1. Department of Engineering Physics, Tsinghua University, Beijing 100084, China 2. State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei 230026, China 3. School of Aerospace Engineering, Tsinghua University, Beijing 100084, China
The opposed-flow flame spreading along a polymethyl methacrylate (PMMA) sheet was investigated numerically. The melting process included a mushy transition region in the energy equation during the flame spreading. The fuel was ignited by applying a fixed heat flow at one position on the upper boundary of the material. The results show the typical procedures of ignition followed by unstable to stable flame spreading. The morphology of the mushy zone and the molten phase thickness were obtained based on the temperature field. The results show that the mushy zone is thin near the flame front and gradually thickens downstream of the flame front. Additionally, the melt region is shallow near the flame front and gradually deepens with increasing the distance from the flame front. The numerical results and a scale analysis show that the melt interface location can be approximated by a quadratic function.
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2020, Vol. 60 
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