Experimental Investigation of Aerodynamics and Combustion Properties of a Multiple-Swirler Array

148 Pages·2014·3.16 MB·English

EXPERIMENTAL INVESTIGATION OF AERODYNAMICS AND
COMBUSTION PROPERTIES OF A MULTIPLE-SWIRLER ARRAY

A dissertation submitted to the
Division of Research and Advanced Studies of the University of Cincinnati

in partial fulfillment of the requirements for the degree of

DOCTORATE OF PHILOSOPHY (Ph.D.)

in the Department of Aerospace Engineering and Engineering Mechanics of the College
of Engineering and Applied Science

2014

by

Yi-Huan Kao

B.S., Natioal Tsing Hua University, 2007
M.S., University of Cincinnati, 2012

Committee Chair: Dr. San-Mou Jeng
I
Abstract
An annular combustor is one of the popular configurations of a modern gas turbine combustor.
Since the swirlers are arranged as side-by-side in an annular combustor, the swirling flow interaction
should be considered for the design of an annular gas turbine combustor. The focus of this dissertation is
to investigate the aerodynamics and the combustion of a multiple-swirler array which features the
swirling flow interaction.
A coaxial counter-rotating radial-radial swirler was used in this work. The effects of confinement
and dome recession on the flow field of a single swirler were conducted for understanding the
aerodynamic characteristic of this swirler. The flow pattern generated by single swirler, 3-swirler array,
and 5-swirler array were evaluated. As a result, the 5-swirler array was utilized in the remaining of this
work. The effects of inter-swirler spacing, alignment of swirler, end wall distance, and the presence of
confinement on the flow field generated by a 5-swirler array were investigated. A benchmark of
aerodynamics performance was established. A phenomenological description was proposed to explain
the periodically non-uniform flow pattern of a 5-swirler array.
The non-reacting spray distribution measurements were following for understanding the effect of
swirling flow interaction on the spray distribution issued out by a 5-swirler array. The spray distribution
from a single swirler/ fuel nozzle was measured and treated as a reference. The spray distribution from a
5-swriler array was periodically non-uniform and somehow similar to what observed in the aerodynamic
result.
The inter-swirler spacing altered not only the topology of aerodynamics but also the flame shape
of a 5-swirler array. As a result, the distribution of flame shape strongly depends on the inter-swirler
spacing.
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Table of Contents
ABSTRACT I
TABLE OF CONTENTS II
LIST OF FIGURES V
LIST OF TABLES XI
LIST OF SYMBOLS XII
CHAPTER 1: INTRODUCTION 1
1.1 Introduction of Gas Turbine Combustor and Swirling Flow ................................................................ 1
1.2 Literature Review and Motivation ........................................................................................................ 2
1.3 Scope and Objective of this Dissertation .............................................................................................. 8
CHAPTER 2: EXPERIMENTAL SETUP AND SWIRLER 10
2.1 Counter-Rotating, Radial-Radial Swirler............................................................................................ 10
2.2 Simplex Fuel Nozzle ........................................................................................................................... 11
2.3 Test Facility ........................................................................................................................................ 12
2.4 Stokes Number and Validation of LDV Measurement ....................................................................... 13
CHAPTER 3: EFFECT OF CONFINEMENT ON THE FLOW FIELD GENERATED BY A
COUNTER-ROTATING RAD-RAD SWIRLER 20
3.1 Test Conditions ................................................................................................................................... 20
3.2 Results and Discussions ...................................................................................................................... 21
3.3 Conclusions ......................................................................................................................................... 25
CHAPTER 4: EFFECT OF DOME RECESSION ON THE FLOW FIELD GENERATED BY A
COUNTER-ROTATING RAD-RAD SWIRLER 35
4.1 Test Conditions ................................................................................................................................... 35
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4.2 Results and Discussions ...................................................................................................................... 35
4.3 Conclusions ......................................................................................................................................... 38
CHAPTER 5: EFFECT OF NUMBER OF SWIRLERS ON THE FLOW FIELD GENERATED BY A
MULTIPLE-SWIRLER ARRAY 45
5.1 Test Conditions ................................................................................................................................... 45
5.2 Results and Discussions ...................................................................................................................... 46
5.3 Conclusions ......................................................................................................................................... 50
CHAPTER 6: EFFECT OF INTER-SWIRLER SPACING ON THE FLOW FIELD GENERATED BY
A 5-SWIRLER ARRAY 58
6.1 Test Conditions ................................................................................................................................... 58
6.2 Results and Discussions ...................................................................................................................... 59
6.3 Conclusions ......................................................................................................................................... 63
CHAPTER 7: EFFECT OF ALIGNMENT OF SWIRLERS ON THE FLOW FIELD GENERATED BY
A 5-SWIRLER ARRAY 70
7.1 Test Conditions ................................................................................................................................... 70
7.2 Results and Discussions ...................................................................................................................... 70
7.3 Conclusions ......................................................................................................................................... 74
CHAPTER 8: EFFECTS OF END WALL DISTANCE AND CONFINEMENT ON THE FLOW
FIELD GENERATED BY A 5-SWIRLER ARRAY 81
8.1 Test Conditions ................................................................................................................................... 81
8.2 Results and Discussions ...................................................................................................................... 82
8.3 Conclusions ......................................................................................................................................... 85
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CHAPTER 9: PHENOMENOLOGICAL DESCRIPTION OF THE PERIODIC BEHAVIOR OF A 5-
SWIRLER ARRAY 95
9.1 Periodic Behavior among 5-swirler Array .......................................................................................... 95
9.2 Switching the Periodic Mode .............................................................................................................. 96
CHAPTER 10: SPRAY DISTRIBUTION OF A 5-SWIRLER ARRAY 100
10.1 Test Conditions ............................................................................................................................... 100
10.2 Results and Discussions .................................................................................................................. 100
10.3 Conclusions ..................................................................................................................................... 105
CHAPTER 11: FLAME SHAPE OF A 5-SWIRLER ARRAY 119
11.1 Test Conditions ............................................................................................................................... 119
11.2 Results and Discussions .................................................................................................................. 119
11.3 Conclusions ..................................................................................................................................... 121
SUMMARY 124
REFERENCES 125

