Effect of Particle Characteristics on Trajectories and Blade Impact Patterns

1988 ◽  
Vol 110 (1) ◽  
pp. 33-37 ◽  
Author(s):  
A. Hamed
Keyword(s):  
Experimental Data ◽  
Trajectory Analysis ◽  
Three Dimensional ◽  
Axial Flow ◽  
Particle Dynamics ◽  
Rotating Blade ◽  
Particle Characteristics ◽  
Sand Particles ◽  
Particle Laden Flows ◽  
Impact Characteristics

This work presents the results of a detailed study of the effect of particle characteristics on the particle dynamics and on the resulting pattern of blade impacts in a two stage axial flow gas turbine operating with particle laden flows. The particle dynamics computations combine the particle-blade impact characteristics, as determined from a three dimensional trajectory analysis with the particle rebound characteristics, which are obtained from experimental data. The results show the pattern of blade impacts in all stationary and rotating blade rows for fly ash and for sand particles. The results demonstrate that drastically different patterns of particle blade impacts are associated with the different particles.

Turbine Erosion Exposed to Particulate Flow

1986 ◽  
Author(s):  
A. Hamed ◽  
W. Tabakoff ◽  
M. L. Mansour
Keyword(s):  
Experimental Data ◽  
Gas Turbine ◽  
Trajectory Analysis ◽  
Three Dimensional ◽  
Axial Flow ◽  
Particulate Flow ◽  
Blade Row ◽  
Material Erosion ◽  
Erosion Equation ◽  
Impact Characteristics

This work presents the results of a detailed study of blade erosion in a two stage axial flow gas turbine. The computations combine particle-blade impact characteristics, as determined from a three dimensional trajectory analysis with blade material erosion equation, which is obtained from experimental data to predict blade erosion. The results show that the pattern and intensity of blade erosion is dependent on the blade row location and that the first rotor is subject to maximum erosion.

Influence of Secondary Flow on Turbine Erosion

1989 ◽  
Vol 111 (3) ◽  
pp. 310-314 ◽  
Author(s):  
A. Hamed
Keyword(s):  
Secondary Flow ◽  
Gas Turbines ◽  
Trajectory Analysis ◽  
Three Dimensional ◽  
Axial Flow ◽  
Coal Ash ◽  
Particle Dynamics ◽  
Experimental Measurements ◽  
Material Erosion ◽  
Erosion Intensity

This work presents the results of an investigation conducted to study the effect of secondary flow on blade erosion by coal ash particles in axial flow gas turbines. The particle dynamics and their blade impacts are determined from a three-dimensional trajectory analysis within the turbine blade passages. The blade material erosion behavior and the particle rebound characteristics are simulated using empirical equations derived from experimental measurements. The results demonstrate that the secondary flow has a significant influence on the blade erosion intensity and pattern for the typical ash particle size distribution considered in this investigation.

An Experimental Arrangement for the Measurement of the Pressure Distribution on High Speed Rotating Blade Rows

1956 ◽  
Author(s):  
K. Leist
Keyword(s):  
Experimental Investigation ◽  
Pressure Distribution ◽  
High Speed ◽  
Three Dimensional ◽  
Axial Flow ◽  
Three Dimensional Flow ◽  
Research Staff ◽  
Rotating Blade ◽  
Flow Through ◽  
Turbine Blading

For several years past, the research staff of the Institute for Turbomachines of the Aachen Technical University has carried out measurements on rotating turbine blading. This program is part of a comprehensive effort directed toward the experimental investigation of the three-dimensional flow through axial-flow turbomachines.

scholarly journals Effect of Particle Size Distribution on Particle Dynamics and Blade Erosion in Axial Flow Turbines

1990 ◽  
Author(s):  
W. Tabakoff ◽  
A. Hamed ◽  
M. Metwally
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Gas Turbines ◽  
Three Dimensional ◽  
Axial Flow ◽  
Coal Ash ◽  
Particle Dynamics ◽  
Material Erosion ◽  
Particles Size Distribution

This work presents the results of an investigation conducted to study the effect of coal ash particles size distribution on the particle dynamics, and the resulting blade erosion in axial flow gas turbines. The particle dynamics and their blade impacts are determined from a three dimensional trajectory analysis within the turbine blade passages. The particle rebound conditions and the blade material erosion characteristics are simulated using empirical equations, derived from experimental measurements. For the typical ash particle size distribution considered in this investigation, the results demonstrate that the size distribution has a significant influence on the blade erosion intensity and pattern.

