Experimental Investigation Of Lean Premixed Combustion

Combustion and pollution of normal resource coal, oil and natural gas is today's one of problems that need desiderating resolve. The oil price is still going up and up, so carrying out the study on high efficient and low emission combustion, the investigation of new device that use oil as fuel is very necessary. Lean premixed combustion is one of those ways of combustion that can keep low emission. This dissertation carries out the investigation on lean premixed combustion.This dissertation designed and produced a lean premixed combustion system, we can complete the investigation on combustion using gas fuel, that on combustion of prevaporizing and premixing using liquid fuel on it, also can complete the experimental investigation of how to induce and control the thermo-acoustic oscillations.This dissertation measured flow field in the combustion room without burning by hot-wire anemometer, find that the downstream from flame stabilizer are the same under different mixing conditions of fuel and air, they are both like a tread of double peak, with only a little difference of velocity.This dissertation investigated the influence of air consumed coefficient on flow field, flame structure, temperature distribution, the NOx emission on the lean premixed combustion device system which use liquefied petroleum gas (LPG). When the air consumed coefficient changes from 0.81 to 1.33, the combustion state changes from incompleteness to completeness, flame shrink from radial and axial, the visual color changes from red and yellow to transparent blue, and the flame temperature become higher.When the air consumed coefficient is about 0.9, the emission of NOx becomes the minimum, the emission of NOx also become more and more with the air consumed coefficient increasing. But when the coefficient is bigger than 1.33, the emission of NOx decreases again because of the effect of dilution.With the air consumed coefficient decreasing, the combustion state changes from completeness to incompleteness, the emission of CO and CxHy increase all the time quickly. And during this process, the emission of CO is less than that of CxHy, show that CxHy is the main factor in the emission of incompleteness production.The investigation shows, the lean premixed combustion can reduce the emission of NOx effectively, but also increase the incomplete combustion production. At mean time under low air consumed coefficient, there will be flame period fluctuation, even lead to flameout. There is important theory value in this dissertation.