Vortical Flow Structure Genesis of Lobed Nozzle Flows

2016 ◽  
Author(s):  
Markus Ruetten ◽  
Fithawi Woldegiorgis
Keyword(s):  
Flow Structure ◽  
Vortical Flow ◽  
Nozzle Flows ◽  
Lobed Nozzle

Disk-driven vortical flow structure in a cubical container

1999 ◽  
Vol 28 (1) ◽  
pp. 41-61 ◽  
Author(s):  
T.P. Chiang ◽  
W.H. Sheu ◽  
S.F. Tsai
Keyword(s):  
Flow Structure ◽  
Vortical Flow

Film Cooling From Short Holes With Sister Hole Influence

2012 ◽  
Author(s):  
Marc J. Ely ◽  
B. A. Jubran
Keyword(s):  
Flow Field ◽  
Flow Structure ◽  
Film Cooling ◽  
Computational Analysis ◽  
Numerical Study ◽  
Vortical Flow ◽  
Injection Hole ◽  
Hole Configuration ◽  
Adiabatic Effectiveness ◽  
Structure Research

This paper reports a computational analysis on the effect of sister hole control on film cooling from short holes. The proposed method includes surrounding a primary injection hole by two or four smaller sister holes to actively maintain flow adhesion along the surface of the blade. A numerical study using the realizable k-ε turbulence model led to the determination that the use of sister holes significantly improves adiabatic effectiveness by countering the primary vortical flow structure. Research was carried out to determine the optimum hole configuration, arriving at the conclusion that placing sister holes slightly downstream of the primary injection hole improves the near-hole effectiveness, while placing sister holes slightly upstream of the primary hole improves downstream effectiveness. Similar results were found in evaluating both long and short hole geometries with a significantly less coherent flow field arising from the short hole. However, on the whole, the sister hole approach to film cooling was found to offer viable improvements over standard cooling regimes.

Experimental and Numerical Visualization of Counter Rotating Vortices

2016 ◽  
Vol 138 (8) ◽  
Author(s):  
Jeongmoon Park ◽  
Axy Pagan-Vazquez ◽  
Jorge L. Alvarado ◽  
Leonardo P. Chamorro ◽  
Scott Lux ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Flow Structure ◽  
Stability Region ◽  
Vortex Generator ◽  
Vortex Generators ◽  
Vortical Flow ◽  
Taper Angle ◽  
Numerical Visualization ◽  
The Stability ◽  
Upstream Flow

Visualization of the flow structure generated by passive vortex generators continues to be a matter of research in the fluid mechanics and heat transfer communities. In this study, self-sustaining counter-rotating vortex pairs (CVP) generated from a series of vortex generators (VG) have been characterized numerically and experimentally to understand the effects of the VG parameters on vortical flow structure formation. Four different types of VGs were considered by varying the taper angle from 0° to 19.3° at a fixed inclination angle of 24.5° and a Reynolds number of 1965. Flow fields were experimentally visualized using a smoke technique. Each VG induced a coherent CVP flow structure in the wake region despite the fact that the upstream flow was laminar. CVPs initially dominate flow dynamics over a certain streamwise length; however, Kelvin-Helmholtz (KH) instability appears to affect the spatial evolution of CVP longitudinally. The CVP within the stability region were reconstructed digitally in 3D by interpolating several 2D smoke images taken at various spanwise planes. The smoke results indicate that as taper angle decreases, the onset location of KH instability decreases. Furthermore, the CVP trajectory within the stability region was observed to be predominantly controlled by a two-dimensional inviscid process, while the effects by the free stream were not significant. Based on the experimental observations and the numerically reconstructed 3D CVP flow structures, VG with smaller taper angle results in CVPs with higher circulation, which is a positive aspect for mass and heat transfer applications. Preliminary numerical simulations based on RANS have shown that heat transfer enhancement is about 50% in the region near the rectangular vortex generator.

scholarly journals Vortical Flow Structure Identification and Flow Transport in Arteries

