PIV Measurement and Numerical Simulation of Flow Structure in a Cap and a Bluff-body Combustor
Date Issued
2014
Date
2014
Author(s)
Huang, Pei-Hsun
Abstract
The present study focused on the stabilizing mechanism of a cap combustor. Based on previous studies, fuel-seeding device, and improvement of the transparency of a quartz cap. With Particle Image Velocimetry (PIV) system, the velocity of central fuel ejection is set at 1.2 m/s while the co-air flow velocity is set at 0.38, 1.5, 2.65, 3.75 m/s for jet-like flame, transition, premixed-like recirculated flame, and premixed-like jet flame. Images are recorded at rate of 1000, 2000, 4000 and 5000 flame per second to investigate mechanism of combustion and mixing of inner of cap. With numerical simulation for bluff body, we can analyze some physical phenomenon which is difficult to analyze in experimental, and thus numerical results could be compared with the experimental ones by disc and cap.
At same boundary condition with previous study, we analyze four types of flame in the inner of cap, and found that while co-air flow velocity raise, the range of vorticity of the inner of cap became larger. With turbulent intensity, we found that at much higher momentum of the co-air flow, the stability of the flame will be reduced.
In numerical analyze, we found CO mole fraction distribution implies the flame outline. While reactions finished, the product (CO2) will follow the flow and be brought to downstream. The temperature field and the heat of reactions specify that while co-air flow velocity raise, the temperature and the heat of reactions will uplift, and the burn ratio in the inner of cap will reduce, promote the burner efficiency on the surface of cap.
Subjects
雙環噴流燃燒器
粒子影像測速儀
帽頂機構
Type
thesis
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