1. Supervised By Prof. Dr. Haroun A.K. Shahad
Experimental Study of The Effect of Hydrogen Blending on Burning Velocity
for Different Fuels
By Ahmed Sh. Yasiry
Supervised By Prof. Dr. Haroun A.K. Shahad
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2. Introduction
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3. Introduction
Increasing concern over the fossil fuel shortage and pollution of air, and the requirement for alternative fuels for Internal Combustion Engines have been considered by researchers.
Researchers have re-evaluated the combustion process and the prospects of alternative fuels to improve the combustion characteristics.
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4. Flame
Flame is a visible part of a highly exothermic chemical reaction. Flame can be classified according to : 1) Composition of The Reactants 2) Basic Character of Gas Flow 3) Motion of Flame
Premixed.
Diffusion.
Laminar.
Turbulent.
Stationary .
Nonstationary .
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5. Laminar Burning Velocity
- Laminar burning velocity (ul) is defined as the velocity at which unburned gases move through the combustion wave in the direction normal to the wave surface. - Burning velocity is a measure of the rate at which reactants are moving into the flame from a reference point located on the moving frame. The Flame speed is a measure of how quickly the flame is traveling from a fixed reference point
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6. Fuels Used in The Study Liquefied petroleum gas (LPG)
liquefied petroleum gas (LPG) consists mainly of butane and propane. Being one of the primary energy sources used for domestic and commercial applications.
LPG has many advantages such as:
High heating value.
cleaner burning with low ash.
Less corrosion and engine wear.
Stable flame and low processing cost.
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7. Fuels Used in The Study LPG component is supplied by
Items
C2H6
C3H8
C4H10
C5H12
Volumetric Fractions (%)
by Volume
0.9
36.3
62.3
0.5
LPG component is supplied by
Gas Filling Company/ Middle Euphrates Branch
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8. Fuels Used in The Study Hydrogen
Hydrogen (H2) is a colorless, odorless, tasteless, non-toxic, non-metallic and highly combustible diatomic gas. It has high flame speed, wide flammability limit, low minimum ignition energy, low self ignition temperature and no emissions of HC or CO2.
Hydrogen addition to a fuel could increase thermal efficiency, lean burn capability and mitigate the global warming concerns.
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9. Aims of The Study The scope of the present work covers:
To investigate the effect of equivalence ratio, initial pressure and hydrogen blending on laminar burning velocity and other parameters.
To validate the accuracy of the self built rig by comparing the measured values of the LBV with available literature.
Correlations between variables are derived for H2-LPG–air mixtures.
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10. Experimental Work
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11. Experimental Setup
The study of flame propagation subject needs high speed photography system because of the short period available for measurement.
It consists of the following units:
Combustion chamber unit.
Ignition circuit and control unit.
Mixture preparing unit.
Capturing unit.
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12. Photograph of The Experimental Apparatus Used in The Study
Combustion
chamber
Mixture
preparing unit
high-speed
camera
Ignition circuit
Photograph of The Experimental Apparatus Used in The Study

13. 10:38 PM Fuel Storage Tank Exhaust Air Compressor Mixer AC Power PC
Ignition System
Control System
AC Power PC
Temperature Recorder
Data Logger
Vacuum
Illuminator
Lens
Combustion
Chamber
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high-speed camera