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List of Figures
Figure 1.1 a sector of typical gas turbine combustor .................................................................................. 9
Figure 1.2: dome geometry of combustor in CFM56 ................................................................................ 9
Figure 2.1: a rad-rad, counter-rotating swirler assembly .......................................................................... 15
Figure 2.2: effective area measurements for 5 swirlers ............................................................................ 15
Figure 2.3: simplex fuel nozzle ................................................................................................................. 15
Figure 2.4: flow number measurement for 5 fuel nozzles (water as working fluid) ................................ 16
Figure 2.5: flow number measurement for 5 fuel nozzles (Jet-A as working fluid) ................................. 16
Figure 2.6: schematic of test facility for non-reacting LDV measurement .............................................. 17
Figure 2.7: schematic of test facility for no-reacting PDPA measurement .............................................. 17
Figure 2.8: Combustion Chamber ............................................................................................................. 18
Figure 3.1: coordinate system (confinement effect) ................................................................................. 27
Figure 3.2: axial velocity and axial-radial velocity vector contours (confinement effect); (a) 2D x 2D, (b)
2.5D x 2.5D, (c) 3D x 3D, (d) unconfined ................................................................................................ 27
Figure 3.3: radial velocity contours (confinement effect); (a) 2D x 2D, (b) 2.5D x 2.5D, (c) 3D x 3D, (d)
unconfined................................................................................................................................................. 28
Figure 3.4: tangential velocity contours (confinement effect); (a) 2D x 2D, (b) 2.5D x 2.5D, (c) 3D x 3D,
(d) unconfined ........................................................................................................................................... 29
Figure 3.5: axial velocity along the Z-axis (confinement effect) .............................................................. 30
Figure 3.6: velocity profiles at Z/D=0.12 (confinement effect); (a) axial velocities, (b) radial velocities,
(c) tangential velocities ............................................................................................................................. 31
Figure 3.7: velocity profiles at Z/D=0.39 (confinement effect); (a) axial velocities, (b) radial velocities,
(c) tangential velocities ............................................................................................................................. 32
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Figure 3.8: velocity profiles at Z/D=0.98 (confinement effect); (a) axial velocities, (b) radial velocities,
(c) tangential velocities ............................................................................................................................. 33
Figure 3.9: velocity profiles at Z/D=1.57 (confinement effect); (a) axial velocities, (b) radial velocities,
(c) tangential velocities ............................................................................................................................. 34
Figure 4.1: description of dome recession distance .................................................................................. 39
Figure 4.2: axial velocity and axial-radial vector contours for a single confined swirler; (a) D=0.03D.
r
(b) D=0.13D ............................................................................................................................................. 39
r
Figure 4.3: velocity profiles at Z/D=0.12, confined case (dome recession effect); (a) axial velocities, (b)
radial velocities, (c) tangential velocities .................................................................................................. 40
Figure 4.4: velocity profiles at Z/D=0.98, confined case (dome recession effect); (a) axial velocities, (b)
radial velocities, (c) tangential velocities .................................................................................................. 41
