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.

The matter of developing counter-rotating fans for advanced next generation aeroengines with ducted and unducted propfans is very important [1]. Counter-rotating fans can be made with fixed blades. This article considers tractor propfans consisting of two counter-rotating rotors of variable pitch (VPR) which valuable property is the possibility to turn their blades about the radial axis in order they can take the optimal position in direct thrust regimes, and to obtain a reverse thrust when turning them by a rather large angle. In this case there is no necessity to use a bulky special clamshell-type thrust reverser. In the 1-st phase of designing new CRFs it is necessary, by calculation or experimentally, to show the possibility of obtaining gasdynamic effectiveness of such fans up to the level of single-rotor fans or, at least, to obtain η*ad.f ≥ 0.90÷0.91. But the main thing is to substantiate the feasibility of getting high acoustic characteristics. CIAM (Central Institute of Aviation Motors) is carrying out calculation-experimental investigations of the SV-92 ducted counter-rotating propfan (DCRP) model (the SV-92 is an advanced fan for ultra-high bypass ratio engine [2]) as well as the SV-27 CRF (Fig. 1, Table 1) with unducted rotors for the test aircraft. This paper presents some results on gasdynamic and acoustic characteristics for the SV-27 CRF only. These investigations are aimed at providing the meeting of the test aircraft perceivable noise to ICAO chapter IV regulations.