顶切风扇级由于固定的通流面积和短的相对叶高,在低速时往往会发生严重的突变型失速,使涡扇发动机船用或工业用改型的燃气发生器的低速喘振裕度大为减小。这是涡扇发动机船用改型顶切方案的一个严重问题,甚至会成为否定该方案的主要理由。 物理模型 全部试验表明,在低压轴相对转速N-1<50％(这时相对功率<10％)范围内,(1)顶切风扇级由于短的相对叶高而出现如图1所示的沿全叶高的突变型失速,它的压力振幅△p/p>1.0(这里p为表压)、相对弧度β=B/2π=30～40％、失速区数目i=1(只有个别情况下才会有i=2～3)。(2)失速区沿通流部份各级衰减 Due to the fixed through-flow area and short relative blade height, the top-cut fan stage tends to have severe sudden stalls at low speeds, resulting in a large low-speed surge margin for turbofan engine-fired or industrial retrofit gas generators To reduce. This is a serious problem for turbofan engine ship retrofitting scheme and may even become the main reason for denying this scheme. All the physical model tests showed that (1) the top cut fan stage appeared as shown in Figure 1 due to the short relative blade height at a low pressure shaft relative rotation speed N-1 <50% (relative power <10% Along the full-height mutant stall, its pressure amplitude Δp / p> 1.0 (where p is the gauge pressure), relative radian β = B / 2π = 30-40%, number of stalls i = 1 Under will have i = 2 ~ 3). (2) Stall area attenuates at all levels along the flow path