Investigation of heat transfer and flame dynamics under acoustic excitation based on infrared and shadow method

The heat transfer of partially premixed laminar flame under Rijke acoustic standing wave was investigated. The flame dynamics and hot products could be captured by the infrared images and the radial temperature gradient distribution could be shown by schlieren imaging. The relationship between the hot products and the radial temperature is characterized with infrared-schlieren information integration. The results show that the hot products attached on the flame front under acoustic excitation present a symmetric structure of tip layer distribution. And the downstream region is wider than the upstream region. In one sound cycle the axial heat evolution shows a tip shape transporting heat to the downstream of the flame through two lifting processes. The temperature gradient induced by the radial heat transfer takes a finger shape whose evolvement is decided by the development of the cusps.