Flame acceleration and DDT run-up distance for smooth and obstacles filled tubes

Silvestrini, Marina; Genova, B.; Parisi, G.; Trujillo, F.J. Leon

doi:10.1016/j.jlp.2008.05.002

Cited by 83 publications

(32 citation statements)

References 15 publications

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“…obstacle shape and blockage ratio (BR), have been the subject of a large number of studies (e.g. Lee et al (1984), Alekseev et al (2001), Silvestrini et al (2008) and Ciccarelli & Dorofeev (2008)). Results show that increasing the BR gives rise to higher flame speeds, due to increased turbulence generation, up to an optimal point where a further increase results in (partial) flame quenching and momentum loss (Beauvais et al 1994).…”

Section: Introductionmentioning

confidence: 99%

Fractal Grid Generated Turbulence—A Bridge to Practical Combustion Applications

Hampp

Lindstedt

2016

Fractal Flow Design: How to Design Bespoke Turbulence and Why

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Abstract.Practical applications typically feature high turbulent Reynolds numbers and, increasingly, low Damköhler numbers leading to distributed combustion. Such conditions are difficult to achieve on a laboratory scale that permits detailed experimental investigations. The aerodynamically stabilised turbulent opposed jet flame configuration is a case point -an exceptionally flexible canonical geometry traditionally featuring low turbulence levels. Fractal grids can be used to increase the turbulent Reynolds number, without any negative impact on other parameters, and to remove the classical problem of a relatively low ratio of turbulent to bulk strain. The use of fractal grids to ameliorate such problems is exemplified for fuel lean combustion with combustion regime transitions achieved through the stabilisation of turbulent premixed flames against hot combustion products. An analysis is presented in the context of a multi-fluid formalism that extends the customary bimodal pdf approach to include multiple fluid states. The approach is quantified via simultaneous OH-PLIF and PIV, permitting the identification of five separate states (reactant, combustion product, mixing, mildly reacting and flamelet fluids). The sensitivity of the distribution between the fluid states to threshold values is also evaluated. The work suggests that a consistent treatment of the delineating thresholds is necessary when comparing different types of simulations (e.g. DNS) and experiments for reacting fluids with multiple states. The use of fractal grids in a flame driven shock tube provides a further example and is shown to generate turbulent Re numbers of the order 10 5 for flows with Mach numbers approaching unity. The conditions are of relevance to flame stabilisation in hypersonics and are analysed through OH-PLIF and high speed PIV with optimal fractal grids selected on the basis of maximum flame acceleration.

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Section: Introductionmentioning

confidence: 99%

Fractal Grid Generated Turbulence—A Bridge to Practical Combustion Applications

Hampp

Lindstedt

2016

Fractal Flow Design: How to Design Bespoke Turbulence and Why

View full text Add to dashboard Cite

show abstract

“…Flame propagation in industrial processes that are built from many different constructions can be complex. For example, obstacles in the processes can enhance flame acceleration (Di Sarli et al, 2010;Di Sarli and Di Benedetto, 2013;Kindracki et al, 2007;Park et al, 2008;Silvestrini et al, 2008). Explosions in pipes with a single bend, a U bend, or a Z bend are also quite different than explosions in straight pipes (Blanchard et al, 2010;Frolov et al, 2007;Zhu et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Flame acceleration in pipes containing bends of different angles

Zhu

Gao

Lin

et al. 2016

Journal of Loss Prevention in the Process Industries

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“…But these studies rarely involved the effects of obstacles on flame transformation process in the early stage before DDT performing [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

“…Lots of experimental and numerical investigations of flame vortexes induced by obstacle aimed at explaining the mechanisms responsible for its formation [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22], including the experiment study on acceleration of flame front [12,15], overpressure [9,10,13,14,16], influence of blockage ratio [16], and obstacle shapes [9]. Flow field and reaction rate were also studied by numerical simulation [17][18][19][20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Premixed CH₄-Air Flame Structure Characteristic and Flow Behavior Induced by Obstacle in an Open Duct

Chen

Zhang

et al. 2014

Advances in Mechanical Engineering

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To study the fuel gas combustion hazards, the methane/air flame structure and flow characteristic in an open duct influenced by a rectangular obstacle were explored by experiment and realizable -model (RKE). In the test, the high-speed schlieren photography technology and dynamic detection technology were applied to record the flame propagation behavior. Meanwhile, the interaction between flame front and flame flow field induced by the obstacle was disclosed. In addition, the laminar-turbulence transition was also taken into consideration. The RKE and eddy dissipation concept (EDC) premixed combustion model were applied to obtain an insight into the phenomenon of flow change and wrinkle appearing, which potently explained the experimental observations. As a result, the obstacle blocked the laminar flame propagation velocity and increased pressure a little in an open duct. Some small-scale vortices began to appear near the obstacle, mainly due to Kelvin-Helmholtz instability (KHI), and gradually grew into large-scale vortices, which led to laminar-turbulent transition directly. The vortices thickened the reaction area and hastened the reaction rate; reversely, the higher reaction rate induced larger vortices. The RKE model result fitted the test data well and explained the wrinkle forming mechanism of two special vortices in the case.

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Flame acceleration and DDT run-up distance for smooth and obstacles filled tubes

Cited by 83 publications

References 15 publications

Fractal Grid Generated Turbulence—A Bridge to Practical Combustion Applications

Fractal Grid Generated Turbulence—A Bridge to Practical Combustion Applications

Flame acceleration in pipes containing bends of different angles

Premixed CH₄-Air Flame Structure Characteristic and Flow Behavior Induced by Obstacle in an Open Duct

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Flame acceleration and DDT run-up distance for smooth and obstacles filled tubes

Cited by 83 publications

References 15 publications

Fractal Grid Generated Turbulence—A Bridge to Practical Combustion Applications

Fractal Grid Generated Turbulence—A Bridge to Practical Combustion Applications

Flame acceleration in pipes containing bends of different angles

Premixed CH4-Air Flame Structure Characteristic and Flow Behavior Induced by Obstacle in an Open Duct

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Premixed CH₄-Air Flame Structure Characteristic and Flow Behavior Induced by Obstacle in an Open Duct