Experimental Investigation on the Characteristics of Turbulent Hydrogen Jet Flames

Cheng, T. S.; Chiou, Chuang-Kai

doi:10.1080/00102209808924166

Cited by 18 publications

(15 citation statements)

References 16 publications

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“…Set 1 & 2 used the direct photography technique to determine the liftoff height, and set 3 used a Schlieren system to visualize the flame. The measured liftoff heights are in good agreement with the results of Kalghatgi [6] and Cheng and Chiou [14]. Blowout of pure hydrogen jet flame was not achieved in these experiments.…”

Section: Stability Of Pure Hydrogen Jet Flamessupporting

confidence: 81%

Prediction of the liftoff, blowout and blowoff stability limits of pure hydrogen and hydrogen/hydrocarbon mixture jet flames

Al-Rahbi

et al. 2009

International Journal of Hydrogen Energy

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The paper presented experimental studies of the liftoff and blowout stability of pure hydrogen, hydrogen/propane and hydrogen/methane jet flames using a 2 mm burner. Carbon dioxide and Argon gas were also used in the study for the comparison with hydrocarbon fuel. Comparisons of the stability of H 2 /C 3 H 8 , H 2 /CH 4 , H 2 /Ar and H 2 /CO 2 flames showed that H 2 /C 3 H 8 produced the highest liftoff height and H 2 /CH 4 required highest liftoff and blowoff velocities. The non-dimensional analysis of liftoff height approach was used to correlate liftoff data of H 2, H 2 -C 3 H 8 , H 2 -CO 2 , C 3 H 8 and H 2 -Ar jet flames tested in the 2 mm burner. The suitability of extending the empirical correlations based on hydrocarbon flames to both hydrogen and hydrogen/hydrocarbon flames was examined. INTRODUCTIONThe stabilization mechanisms of turbulent jet flames have been the topic of many papers and the most recent review was given by Peters [1]. It has emerged that the most successful theories to explain and predict the liftoff height location are the premixed flame propagation models [2][3][4][5][6][7] based on proposal by Vanquickenborne and van Tiggelen [2]. The importance of the isothermal mixing process of the jet was emphasised by Pitts [3][4][5]. The turbulent burning velocity has been one of the focused points for discussion using the premixed flame stabilization approach. Kalghatgi [6] assumed that the ratio of burning velocity to laminar burning velocity was proportional to the square root of the local turbulence Reynolds number based on the integral length scale. He successfully correlated the experimental data for CH 4 , C 2 H 4 , C 3 H 8 and H 2 into a single formula. More recent studies focused on the role of intermittence and large scale eddies and associated with premixed combustion by Broadwell et al. [7] and Burgess and Lawn [8]. Experimental studies of the large scale vortical structures in lifted flame were carried out by Schefer et al [9-10] using planar images of CH 4 , CH and temperature.So far most jet flame researchers have used pure hydrocarbon fuels or fuels diluted with air or nitrogen. Empirical correlations were developed to predict flame stability limits for pure and inert gas diluted hydrocarbon fuels. As hydrogen is becoming an important part of energy sector, there is a need to study the stability characteristics of both hydrogen and hydrogen/hydrocarbon flames. Studies on stability of hydrogen/hydrocarbon blended fuels are scarce. Recently, the stability of hydrogen and natural gas blended fuel was discussed by Choudhuri and Gollahalli [11]. The effect of hydrogen addition into methane on the flame stability under fuel lean condition was studied by Schefer [12] using swirlstabilized flame. However it is not clear if the established premixed flame propagation models can be applied to jet flames of blended fuels. It is also necessary to examine the suitability of extending the empirical correlations based on hydrocarbon flames to both hydrogen and hydrogen/hydrocarbon fl...

