Flame Phenomena in Premixed Combustible Gases

Glassman, Irvin; Yetter, Richard A.

doi:10.1016/b978-0-12-088573-2.00004-x

Cited by 9 publications

(5 citation statements)

References 86 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…where D = λ ρ•c P is the thermal diffusivity of the flammable mixture, C 0 is the total initial fuel concentration, T f is the end temperature in the flame front, and n and E a are the overall activation parameters (reaction order and activation energy) of the oxidation reaction [74]. The thermophysical properties of CH 4 , H 2 , O 2 , and N 2 are listed in Table 4.…”

Section: Resultsmentioning

confidence: 99%

Laminar Burning Velocities of Hydrogen-Blended Methane–Air and Natural Gas–Air Mixtures, Calculated from the Early Stage of p(t) Records in a Spherical Vessel

2021

View full text Add to dashboard Cite

The flammable hydrogen-blended methane–air and natural gas–air mixtures raise specific safety and environmental issues in the industry and transportation; therefore, their explosion characteristics such as the explosion limits, explosion pressures, and rates of pressure rise have significant importance from a safety point of view. At the same time, the laminar burning velocities are the most useful parameters for practical applications and in basic studies for the validation of reaction mechanisms and modeling turbulent combustion. In the present study, an experimental and numerical study of the effect of hydrogen addition on the laminar burning velocity (LBV) of methane–air and natural gas–air mixtures was conducted, using mixtures with equivalence ratios within 0.90 and 1.30 and various hydrogen fractions rH within 0.0 and 0.5. The experiments were performed in a 14 L spherical vessel with central ignition at ambient initial conditions. The LBVs were calculated from p(t) data, determined in accordance with EN 15967, by using only the early stage of flame propagation. The results show that hydrogen addition determines an increase in LBV for all examined binary flammable mixtures. The LBV variation versus the fraction of added hydrogen, rH, follows a linear trend only at moderate hydrogen fractions. The further increase in rH results in a stronger variation in LBV, as shown by both experimental and computed LBVs. Hydrogen addition significantly changes the thermal diffusivity of flammable CH4–air or NG–air mixtures, the rate of heat release, and the concentration of active radical species in the flame front and contribute, thus, to LBV variation.

show abstract

Section: Resultsmentioning

confidence: 99%

Laminar Burning Velocities of Hydrogen-Blended Methane–Air and Natural Gas–Air Mixtures, Calculated from the Early Stage of p(t) Records in a Spherical Vessel

2021

View full text Add to dashboard Cite

show abstract

“…The design and manufacture of micro burners, which have dimensions at the millimeter or submillimeter level, pose unique challenges when compared to conventional combustors, which make it not trivial to obtain a stable flame, as documented in Hossain and Nakamura [10], Ju and Maruta [1], Nakamura et al [2], Resende et al [11], and Lee et al [12]. These challenges extend to combustion in microscale environments, where the effects of viscosity are amplified in small channels, the physical residence time of mixed gases is shortened, and the ratio of area to volume of the combustion chamber increases sharply [13,14]. These factors have direct or indirect effects on the flame and the heat release of chemical energy, thereby leading to significant differences in combustion characteristics between micro and conventional combustors [15]:…”

Section: Challenges Within Microcombustionmentioning

confidence: 99%

A Review on Micro-Combustion Flame Dynamics and Micro-Propulsion Systems

Dias,

Resende,

Afonso

2024

Energies

View full text Add to dashboard Cite

This work presents a state-of-the-art review of micro-combustion flame dynamics and micro propulsion systems. In the initial section, we focus in on the different challenges of micro-combustion, investigating the typical length and time scales involved in micro-combustion and some critical phenomena such as flammability limits and the quenching diameter.We present an extensive collection of studies on the principal types of micro-flame dynamics, including flashback, blow-off, steady versus non-steady flames, mild combustion, stable flames, flames with repetitive extinction, and ignition and pulsatory flame burst. In the final part of this review, we focus on micropropulsion systems, their performance metrics, conventional manufacturing methods, and the advancements in Micro-Electro-Mechanical Systems manufacturing.

show abstract

“…A cold swirling flow of oxygen passes near the combustion chamber wall, effectively protecting it from the high temperature of the flame, which could reach up to 3030 K for the stoichiometric mixture at 1 atm, according to [14]. A gas mixture exiting the igniter is always oxidizer-rich, which helps, on the one hand, to cool down effectively the igniter wall, and on the other hand, to initiate combustion inside a solid fuel ramjet [17] or hybrid rocket engine [18] with solid fuel grain of paraffin or high-density polyethylene tested in the Laboratory.…”

Section: Ignitermentioning

confidence: 99%

“…Experimental tests provided in the Laboratory [2] entirely discovered this problem. Therefore, flow conditions favorable for ignition must be created inside the igniter, which is generally characterized by a slow flow velocity close to the flame velocity for methane-oxygen mixtures, previously discussed in [2,14,15].…”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Study of the Flammability Limits in a CH4/O2 Torch Ignition System

et al. 2022

View full text Add to dashboard Cite

The current work is devoted to studying combustion initiation inside the methane-oxygen torch igniter for a hybrid rocket motor. The ignition system can generate a wide range of power and oxidizer-to-fuel ratios. It has a self-cooled vortex combustion chamber with one fuel jet injector and one circumferential vortex oxidizer injector. The system adjusts the mass flow rates of the propellants through the control valves and organizes cooling of the wall and flame stabilization. Experimental analysis of the ignition limits was investigated on the laboratory test bench. The propellants’ pressure and mass-flow rates, combustion temperature, ignition delay, and spark frequency were controlled during the tests. The authors executed a series of tests with different propellants’ mass flow rates. As a result, the region of stable ignition was found as well as the regions of ignition failure or unreliable ignition. A previously validated numerical model was used to analyze the flow in the reliable ignition region and the ignition failures region. Several numerical simulations of the transient three-dimensional chemically reacting flow were implemented. Consequently, the ignition delay and the thermal impact on the combustion chamber wall were determined numerically. Results of the simulations were compared with theoretical and experimental data showing good correspondence.

show abstract

Flame Phenomena in Premixed Combustible Gases

Cited by 9 publications

References 86 publications

Laminar Burning Velocities of Hydrogen-Blended Methane–Air and Natural Gas–Air Mixtures, Calculated from the Early Stage of p(t) Records in a Spherical Vessel

Laminar Burning Velocities of Hydrogen-Blended Methane–Air and Natural Gas–Air Mixtures, Calculated from the Early Stage of p(t) Records in a Spherical Vessel

A Review on Micro-Combustion Flame Dynamics and Micro-Propulsion Systems

Experimental and Numerical Study of the Flammability Limits in a CH4/O2 Torch Ignition System

Contact Info

Product

Resources

About