Abstract
Propagation and extinction behavior of CH4/air premixed flame passing through straight and converging-diverging (C-D) microchannels (diameters ranging from 1 to 10 mm) were investigated both experimentally and numerically. The dynamic behavior of flame propagation inside the channels was experimentally studied by using CH* chemiluminescence and direct imaging. Three patterns of flame propagation were observed, i.e., the flame can survive, partially extinguish and then re-ignite downstream, or completely extinguish. Regime diagrams showing these different patterns as functions of channel geometry and equivalence ratio were generated for both the straight and C-D channels. Numerical simulations were carried out to explain the experimentally observed flame dynamics inside the channels using a detailed CH4/air chemistry. In general, flames were easier to extinguish in C-D channels than in straight channels for a fixed channel diameter and equivalence ratio. Additionally, flames were harder to survive in C-D channels with larger exit-to-throat area ratios. Both heat loss and flame stretch were key factors that can generally cause flame extinction in narrow C-D channels.
Original language | English |
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Title of host publication | AIAA Aerospace Sciences Meeting |
Publisher | American Institute of Aeronautics and Astronautics Inc, AIAA |
ISBN (Print) | 9781624105241 |
DOIs | |
State | Published - 2018 |
Externally published | Yes |
Event | AIAA Aerospace Sciences Meeting, 2018 - Kissimmee, United States Duration: Jan 8 2018 → Jan 12 2018 |
Publication series
Name | AIAA Aerospace Sciences Meeting, 2018 |
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Conference
Conference | AIAA Aerospace Sciences Meeting, 2018 |
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Country/Territory | United States |
City | Kissimmee |
Period | 01/8/18 → 01/12/18 |
Funding
This work was supported by the National Science Foundation with Dr. Song-Charng Kong as the technical monitor.