Study On Hydrogen Non-premixed Combustion Characteristics Of Micro Nozzle And Its Field Synergy Analysis

The high energy density of hydrocarbon fuel creates a good opportuni ty for the development of combustion based micro power generation system.The growing demand for portable power devices,micro satellite thrusters,micro chemical reactors and sensors also greatly promotes the development of micro energy systems.Today,these portable devices rely heavily on batteries,creating a battery market of about $37 billion a year.With the rapid growth of portable devices such as mobile phones,laptops and personal power supply,the market demand for small generators will continue to grow.Unfortunately,the energy density of existing batteries is very low.Even the most advanced lithium-ion batteries have an energy density of only about 0.20 k W·h/kg.This low energy density can only support laptops and cameras for a few hours.In addition,it takes several hours for the battery to be fully charged,and only a limited number of rechargeable cycles can be carried out.Moreover,the current battery handling methods will cause various environmental problems.The development of MEMS(Micro-Electro-Mechanical System)and chemical systems in various applications has been greatly limited by the lack of power supply which is small enough,durable,efficient and light enough for immediate charging.In this paper,based on the research on the mec hanism and application of micro scale porous medium combustion,which is funded by the national fund for studying abroad,numerical simulation and experimental verification are used to study and analyze the influence law of combustion characteristics of no zzle jet micro combustor.The main research work and innovations of the thesis are expressed as follows:(1)The physical model and mathematical model of the micro combustor are established by selecting the structure of the micro nozzle non premixed combus tor.Through the numerical simulation of the micro combustor under different physical conditions,the effects of the physical boundary conditions such as the inlet velocity,inlet temperature and convective heat transfer coefficient of hydrogen and air on the combustion characteristics of the combustion chamber are obtained.(2)The field synergy theory is used to perform field synergy analysis on the combustion zone in the micro-combustor,the synergy between the velocity vector field and the temperature gradient field is obtained with the intake velocity,inlet temperature and convective heat transfer coefficient of hydrogen and air gas.The law when the physical boundary conditions change.(3)In order to verify the positive guidance of the field synergy theory for the heat exchange and combustion process,the numerical simulation method is used to optimize the field synergy of the micro combustor and analyze the stable combustion effect of the micro combustor before and after the field synergy optimizati on.