微型燃气轮机低热值燃料燃烧室喷嘴流动实验研究

为适应生物质气低热值、组分变化大的特点,达到燃烧室燃烧稳定、低排放要求,在某60 kW级微型燃气轮机环形燃烧室结构的基础上,新设计了一种具有不同预混孔结构的新喷嘴,并在上海交通大学微型燃气轮机单喷嘴燃烧室实验台上对原喷嘴及新设计喷嘴进行冷态流动实验,对比分析不同稀释孔直径及工质参数条件下原喷嘴及新喷嘴对燃烧室空气流量分配比及过量空气系数的影响。研究表明:燃料流量、空气流量变化会影响燃烧室空气流量分配,空气温度变化对燃烧室空气流量分配无影响;燃料热值降低会导致燃烧室过量空气系数增大,需要匹配直径更大的燃烧室稀释孔;相比于原喷嘴新喷嘴的流量分配比较大,为使其适应低热值燃料,需要匹配的燃烧室稀释孔直径为11.0 mm,该条件下新喷嘴可适应CH_4摩尔分数为50%~90%的燃料。

Experimental Research of Nozzle Flow of Low Calorific Value Fuel Combustion Chamber for Micro Gas Turbine

In order to adapt to the characteristics of low calorific value of biogas and changes of composition, to meet the requirements of combustion stability and low emission, an experiment is applied to research the structure of nozzle and dilution holes of a 60 kW micro gas turbine combustor, to determine the influence of distribution on combustion and cooling air flow, to find the influence of flow parameters and the best match between nozzle and mixing holes. The results show that: changes in air flow and fuel flow will affect air distribution, while air temperature has no effect on air distribution. Greater dilution holes are required to meet the low calorific fuel condition for the air excess ratio increasing dramatically. Compared with the original nozzle, the air distributed ratio of the new nozzle is greater, thus in order to fit the low calorific fuel condition, the diameter of the dilution holes need to be adjusted to 11.0 mm so that the new nozzle can work under the fuel condition with 50%-90% mole fraction of CH4.