Wyniki 1-1 spośród 1 dla zapytania: authorDesc:"RAFAŁ DALEWSKI"

Experimental testing and numerical simulations of a ducted counter-rotating MAV propelling system aeroacoustics DOI:10.15199/148.2017.5.6


  Micro Air Vehicles propulsion system under investigation is an efficient but also a noisy one. The scope of presented research was to experimentally quantify acoustic field and simulate it to analyse sources and potential of noise reduction. The other aim was to investigate potential flow quality assessment on the basis of noise signal analysis. Therefore a test setup was designed and manufactured allowing for 360 deg. observation of sound power and identification of dominating frequencies. Tests were performed to investigate best relative setting of rotors and inlet taking into account noisiness. A tested model, presented in Figure 1 was a MAV propulsion system comprising two counter-rotating propellers driven by one BLDC motor each. An inlet was formed by a contracted duct. The three elements are set along common axis and can be relatively translated. To investigate and quantify the most interesting cases a numerical model was built and solved using Ansys/CFD tools (Fluent 15). This analysis was used predominantly for sound sources power and placement identification and quantification. Finally data was set and compared. Results were discussed. Test rig An experimental part was conducted using a setup comprising following elements: 45 AKUSTYKA rok wyd. LXXVI - zeszyt 5/2017 - an anechoic chamber 1000 x 1000 x 1000 mm (in Figure 2), - a stand allowing for relative translation of the inlet duct, upper and lower rotor, - a microphone positioning mechanism, allowing for microphone rotation around the tested objects with - various radii (in Figure 3), - calibrated microphone with data acquisition and analyse system, - a control setup for rotational velocity regulation. In the experiment a calibrated microphone setup was used. Signal was processed using fast Fourier transform method (FFT) and analysed with regard to various rotors velocities and inlet positions (those three elements can be set in different relative pos[...]

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