14. Combustion Chamber Unit

15. Combustion Chamber Unit
The present work used a cylindrical chamber with a (190mm) inner diameter, (250mm) height and (10 mm) thickness. It also has two (20 mm) thick upper and lower flanges with a diameter of (300 mm). Each flange are joined by 16 hex bolts. Two thermocouples and two pressure gauges are placed inside the cylinder.
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16. Ignition Circuit and Control Unit
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17. Ignition Circuit and Control Unit
CVC is provided with centrally electrodes connected to the ignition system. An ignition power is produced a powerful spark for the electrodes from a transformer connected to AC power. The transformer is 14KV. An electronic circuit is constructed to control the duration of the triggering (electronic push bottom). It is placed on the transformer to produce an on-off signal. It can be controlled manually from (1 – 1000) ms.
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18. Mixture Preparing Unit
Gaseous mixer has been designed and constructed for gaseous fuels with low partial pressure. The purpose of using the mixer is to increase the total pressure of the mixture. Consequently, this increases the partial pressure of each component of the mixture.
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19. Capturing Unit
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20. Capturing Unit
An optical system is used to visualize the flame and flame propagation process by a high-speed camera. - Two circular optical windows of diameter (108.2 ±1) mm on the opposite side of the CVC. - 2 lenses with a diameter of (90 mm) and focal length of (400 mm). - AOS high-speed camera, with a (16,000 FPS).
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21. Test Procedure
A- Mixture Preparation 1- Flushing Process 2- Vacuum Process 3- Mixing Process B- CVC Preparation 2- Scavenging Process 3- Filling Process C- Combustion and Recoding
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22. P= 1 bar P= 1.5 bar P= 3bar P= 2 bar P= 2.5 bar 10:38 PM 100% 80% 60%
40%
20% 0% X% H2 Ø
0.8 1
1.3
P= 1.5 bar
100%
80%
60%
40%
20% 0% X% H2 Ø
0.8 1
1.3
P= 3bar
100%
80%
60%
40%
20% 0% X% H2 Ø
0.8 1
1.3
P= 2 bar
100%
80%
60%
40%
20% 0% X% H2 Ø
0.8 1
1.3
P= 2.5 bar
100%
80%
60%
40%
20% 0% X% H2 Ø
0.8 1
1.3
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23. Difficulties of The Work
Time
As a new experimental rig take about 7 months to build and be valid to use.
This affect on the procedure of the work.
Cost
Because of impurity of available local neat hydrocarbon fuel and high cost of pure hydrocarbon fuel
This led us to test only LPG.
Photography
Because of lack equipment of the Schlieren photography to make it work perfectly
This affect on the quality of recorded videos
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24. Theoretical Analysis
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25. Flame Propagation Analysis
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26. Flame Propagation Analysis
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27. Flame Propagation Analysis
A FORTRAN program is written to calculate the physical properties of reactance and expected product, in addition to adiabatic flame temperature and initial admitting pressure for each of reactance mixture. The program is designed to operate with neat hydrocarbon fuel (CH4, C2H6, C3H8, C4H10, C5H12), blend with H2 or mixture of multi hydrocarbons blended with H2.
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28. Results
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29. Validation Theoretical Analysis
The adiabatic flame temperate is the most influential parameter to determine the properties of the burnt mixture. The validation has been done by comparing the flame temperature of CH4 and C3H8 with researcher [2] and 2 software (Cantera and GASEQ)
Another comparison of hydrogen adiabatic flame temperature of the present work with Cantera and GASEQ software.
The last comparison with the results with research [66] who investigated the laminar burning velocity of LPG (30% propane and 70% butane) with different hydrogen blends.
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31. Percentage Error for CH4 and C3H8 Physical Properties at Different Equivalence Ratio Comparing with GASEQ Software.

32. Theoretical Physical Properties Results

33. Experimental Results Repeatability
A pre-set mixture is prepared in the mixing chamber at fixed condition.
Three consecutive combustion tests are carried out using the same mixture. Another three tests are performed using different pre-set mixture.
Also to test the accuracy of our system, the results of burning mixture of Methane and properties are compared with results of other researchers.
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34. Repeatability Results
Measured Schlieren Radius with Flame Speed for Six Consecutive Experiments with (60% H2 blend, ϕ = 0.8 and P0 = 1 bar).
Comparison of Experimental Data for The Burning Velocity of Methane at T0 = 298 K and p0 = 1 bar with The Data Obtained from [33 & 83].
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35. 40% H2
60% H2
80% H2
Photographs of Flame Propagation for Initial Pressure 3 bar with dt of 3.75 ms at Different Hydrogen Blend at Equivalence Ratio 0.8.
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36. Φ= Φ= Φ=1.3
Photographs of Flame Propagation for Initial Pressure 3 bar with dt of 3.75 ms at Different Equivalence Ratio for 60% H2
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37. Stretched Laminar Flame Speed
100% LPG
20 % H2
60 % H2
80 % H2
Φ=0.8
Φ=1
Φ=1.3

