转子叶尖间隙形状对跨声速轴流压气机性能影响机理分析

为研究转子不同叶尖间隙形状对跨声速轴流压气机性能的影响机理，分别对平行式叶尖间隙进行渐变式和阶梯式改型 优化，并利用商业软件NUMECA进行数值模拟。结果表明：对平行式叶尖间隙进行渐变式和阶梯式改型优化后，压气机性能有较 大提高，改型后 0.204-0.408的各类间隙压气机性能优于 0.408-0.204间隙的。相比较平行间隙 PTC 0.204-0.204，渐变式 TTC 0.204-0.408和阶梯式STC 0.204-0.408的失速裕度分别提高1.12%和1.61%，峰值效率基本不变，同时近失速工况下的总压比和效 率也略有提高。叶尖泄漏涡得到抑制，间隙处的流体低速区明显减小，流动损失减小，流场得到较大改善。转子通道的总压比在 85%叶高处明显提高，分别提高了1.01%和3.13%。阶梯式叶尖间隙压气机的静子通道40%叶高处总压损失系数减小达75.4%。 对平行式叶尖间隙进行改型处理能够有效提高压气机性能，且阶梯式叶尖间隙比渐变式的对压气机性能提高的效果更加显著。

Analysis of Effect Mechanism of Rotor Tip Clearance Shapes on Transonic Axial Compressor

In order to study the effects of different rotor tip clearance shapes on the performance of a transonic axial compressor, the Parallel Tip Clearances (PTC) were modified by Tapered Tip Clearances (TTC) or Stepped Tip Clearances (STC), and the commercial software NUMECA was used for numerical simulation. The results show that the performance of the modified compressor is significantly improved. After the modifications, the performance of the modified compressor with 0.204-0.408 tip clearances is better than that with 0.408-0.204 tip clearances. Compared with the compressors with PTC 0.204-0.204, stall margins of the compressors with TTC 0.204-0.408 and STC 0.204-0.408 is increased by 1.12% and 1.61%, respectively, while the peak efficiencies remain essentially unchanged. In addition,the total pressure ratios and efficiencies also increase slightly under near-stall conditions. The tip leakage vortices are suppressed, and the tip low-speed flow areas are significantly reduced, resulting in reduced flow loss and greatly improved flow fields. The total pressure ratios at 85% span-height of the rotor passage increase significantly, and they increase by 1.01% and 3.13% respectively. The total pressure loss coefficient at 40% span-height of the stator passage with stepped blade tip clearances decreases by 75.4%. It can be seen that the modification of the parallel tip clearance can effectively improve the performance of the compressor, and the stepped shape has a more prominent effect on the compressor performance than the tapered shape.