Mechanism Study On Mocro-combustion And Thermoelectric Transformation

With the development of MEMS, micro-combustion is studied to meet the demand of the portable electronic equipment and the need of efficient drive and electric power for the micro-system in military field. At the beginning of its study from the middle of the 1990's, there are still a number of scientific and technical problem needs to be resolved.This thesis focuses on the micro-combustion characteristic and its energy transformation. Some work was developed with experimental and academic methods. First, the flame combustion model was established in consideration of the quenching distance; secondly, some experiment reseaches were described; thirdly, the thermoelectric micro-combustor was studied; fourthly, the author described the micro-combustion numerical simulation; and finally, some suggestion were put forword the design of the new micro-combustor.In order to study the characteristic of micro-combustion, a two-dimensional flame-burning model was established, in which the quenching distance is considered. The conclusion is that the flame is easy to quench and blowout but difficult to backfire on the microscale. The laminar flame propagation speed was analyzed theoretically with two methods and the expression of the laminar flame propagation speed was described when the quenching distance is under consideration. The analytic results showed that the quenching distance is the important factor which effects the laminar flame propagation. Both the quenching distance and the flame propagation speed interact and they make the flame stabilization deteriorate on the microscale.This thesis describes the premixed combustion of hydrogen and air in microscale T style tube and finds this structure helpful for stable burning. Some conclusions were drawn about flame temperature, flux, hydrogen-air equivalence ratio, and combustion efficiency. The stable burning can be observed when the premixed gas velocity changed from 0.57m/s to 18.4m/s in a suitable hydrogen-air equivalence ratio. It is easy to flameout for the heat loss influence distinctly when the premixed gas flux is small. In a certain hydrogen flux, there exists the highest combustion efficiency near to the complete combustion equivalence ratio, and the combustion efficiency about 100%. In a certain condition, the heat loss for the level part of the T style tube is one third of the reaction heat. In comparation with the macroscale combustion, the high fuel concentration limit decreases but for low limit there is no obvious difference.In the experiment, when the premixed gas velocity was high, some flame noise could be heard. With the increase of the flux, the maximum sound level will be...