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Section: Stability Of Pure Hydrogen Jet Flamessupporting

confidence: 81%

Prediction of the liftoff, blowout and blowoff stability limits of pure hydrogen and hydrogen/hydrocarbon mixture jet flames

Al-Rahbi

et al. 2009

International Journal of Hydrogen Energy

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“…In addition, liftoff height data would suggest that both types of lifted flames have been observed previously in the pure hydrogen flames of Kalghatgi (1984) and Cheng & Chiou (1998), as well as in the nitrogen diluted hydrogen flames of Brockhinke et al (2000) and Meier et al (1996). Further, because the bases of LLB flames reside in the low-velocity region outside the jet shear layer, their stability is dependent on a relatively steady, unperturbed flow field in the region immediately outside the jet exit, which is typically best achieved with a thin-lipped fuel tube issuing into a quiescent atmosphere.…”

Section: Introductionmentioning

confidence: 73%

“…Although the dual lifted flame behavior has not been specifically reported in lifted hydrogen=diluent turbulent flame studies (Brockhinke et al, 2000;Cabra et al, 2002;Chao et al, 2004;Cheng & Chiou, 1998;Meier et al, 1996;Tacke et al, 1998; TURBULENT DILUTE DIFFUSION FLAME STABILITY 757 Wu et al, 2007), mention is made of 'high' and 'low' lifted flames in the pure hydrogen=coaxial air flame stability study of Vranos et al (1968). In addition, liftoff height data would suggest that both types of lifted flames have been observed previously in the pure hydrogen flames of Kalghatgi (1984) and Cheng & Chiou (1998), as well as in the nitrogen diluted hydrogen flames of Brockhinke et al (2000) and Meier et al (1996).…”

Section: Introductionmentioning

confidence: 96%

Stability Characteristics of Turbulent Hydrogen Dilute Diffusion Flames

Weiland

Strakey

2009

Combustion Science and Technology

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Diffusion flame combustion of high-hydrogen fuels in land-based gas turbine combustors may include dilution of the fuel with inert gases and high velocity fuel injection to reduce NO x emissions. Stability regimes of such combustors are investigated in this study by examining turbulent dilute diffusion flames of hydrogen/nitrogen mixtures, issuing into a quiescent environment from a thin-lipped tube. This study has revealed two distinctly different types of lifted flames: lifted, laminar-base flames, for which liftoff heights vary from 1 to 3 jet diameters above the jet exit and are controlled by differential diffusion, and lifted, turbulentbase flames that stabilize much further downstream and are dominated by turbulent processes. In addition, stability limits governing the detachment or reattachment of the flame to the lip of the burner are examined, as well as the limits governing transitions between the two types of lifted flames and transition from these lifted flames to blowout.

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“…In 1998 Cheng and Chiou [32] observed that an increase of the lift-off velocity increases the lift-off height without significantly altering the hydrogen flame height. For example, an increase of lift-off velocity from 530 to 1120 m/s for a nozzle of 1.8 mm diameter increases the flame height from 37 to 49 cm.…”

mentioning

confidence: 98%

Hydrogen jet flames

Molkov

Saffers

2013

International Journal of Hydrogen Energy

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Jet flame length The similarity law Dimensionless correlation Flame tip location a b s t r a c t A critical review and rethinking of hydrogen jet flame research is carried out. Froude number only based correlations are shown to be deficient for under-expanded jet fires. The novel dimensionless flame length correlation is developed accounting for effects of Froude, Reynolds, and Mach numbers. The correlation is validated for pressures 0.1e90.0 MPa, temperatures 80e300 K, and leak diameters 0.4e51.7 mm. Three distinct jet flame regimes are identified: traditional buoyancy-controlled, momentum-dominated "plateau" for expanded jets, and momentum-dominated "slope" for under-expanded jets. The statement "calculated flame length may be obtained by substitution the concentration corresponding to the stoichiometric mixture in equation of axial concentration decay for non-reacting jet"is shown to be incorrect. The correct average value for non-premixed turbulent flames is 11% by volume of hydrogen in air (range 8%e16%) not stoichiometric 29.5%. All three conservative separation distances for jet fire are shown to be longer than separation distance for non-reacting jet.

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Experimental Investigation on the Characteristics of Turbulent Hydrogen Jet Flames

Cited by 18 publications

References 16 publications

Prediction of the liftoff, blowout and blowoff stability limits of pure hydrogen and hydrogen/hydrocarbon mixture jet flames

Prediction of the liftoff, blowout and blowoff stability limits of pure hydrogen and hydrogen/hydrocarbon mixture jet flames

Stability Characteristics of Turbulent Hydrogen Dilute Diffusion Flames

Hydrogen jet flames

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