Aeroengine fans and compressors increasingly operate subject to inlet distortion in the transonic flow regime. In this paper,\ninnovations to low-order numerical modeling of fans and compressors via volumetric source terms (body forces) are presented.\nThe approach builds upon past work to accommodate any axial fan/compressor geometry and ensures accurate work input and\nefficiency prediction across a range of flow coefficients. In particular, the efficiency drop-off near choke is captured. The model\nfor a particular blade row is calibrated using data from single-passage bladed computations. Compared to full-wheel unsteady\ncomputations which include the fan/compressor blades, the source termmodel approach can reduce computational cost by at least\ntwo orders of magnitude through a combination of reducing grid resolution and, critically, eliminating the need for a time-resolved\napproach. The approach is applied to NASA stage 67. For uniform flow, at 90% corrected speed and peak-efficiency, the body force\nmodel is able to predict the total-to-total pressure rise coefficient of the stage to within 1.43% and the isentropic efficiency to within\n0.03%.With a 120âË?Ë? sector of reduced inlet total pressure, distortion transfer through the machine iswell-captured and the associated\nefficiency penalty predicted with less than 2.7% error.
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