Computation of Three-Dimensional Flow Fields Through Rotating Blade Rows and Comparison With Experiment

1982 ◽  
Vol 104 (2) ◽  
pp. 394-400 ◽  
Author(s):  
K. P. Sarathy
Keyword(s):  
Pressure Ratio ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Peak Efficiency ◽  
Three Dimensional Flow ◽  
Flow Solver ◽  
Rotating Blade ◽  
Blade Row ◽  
Time Marching ◽  
Design Speed

A three-dimensional inviscid time-marching calculation solving the unsteady Euler equations in a coordinate system rotating with the blade row has been developed, based on the Denton flow solver. This calculation was used to compute the flow field through the rotor of a transonic axial compressor and compared to measurements made with an advanced laser velocimeter at DFVLR. The comparison is made at design speed at pressure ratio corresponding to peak efficiency. Comparisons of the calculated and experimentally determined Mach number contours indicate excellent agreement in the entrance region where the viscous blockage effects are small. The methodology of the analysis is also described in this paper.

Calculation of the Quasi Three-Dimensional Flow in a Turbomachine Blade Row

1977 ◽  
Vol 99 (1) ◽  
pp. 53-62 ◽  
Author(s):  
Jean-Pierre Veuillot
Keyword(s):  
Finite Difference ◽  
Three Dimensional ◽  
Three Dimensional Flow ◽  
Through Flow ◽  
Blade Row ◽  
Time Marching ◽  
Space Discretization ◽  
Finite Volume Approach ◽  
Marching Method ◽  
Finite Difference Techniques

The equations of the through flow are obtained by an asymptotic theory valid when the blade pitch is small. An iterative method determines the meridian stream function, the circulation, and the density. The various equations are discretized in an orthogonal mesh and solved by classical finite difference techniques. The calculation of the steady transonic blade-to-blade flow is achieved by a time marching method using the MacCormack scheme. The space discretization is obtained either by a finite difference approach or by a finite volume approach. Numerical applications are presented.

Some Experiments With a Supersonic Axial Compressor Stage

1987 ◽  
Vol 109 (3) ◽  
pp. 388-397 ◽  
Author(s):  
A. J. Wennerstrom
Keyword(s):  
Pressure Ratio ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Design Flow ◽  
Vortex Generators ◽  
Boundary Layer Control ◽  
Compressor Stage ◽  
Design Speed ◽  
Isentropic Efficiency ◽  
Layer Control

Between 1970 and 1974, ten variants of a supersonic axial compressor stage were designed and tested. These included two rotor configurations, three rotor tip clearances, addition of boundary-layer control consisting of vortex generators on both the outer casing and the rotor, and the introduction of slots in the stator vanes. Design performance objectives were a stage total pressure ratio of 3.0 with an isentropic efficiency of 0.82 at a tip speed of 1600 ft/s (488 m/s). The first configuration passed only 70 percent of design flow at design speed, achieving a stage pressure ratio of 2.25 at a peak stage isentropic efficiency of 0.61. The rotor was grossly separated. The tenth variant passed 91.4 percent of design flow at design speed, producing a stage pressure ratio of 3.03 with an isentropic efficiency of 0.75. The rotor achieved a pressure ratio of 3.59 at an efficiency of 0.87 under the same conditions. Major conclusions were that design tools available today would undoubtedly permit the original goals to be met or exceeded. However, the application for such a design is currently questionable because efficiency goals considered acceptable for most current programs have risen considerably from the level considered acceptable at the inception of this effort. Splitter vanes placed in the rotor permitted very high diffusion levels to be achieved without stalling. However, viscous effects causing three-dimensional flows violating the assumption of flow confined to concentric stream tubes were so strong that a geometry optimization does not appear practical without a three-dimensional, viscous analysis. Passive boundary-layer control in the form of vortex generators and slots does appear to offer some benefit under certain circumstances.