Figure 4.5: axial velocity and axial-radial vector contours for a single unconfined swirler; (a) D=0.03D.
r
(b) D=0.13D ............................................................................................................................................. 42
r
Figure 4.6: velocity profiles at Z/D=0.12, unconfined case (dome recession effect); (a) axial velocities,
(b) radial velocities, (c) tangential velocities ............................................................................................ 43
Figure 4.7: flow pattern sketches for an unconfined single swirler with difference dome recession: (a)
(nearly) no recession; (b) further recession .............................................................................................. 43
Figure 4.8: velocity profiles at Z/D=0.98, unconfined case (dome recession effect); (a) axial velocities,
(b) radial velocities, (c) tangential velocities ............................................................................................ 44
Figure 5.1: coordinate system (multi-swirler array) ................................................................................. 52
Figure 5.2: axial velocity and axial-radial velocity vector contours (no. of swirlers); (a) single swirler,
(b) three swirlers, (c) five swirlers ............................................................................................................ 53
Figure 5.3: velocity profiles at Z/D=0.12 (no. of swirlers), (a) axial velocities, (b) radial velocities ...... 54
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Figure 5.4: velocity and turbulent kinetic energy profiles at Z/D=0.63 (no. of swirlers), (a) axial
velocities, (b) radial velocities, (c) tangential velocities, (d) turbulent kinetic energy distributions ........ 55
Figure 5.5: velocity profiles at Z/D=1.77 (no. of swirlers), (a) axial velocities, (b) radial velocities, (c)
tangential velocities .................................................................................................................................. 56
Figure 5.6: velocity profiles at Z/D=3.94 (no. of swirlers), (a) axial velocities, (b) radial velocities, (c)
tangential velocities .................................................................................................................................. 57
Figure 6.1: descriptions of inter-swirler spacing (S) and end wall distance (D ) .................................... 64
w
Figure 6.2: axial velocity and axial-radial vector contours (spacing effect); (a) S=1.75, (b) S=2, (c)
S=2.5, (d) S=2.75 ...................................................................................................................................... 65
Figure 6.3: velocity profiles at Z/D=0.12 (spacing effect); (a) axial velocities, (b) radial velocities ....... 66
Figure 6.4: velocity profiles at Z/D=0.63 (spacing effect), (a) axial velocities, (b) radial velocities, (c)
tangential velocities, (d) turbulent kinetic energy distributions................................................................ 67
Figure 6.5: velocity profiles at Z/D=1.77 (spacing effect), (a) axial velocities, (b) radial velocities, (c)
tangential velocities .................................................................................................................................. 68
Figure 6.6: velocity profiles at Z/D=3.94 (spacing effect), (a) axial velocities, (b) radial velocities, (c)
tangential velocities .................................................................................................................................. 69
Figure 7.1: coordinate system (multiple-swirler array, modified configuration with 1/8D offset from the
center swirler) ........................................................................................................................................... 76
Figure 7.2: axial velocity and axial-radial vector contours (alignment effect); (a) baseline (b) 1/8D offset
(modified) ................................................................................................................................................. 76
Figure 7.3: velocity profiles at Z/D=0.20 (alignment effect), (a) axial velocities, (b) radial velocities ... 77
Figure 7.4: velocity and turbulent kinetic energy profiles at Z/D=0.63 (alignment effect), (a) axial
velocities, (b) radial velocities (c) tangential velocities (d) turbulent kinetic energy ............................... 78
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