基于适航认证背景下大涵道比弯掠风扇转子变稠度数值研究

基于适航认证背景,以大涵道比弯掠风扇转子作为研究对象,通过改变风扇转子稠度,采用数值方法进行相关研究分析,在保证风扇转子基本性能的基础上,通过调整叶片数量N(18、20、22、24)获得4种不同稠度(N18、N20、N22、N24)风扇转子,在不同背压条件下进行数值模拟并获得近失速工况流场。一系列结果表明,适当增加稠度设计,可以提高风扇转子的效率。N18稠度下喘振裕度为0.082 9,当稠度增加到N20时,喘振裕度达到峰值0.106,随着稠度继续增加到N22,喘振裕度下降到0.084 6,但还是高于N18;当稠度增加到N24时,喘振裕度下降到0.076,随着稠度增加,效率峰值点所需流量逐渐降低。研究结果表明:该弯掠风扇转子在变稠度条件下效率峰值变化不明显;基于适航认证相关条例,喘振裕度是重要的考察内容;随着稠度增大,峰值效率也随着增大但是幅值非常微小,在实际应用中几乎可以忽略。研究结果可为匹配压气机整体设计,获得适航认证提供相应的参考。

Numerical Study of the Different Solidities Effect on High Bypass Fan Rotor Based on Airworthiness Certification

Based on the background of airworthiness certification, the fan rotor with a large bypass ratio is taken as the research object. By changing the fan rotor solidity, the CFX software numerical method was used for related research and analysis. On the basis of ensuring the basic performance of the fan rotor, four different solidities fan rotor were obtained by adjusting the number of blades N (18, 20, 22, and 24). Numerical simulations were carried out under different back pressure conditions and the near-stall working condition flow field was obtained. A series of results have been obtained to show that increasing the solidity design can increase the efficiency of the fan rotor. The surge margin at N18 was 0.0829, and when the solidity increased to N20, the surge margin reached a peak of 0.106 in four solidities. As the solidity continues to increase to N22, the surge margin drops to 0.0846 but is still above N18. When the solidity is increased to N24, the surge margin drops to 0.076. As for solidity increases, the flow rate required for the peak point of efficiency gradually decreases. The results show that the peak value of the curve, the fan and the sub-strain are not obvious under the condition of constant solidity. Surge margin is an important consideration based on regulations related to airworthiness certification. As the solidity increases, the peak efficiency also increases with the amplitude being very small, which is almost negligible in practical applications.