The imaging experiment of Methylidyne (CH) radical generated from methane combustion on a swirl burner was carried out using Planar Laser Induced Fluorescence technology (PLIF), and the C-X (0,0) band was selected as the excitation method. The laser wavelength and laser energy have a significant impact on the signal strength and signal-to-noise ratio of CH radical, and the imaging quality of CH reached the best with the laser wavelength and energy are of 314.415 nm and 0.3 mJ. The fluorescence signal of CH radical from swirling flame mainly distributed on the outside of the image and exists in a narrow area. As the of equivalence ratio of methane combustion increased, the signal of CH radical gradually strengthened, and the flame profile of chemiluminescence gradually evolved from "V" type to "M" type, and the number of vortices formed by CH radical from PLIF imaging gradually increased.
A nanosecond pulsed dielectric barrier discharge (ns-DBD) setup is built to preliminarily analyze effect of different discharge repetition (600Hz ~ 1800Hz) and voltage (6.0kV ~ 10.4kV) on CH4-air diffusion flame. Emission spectral is used to understand temperature and relative change of components’ concentrations in diffusion flame, such as O radical (777nm band), OH radical (308nm band). Plasma induced consumption process of repetitive pulsed nanosecond discharges on O radical has been directly observed at 900Hz discharge repetition. Based on time resolved emission spectral, significant changes of OH radical distribution at early discharge stage can be observed, which can be due to air-discharge plasma, and rapidly recover in microsecond scale due to rapidly consumption of generated OH radical. Besides, great differences in reaction time scale of OH radical (half-value period of OH radical consumption ~81.8μs) and O atom (half-value period of O atom consumption ~3.6min) is observed, corresponding to different chemical reaction mechanism of O atom and OH radical. A model based on rate equation is built to describe generation and consumption process of O atom and OH radical, which can also well predict voltage behavior of 777nm band at steady state (6.0kV ~ 10.4kV).
Planar laser induced fluorescence (PLIF) is a powerful tool to visualize the flame structure, especially for the turbulent flame. In this paper, we employ OH-PLIF technique to analyze the structure of a supersonic ethylene jet flame on a turbulent burner. This burner consists of a central jet and hot coflow. The Mach numbers of the jet vary from 1.0 to 1.6, corresponding to Reynolds numbers ranging from 40893 to 65455. The flame structures are imaged by OH-PLIF measurement. The measurement results reveal that the OH concentrations decrease with the increase of jet velocity or decrease of the O2 fraction. And the extinction and re-ignition of flame take place when the jet velocity is high or the O2 fraction is small. These measurement results help to understand the interaction between flame and highly turbulent flow.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.