Next Article in Journal
Numerical Study of Noise Barriers’ Side Edge Effects on Pollutant Dispersion near Roadside under Various Thermal Stability Conditions
Previous Article in Journal
Theoretical Modeling, Design and Simulation of an Innovative Diverting Valve Based on Coanda Effect
Article Menu

Export Article

Open AccessArticle
Fluids 2018, 3(4), 104; https://doi.org/10.3390/fluids3040104

Impact of Radiative Losses on Flame Acceleration and Deflagration to Detonation Transition of Lean Hydrogen-Air Mixtures in a Macro-Channel with Obstacles

Department of Chemical Engineering, University of North Dakota, Upson II Room 365, 243 Centennial Dr Stop 8155, Grand Forks, ND 58202-8155, USA
*
Author to whom correspondence should be addressed.
Received: 12 November 2018 / Revised: 4 December 2018 / Accepted: 6 December 2018 / Published: 8 December 2018
Full-Text   |   PDF [2112 KB, uploaded 8 December 2018]   |  

Abstract

While there has been some recognition regarding the impact of thermal boundary conditions (adiabatic versus isothermal) on premixed flame propagation mechanisms in micro-channels (hydraulic diameters <10 mm), their impact in macro-channels has often been overlooked due to small surface-area-to-volume ratios of the propagating combustion wave. Further, the impact of radiative losses has also been neglected due to its anticipated insignificance based on scaling analysis and the high computational cost associated with resolving it’s spatial, temporal, directional, and wavelength dependencies. However, when channel conditions promote flame acceleration and deflagration-to-detonation transitions (DDT), large pressures are encountered in the vicinity of the combustion wave, thereby increasing the magnitude of radiative losses which in turn can impact the strength and velocity of the combustion wave. This is demonstrated for the first time through simulations of lean (equivalence ratio: 0.5) hydrogen-air mixtures in a macro-channel (hydraulic diameter: 174 mm) with obstacles (Blockage ratio: 0.51). By employing Planck mean absorption coefficients in conjunction with the P-1 radiation model, radiative losses are shown to affect the run-up distances to DDT in a long channel (length: 11.878 m). As anticipated, the differences in run-up distances resulting from radiative losses only increased with system pressure. View Full-Text
Keywords: flame acceleration; DDT; radiative heat transfer; thermal boundary conditions; CFD flame acceleration; DDT; radiative heat transfer; thermal boundary conditions; CFD
Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).
SciFeed

Share & Cite This Article

MDPI and ACS Style

Krishnamoorthy, G.; Mulenga, L.N. Impact of Radiative Losses on Flame Acceleration and Deflagration to Detonation Transition of Lean Hydrogen-Air Mixtures in a Macro-Channel with Obstacles. Fluids 2018, 3, 104.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Fluids EISSN 2311-5521 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top