Effect of Particle Size Distribution on Particle Dynamics and Blade Erosion in Axial Flow Turbines

1991 ◽  
Vol 113 (4) ◽  
pp. 607-615 ◽  
Author(s):  
W. Tabakoff ◽  
A. Hamed ◽  
M. Metwally
Keyword(s):  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Gas Turbines ◽  
Three Dimensional ◽  
Axial Flow ◽  
Coal Ash ◽  
Particle Dynamics ◽  
Material Erosion ◽  
Effect Of Particle Size

This work presents the results of an investigation conducted to study the effect of coal ash particle size distribution on the particle dynamics, and the resulting blade erosion in axial flow gas turbines. The particle dynamics and their blade impacts are determined from a three-dimensional trajectory analysis within the turbine blade passages. The particle rebound conditions and the blade material erosion characteristics are simulated using empirical equations, derived from experimental measurements. For the typical ash particle size distribution considered in this investigation, the results demonstrate that the size distribution has a significant influence on the blade erosion intensity and pattern.

Mixing in Axial-Flow Compressors: Conclusions Drawn From Three-Dimensional Navier–Stokes Analyses and Experiments

1991 ◽  
Vol 113 (2) ◽  
pp. 139-156 ◽  
Author(s):  
J. H. Leylek ◽  
D. C. Wisler
Keyword(s):  
Experimental Data ◽  
Numerical Solutions ◽  
Turbulence Modeling ◽  
Three Dimensional ◽  
Axial Flow ◽  
Separated Flow ◽  
Navier Stokes ◽  
Tracer Gas ◽  
Flow Through ◽  
Axial Flow Compressors

Extensive numerical analyses and experiments have been conducted to understand mixing phenomena in multistage, axial-flow compressors. For the first time in the literature the following are documented: Detailed three-dimensional Navier–Stokes solutions, with high order turbulence modeling, are presented for flow through a compressor vane row at both design and off-design (increased) loading; comparison of these computations with detailed experimental data show excellent agreement at both loading levels; the results are then used to explain important aspects of mixing in compressors. The three-dimensional analyses show the development of spanwise (radial) and circumferential flows in the stator and the change in location and extent of separated flow regions as loading increases. The numerical solutions support previous interpretations of experimental data obtained on the same blading using the ethylene tracer-gas technique and hot-wire anemometry. These results, plus new tracer-gas data, show that both secondary flow and turbulent diffusion are mechanisms responsible for both spanwise and circumferential mixing in axial-flow compressors. The relative importance of the two mechanisms depends upon the configuration and loading levels. It appears that using the correct spanwise distributions of time-averaged inlet boundary conditions for three-dimensional Navier–Stokes computations enables one to explain much of the flow physics for this stator.

On the Aerodynamics of Swept and Leaned Transonic Compressor Rotors

2006 ◽  
Author(s):  
Ernesto Benini ◽  
Roberto Biollo
Keyword(s):  
Experimental Data ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Axial Flow ◽  
Systematic Investigation ◽  
Control Points ◽  
Complex Flow ◽  
Transonic Compressor ◽  
Curvature Effects ◽  
The Impact

A systematic investigation to understand the impact of axially swept and tangentially leaned blades on the aerodynamic behaviour of transonic axial flow compressor rotors was undertaken. Effects of axial and tangential blade curvature were separately analyzed. A commercial CFD package which solves the Reynolds-average Navier-Stokes equations was used to compute the complex flow field of transonic compressor rotors. The code was validated against NASA Rotor 37 existing experimental data. Computed performance maps and downstream profiles showed a very good agreement with measured ones. Furthermore, comparisons with experimental data indicated that the overall features of the three-dimensional shock structure, the shock-boundary layer interaction, and the wake development are calculated very well in the numerical solution. Next, a quite large number of new transonic swept rotors (26) were modeled from the original Rotor 37, by changing the meridional curvature of the original stacking line through three previously defined control points (located at 33%, 67% and 100% of the span). An attempt was made to not modify any other design parameter. In particular, in order to isolate the influence of sweep on the aerodynamic behaviour of the new rotors, the meridional position of the tip blade profiles was not changed. Similarly, 26 new transonic leaned rotors were modeled from the same Rotor 37 by changing the circumferential position of the same control points. All the new transonic rotors were simulated and the results revealed many interesting aspects which are believed to be very helpful to better understand the blade curvature effects on the shock and secondary losses within a transonic rotor.

