Investigation and modeling of progressive dilution effect on ignition delay of non-premixed flame

2016 Fiscal Year Final Research Report

• Project/Area Number: 26420146
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Thermal engineering
• Research Institution: The University of Tokushima
• Principal Investigator: Nada Yuzuru 徳島大学, 大学院理工学研究部, 准教授 (50383485)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 非予混合浮き上がり火炎 / 既燃ガス希釈 / 着火遅れ時間 / 浮き上がり高さ / フレームレット着火モデル / 予混合モデル

Outline of Final Research Achievements

In order to clarify and model the progressive dilution effect on ignition delay of non-premixed flame, we conducted numerical simulations for opposed laminar diffusion flames, and measured liftoff heights of turbulent lifted flames entraining diluent gases with high temperatures. The results obtained from the simulations reveal that dilution with high temperature gases shortens the ignition delay time whereas an excessive dilution delays the ignition. In addition, a time variation of dilution ratio of oxidizer significantly influences the ignition delay time. The experimental results demonstrate the increase in liftoff height with decreasing concentrations of reactant resulting from entrainments of diluent gas, and also the decrease in the height with elevating temperature of diluent gas. A model suggested in the present study successfully predicts the liftoff height variation associated with the diluent entrainments.

Free Research Field

燃焼工学