scholarly journals Discussion: “Experimental Study on the Three-Dimensional Flow Within a Compressor Cascade With Tip Clearance: Part II—The Tip Leakage Vortex” (Kang, S., and Hirsch, C., 1993, ASME J. Turbomach., 115, pp. 444–450)

1993 ◽  
Vol 115 (3) ◽  
pp. 450-451
Author(s):  
N. A. Cumpsty ◽  
E. M. Greitzer
Keyword(s):  
Experimental Study ◽  
Three Dimensional ◽  
Tip Clearance ◽  
Compressor Cascade ◽  
Three Dimensional Flow ◽  
Tip Leakage Vortex ◽  
Tip Leakage ◽  
Dimensional Flow

Experimental Study on the Three-Dimensional Flow Within a Compressor Cascade With Tip Clearance: Part I—Velocity and Pressure Fields

1993 ◽  
Vol 115 (3) ◽  
pp. 435-443 ◽  
Author(s):  
S. Kang ◽  
C. Hirsch
Keyword(s):  
Three Dimensional ◽  
Leading Edge ◽  
Surface Flow ◽  
Tip Clearance ◽  
Tip Vortex ◽  
Compressor Cascade ◽  
Three Dimensional Flow ◽  
Tip Leakage Vortex ◽  
Tip Leakage ◽  
Dimensional Flow

Experimental results from a study of the three-dimensional flow in a linear compressor cascade with stationary endwall at design conditions are presented for tip clearance levels of 1.0, 2.0, and 3.3 percent of chord, compared with the no-clearance case. In addition to five-hole probe measurements, extensive surface flow visualizations are conducted. It is observed that for the smaller clearance cases a weak horseshoe vortex forms in the front of the blade leading edge. At all the tip gap cases, a multiple tip vortex structure with three discrete vortices around the midchord is found. The tip leakage vortex core is well defined after the midchord but does not cover a significant area in traverse planes. The presence of the tip leakage vortex results in the passage vortex moving close to the endwall and the suction side.

Experimental Study on the Three-Dimensional Flow Within a Compressor Cascade With Tip Clearance: Part II—The Tip Leakage Vortex

1993 ◽  
Vol 115 (3) ◽  
pp. 444-450 ◽  
Author(s):  
S. Kang ◽  
C. Hirsch
Keyword(s):  
Vortex Core ◽  
Three Dimensional ◽  
Leading Edge ◽  
Tip Clearance ◽  
Tip Vortex ◽  
Vortex Center ◽  
Compressor Cascade ◽  
Suction Surface ◽  
Tip Leakage Vortex ◽  
Tip Leakage

An analysis of the experimental data of a linear compressor cascade with tip clearance is presented with special attention to the development of the tip leakage vortex. A method for determining the tip vortex core size, center position, and vorticity or circulation from the measured data is proposed, based on the assumption of a circular tip vortex core. It is observed that the axial velocity profile passing through the tip vortex center is wavelike. The vorticity of the tip vortex increases rapidly near the leading edge and reaches its highest values at a short distance downstream, from which it gradually decreases. In the whole evolution, its size is growing and its center is moving away from both the suction surface and the endwall, approximately in a linear way.

scholarly journals Experimental Study on the Three Dimensional Flow Within a Compressor Cascade With Tip Clearance: Part II — The Tip Leakage Vortex

1992 ◽  
Author(s):  
Shun Kang ◽  
Ch. Hirsch
Keyword(s):  
Vortex Core ◽  
Three Dimensional ◽  
Leading Edge ◽  
Tip Clearance ◽  
Tip Vortex ◽  
Compressor Cascade ◽  
Suction Surface ◽  
Tip Leakage Vortex ◽  
Tip Leakage ◽  
Vortex Centre

An analysis of the experimental data of a linear compressor cascade with tip clearance is presented with special attention to the development of the tip leakage vortex. A method for determining the tip vortex core size, centre position and vorticity or circulation from the measured data is proposed, based on the assumption of a circular tip vortex core. It is observed that the axial velocity profile passing through the tip vortex centre is wake-like. The vorticity of the tip vortex increases rapidly near the leading edge and reaches its highest values at a short distance downstream, from which it gradually decreases. In the whole evolution, its size is growing and its centre is moving away from both the suction surface and the endwall, approximately in a linear way.

scholarly journals Experimental Study on the Three Dimensional Flow Within a Compressor Cascade With Tip Clearance: Part I — Velocity and Pressure Fields

1992 ◽  
Author(s):  
Shun Kang ◽  
Ch. Hirsch
Keyword(s):  
Three Dimensional ◽  
Leading Edge ◽  
Suction Side ◽  
Horseshoe Vortex ◽  
Surface Flow ◽  
Tip Clearance ◽  
Tip Vortex ◽  
Compressor Cascade ◽  
Tip Leakage Vortex ◽  
Tip Leakage

Experimental results from a study of the 3-D flow in a linear compressor cascade with stationary endwall at design conditions are presented for tip clearance levels of 1.0, 2.0 and 3.3 percent of chord, compared with the no clearance case. In addition to five-hole probe measurements, extensive surface flow visualizations are conducted. It is observed that for the smaller clearance cases a weak horseshoe vortex forms in the front of the blade leading edge. At all the tip gap cases, a multiple tip vortex structure with three discrete vortices around the midchord is found. The tip leakage vortex core is well defined after the midchord but does not cover a significantly great area in traverse planes. The presence of the tip leakage vortex results in the passage vortex moving close to the endwall and to the suction side.