Three-Dimensional-Flow Theories for Axial Compressors and Turbines

1948 ◽  
Vol 159 (1) ◽  
pp. 255-268 ◽  
Author(s):  
A. D. S. Carter
Keyword(s):  
Three Dimensional ◽  
Axial Compressor ◽  
Physical Nature ◽  
Secondary Flows ◽  
Operating Conditions ◽  
Tip Clearance ◽  
Three Dimensional Flow ◽  
Axial Compressors ◽  
Dimensional Flow ◽  
Blade Row

It has long been known that the energy losses occurring in an axial compressor or turbine cannot be fully accounted for by the skin-friction losses on the blades and annulus walls. The difference, usually termed secondary loss, is attributed to miscellaneous secondary flows which take place in the blade row. These flows both cause losses in themselves and modify the operating conditions of the individual blade sections, to the detriment of the overall performance. This lecture analyses the three-dimensional flow in axial compressors and turbines, so that, by appreciation of the factors involved, possible methods of improving the performance can readily be investigated. The origin of secondary flow is first examined for the simple case of a straight cascade. The physical nature of the flow, and theories which enable quantitative estimates to be made, are discussed at some length. Following this, the three-dimensional flow in an annulus with a stationary blade row is examined, and, among other things, the influence of radial equilibrium on the flow pattern is noted. All physical restrictions are then removed, and the major factors governing the three-dimensional flow in an actual machine are investigated as far as is possible with existing information, particular attention being paid to the influence of a non-uniform velocity profile, tip clearance, shrouding, and boundary layer displacement. Finally the various empirical factors used in design are discussed, and the relationships between them established.

A Deep Insight Into the Transonic Flow of an Advanced Centrifugal Compressor Design

2019 ◽  
Author(s):  
D. Wittrock ◽  
M. Junker ◽  
M. Beversdorff ◽  
A. Peters ◽  
E. Nicke
Keyword(s):  
Centrifugal Compressor ◽  
Pressure Ratio ◽  
Three Dimensional ◽  
Leading Edge ◽  
Free Form ◽  
Numerical Verification ◽  
Deep Insight ◽  
Flow Solver ◽  
Compressor Design ◽  
Design Speed

Abstract In the last decades major improvements in transonic centrifugal compressor design have been achieved. The further exploration of design space is enabled by recent progress in structural mechanics and manufacturing. A challenging task of inducer design especially in terms of transonic inflow conditions is to provide a wide flow range and reduced losses due to a sufficient shock control. The use of so called multidisciplinary design optimization with an extensive amount of free parameters leads finally to complex designs. DLR’s latest Fast Rotating Centrifugal Compressor (SRV5) operates at a design speed of Mu2 = 1.72 and a total pressure ratio of 5.72. This compressor design is characterized by an S-shaped leading edge and free-form blade surfaces. Due to the complex design the key design features are difficult to explore. Therefore, non-intrusive measurements are conducted on the highly loaded SRV5. The Laser-2-Focus (L2F) approach that is used in addition with the Doppler Global Velocimetry (DGV) delivers a three dimensional velocity field. Besides the impeller inflow the ouflow is also part of the experimental and numerical verification of the advanced compressor design. Experimental results are compared with the numerical analysis of the compressor using DLR’s RANS Flow Solver TRACE. The deep insight of the inflow leads to a better understanding of the operating behavior of such impeller designs.

Numerical Analysis of Internal Flow Field in an Impeller with the Time Marching Method

2011 ◽  
Vol 94-96 ◽  
pp. 1476-1480
Author(s):  
Cai Hua Wang
Keyword(s):  
Flow Field ◽  
High Speed ◽  
Pressure Ratio ◽  
Three Dimensional ◽  
Internal Flow ◽  
Centrifugal Impeller ◽  
Three Dimensional Flow ◽  
Vector Distribution ◽  
Time Marching ◽  
Marching Method

Centrifugal compressors are power machineries used widely. Fully understanding of the complex three-dimensional flow field is very important to design higher pressure ratio, higher efficiency centrifugal compressor. In this paper, time marching method is adopted to solve the three-dimensional viscous N-S equations under the relative coordinate system. The internal flow field of the “full controllable vortex” high speed centrifugal impeller is analyzed and the medial velocity vector distribution and the development of the velocity of each section in the impeller are showed. From the figures, it can be seen that the “wake” phenomenon, such as Ecckart described, caused by the curvature, Coriolis force and the boundary layer is exist