38. Factors Effect on Stretched Laminar Flame Speed
Stoichiometry at Atmospheric Pressure
Initial Pressure
Hydrogen Blend at Atmospheric Pressure
Variation of Sn with Equivalence Ratios for LPG with Various Hydrogen Percentages at Atmosphere Pressure.
Variation of Sn with Hydrogen Percentages at Equivalence Ratio=1 at different initial Pressure.
Variation of Sn with Initial Pressures for LPG with Various Hydrogen Blends at (ϕ =1).
All Data at Flame Radius of 20 mm
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39. Stretched rate
100% LPG
20 % H2
60 % H2
80 % H2
Φ=0.8
Φ=1
Φ=1.3

40. Factors Effect on Unstretched Laminar Flame Speed
Stoichiometry at Atmospheric Pressure
Initial Pressure
Hydrogen Blend at Atmospheric Pressure
Unstretched Flame Propagation Speed Versus Different Initial Pressure for Stoichiometric Mixtures
Unstretched Flame Propagation Speed Versus Equivalence Ratios at 1 bar with Different Hydrogen Blends.
Unstretched Flame Propagation Speed Versus Different Hydrogen Blends for Stoichiometric Mixtures
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41. Laminar Burning Velocity
Laminar Burning Velocity Versus Equivalence Ratio for Different Hydrogen Blend at Atmosphere Pressure.
Comparison of Laminar Burning Velocity Versus Hydrogen Blend with Miao et al. (2014)[66] for Stoichiometric Mixture at Atmosphere Pressure
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42. Factors Effect on Unstretched Laminar Burning Velocity
Stoichiometry at Atmospheric Pressure
Initial Pressure
Hydrogen Blend at Atmospheric Pressure
Laminar Burning Velocity Versus Initial Pressure for Different Hydrogen Blend at Stoichiometric Mixture
Laminar burning velocity versus equivalence ratio for different hydrogen blend at atmosphere pressure
Laminar burning velocity versus hydrogen blend for different equivalence ratio at atmosphere pressure
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43. Correlation of Laminar Burning Velocity
0.9216
(R-squared)
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44. Flame Thickness and Combustion Pressure
Flame Thickness Versus Equivalence Ratio for different Hydrogen Blend at Initial Pressure of 1.0 bar
Maximum Combustion Pressure Versus Hydrogen blend for different Initial Pressure at Equivalence Ratio =1.3.
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45. Conclusions and Suggestions
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46. Conclusions
A new experimental apparatus has been built for the measurement of laminar flame speed and burning velocity of the fuel-air mixture.
H2 addition accelerates LBV of LPG flames for all equivalence ratios and pressures. The effectiveness is more evident when H2 blend is larger than 60%.
20% LPG decreases the LBV to 70% of H2 .
Increasing the initial pressure, decreases the laminar burning velocity.
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47. Conclusions
The flame thickness increases with increasing the initial pressure and decreases with increasing H2 blend.
H2 addition increases thermal diffusivity of reacting mixtures, the density ratio and adiabatic flame temperature.
Combustion pressure increases with increasing the equivalence ratio, H2 blends and initial pressure.
Correlations between variables are derived for H2-LPG-air mixtures.
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48. Suggestions for Future Work
The experimental apparatus can be used for other types of gaseous fuels.
The experimental apparatus can be modified to study the laminar burning velocity for other types of liquid fuels
Studying the effect of initial temperature on the laminar burning velocity for temperatures higher than the atmospheric conditions.
Improving the capturing unit by replacing the schlieren photography system with Z-type schlieren photography.
Developing the CVC to derive burning velocity measurements from the pressure record.
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49. Suggestions for Future Work
Increasing the diameter of the glass window of the bomb to detect cellularity by using high-speed Schlieren photography system
Modifying ignition unit to study the effect of ignition energy and spark gap.
Extending the theoretical part to study the laminar burning velocity of blended.
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50. Thank You …
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