2002 ◽  
Vol 5 (3) ◽  
pp. 261-273 ◽  
Author(s):  
D.J. Doorly ◽  
S.J. Sherwin ◽  
P.T. Franke ◽  
J. Peiró
Keyword(s):  
Flow Structure ◽  
Vortical Flow ◽  
Structure Identification ◽  
Flow Transport

Vortical Flow Structure and Loss Generation Process in a Transonic Centrifugal Compressor Impeller

2007 ◽  
Author(s):  
Seiichi Ibaraki ◽  
Masato Furukawa ◽  
Kenichiro Iwakiri ◽  
Kazuya Takahashi
Keyword(s):  
Flow Field ◽  
Flow Structure ◽  
Centrifugal Compressor ◽  
Secondary Flows ◽  
Vortical Flow ◽  
Generation Process ◽  
Tip Leakage ◽  
Transonic Centrifugal Compressor ◽  
Compressor Impeller ◽  
Flow Phenomena

Transonic centrifugal compressors are used in turbochargers and turboshaft engines because of their small dimensions, relatively high efficiency and wide operating range. The flow field of the transonic centrifugal compressor impeller is highly three dimensional, and is complicated by shock waves, tip leakage vortices, secondary flows and the interactions among them. In order to improve the performance, it is indispensable to understand these complicated flow phenomena in the impeller. Although experimental and numerical research on transonic impeller flow has been reported, thus providing important flow physics, some undetected flow phenomena remain. The authors of the present report carried out detailed Navier-Stokes computations of a transonic impeller flow measured by Laser Doppler Velocimetry (LDV) in previous work. The highly complicated vortical flow structure and the mechanism of loss generation were revealed by a visual data mining technique, namely vortex identification based on the critical point theory and limiting streamline mapping by means of line integral convolution. As a result, it was found that the tip leakage vortices have a significant impact on the flow field and vortex breakdowns that increase the blockage of the flow passage, and that these were caused by shock wave interaction.

An Experimental Investigation of a Vortex Flow Cascade

1988 ◽  
Author(s):  
Tang Yan-Ping ◽  
Chen Mao-Zhang
Keyword(s):  
Experimental Investigation ◽  
Flow Pattern ◽  
Flow Structure ◽  
Large Scale ◽  
Vortex Flow ◽  
Vortex Generator ◽  
Vortical Flow ◽  
Compressor Cascade ◽  
Loss Mechanism ◽  
New Type

A new type of compressor cascade, called the vortex flow cascade (shortly VFC), has been developed in the paper. The VFC is made up of the normal compressor cascade (shortly NCC) with NACA-65-0010 profile and vortex generator. Experiments are conducted for researching the effects of a large scale streamwise control vortex on the flow structure inside cascade passage. The results are encouraging. Based on the present investigation the vortical flow pattern and loss mechanism of VFC have been discussed.

A Parametric Study on the Effect of Sister Hole Location on Active Film Cooling Flow Control

2010 ◽  
Author(s):  
Marc J. Ely ◽  
B. A. Jubran
Keyword(s):  
Flow Structure ◽  
Parametric Study ◽  
Film Cooling ◽  
Numerical Evaluation ◽  
Vortical Flow ◽  
Injection Hole ◽  
Cooling Flow ◽  
Hole Configuration ◽  
Adiabatic Effectiveness ◽  
Structure Research

This paper presents an investigation on the effect of sister holes on film cooling. The proposed technique surrounds a primary injection hole by two or four smaller sister holes to actively maintain flow adhesion along the surface of the blade. A numerical evaluation using the realizable k-ε turbulence model led to the determination that the use of sister holes significantly improves adiabatic effectiveness by countering the primary vortical flow structure. Research was performed to determine the optimal hole configuration, arriving at the conclusion that placing sister holes slightly downstream of the primary injection hole improves the near-hole effectiveness, while placing sister holes slightly upstream of the primary hole improves downstream effectiveness. On the whole, the sister hole approach to film cooling was found to offer viable improvements over standard cooling regimes.

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