Two-Dimensional Method for Calculating Separated Flow in a Centrifugal Impeller

1975 ◽  
Vol 97 (4) ◽  
pp. 581-591 ◽  
Author(s):  
D. P. Sturge ◽  
N. A. Cumpsty
Keyword(s):  
Compressible Flow ◽  
Experimental Observation ◽  
Calculation Method ◽  
Separated Flow ◽  
Suction Side ◽  
Inviscid Flow ◽  
Centrifugal Impeller ◽  
Two Dimensional

A method of calculating a two-dimensional incompressible and inviscid flow within a centrifugal impeller where the flow separates from the suction side has been developed. Based on experimental observation it has been assumed that mixing of the throughflow with the separated region is suppressed. After a description of the calculation method, which is rather unusual, some results are presented and the implications discussed. The possibility of extending the method to handle compressible flow is outlined.

Effects of System Rotation on the Performance of Two-Dimensional Diffusers

1976 ◽  
Vol 98 (3) ◽  
pp. 422-429 ◽  
Author(s):  
P. H. Rothe ◽  
J. P. Johnston
Keyword(s):  
Rotation Number ◽  
Rectangular Cross Section ◽  
Flow Distribution ◽  
Suction Side ◽  
Area Ratio ◽  
Pressure Recovery ◽  
Centrifugal Impeller ◽  
Two Dimensional ◽  
Recovery Coefficient ◽  
Coriolis Acceleration

Experiments with incompressible flow are reported concerning the effects of Coriolis acceleration on flow separation and on separated flow in plane-wall diffusers of rectangular cross section. The diffusers were rotated about an axis perpendicular to the plane of the nearly two-dimensional flow in order to simulate some features of the blade-to-blade flow distribution in the radial portion of the centrifugal impeller. Various stall regimes are mapped on coordinates of rotation number and diffuser area ratio (at fixed wall length). Diffuser pressure-recovery coefficient is reported as a function of area ratio and rotation number. These data demonstrate that, by suppressing turbulent mixing and shear stress in the suction-side boundary layers, the Coriolis acceleration field greatly enhances the tendency for stall to appear in a diffuser. This effect causes a corresponding reduction in the throat-to-exit pressure recovery as compared to that of nonrotating diffusers of the same geometry and inlet flow blockage.

Inviscid Flow Through a Cascade of Thick, Cambered Airfoils: Part 2—Compressible Flow

1973 ◽  
Vol 95 (3) ◽  
pp. 227-232 ◽  
Author(s):  
D. A. Frith
Keyword(s):  
Numerical Methods ◽  
Compressible Flow ◽  
Stream Function ◽  
Inviscid Flow ◽  
Two Dimensional ◽  
Regular Array ◽  
Unique Method ◽  
Flow Through ◽  
Grid Points ◽  
Inviscid Compressible Flow

Evaluation of two-dimensional, inviscid, compressible flow through a cascade of airfoils must involve numerical methods. Some of the associated problems are avoided if the flow field is mapped to the interior of a unit circle as the airfoil boundaries become grid points of the regular array in this domain. Further, far upstream and far downstream map to points in this circle so the uniform inlet and outlet flows are simply defined. For a solution obtained in terms of a stream function the compressible flow may be derived as a numerical perturbation from an analytical, incompressible stream function. A method incorporating these features is described in detail and some results for thick, cambered airfoils in cascade are presented. As supersonic patches can exist on the airfoils for high subsonic inlet Mach numbers, a unique method of relating the density to the stream function is employed in order to enable such flows to be calculated.

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