环形分配器式扩压器性能数值模拟

Numerical Simulation for Annular Distributor Type Diffuser Performance

关键词:  航空发动机  燃烧室  分配器式扩压器  总压损失  数值模拟

Key words:  Aircraft engine  Combustor  Distributor type diffuser  Total pressure loss  Numerical simulation

摘要:

为降低航空发动机燃烧室扩压器的总压损失,提高其静压恢复系数和流动稳定性,设计了一种分配器式扩压器。采用计算流体动力学(CFD)方法。对矩形分配器式扩压器和环形分配器式扩压器进行了数值模拟,并将前者与试验结果进行对比,两者相互吻合,然后将此计算处理方法应用到环形分配器式扩压器中。研究结果表明:CFD软件能够准确地模拟矩形分配器式扩压器的内部流动,且准确度较高,数值模拟结果与试验结果偏差不大于±5%；环形分配器式扩压器具有优良的减速增压功能。在燃烧室进口Ma数高达0.36时,设计的环形分配器式扩压器的总压损失仅为2.89%,静压恢复系数为0.647；Ma数为0.42时,总压损失和静压恢复系数分别为4.12%和0.653,小于短突扩扩压器的总压损失。并且扩压器内均无流动分离。因此分配器式扩压器具有较大潜力,能够满足未来先进燃烧室的性能要求。 

Abstract:

To decrease the total pressure loss of diffuser of aircraft engine combustor and increase its static pressure recovery as well as flow stability, a distributor type diffuser was designed. Numerical simulation of rectangular and annular distributor type diffusers were conducted at different Mach numbers by means of computational fluid dynamics (CFD). The simulation results of rectangular distributor type diffuser are in good agreement with the experimental data, showing a deviation of less than ±5%. Results show that CFD software can accurately simulate the inner flow of rectangular distributor type diffuser.The calculation approach was used to study the performance of annular distributor type diffuser. The accuracy is high enough that the difference between simulation results and experimental results is less than±5%. Annular distributor type diffuser has excellent diffusion performance. When combustor inlet Mach number is 0.36, the total pressure loss coefficient and static pressure recovery coefficient of the designed annular distributor type diffuser are 2.89% and 0.647,respectively.When Mach number is 0.42, the total pressure loss coefficient and static pressure recovery coefficient are 4.12% and 0.653, respectively. These figures are less than those of dump diffuser. In addition, the flow separation was not found in the diffuser. Hence, an annular distributor type diffuser potentially satisfies the requirements of high performance combustors. 