带升力风扇的垂直起降推进系统建模研究

Modeling of a STOVL Propulsion System with a Lift Fan

关键词:  常规/对转升力风扇  基元级理论  中介推力修正系数  趋同作用

Key words:  Common/contra lift fan  Elementary stage theory  Assist-thrust correction factor  Convergence

摘要:

为了填补国内对转升力风扇研究与垂直起降系统建模研究相结合的空缺， 分别针对常规与对转升力风扇， 建立了垂直起降推进系统的部件级实时数学模型， 并进行了性能对比。针对减阻的要求， 通过插值将升力风扇进气道的阻力系数选为0.0470；针对升力风扇非设计点特性准确性的要求， 采用基元级理论对风扇进行半设计半计算；特别引入中介推力修正系数([κ])用于对转风扇的参数设计， 该方法下两升力风扇推力相等， 轴功率偏差为0.0265。进一步的动态仿真表明， 由于风扇特性的影响， 同样工况下非设计点处对转风扇的升力和轴功率更大；并且由于升力风扇与发动机的耦合性， 针对不同升力风扇的差异性， 发动机会通过调整转速而产生“趋同”的作用效果。

Abstract:

In allusion to the blank of domestic research of combining contra lift fan with STOVL’s propulsion system’s modeling， this text built the component level real-time mathematical model of a STOVL’s propulsion system with contra lift fan and common lift fan respectively and contrasted them. In order to decrease drag， a suitable drag coefficient as 0.0470 was chosen to the lift fan’s inlet by the interpolation. In order to satisfy the accuracy of fan’s off-design points’ characteristics， elementary stage theory was introduced to iteratively design and compute the fan’s blades at the same time. This text specially applied assist-thrust correction factor ([κ])to design the contra fan， with this way， their thrusts equal and shaft power’s deviation is only 0.0265. Further dynamic simulation shows that contra lift fan’s thrust and shaft power are a little larger on off-design points because of the characteristics’ differences. On account of the coupling between lift fan and engine， engine will adjust its rotational speed to attempt to reduce the effect of lift fans’ differences.