压气机中介机匣全流量工况特性的数值研究

Numerical Study on Characteristics of Compressor Intermediate Duct Within Full Mass Flow Working Condition

关键词:  压气机  中介机匣  节流特性  进气畸变  流动损失  流量阻塞

Key words:  Compressor  Intermediate duct  Throttle characteristic  Inlet distortion  Flow loss  Flow blockage

摘要:

为全面评价压气机中介机匣性能，从上下游匹配角度，定义了中介机匣节流特性，从流动损失、出口畸变和流量阻塞三个方面，在全流量工况范围内评估中介机匣的性能，并给出了相应性能参数表达式。在均匀和实际不均匀总压入口条件下，对小型涡扇发动机压气机中介机匣流场进行数值计算，获取其全流量工况性能参数，并分析其流动机理。计算结果表明：中介机匣的出口总压损失和总压畸变程度随流量增加而增加；在实际不均匀进气条件下，流动损失和畸变程度均大于均匀进气条件；当中介机匣的设计流量和最大流量接近时，会造成压气机和中介机匣共同工作的阻塞流量明显减少。因此，对中介机匣进行性能评价时应考虑到实际的入口条件和非设计点的影响，在设计和选配中介机匣时应保证足够的流量裕度。

Abstract:

To evacuate the performance of the compressor intermediate duct （CID） comprehensively， the throttle characteristic was defined from the perspectives of the upstream and downstream matching. It was proposed that the performance of CID should be evacuated from three aspects， which are flow loss， outlet distortion and flow blockage， within the range of full mass flow working conditions. The corresponding evacuating expressions were deduced. To acquire the performance parameters and flow mechanism of full mass flow working conditions， CID flow fields of a small turbofan engine were calculated by numerical methods in uniform and actual non-uniform total pressure distribution conditions. The results show that the flow loss and the outlet distortion increase with the mass flow. In the actual non-uniform inlet condition， the flow loss and the outlet distortion are much higher than those in uniform inlet condition. When the design mass flow is close to the maximum value of the CID， the chocking mass flow of co-working between the CID and the compressor decreases obviously. It can be concluded that the actual inlet condition and off-design points should be considered during evaluating CIDs and sufficient flow margin should be ensured during designing or matching CIDs.