Computational Investigation Of Aerodynamic And Acoustic Characteristics Of Counter-Rotating Fan With Ultra High Bypass Ratio

Abstract

A computational investigation of aerodynamic characteristics of model counter-rotating fan with BPR=20, developed in CIAM in the framework of European Project COBRA (Innovative Counter rOtating fan system for high Bypass Ratio Aircraft engine), is presented in the work. Unsteady nature of the flow in counter-rotating fan has been studied including analysis of rotor-rotor interaction intensity and unsteady viscous wakes propagation through the axial gap and second rotor blade passages.The results of numerical investigation of the fan tone noise in approach operational conditions are also presented. The acoustic calculations were performed using in-house CIAM aeroacoustic code 3DAS. Directivity diagrams for the first 16 harmonics of tone noise in the forward hemisphere, obtained in the calculation, are shown. Comparison between these results and analogous results for model HBR counter-rotating fan with BPR=10 (designed in VITAL project) is performed. Additionally results were compared with experimental results for HBR fan.

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

“…During the fan design process, a calculation of the tonal noise of the COBRA1 model at approach conditions was performed [13]. For this operational point the fan parameters are: G cor = 46.276 kg/s, π* = 1.061, N1/N2 = 0.90, N = 54%.…”

“…Figure 34 shows a photo of the COBRA1 model fan installed at the C-3A test facility. Geometric and kinematic parameters of the tested fan are given below [13]: Geometric and kinematic parameters of the tested fan are given below [13]:…”

“…Partners in the COBRA project from the Russian party were CIAM, JSC Kuznetsov, Aerosila, and the Moscow Institute of Physics and Technology (MIPT). At that time, a counter rotating model fan designed by CIAM with m = 20 bypass ratio had been tested [13]. By the end of 2017, a European version of a counter rotating fan with m = 18 bypass ratio had to be manufactured and tested for gas dynamic and acoustic performance.…”

“…From 2013 to 2017, the C-3A test facility was used as a key test bench for gasdynamic, strength, and acoustic tests of counter rotating fan models with an ultra-high bypass ratio (m = 18-20) under a new international research program-the Innovative Counter rOtating fan system for high Bypass Ratio Aircraft engine (COBRA) [12,13]. European participants in this international project (collaboration between Russia and Europe) were ONERA, Safran Aircraft Engines (France), DLR (Germany), and COMOTI (Romania).…”