  
Inviscid Flow ◽  
Picture Plane ◽  
Mixed Flow ◽  
Stream Surface ◽  
Surface Of Revolution ◽  
Flow Type ◽  
Compressor Rotor ◽  
Through Flow ◽  
Annular Cascade

In this report a method of analyzing subsonic inviscid flow between blades on a stream surface of revolution of a turbomachine, which may be an axial, a radial, or a mixed-flow type, is presented. There may be a change in thickness of stream surface of revolution in the through flow direction. The stream surface of revolution is mapped onto a plane. In this picture plane the influence of rotation of the system is not always represented by uniformly distributed vorticity. Instead, the distribution of vorticity varies with radius. For the calculation of velocity distribution in the picture plane, an available rotating annular cascade theory is modified so that the variation of vorticity with respect to radius is properly considered. Numerical examples for a mixed flow type compressor rotor are included.

A model incorporating the effects of flow type on fiber orientation for flows with mixed flow kinematics

2019 ◽  
Vol 63 (3) ◽  
pp. 455-464 ◽  
Author(s):  
Hongyu Chen ◽  
Peter Wapperom ◽  
Donald G. Baird
Keyword(s):  
Fiber Orientation ◽  
Mixed Flow ◽  
Flow Type

Particle Image Velocimetry in a High-Pressure Turbine Stage at Aerodynamically Engine Representative Conditions

2020 ◽  
Author(s):  
Daniel Inman ◽  
David Gonzalez Cuadrado ◽  
Valeria Andreoli ◽  
Jordan Fisher ◽  
Guillermo Paniagua ◽  
...  
Keyword(s):  
High Pressure ◽  
Particle Image Velocimetry ◽  
Vector Fields ◽  
Particle Image ◽  
Flow Direction ◽  
Operating Conditions ◽  
Velocity Magnitude ◽  
Resultant Velocity ◽  
Image Velocimetry ◽  
Annular Cascade

Abstract Particle Image Velocimetry (PIV) is a well-established technique for determining the flow direction and velocity magnitude of complex flows. This paper presents a methodology for executing this non-intrusive measurement technique to study a scaled-up turbine vane geometry within an annular cascade at engine-relevant conditions. Custom optical tools such as laser delivery probes and imaging inserts were manufactured to mitigate the difficult optical access of the test section and perform planar PIV. With the use of a burst-mode Nd: YAG laser and Photron FASTCAM camera, the frame straddling technique is implemented to enable short time intervals for the collection of image pairs and velocity fields at 10 kHz. Furthermore, custom image processing tools were developed to optimize the contrast and intensity balance of each image pair to maximize particle number and uniformity, while removing scattering and background noise. The pre-processing strategies significantly improve the vector yield under challenging alignment, seeding, and illumination conditions. With the optical and software tools developed, planar PIV was conducted in the passage of a high-pressure stator row, at mid-span, in an annular cascade. Different Mach and Reynolds number operating conditions were achieved by modifying the temperature and mass flow. With careful spatial calibration, the resultant velocity vector fields are compared with Reynolds Averaged Navier Stokes (RANS) simulations of the vane passage with the same geometry and flow conditions. Uncertainty analysis of the experimental results is also presented and discussed, along with prospects for further improvements.

A Comparison Between Full and Simplified Navier-Stokes Equation Solutions for Rotating Blade Cascade Flow on S1 Stream Surface of Revolution

1985 ◽  
Author(s):  
Chen Naixing ◽  
Zhang Fengxian
Keyword(s):  
Stokes Equation ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Navier Stokes Equation ◽  
Navier Stokes Equations ◽  
Stream Surface ◽  
Surface Of Revolution ◽  
Rotating Blade ◽  
Blade Cascade ◽  
Cascade Flow

A method for solving the Navier-Stokes equations of the rotating blade cascade flow on S1 stream surface of revolution is developed in the present paper. In this paper a complete set of full and simplified Navier-Stokes equations is given which includes stream-function equation, energy equation and entropy equation, equation of state for a perfect gas, formula for estimating density and formulas for calculating viscous forces, work done by viscous force, dissipation function and heat-transfer term. A comparison between the full and the simplified Navier-Stokes equations is made. The viscous terms of both full and simplified Navier-Stokes equation solutions are also compared in the present paper. The comparison shows that the simplified Navier-Stokes equations are applicable.

