Linearized Solutions for the Supersonic Flow Through Turbomachinery Blade Rows (Using Actuator Disk Theory)

1980 ◽  
Vol 102 (3) ◽  
pp. 330-337
Author(s):  
J. H. Horlock ◽  
C. F. Grainger
Keyword(s):  
Supersonic Flow ◽  
Method Of Characteristics ◽  
Three Dimensional ◽  
Actuator Disk ◽  
Blade Row ◽  
Flow Through ◽  
Twisted Blade ◽  
Disk Method

An actuator disk method is developed for calculating the flow through the blade rows of a turbomachine in which the velocity relative to the blading may be supersonic. The method is compared with calculations of the fully supersonic flow through a twisted blade row using a three-dimensional method of characteristics.

The Simulation of Turbomachinery Blade Rows in Asymmetric Flow Using Actuator Disks

1997 ◽  
Vol 119 (4) ◽  
pp. 723-732 ◽  
Author(s):  
W. G. Joo ◽  
T. P. Hynes
Keyword(s):  
Supersonic Flow ◽  
Flow Field ◽  
Boundary Conditions ◽  
High Speed ◽  
Axial Position ◽  
Numerical Implementation ◽  
Asymmetric Flow ◽  
Actuator Disk ◽  
Blade Row ◽  
Flow Through

This paper describes the development of actuator disk models to simulate the asymmetric flow through high-speed low hub-to-tip ratio blade rows. The actuator disks represent boundaries between regions of the flow in which the flow field is solved by numerical computation. The appropriate boundary conditions and their numerical implementation are described, and particular attention is paid to the problem of simulating the effect of blade row blockage near choking conditions. Guidelines on choice of axial position of the disk are reported. In addition, semi-actuator disk models are briefly described and the limitations in the application of the model to supersonic flow are discussed.

Spatial Supersonic Flow Through Annular Cascades

1976 ◽  
Vol 98 (2) ◽  
pp. 274-280
Author(s):  
H. H. Fruehauf
Keyword(s):  
Supersonic Flow ◽  
Approximation Method ◽  
Method Of Characteristics ◽  
Three Dimensional ◽  
Dimensional Approximation ◽  
Practical Design ◽  
Dynamical Parameters ◽  
Flow Through ◽  
Guiding Principles

The spatial supersonic flow through rotating and stationary annular cascades is analyzed by means of a nonlinear three-dimensional method of characteristics. Three-dimensional corrections for flow quantities referred to a quasi-three-dimensional approximation method are determined depending on geometric and gas dynamical parameters. Characteristic properties of spatial supersonic flow through annular cascades are analyzed, leading to guiding principles for practical design purposes.

Excess Streamwise Vorticity and Its Role in Secondary Flow

1987 ◽  
Vol 201 (6) ◽  
pp. 413-420 ◽  
Author(s):  
P W James
Keyword(s):  
Secondary Flow ◽  
Gas Turbines ◽  
Three Dimensional ◽  
Point Of View ◽  
Streamwise Vorticity ◽  
Three Dimensional Flow ◽  
Approximate Methods ◽  
Blade Row ◽  
Flow Through ◽  
Loss Term

The purpose of this paper is, firstly, to show how the concept of excess secondary vorticity arises naturally from attempts to recover three-dimensional flow details lost in passage-averaging the equations governing the flow through gas turbines. An equation for the growth of excess streamwise vorticity is then derived. This equation, which allows for streamwise entropy gradients through a prescribed loss term, could be integrated numerically through a blade-row to provide the excess vorticity at the exit to a blade-row. The second part of the paper concentrates on the approximate methods of Smith (1) and Came and Marsh (2) for estimating this quantity and demonstrates their relationship to each other and to the concept of excess streamwise vorticity. Finally the relevance of the results to the design of blading for gas turbines, from the point of view of secondary flow, is discussed.

Nonaxisymmetric Flow through Annular Actuator Disks: Inlet Distortion Problem

1978 ◽  
Vol 100 (4) ◽  
pp. 604-617 ◽  
Author(s):  
W. R. Hawthorne ◽  
N. A. Mitchell ◽  
J. E. McCune ◽  
C. S. Tan
Keyword(s):  
Three Dimensional ◽  
Axial Compressor ◽  
Recent Experimental Data ◽  
Recent Theory ◽  
Inlet Distortion ◽  
Actuator Disk ◽  
Beltrami Flow ◽  
Compressor Rotor ◽  
Flow Through ◽  
Absolute Coordinates

The passage of distorted flow through an annular axial compressor rotor or stator is analyzed in the actuator disk limit. In such a description the flow is steady in absolute coordinates. The resulting analysis yields an overall description of the blade row performance in the presence of inlet flow defects. The present (actuator-disk) analysis is compared successfully with Dunham’s earlier three-dimensional analysis as well as with recent experimental data. In addition, comparison with a recent theory by Greitzer, employing an alternative approach, is made. The analysis shows that at least two important distinct types of vorticity arise, the one being directly analogous to the trailing vorticity (shed circulation) of classical wing theory, and the second being analogous to the vorticity occurring in “secondary flow” theory. The latter arises directly as a result of inlet distortion. The resulting varying flow angles produce spanwise variation in blade loading, and consequent trailing vorticity (Beltrami Flow). The two types of vorticity are therefore interrelated. The static pressure field is also affected by this coupling in agreement with experiment. This problem provided a striking example for which three-dimensional and two-dimensional analyses disagree qualitatively. The vorticity as viewed in coordinates fixed in the rotor is discussed in the Addendum.

scholarly journals Loss and Deviation in Windmilling Fans

2016 ◽  
Vol 138 (10) ◽  
Author(s):  
Ewan J. Gunn ◽  
Cesare A. Hall
Keyword(s):  
Control Volume ◽  
Three Dimensional ◽  
Flow Coefficient ◽  
High Loss ◽  
Pressure Surface ◽  
Blade Row ◽  
Computational Fluid Dynamics Cfd ◽  
Flow Through ◽  
Transonic Fan ◽  
Cruise Flight

For an unpowered turbofan in flight, the airflow through the engine causes the fan to freewheel. This paper considers the flow field through a fan operating in this mode, with emphasis on the effects of blade row losses and deviation. A control volume analysis is used to show that windmilling fans operate at a fixed flow coefficient which depends on the blade metal and deviation angles, while the blade row losses are shown to determine the fan mass flow rate. Experimental and numerical results are used to understand how the loss and deviation differ from the design condition due to the flow physics encountered at windmill. Results are presented from an experimental study of a windmilling low-speed rig fan, including detailed area traverses downstream of the rotor and stator. Three-dimensional computational fluid dynamics (CFD) calculations of the fan rig and a representative transonic fan windmilling at a cruise flight condition have also been completed. The rig test results confirm that in the windmilling condition, the flow through the fan stator separates from the pressure surface over most of the span. This generates high loss, and the resulting blockage changes the rotor work profile leading to modified rotational speed. In the engine fan rotor, a vortex forms at the pressure surface near the tip and further loss results from a hub separation caused by blockage from the downstream core and splitter.

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