燃烧室出口温度分布偏差的机理

Mechanism of Exit Temperature Profile of Gas Turbine Combustor

为找出R0110重型燃气轮机干式低污染(DLN)燃烧室实测的出口温度分布偏离设计曲线的原因,以燃烧室掺混过渡段为几何模型,数值研究了来流高温燃气的温度和速度分布、掺混射流特性等因素对出口温度分布的影响.发现逆流式燃烧室设计使二次流道中的流动非常不均匀,导致上下对称开设的掺混孔的射流流量产生很大差异,这个差异是决定最高温度点径向位置的主要因素;掺混射流方向亦发生显著偏转,对温度分布形态有关键性影响;实测的叶根、叶尖温度畸变的原因是试验装置出口存在漏气.

It has been found that the measured exit temperature distribution of the DLN combustor of R0110 heavy- duty gas turbine deviates from design expectation. In order to reveal the reason, the dilution zone as geometrical model is investigated numerically. Several influence factors, such as temperature and velocity profiles of upstream hot gas and dilution characteristics, are studied. The results show that the reverse-flow structure of annulus generates an irregular flow field and results in much higher mass flow rate through lower dilution holes than through upper ones, which pushes up the radial position of the hot zone. Jet angles have great effects on temperature distribution. The sharp temperature drop both at blade tip and root is caused by air leak near the exit section.