Application of a Two-Dimensional Supersonic Passage Analysis to the Design of Compressor Rotors

1974 ◽  
Author(s):  
R. G. Hantman ◽  
A. A. Mikolajczak ◽  
F. J. Camarata
Keyword(s):  
Leading Edge ◽  
Inviscid Flow ◽  
Two Dimensional ◽  
Compressor Rotor ◽  
Pressure Distributions ◽  
Displacement Thickness ◽  
Blade Section ◽  
Comparison Of The Results ◽  
Rotational Method ◽  
Good Agreement

A description of a two-dimensional supersonic cascade passage analysis and its application to the design of a high hub-to-tip ratio supersonic compressor rotor is presented. The analysis, applicable to the case in which the inviscid flow is everywhere supersonic, includes an entrance region calculation which accounts for blade leading edge bluntness effects, and a passage and wake region calculation. The inviscid part of the analysis is solved using a rotational method of characteristics. The effect of the blade boundary layer displacement thickness is taken into consideration. Comparison of the results of the analysis with supersonic cascade data is made, showing good agreement in overall performance prediction, in blade surface static pressure distributions, and in achievement of the desired shock wave patterns. A comparison of the results of the analysis is made also with the performance of a blade section of a high hub-to-tip ratio supersonic compressor and acceptable agreement obtained.

Development and Industrial Application of the “All-Over-Controlled Vortex Distribution Method” for Designing Radial and Mixed Flow Impellers

1992 ◽  
Author(s):  
S. J. Wang ◽  
M. J. Yuan ◽  
G. Xi ◽  
S. X. Liu ◽  
D. T. Qi ◽  
...  
Keyword(s):  
Flow Field ◽  
Centrifugal Compressor ◽  
Inverse Method ◽  
Three Dimensional ◽  
Industrial Applications ◽  
Mixed Flow ◽  
Distribution Method ◽  
Stream Surface ◽  
Surface Theory ◽  
Performance Curves

Sixteen years ago an inverse method of designing radial, mixed flow impellers was proposed by the first author of this paper, which was based on a quasi-three-dimensional stream surface theory. The contradictions between the full controlling of the flow field in the whole impeller and the designed bables’ smooth machinability can be perfectly resolved with the above method (So it is called “all-over-controlled vortex distribution method”). This paper presents the developments and industrial applications of the above method in the last decade. Two single centrifugal compressor model stages with the 3-D impellers designed by this method are studied in detail, and several performance curves of the multistage centrifugal compressors designed by this method are also presented.

Towards a High Order Throughflow: Part II—Investigation of the Nonlinear Harmonic Method Coupled With an Immersed Boundary Method for the Modeling of the Circumferential Stresses

2010 ◽  
Author(s):  
J. P. Thomas ◽  
O. Le´onard
Keyword(s):  
Immersed Boundary Method ◽  
Computational Cost ◽  
Inviscid Flow ◽  
Meridional Flow ◽  
Immersed Boundary ◽  
Harmonic Method ◽  
Boundary Method ◽  
Multi Stage ◽  
Through Flow ◽  
Second Category

Capturing a level of modeling of the flow inside a multi-stage turbomachine, such as unsteadiness for example, can be done at different degrees of details, either by capturing all deterministic features of the flow with a pure unsteady method or by settling for an approximated solution at a lower computational cost. The harmonic methods stand in this second category. Amongst them the “Nonlinear Harmonic Method” from He revealed the most efficient. This method consists of solving the fully nonlinear 3D steady problem and a linearized perturbation system in the frequency domain. As it has been shown by the authors that the circumferential variations exhibit a harmonic behavior, it is proposed here to adapt this method to the through-flow model, where the main nonlinear system would be the common throughflow equations and the auxiliary system would give access to the circumferential stresses. As the numerical local explicit impermeability conditions are unsupported by Fourier series, the adaptation of this technique to the throughflow model passes through a reformulation of the blade effect by a smooth force field as in the “Immersed Boundary Method” from Peskin. A simple example of an inviscid flow around a cylinder will illustrate the preceding developments, bringing back the mean effect of the circumferential non uniformities into the meridional flow.

Computation of Potential Flow on S2 Stream Surface for a Transonic Axial-Flow Compressor Rotor

1985 ◽  
Vol 107 (2) ◽  
pp. 323-328 ◽  
Author(s):  
Pan-Ming Lu¨ ◽  
Chung-Hua Wu
Keyword(s):  
Potential Function ◽  
Axial Compressor ◽  
Axial Flow ◽  
Full Potential ◽  
Stream Surface ◽  
Compressor Rotor ◽  
Transonic Axial Compressor ◽  
Design Speed ◽  
Flow Compressor ◽  
Good Agreement

A set of conservative full potential function equations governing the fluid flow along a given S2 streamsurface in a transonic axial compressor rotor was obtained. By the use of artificial density and a potential function/density iteration, this set of equations can be solved, and the passage shock on the S2 streamsurface can be captured. A computer program for this analysis problem has been developed and used to compute the flow field along a mean S2 streamsurface in the DFVLR transonic axial compressor rotor. A comparison of computed results with DFVLR L2F measurement at 100 percent design speed shows fairly good agreement.

