Numerical Simulation Analysis On Flame Stability In Plate Type Micro Combustor With Bluff Body

Micro scale combustion components took a significant impact on many fields, and the development of miniaturized device and micro system has become an important study in today's research. However, the research and development of micro power system is facing many problems, which were mainly displayed in the high heat loss, short residence time of the gas mixture, material constraints and the wall's surface quenching of chemical elements. The above problems caused a large heat loss, heat transfer loss, instability of combustion and the low combustion efficiency. Prolonging the residence time of the combustor's fuel and making sure the stability of the flame is the core issue to solve the problems of micro scale combustion. Only to solve these key problems, micro energy systems can be applied in engineering as soon as possible.In this paper, on the basis of synthesizing the research on micro combustion at home and abroad and the Projects(51176045) supported by the National Natural Science Foundation of China and Projects(201208430262) supported by the National Studying Abroad Foundation Project of China. the relevant technology of micro thermo photovoltaic combustor were analyzed and studied in depth. Micro scale combustion chamber was taken advantage of the recirculation zone ignition principle by placing bluff body and making sudden expansion step to make steady combustion which was confirmed effectively in the conventional combustion. FLUENT software was used to simulate the plate type micro combustor with and without a bluff body. According to the calculation results, the effects of bluff body shape on the micro combustion chamber was explored, a planar micro combustor combined with sudden expansion step and bluff body was designed. The main innovation points and the research work of the paper are as follows:(1) A plate type of micro combustor model was established, and compared the simulation analysis between the situation of with and without a bluff body, obtained the distribution regularities of temperature field, pressure field, combustion efficiency and blow off limit of them. The test results were verified that the numerical simulation was effective.(2) Studied on the flow field and combustion characteristics of bluff body with different shapes in the plate type micro combustor, revealed the changing regularitiesof temperature field distribution, combustion efficiency, flow field, reaction zone and combustion limit with the variation of inlet velocity, equivalence ratio and bluff body shape in the micro combustor.(3) A plate type micro combustor with sudden expansion step and bluff body was designed, obtained the influence of inlet velocity, equivalence ratio and blockage ratio on the combustion chamber of the plate type combustor. The results were shown that the bluff body could help to stabilize the combustion in the plate type micro combustor.