This document reports on an experimental study investigating the effect of burner shape on flashback in gas turbines. Specifically, it aims to modify a small commercial diesel burner to operate with LPG, determine the burner's operating window with LPG, and investigate how burner geometry affects the operating window. It presents results showing increased burner neck length moves the flame stagnation point outward and widens the operating window by providing higher stability at constant equivalence ratios. However, a longer neck also precipitates flashback. The study concludes neck length and shape impact flame structure, stability and emissions, warranting future work exploring confinement effects and different neck geometries.

1. Experimental study of the effect of the
burner shape on the flashback in gas
turbines
supervisors
Asst .prof .Dr. Qahtan A. Abed
Lect .Dr. Mohammed AL- fahham
Jameel AL-Naffakh
4-Dec.-2019

2. Contents
1. INTRODUCTION.
2. Highlights.
3. Operation window of burner.
4. Blowoff .
5. Flashback.
6. AIM OF STUDY.
7. Aims of this work.
8. References.

3. INTRODUCTION

5. Combustion
swirl
Premixed
Non-
premixed
diffusion
Premixed
Non-
premixed
Highlights

6. Operation window of burner

7. Blowoff
0
1
2
3
4
5
6
7
0.1 0.3 0.5 0.7 0.9 1.1
TangentialVelocitym/s
Equivaliance Ratio
Blow Off
Flashback

8. Flashback
A. Combustion Induced
Vortex Breakdown (CIVB).
B. Boundary Layer Flashback
(BLF).
C. Turbulent Core Flashback.
D. Combustion instabilities
flashback
0
1
2
3
4
5
6
7
0.1 0.6 1.1
TangentialVelocitym/s
Equivaliance Ratio
Blow Off
Flashback

9. AIM OF STUDY
Modifying an exist small commercial diesel burner to
work with LPG without any additional cost.
Finding the operation widow (stability map) of the
burner after using LPG.
 Investigating the effect of burner geometry on the
operation window of the burner. The blowoff limits and
flashback limits will be addressed for different diameter
to length ratio burner .

10. Photographic system

11. Schematic photo system

12. RESULTS & DISCUSSION
Effect of Fuel Type

13. Effect of Burner Geometry on Flame Structure

14. Effect of Neck Length on Flame Stagnation Point
Stagnation point of flame at different neck length

15. The effect of The Length of The Burner Neck on The
Operating Window

16. Operation widow of the burner with 10 cm long
neck

17. Operation widow of the burner with 15 cm long
neck

18. CONCLUSION
 The possibility of modifying any external combustion system (Burner)
powered by diesel fuel to use liquefied gas fuel (LPG), and without any
distortion of the system while maintaining the basic parts of the system
and thus not affecting the overall design of the system.
 From the aerodynamic point of view, it is concluded that the strength of
the vortex will decrease with increase length due the friction with burner
inner walls. As a consequence, the swirl flow will turn to jet or diffusion.

19.  Through practical experiments, it was shown that the increased
length of the burner's neck leads to move the stagnation point
towards the edge of the burner where it was graphically
represented.
 Increasing the length of the neck of the burner leads to higher
stability in term of the equivalent ratio. At constant equivalence
value, the burner showed higher stability than the other two
models and therefore requires
 increase in the rate of air flow in the mixture area and thus get a
poor mixture so it works it is application in the few loads for
power plants.
 Increasing the length of the burner neck has precipitated the
flashback phenomenon.

20. Recommendations (future work)
Studying the effect of the use of confinement in the
combustion area on the stability of the flame and the
operating window.
 Studying the amount of emissions with a change in the
length and shape of the burner neck.
 Studying the effect of changing the shape of the burner
neck from the cylindrical to other forms such as slot
(rectangular), square, triangular or oval on the amount
of the operating window.

21. Multi-Knowledge Electronic
Comprehensive Journal For
Education And Science Publications
( MECSJ ) ISSUE(24),sep(2019) ISSN:
2616-9185 (ISI)
Energy Research Journal
DOI: 10.3844/erjsp.2019. Scopus
3rd International Conference on
Engineering Sciences (ICES.ME52)
Scopus
Accepted and published papers
Paper Title Journal Name
1- Burner rim geometry effect
on flame stability
2- Experimental Investigate the
Effect of Burner Geometry on the
Operation Window of the Burner
3- The blowoff limits and
flashback limits for different
diameter to length ratio burner

22. Thank you for your attention