Comparison of Experimental and Computational Shock Structure in a Transonic Compressor Rotor

1981 ◽  
Vol 103 (1) ◽  
pp. 78-88
Author(s):  
G. Haymann-Haber ◽  
W. T. Thompkins
Keyword(s):  
Boundary Layer ◽  
Three Dimensional ◽  
Inviscid Flow ◽  
Boundary Layer Separation ◽  
Shock Strength ◽  
Layer Separation ◽  
Transonic Compressor ◽  
Compressor Rotor ◽  
Pressure Peak ◽  
Rotor Losses

Measurement of passage shock strength in a transonic compressor rotor using a gas fluorescent technique revealed an unexpected variation in shock strength in the radial direction. An axisymmetric idealization would normally predict that the passage shock strength would gradually weaken when moving radially inward until disappearing at the sonic radius. However, the measurements indicated a sharp peak in strength at the nominal sonic radius. Blade boundary layer separation originating at this point accounts for about one half of the total rotor losses. A numerical computation of the three-dimensional inviscid flow, using time-marching techniques, has accurately predicted in general the radial and tangential variations in passage shock strength and in particular the sharp pressure peak at the nominal sonic radius. The overall shock strength was somewhat over-predicted, but this overprediction may be the result of boundary layer separation in the experiment. This paper presents comparisons between the optical density measurements and computational results and in addition a short analytical discussion which demonstrates that the sharp shock strength rise may occur in many transonic compressor rotors.

A Study on the Mechanism of Tip Leakage Flow Unsteadiness in an Isolated Compressor Rotor

2006 ◽  
Author(s):  
Hongwu Zhang ◽  
Xiangyang Deng ◽  
Feng Lin ◽  
Jingyi Chen ◽  
Weiguang Huang
Keyword(s):  
Pressure Difference ◽  
Operating Conditions ◽  
Static Balance ◽  
Leakage Flow ◽  
Flow Mechanism ◽  
Tip Leakage Flow ◽  
Tip Leakage ◽  
Aerodynamic Loading ◽  
Compressor Rotor ◽  
Through Flow

A numerical study of unsteady tip leakage flow in an isolated axial compressor rotor is presented, aiming at clarifying the originating flow mechanism of this unsteady phenomenon. First, CFD simulations utilizing a three-dimensional, time-accurate, Reynolds-averaged Navier-Stokes solver demonstrates that the tip leakage flow pattern, which manifests itself as an interacting cross- and through-flow in the tip region, can become periodically oscillatory in a range of operating conditions. A flow mechanism is then clarified to explain this unsteady flow phenomenon at its onset that this periodic flow oscillation is a result of dynamic balance, as opposed to static balance, between two counter-acting driving “forces”. One such “force” is the aerodynamic loading of the blades, i.e. the pressure difference across the pressure and suction sides of the compressor blades created by the main through flow. Its counter-acting “force” is the unloading of the blades, i.e. the reduction of the pressure difference caused by the tip leakage cross flow that originates from the pressure side, rushes into the suction side through the tip clearance. At operating conditions in which both “forces” are strong and in the same order, their static balance will be broken. While a larger blade loading creates a stronger tip leakage flow, the tip leakage flow tends to diminish itself because its accompanying effect is to unload the blade. Since the weaker tip leakage flow cannot overcome the ability of the main through flow to recover the original aerodynamic loading for the blade, the whole process restarts and periodically oscillatory tip leakage flow forms. Furthermore, a dimensionless analysis shows that the onset of the observed unsteadiness is conditioned by the tip leakage flow, which can or cannot reach the neighboring blade before mixing with the main flow.

scholarly journals A Quasi-Three Dimensional Analysis of Choking Flow for Radial Gas Turbines

1978 ◽  
Author(s):  
Yoshiyuki Nakase ◽  
Junichiro Fukutomi ◽  
Masanobu Inubushi ◽  
Takashi Watanabe ◽  
Yoshiyasu Hama ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Energy Recovery ◽  
Three Dimensional ◽  
Layer Growth ◽  
Meridional Plane ◽  
Mixed Flow ◽  
Numerical Examples ◽  
Annular Cascade ◽  
Boundary Layer Growth

A quasi-three dimensional.flow analysis has previously been reported for a mixed flow impeller by one of the present authors. In the analysis, the velocity gradient method has been used in meridional plane and the rotating annular cascade theory has been used for blade-to-blade solution. In this report, the analysis is generalized to allow prediction and analysis of choking flow for a radial inflow gas turbine. Moreover, this analysis is corrected to include passage contraction effects and passage loss effects due to boundary-layer growth. The efficiency and choking flow rate of gas turbine may be obtained in a single computer run without the complicated throat area estimation. Some numerical examples for a burst furnace gas energy recovery turbine are presented.

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