Measurement of Local Structure of Turbulent Premised Flame by Using an Ion Probe Method and Laser Ibmography

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Generally the flame structure of turbulent premixed flames is expressed as a wrinkled laminar flame model Therefore the burning rate is expressed as a function of the local burning velocity and the flame surface area In our previoia studies the fractal burning model for modeling a flame surface area was used for the simulation of turbulent propagation process in a spark ignition engine. However as the local burning velocity is affected by the flame stretch and flame curvature, the local velocity is changed from the laminar burning velocity. The local burning velocity model is essential for modeling die turbulent burning model In present study the effect of the analyzing area on the PDF distribution of flame curvature was investigated. When the flame curvature is obtained from the flame geometry, the optimal analyzing area must be chosen. As the turbulence intensity increase, the mean radius of flame curvature decreases and the PDF distribution of flame curvature becomes to be axial symmetry. It was found that the non-dimensional radius of flame curvature is expressed as a function of the non-dimensional turbulence intensity considered the mixture density.The characteristic value of flame thickness was measured by using ion probe method Tte flame Ihiclmess measured by ion probe method was compared with the thickness of preheat zone. It was confirmed that the thickness obtained by ion probe method is proportional to the thickness of the preheat zone of the laminar flame.In the future study the laser tomography and ion probe method simultaneously are applied for the measuring the flame structure of turbulent premised flames.