Numerical Method for Turbomachinery Tonal Noise Generation and Radiation Simulation Using CAA Approach

Abstract

The numerical method for 3D calculation of the turbomachinery tonal noise generation, propagation and radiation in the near and far fields taking account of the rotor-stator interaction is developed in CIAM. The method is based on the direct numerical solution of three-dimensional Euler equations for disturbances in time or in frequency domain using numerical methods of computational acoustics (CAA). For far-field radiation calculation the Ffowcs Williams method is used. The method is build into CIAM domestic aeroacoustic solver 3DAS (3 Dimensional Acoustics Solver). In this paper we present some examples of our method applications for calculation of rotor-stator interaction and propagation: • Ducted fan tonal noise simulation; • Ducted counter-rotated fan noise simulation; • Low pressure turbine tonal noise simulation.

Mathematical simulation of sound propagation in a flow channel with impedance walls

“…The transition from dark to light filling corresponds to a decrease in acoustic pressure. In the figures, dark lines with arrows show the stream lines of the acoustic power, which are the envelopes of the vector field defined by formula (12). In case 1, the right hand uniform field of lines is deformed on the lined portion of the channel in such a way that the majority of the acoustic power is absorbed by the lin ing, whereas only a small part of it remains at the left end of the calculation domain.…”

“…The quantity specified in the tables is the value of the acoustic power absorbed by the acoustic lining of the channel wall. The instant value of the vector of acoustic power flow density at any point of acoustic field in the inhomogeneous vor tex free isentropic gas flow is determined by the for mula (12) where and are the vectors of, respectively, the velocity of the main stationary flow and the perturba tion of the gas velocity.…”

“…As applied to solving avi ation acoustics problems, this approach is reduced, as a rule, to numerical integration of the linearized non stationary Euler equations. This corresponds to direct numerical simulation of the physical process of weak acoustic perturbations propagating in nonuniform gas flows without taking into account the effects of viscos ity and heat conductivity [7][8][9][10][11][12][13]. Modern computer capabilities are such that solving a problem of such a level as calculating sound radiation along engine gas paths becomes actually achievable; however, this requires very computing resource expenditures.…”

Frequency-domain method for multistage turbomachine tone noise calculation

“…9 The method was implemented in the Three Dimensional Acoustics Solver (3DAS) Central Institute of Aviation Motor (CIAM) in-house solver. 16,17 It was designed for the calculations of tone noise, generated by the inter-row interaction in a turbomachine, in the near and far acoustic fields. The solver was used for calculation of tone noise of open rotors, 16,18 low pressure compressors, 9 turbines, 17 and of different types of fans.…”

A Review of New Experimental Technologies for the Development of Advanced Fans with High Bypass Ratio

“…Calculations for the COBRA1 and CRTF1 fans were performed using the 3DAS in-house developed solver [32], which was previously used for the calculation of the tonal noise of different types of fans, compressors and open rotors (see [29] and references therein). An approximate rotor-stator interaction method is implemented in the solver which is based on the solution of three-dimensional Euler equations for disturbances occurring in the blade rows reference frame.…”