Three-Dimensional Potential Flow and Effects of Blade Dihedral in Axial Flow Propeller Pumps

1977 ◽  
Vol 99 (1) ◽  
pp. 167-175 ◽  
Author(s):  
R. Howells ◽  
B. Lakshminarayana
Keyword(s):  
Potential Flow ◽  
Three Dimensional ◽  
Axial Flow ◽  
Three Dimensional Flow ◽  
Dimensional Flow ◽  
Pressure Distributions ◽  
Rotating Blade ◽  
Satisfactory Approximation ◽  
Flow Through ◽  
Flow Effects

A relatively simple and rapid method for predicting the three-dimensional flow effects in axial flow turbomachinery was investigated. Although the two-dimensional cascade is a satisfactory approximation for the design and analysis of some types of turbo-machines, the flow through devices, such as propeller pumps and inducers, may deviate significantly. A three-dimensional lifting surface theory was used to predict the potential flow around blades, represented by line vortices and sources, spanning an annulus. A rotor was designed, built, and tested (with air as the test medium) for comparison with the theory. Static pressure distributions on a rotating blade were measured. The effect of blade dihedral on these pressures was also measured. Deviation from cascade predictions caused by the three-dimensional flow effects is found to be appreciable for propeller pumps. No theory was developed, but variation of the experimental blade pressure distributions caused by dihedral was found to be considerable.

Three-Dimensional Structure and Decay of Vortices Behind an Axial Flow Rotating Blade Row

1984 ◽  
Vol 106 (3) ◽  
pp. 561-569 ◽  
Author(s):  
M. Inoue ◽  
M. Kuroumaru
Keyword(s):  
Three Dimensional ◽  
Axial Flow ◽  
Numerical Differentiation ◽  
Horseshoe Vortex ◽  
Dimensional Structure ◽  
Sampling Point ◽  
Three Dimensional Structure ◽  
Rotating Blade ◽  
Blade Row ◽  
Trailing Vortices

Detailed measurements were made of the three-dimensional turbulent flow field behind an axial-flow rotating blade row. The flow was surveyed at 15 radial locations and 70 circumferential sampling points in five measuring planes parallel to the trailing edge of the rotor. Statistically accurate mean velocities as well as turbulence stresses were obtained from numerous hot-wire signals, more than 12,000 for each sampling point. Vorticities were derived by the numerical differentiation of these data. The three-dimensional structure of various kinds of vortices generated through the rotor, such as a leakage vortex, trailing vortices, scraping vortices, a horseshoe vortex, etc. were elucidated quantitatively by use of the local streamwise, lateral and normal components of vorticity. The decay characteristics of these vortices were investigated in relation to the distribution of the turbulent stresses.

SAF file: It's really three dimensional file

2018 ◽  
Vol 14 (1) ◽  
pp. 1
Author(s):  
Prof. Dr. Jamal Aziz Mehdi
Keyword(s):  
Cross Section ◽  
Root Canal ◽  
Three Dimensional ◽  
Circular Cross Section ◽  
Circular Motion ◽  
Root Canal Treatment ◽  
Metal Core ◽  
Rotating Blade

The biological objectives of root canal treatment have not changed over the recentdecades, but the methods to attain these goals have been greatly modified. Theintroduction of NiTi rotary files represents a major leap in the development ofendodontic instruments, with a wide variety of sophisticated instruments presentlyavailable (1, 2).Whatever their modification or improvement, all of these instruments have onething in common: they consist of a metal core with some type of rotating blade thatmachines the canal with a circular motion using flutes to carry the dentin chips anddebris coronally. Consequently, all rotary NiTi files will machine the root canal to acylindrical bore with a circular cross-section if the clinician applies them in a strictboring manner

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