Author: D. BaraldiPublisher:
ISBN:
Category :
Languages : en
Pages : 13
Book Description
Numerical Simulation of Premixed Flame Propagation in a Channel with Two Obstacles
Author: D. BaraldiNumerical Methods in Laminar Flame Propagation
Author: Norbert PetersPublisher: Springer-Verlag
ISBN: 3663140067
Category : Mathematics
Languages : de
Pages : 211
Book Description
Numerical Simulation of Premixed Flames Interacting with Obstacles
Author: Fabio ParaventoPublisher:
ISBN: 9789064643156
Category :
Languages : en
Pages : 137
Book Description
Numerical Simulation of Pre-mixed Flame Propagation in a Closed Tube
Author: Kazuto KuzuuTurbulent Premixed Flames
Author: Nedunchezhian SwaminathanPublisher: Cambridge University Press
ISBN: 1139498584
Category : Technology & Engineering
Languages : en
Pages : 447
Book Description
A work on turbulent premixed combustion is important because of increased concern about the environmental impact of combustion and the search for new combustion concepts and technologies. An improved understanding of lean fuel turbulent premixed flames must play a central role in the fundamental science of these new concepts. Lean premixed flames have the potential to offer ultra-low emission levels, but they are notoriously susceptible to combustion oscillations. Thus, sophisticated control measures are inevitably required. The editors' intent is to set out the modeling aspects in the field of turbulent premixed combustion. Good progress has been made on this topic, and this cohesive volume contains contributions from international experts on various subtopics of the lean premixed flame problem.
Numerical Simulation of the Propagation of Premixed Flames Without Vorticity Production
Author: Julian L. HodgsonCombustion Wave Propagation Regimes in a Channel Equipped with an Array of Cross-flow Cylindrical Obstacles
Author: Thomas Arthur Richard PinosPublisher:
ISBN:
Category :
Languages : en
Pages : 214
Book Description
Flame propagation through a channel equipped with obstacles was studied experimentally. Two types of obstacle geometries were investigated, i.e., wall-mounted cross-flow cylinders and fence-type obstacles mounted on the top and bottom channel surfaces. The motivation for this research is its applications to both high-speed propulsion and industrial explosion safety. The effect of obstacle distribution and blockage ratio on flame acceleration was investigated in a 2.54cm x 7.6cm "narrow" channel with wall-mounted cross-flow cylindrical obstacles. The cylinders were arranged in a "staggered" or "inline" pattern, with blockage ratios of 0.5 and 0.67. Schlieren images were used to study the flame shape and its leading edge velocity for a range of fuel-air mixtures compositions. It was determined that initial flame propagation occurs faster in higher blockage ratios due to the higher frequency perturbation to the flow. Flame acceleration led to different quasi-steady flame and detonation propagation regimes. In general, higher final steady flame velocities were reached in the lower blockage ratios, and detonation limits were found to be influenced by the geometry. The influence of channel width on flame acceleration was also determined using fence-type obstacles with a single blockage ratio. Experiments were performed in a 2.54cm x 7.6cm and 7.6cm x 7.6cm channel. Schlieren images were again used to study the flame shape and to obtain leading edge velocity. The flame tip was found to have a parabolic profile across the channel width for the narrower channel and flatter profile in the wider channel. It was determined that the channel width has a weak effect on the flame velocity down the channel length. As such, flame acceleration was initially only slightly more pronounced in the narrow channel before the reverse became true later in the wide channel.
Experimental and Numerical Investigation of Flame Acceleration in an Obstructed Channel
Author: Craig Thomas JohansenPublisher:
ISBN:
Category :
Languages : en
Pages : 392
Book Description
The purpose of this study is to experimentally and numerically investigate flame acceleration in an obstructed channel. The motivation for this research is for the development of Pulse Detonation Engines (PDEs), which are unsteady propulsion devices that utilize the detonative mode of combustion. A literature survey on flame acceleration in the context of PDEs is presented, which covers a wide range of combustion regimes including laminar combustion, turbulent combustion, and finally detonation. An overview of current numerical modeling strategies is also presented along with a selection of recent numerical studies focused on flame acceleration in obstructed channels. Experimentally, the effect of obstacle blockage ratio on flame acceleration was investigated in a modular channel. The channel had a square cross-section and obstacles were mounted onto the top and bottom surfaces. Schlieren images were used to study the flame shape and the centerline flame velocity. A novel visualization technique has been developed to study the unburned gas flow ahead of the flame front. Flame propagation at speeds above the speed of sound in the reactants was also studied as compression waves formed in the unburned gas. It was found that shock reflection from obstacle surfaces and subsequent flame interaction dominates flame acceleration at these higher flame speeds. The unburned gas flow field ahead of the flame front was simulated using Large Eddy Simulation (LES) and was compared to the visualization technique developed experimentally. The detailed unsteady calculation was used to further study the development of recirculation zones behind the obstacle surfaces and the generation of turbulence in the shear layers. The unburned gas flow field was investigated to give insight into the speed and shape of the flame as it propagates into these regions. Flame propagation was modeled using a flame surface density combustion model and simulations showed flame interactions with the turbulent flow field and how three-dimensional vortical structures augmented the flame shape and increase total area.
Scientific and Technical Aerospace Reports
Author: Combustion Waves and Fronts in Flows
Author: Paul ClavinPublisher: Cambridge University Press
ISBN: 1107098688
Category : Mathematics
Languages : en
Pages : 723
Book Description
A self-contained presentation of the dynamics of nonlinear waves in combustion and other non-equilibrium energetic systems for students and specialists.