J0570301 Swirl Number Effects on Local Flame Structures of ydrogen-Air Turbulent Swirling Premixed Flame in a Cuboid Combustor

The premixed combustion efficiency and emissions characteristics of four axial vane swirlers are compared with a simple grid plate stabilised premixed flame. The four swirlers are designed to investigate the influence of Swirl Number, pressure loss and swirler design. The results show that efficient combustion of weak mixtures at simulated gas turbine combustion conditions is difficult with swirl systems, but relatively easily achieved with grid plate systems. High swirl numbers are shown to have the worst combustion efficiency with a major unburned hydrocarbon problem. NOx emissions are similar for all the stabilisers and they all exhibit a very high proportion of NO2 and NOx emissions for weak mixtures.

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110 The Effect of Hydrogen Concentration on Turbulent Premixed Flame Structures for Syngas at High Pressure

The Proceedings of Conference of Tohoku Branch ◽

10.1299/jsmeth.2013.48.24 ◽

2013 ◽

Vol 2013.48 (0) ◽

pp. 24-25

Author(s):

Ryota SATO ◽

Futoshi MATSUNO ◽

Taku KUDO ◽

Hideaki KOBAYASHI

Keyword(s):

High Pressure ◽

Hydrogen Concentration ◽

Premixed Flame ◽

Turbulent Premixed Flame ◽

Flame Structures ◽

Turbulent Premixed

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Analysis of Heat Release Rate in the Partially Premixed Flame Structures During Autoignition of Unstrained, Laminar Mixing Layers

Volume 7: Fluids and Heat Transfer, Parts A, B, C, and D ◽

10.1115/imece2012-86162 ◽

2012 ◽

Author(s):

Inkant Awasthi ◽

George Gogos

Keyword(s):

Heat Release ◽

Release Rate ◽

Diffusion Flame ◽

Mixing Layer ◽

Premixed Flame ◽

Release Rates ◽

Laminar Mixing ◽

Flame Structures ◽

Partially Premixed Flame ◽

Fuel Stream

Autoignition in an unstrained, laminar mixing layer of methanol/air is investigated using detailed reaction mechanism and full multicomponent mass diffusion formulation. The temperature of the fuel stream is varied from 400 K to 1200 K, whereas the oxidizer stream is held at a fixed temperature of 1200 K. The calculations are performed for pressure p = 1 bar. Transient evolution of the autoignition kernel from initial partially premixed flame structures to final diffusion flame is demonstrated. The flame structures have been analysed for individual heat release rates. For equal fuel and oxidizer stream temperatures (1200 K), heat release in extremely fuel rich locations (with mixture fraction values up to 0.8) is found. A transient triple flame structure (two deflagrations and, one diffusion flame) is shown to exist even in cases when the temperature difference between the two streams is large. The heat release rates in the deflagrations depend on the temperatures of the two streams. When compared with the surviving diffusion flame, the heat release rate in the short-lived deflagrations is one to two orders of magnitude higher. It is shown that increasing the fuel stream temperature also decrease the ignition delay time in the mixing layer.

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A Study on Flame Structures in CH4 Counterflow Partially Premixed Flame

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.694.474 ◽

2014 ◽

Vol 694 ◽

pp. 474-477

Author(s):

Jing Luo ◽

Lian Sheng Liu ◽

Zi Zhong Chen

Keyword(s):

Reaction Zone ◽

Equivalence Ratio ◽

Flame Structure ◽

Premixed Flame ◽

Counterflow Flame ◽

Partially Premixed ◽

Flame Structures ◽

The Rich ◽

Partially Premixed Flame ◽

Two Temperature

An experimental and simulation work had been conducted to study a one-dimensional partially premixed methane/air counterflow flame in this paper. Flame images are obtained through experiments and computations using GRIMech 3.00 chemistry were performed for the flames studied. The partially premixing effects upon the flame were revealed by comparing the flame structures and emissions with premixed flames at the same equivalence ratio. The results show the premixed flame only has a single flame structure. However, PPF has distinct double flame structures at present equivalence ratio. Temperature is relatively high in the whole combustion zone for premixed flame, while, for PPF, there are two temperature peaks in a rich premixed reaction zone on the fuel side and a nonpremixed reaction zone on the oxidizer side respectively. For PPF, NO concentration in the nonpremixed zone is much higher compared to that in the rich premixed zone because of higher OH concentration in the nonpremixed zone.

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PLIF measurements of instantaneous flame structures and curvature of an acoustically excited turbulent premixed flame

Aerospace Science and Technology ◽

10.1016/j.ast.2020.105950 ◽

2020 ◽

Vol 104 ◽

pp. 105950 ◽

Cited By ~ 1

Author(s):

Yongchao Sun ◽

Mingbo Sun ◽

Jiajian Zhu ◽

Dan Zhao ◽

Qian Wang ◽

...

Keyword(s):

Premixed Flame ◽

Turbulent Premixed Flame ◽

Flame Structures ◽

Turbulent Premixed

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Influence of Swirl Number on NOX Formation in a Turbulent Non-Premixed Flame

ASME 2010 10th Biennial Conference on Engineering Systems Design and Analysis, Volume 3 ◽

10.1115/esda2010-25001 ◽

2010 ◽

Cited By ~ 1

Author(s):

H. Zeinivand ◽

F. Bazdidi-Tehrani

Keyword(s):

Temperature Distribution ◽

Flow Behavior ◽

Flame Temperature ◽

Premixed Flame ◽

Staggered Grid ◽

Maximum Temperature ◽

Swirl Number ◽

Nox Formation ◽

Flow Swirl ◽

No Formation

A numerical simulation of swirling methane/air non-premixed flame (TECFLAME swirl burner) in a two-dimensional model combustion chamber is carried out to assess the influence of entrance flow swirl number on temperature distribution, flow behavior and NO pollutant formation. A Finite Volume staggered grid approach is employed to solve the governing equations. The second-order upwind scheme is applied for the space derivatives of the advection terms in all transport equations. The eddy dissipation-finite rate model is employed to predict the heat release and the Reynolds stress turbulence model is applied to simulate the flow behavior. NO formation is modeled as a post-processing solution. NO formation prediction has reasonable agreement with experiments for smaller swirl numbers but with the increase of swirl number, deviations between numerical results and the experimental data increase. It may be due to incorrect prediction of temperature distribution in higher swirl numbers. With the increase of swirl number, maximum temperature of chamber decreases from 1900 (K) to 1650 (K). With temperature decline, NO concentration in the exhaust decreases from 27 (ppm) at swirl number of 0.7, to 4 (ppm) at swirl number of 2. On the other hand, with increase of swirl number, ratio of prompt NO formation to thermal NO increase rapidly. In another word, with decrease of flame temperature, prompt NO roles increase noticeably.

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