Three-dimensional flow field downstream of an embedded stator in a multistage axial flow compressor: Part 1: Steady and unsteady flow fields

Author(s):  
J Prato ◽  
B Lakshminarayana ◽  
N Suryavamshi
1992 ◽  
Vol 114 (3) ◽  
pp. 675-685 ◽  
Author(s):  
A. Goto

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.


Author(s):  
J. Prato ◽  
B. Lakshminarayana ◽  
N. Suryavamshi

A comprehensive investigation of the three-dimensional unsteady flow and thermal field downstream of an embedded stator in a multistage compressor, acquired with a high-response hot-film probe and aspirating probe, is presented and analyzed. Some of the earlier data (five-hole probe and high-response Kulite probe) from the same compressor is used with the present data to provide an integrated and comprehensive interpretation of the flow and thermal fields. The emphasis is on the unsteady flow, unsteady thermal, and integrated flow fields. Part 1 covers the description of the facility and the development of the hot-film technique for multistage flow field measurement. In addition, the unsteady velocity field is presented and interpreted. Part 2 provides an integrated assessment of the stagnation pressure, temperature and velocity fields to derive a comprehensive understanding of the time-averaged flow features. The final part covers velocity-velocity and velocity-temperature correlations and the assessment of their magnitudes in the average-passage equations. The results from an area traverse of the unsteady velocity field derived from a 45 degree slanted film probe downstream of the second stator of a three-stage axial flow compressor are presented and discussed in this paper. The measurements were conducted at the peak efficiency operating point using a four-rotation method. The ensemble-averaged unsteady three-dimensional velocity data is resolved into the time-averaged component, revolution and blade periodic, and aperiodic components. Some of the features of the rotor 2 flow, measured at the exit of stator 2, reveal the extent of the spread of the upstream rotor wakes and the unsteadiness due to rotor hub and leakage flow regions and levels of periodic and aperiodic unsteadiness. Both the revolution and blade periodic velocity fluctuations are seen to be significantly greater than the aperiodic fluctuations.


Author(s):  
Zhaohui Du ◽  
Wanlai Lin ◽  
Xiaocheng Zhu ◽  
Yan Zhao

In this paper, a three-color dual-beam PDA (Particle Dynamic Analyzer) system (made by DANTEC Measurement Technology) is used to measure the three-dimensional velocity of an axial flow fan. Due to the geometrical limit of fan rotor, non-orthogonal velocity components are measured first, from which the orthogonal three-dimensional components of the velocity field are computed through transformation equations. The detailed flow fields at 15 axial locations upstream, inside and at the exit of the rotor are measured, respectively. On each cross section perpendicular to the rotating axis, the flow field measurement at 15 different radial locations from 50% of the blade span to the region inside the tip clearance (between the tip blade and the casing wall) are taken. The experimental technique is described, and the three dimensional flow fields (including the tip clearance flow) are presented and analyzed.


2006 ◽  
Vol 2006 (0) ◽  
pp. _G607-1_-_G607-4_
Author(s):  
Ken-ichiro IWAKIRI ◽  
Ryusuke OHTAGURO ◽  
Sho BONKOHARA ◽  
Yasuhiro SHIBAMOTO ◽  
Kazutoyo YAMADA ◽  
...  

Author(s):  
Akira Goto

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 hot-wire 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 spanwise 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.


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