Experimental Study of the Flow Field Within a Transonic Axial Compressor Rotor by Laser Velocimetry and Comparison With Through-Flow Calculations

1978 ◽  
Vol 100 (2) ◽  
pp. 279-286 ◽  
Author(s):  
R. J. Dunker ◽  
P. E. Strinning ◽  
H. B. Weyer
Keyword(s):  
Flow Field ◽  
Pressure Ratio ◽  
Analytical Data ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Compressor Rotor ◽  
Through Flow ◽  
Equivalent Mass ◽  
Transonic Axial Compressor ◽  
Design Speed

The flow field ahead, within, and behind the rotor of a transonic axial compressor designed for a total pressure ratio of 1.51 at a relative tip Mach number of 1.4 has been studied in detail using an advanced laser velocimeter. The tests were carried out at 70 and 100 percent design speed (20,260 rpm) and equivalent mass flows corresponding to the point of maximum isentropic efficiency. The tests yielded quite complete data on the span- and gap-wise velocity profiles, on the three-dimensional shock waves in and outside of the rotor blade channels, and on the blade wakes. Some of the experimental results will be submitted, discussed, and compared to corresponding analytical data of a through-flow calculation. The comparison reveals considerable discrepancies inside the blade row between the two-dimensional calculation and the experiments primarily due to the loss and deviation correlations used, as well as to the distribution of losses and flow angles inside the blade channels.

scholarly journals The Turbine Regime of a Rear Axial Compressor Stage

1990 ◽  
Author(s):  
Václav Cyrus
Keyword(s):  
Aspect Ratio ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Compressor Stage ◽  
Flow Mechanism ◽  
Three Dimensional Flow ◽  
Low Speed ◽  
Dimensional Flow ◽  
Blade Row ◽  
Stator Blade

A detailed investigation of three-dimensional flow has been carried out in a low speed rear axial compressor stage with aspect ratio of 1 at the extreme off-design condition-turbine regime. Measurements were performed by means of both stationery and rotating pressure probes. The mechanism of flow in the rotor and stator blade row in the turbine regime is analysed. Comparison is made with flow mechanism at the design condition.

Experimental Study of an Axial Compressor Rotor Transfer Function With Non-Uniform Inlet Flow

1978 ◽  
Author(s):  
J. Colpin ◽  
P. Kool
Keyword(s):  
Flow Field ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Hot Wire ◽  
Flow Angle ◽  
Compressor Rotor ◽  
Rotating Blade ◽  
Absolute Flow ◽  
Blade Row ◽  
Upstream Flow

The aim of the investigation is to study the propagation of a non-uniform upstream flow field through a rotating blade row. The flow is investigated using classical pneumatic instrumentation and hot wire anemometry. The latter allows one to determine the average flow values as well as the instantaneous blade-to-blade flow field. These measurements were performed upstream and downstream of a low-speed axial compressor stage rotor. A triangular inlet total pressure distortion was generated with a grid system, movable in the circumferential direction. The hot-wire data were processed with a periodic sampling and averaging technique to obtain the three-dimensional blade-to-blade flow downstream of the rotor at mid-span. The modification of the blade wakes and the existence of large absolute flow angle fluctuations are evidenced for different relative positions of the distortion and stationary hot wire.

Experimental Study of Three-Dimensional Flow in an Axial Compressor Stage

1986 ◽  
Author(s):  
Vaclav Cyrus
Keyword(s):  
Three Dimensional ◽  
Axial Compressor ◽  
Loss Coefficient ◽  
Flow Coefficient ◽  
Compressor Stage ◽  
Three Dimensional Flow ◽  
High Loss ◽  
Dimensional Flow ◽  
Blade Row ◽  
Stator Blade

A detailed investigation of three-dimensional flow was carried out in a low speed axial compressor stage with aspect ratio of 2. Data were obtained over a range of flow coefficient. The origin of large high loss regions in each blade row was found by means of a diffusion factor. The loss coefficient of rotor and stator blade rows was established on the basis of both rotating and stationary pressure probes. The predicted rotor and stator loss coefficient was compared with experiment.

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