Research On Fluid-Structure Interaction Characteristic Of Counter Rotating Axial Flow Fan And Its Application Based On Nonlinear Dynamics

This paper experimentally and numerically analyze the three dimensional flow field characteristics and the blade's dynamic characteristics based on the consideration of fluid-solid coupling by using the counter rotating axial flow fan in mine as the example,then pointed a method to improve the flow condition and blade vibration. On the basis, according to the characteristic of the fluid-solid interaction in counter rotating axial flow fan, vibrated non-contact measuring technique was used to feasibility study, fan operation forecast and fault distinction based on the nonlinear theory.Firstly, taking the blade vibrated non-contact test based on the single sensor and the flow field test to obtain the gas pressure fluctuation and the blade vibration signal. Through spectrum analyzing, promulgated the phenomenon that the flow field coupled with blade in counter rotating axial flow fan.Then, the fan full channel three dimensional unsteady fluid-solid interaction numerical simulation was carried by using the dynamic LES model.Through the experiment and numerical research on the flow field, unsteady characteristics about the counter rotating axial flow fan's coupling flow field and some dynamic characteristics including blade surface pressure distribution and distortion and stress were obtained in this paper.Finally the pulsating time sequence signal inter-stage flow field has first carried on wavelet de-noising processing, taking phase space reconstruction to the blade vibration signal and the de-noising pulsation signal, simultaneously obtained the quantitative data of correlation dimension, the approximate entropy, the L-Z complexity quantification data. Discovered the structure change tendency of the blade vibration signal and the air pulsation signal quantitative data is consistent under the different operation. Based on this, according to the fluid-solid interaction characteristic, proposed the method of blade non-contact measurement and monitor, and has confirmed this method feasibility; The correlation dimension to stall signal is sensitive which served as characteristic quantity to judge the rotating stall. Meanwhile has established the fan flow field nonlinear system forecast model according to combine the quantification data and the computation result of characteristic parameter and the support vector machines, has carried on the preliminary study of fan operation condition forecast and diagnosis.