基于可穿透面的叶轮机械流场/声场混合模型研究

A study on a flow/acoustic field hybrid model for turbomachinery based on the permeable data surface

  • 摘要: 针对管道内叶片排气动噪声声类比(ducted blade-row acoustic analogy, DBAA)方法在多级叶轮机械中未充分考虑叶片排屏蔽效应等声源建模缺陷的问题,本文结合Goldstein声类比方法,提出一种基于可穿透面(permeable data surface, PDS)的管道内叶片排气动噪声声类比方法DBAAPDS,并发展了基于该方法的流场/声场混合模型。该混合模型通过三维数值模拟获取可穿透表面的非定常载荷等关键参数,将其作为声源输入至DBAAPDS方法,以计算各模态的声压级。以两级风扇模型为研究对象,以经试验验证的三平面压力模态匹配方法(three-plane pressure modal matching, TPP)为基准,结果发现:相对于DBAA方法,DBAAPDS方法可以有效计算受叶片排屏蔽的模态,部分模态的预测精度较DBAA方法提高了67%。为进一步降低计算成本,对单级风扇模型进一步研究发现:TPP与DBAAPDS两种方法对物理计算域网格数量的要求是一致的,且DBAAPDS方法计算出的结果较TPP方法在轴向维度上展现出较好的鲁棒性。

     

    Abstract: To address the limitations of the ducted blade-row acoustic analogy (DBAA) method in multi-stage turbomachinery where the acoustic source modeling does not adequately consider blade row shielding effects, this paper proposes a novel acoustic analogy method, DBAAPDS, based on the permeable data surface (PDS), for ducted blade-row noise prediction, combining Goldstein’s acoustic analogy methodology, and further develops a flow/acoustic field hybrid model based on this method. This hybrid model acquires key parameters, such as unsteady loading on the permeable data surface through three-dimensional numerical simulation, which are then input into the DBAAPDS method as acoustic sources to calculate the sound pressure levels for each acoustic mode. A two-stage fan model is taken as the test case, and the experimentally validated three-plane pressure modal matching (TPP) method is used as a reference. The comparison reveals that, for most acoustic modes, the proposed method DBAAPDS can effectively calculate modes shielded by blade rows, with certain modes achieving a 67% improvement in accuracy over the DBAA method. To reduce computational costs, further investigation on a single-stage fan model reveals that both the TPP and DBAAPDS methods have the same requirement for the grid number in the physical computational domain. Moreover, the results calculated by DBAAPDS method demonstrate better robustness in the axial direction compared to the TPP method.

     

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