Effects of Reynolds Number and Freestream Turbulence on Turbine Tip Clearance Flow

2005 ◽  
Vol 128 (1) ◽  
pp. 166-177 ◽  
Author(s):  
Takayuki Matsunuma
Keyword(s):  
Reynolds Number ◽  
Turbulence Intensity ◽  
Three Dimensional ◽  
Tip Clearance ◽  
Pressure Probe ◽  
Turbine Cascade ◽  
Freestream Turbulence ◽  
Tip Leakage Flow ◽  
Three Dimensional Flow ◽  
Dimensional Flow

Tip clearance losses represent a major efficiency penalty of turbine blades. This paper describes the effect of tip clearance on the aerodynamic characteristics of an unshrouded axial-flow turbine cascade under very low Reynolds number conditions. The Reynolds number based on the true chord length and exit velocity of the turbine cascade was varied from 4.4×104 to 26.6×104 by changing the velocity of fluid flow. The freestream turbulence intensity was varied between 0.5% and 4.1% by modifying turbulence generation sheet settings. Three-dimensional flow fields at the exit of the turbine cascade were measured both with and without tip clearance using a five-hole pressure probe. Tip leakage flow generated a large high total pressure loss region. Variations in the Reynolds number and freestream turbulence intensity changed the distributions of three-dimensional flow, but had no effect on the mass-averaged tip clearance loss of the turbine cascade.

Three-Dimensional Flow and Mixing in an Axial Flow Compressor With Different Rotor Tip Clearances

1992 ◽  
Vol 114 (3) ◽  
pp. 675-685 ◽  
Author(s):  
A. Goto
Keyword(s):  
Velocity Fluctuation ◽  
Three Dimensional ◽  
Axial Flow ◽  
Flow Fields ◽  
Tip Clearance ◽  
Small Scale ◽  
Three Dimensional Flow ◽  
Axial Flow Compressor ◽  
Dimensional Flow ◽  
Flow Compressor

The effect of difference in rotor tip clearance on the mean flow fields and unsteadiness and mixing across a stator blade row were investigated using hot-wire anemometry, pressure probes, flow visualization, and the ethylene tracer-gas technique on a single-stage axial flow compressor. The structure of the three-dimensional flow fields was discussed based on results of experiments using the 12-orientation single slanted hotwire technique and spectrum analysis of velocity fluctuation. High-pass filtered measurements of turbulence were also carried out in order to confirm small-scale velocity fluctuation, which is more realistically referred to as turbulence. The span-wise distribution of ethylene gas spreading, estimated by the measured small-scale velocity fluctuation at the rotor exit, agreed quite well with that which was experimentally measured. This fact suggests the significant role of turbulence, generated within the rotor, in the mixing process across the downstream stator. The value of the maximum mixing coefficient in the tip region was found to increase linearly as the tip clearance became enlarged, starting from the value at midspan.

Three-Dimensional Separated Flow Field in the Endwall Region of an Annular Compressor Cascade in the Presence of Rotor-Stator Interaction: Part I — Quasi-Steady Flow Field and Comparison With Steady-State Data

1989 ◽  
Author(s):  
H. D. Schulz ◽  
H. E. Gallus ◽  
B. Lakshminarayana
Keyword(s):  
Flow Field ◽  
Separation Bubble ◽  
Three Dimensional ◽  
Separated Flow ◽  
Major Influence ◽  
Compressor Cascade ◽  
Three Dimensional Flow ◽  
Dimensional Flow ◽  
Corner Flow ◽  
Rotor Stator Interaction

An experimental study of three-dimensional flow field in an annular compressor cascade with an upstream rotor has been carried out at four different incidences to the stator blade. Blade boundary layers and the three-dimensional flow field at the exit are surveyed using a hot wire sensor and a five hole probe, respectively. The data on the blade boundary layer, passage flow and separated corner flow is presented. The upstream rotor wake has a major influence on the transition, laminar separation bubble, extent of wall/corner flow separation, aerodynamic losses, secondary flow and three-dimensional flow inside the passage. Detailed interpretation of the effects of upstream wakes on the entire passage flow is presented and compared with the data in the absence of a rotor.

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