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, DBAA
PDS, 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 DBAA
PDS 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 DBAA
PDS 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 DBAA
PDS methods have the same requirement for the grid number in the physical computational domain. Moreover, the results calculated by DBAA
PDS method demonstrate better robustness in the axial direction compared to the TPP method.