Combined effect of ignition position and equivalence ratio on the characteristics of premixed hydrogen/air deflagrations

Zheng, Ligang; Zhu, Xun; Wang, Yalei; Li, Gang; Shu, Yu; Pei, Bei; Wang, Yan; Wang, Wei

doi:10.1016/j.ijhydene.2018.06.189

Cited by 49 publications

(21 citation statements)

References 52 publications

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“…However, the thickness of the reaction layer is insensitive to turbulence intensity even though the layer was seriously distorted at high Ka. Zheng et al [14] studied premixed H2/air flames under various equivalence ratios in an explosion duct. Under certain ignition positions, typical tulip flames could be formed under fuel lean and fuel ultra-rich conditions, while no tulip flames could be formed under slightly rich conditions.…”

Section: Introductionmentioning

confidence: 99%

Response of heat release to equivalence ratio variations in high Karlovitz premixed H2/air flames at 20 atm

Wang

Jin

Luo

2019

International Journal of Hydrogen Energy

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Reaction layer thickness Δx Grid resolution κ Mean curvature v Kinematic viscosity v'kj Forward stoichiometric coefficient for species k in reaction j v''kj Reverse stoichiometric coefficient for species k in reaction j φ Equivalence ratio of the fresh mixture φL Local equivalence ratio ω  Species reaction rate Ai Pre-exponential factor of Arrhenius equation c Progress variable Ei Activation energy of a reaction Ka Karlovitz number Kf Forward reaction rate constant Kr Reverse reaction rate constant K0 Limit of low-pressure reaction rate constant K∞ Limit of high-pressure reaction rate constant Kci Equilibrium constant t l Integral length scale [M] Overall contribution of different species in Three-body reactions Re Reynolds number SL Laminar flame speed Syz Cross-section area T Local temperature Tu Temperature of unburnt gas Tb Temperature of burnt gas ' u Root-mean-square turbulent velocity fluctuation Vrec Reaction zone volume Xk Molar concentration of species k , f k Y Local mass fraction of species k

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Section: Introductionmentioning

confidence: 99%

Response of heat release to equivalence ratio variations in high Karlovitz premixed H2/air flames at 20 atm

Wang

Jin

Luo

2019

International Journal of Hydrogen Energy

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“…From the perspective of explosion safety, the greater the overpressure, the greater the harm. 46 Therefore, it was more meaningful to further analyze the overpressure profiles recorded at the closed end. In this study, the peak overpressure (i.e., P max ) was defined as the maximum value among the overpressure peaks.…”

Section: Resultsmentioning

confidence: 99%

“…The peak overpressure changed obviously with the change in the equivalence ratio. 46 Figure 3 shows the variation of the peak overpressure with the equivalence ratio. The peak overpressure increased first and then decreased as the combustion state changed from the fuel lean to rich condition at IP 0 .…”

Section: Resultsmentioning

confidence: 99%

“…The position of the pressure sensor was appropriate because it had been shown that the position of the pressure sensor did not have effects on the overpressure variation. 46 It was worth noting that the spark igniter used a 6 V direct current as the power source, and the position of the igniter changed according to the experimental conditions. The measurement rang of the pressure transducer was from −0.1 to 1 MPa, and the electrical signal was from 1 to 5 V.…”

Section: Methodsmentioning

confidence: 99%

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Experimental Studies on the Explosion Behaviors of Premixed Hydrogen–Air Mixtures in a Narrow Channel

Zhang

Wen

et al. 2022

ACS Omega

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Premixed hydrogen–air explosion experiments were carried out in a 1000 mm × 50 mm × 10 mm half-open narrow channel, concerning with the influences of equivalence ratio and ignition position on explosion behaviors. Experimental phenomena were different from explosion in large space. The results indicated that when ignited at the closed end of the channel, three overpressure peaks appeared, caused by the rupture of the film, Helmholtz Oscillation, and the flame-acoustic interaction, respectively. As the equivalence ratio of the hydrogen–air mixtures varied from 0.6 to 1.6, the peak overpressure first increased and then decreased. The maximum peak overpressure occurred at ϕ = 1.2. The hydrogen flame would develop into the plane tulip structure without the influence of the end wall. With the ignition position moved to the open end, overpressure wave and flame oscillated significantly. Compared with other ignition positions, the minimum value of P max was obtained at IP 950 . Based on the explosion behaviors in the narrow channel, it was concluded that the closer the ignition was to the open end, the easier the oscillation was to be formed, the smaller the explosion hazard was.

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“…Li [34] studied the effects of obstacle distance from ignition point, the blockage ratio of obstacle and the separation distance of obstacles on the characteristics of gasoline-air mixture explosions in a semi-confined organic glass pipe. Zheng [35] studied the effect of ignition position and equivalence ratio on the characteristics of premixed hydrogen/air explosions. Wang [36] studied the effect of concentration and obstacles on methane-air mixture deflagration to detonation transition, showed that a high number of obstacles in the duct can increase flame turbulence and lead to flame acceleration [20][21][22][23][24][25][26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on the Effect of Air Pollution Caused by Methane-Air Deflagration Characteristics

Zhang¹,

Feng²,

Zhang³

et al. 2020

Rev. Chim.

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In order to study the effect of combustible gas cloud releasing from FPSO upper deck facilities deflagration characteristics on air pollution, a semi-open open test pipe system was built. By changing the initial conditions such as the obstacles length, distance between obstacles, section shape of obstacles and pipe system structure, the flame propagation mechanism and overpressure changing rules of methane / air deflagration were analyzed. As a result of that, the degree of sufficiency of methane combustion was analyzed, which could be seen as air pollution level. With the increase of the length of obstacle and decrease of the distance between obstacles, the induced turbulence increased, the compression effect of unburned gas became stronger, the combustion of combustible gas became more intense and sufficient, and the flame propagation speed and the maximum overpressure increased. The effect of square cross section was more obvious on inducing turbulence than that of rectangular cross section and circular cross section. The flame front was divided into many small flames by the pipe structure obstacle, and the flame front showed as a `spiny` shape. Under the effect of �spiny� flame, the methane combustion was more sufficient, and the maximum overpressure value was 3.1 times of the circular section obstacle condition. In conclusion, as the methane-air deflagration becoming more serious, although the overpressure and flame speed would be higher and the extent of damage to the surrounding facilities would be more serious, the air pollution causing by unburned gas would abate.

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Combined effect of ignition position and equivalence ratio on the characteristics of premixed hydrogen/air deflagrations

Cited by 49 publications

References 52 publications

Response of heat release to equivalence ratio variations in high Karlovitz premixed H2/air flames at 20 atm

Response of heat release to equivalence ratio variations in high Karlovitz premixed H2/air flames at 20 atm

Experimental Studies on the Explosion Behaviors of Premixed Hydrogen–Air Mixtures in a Narrow Channel

Experimental Study on the Effect of Air Pollution Caused by Methane-Air Deflagration Characteristics

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