Dynamic Characteristics Analysis Of Centrifugal Fan Impeller Based On Fluid-structure Interaction

The centrifugal fan is widely used in industrial production sector, and it plays an important role in power, petroleum, chemical fields and so on. Whether it can work safely or not is directly related to the economical benefit of the production departments. The impeller is the most critical component of fan, its insufficient strength or fatigue damage can cause fan accident. The traditional method of impeller strength makes a lot of simplifications for impeller, which leads to larger calculation error and brings some difficulty for evaluating the safety of impeller. While using the finite element method can solve this problem well.In this paper, G4-73No.8D centrifugal fan impeller is chosen as the study object. Considering the impeller deformation on the flow field and the three loads on the impeller deformation and stress, the loose coupling method is used to investigate the impeller based on fluid-structure interaction by the computed fluid dynamics software CFX to simulate the flow field and the finite element method software ANSYS to simulate the structure field, both the computational results are shared on the coupling platform MFX-ANSYS/CFX. The simulation results show that the fluid-structure interaction on impeller has little effect on the flow field, which can be neglected, while it has some effect on the impeller deformation and stress, which makes the maximum total deformation of impeller reduced by2.5%and the maximum equivalent stress of impeller increased by3.6%. The prestressing effect will improve the values of impeller natural frequencies, but the increase rates of the natural frequencies are different, the maximum increase rate is2.6%, the centrifugal force plays a critical role for the natural frequencies increase in the three loads, the others can be neglected. The frequency margin of impeller is calculated, the natural frequencies of impeller partly fall into local resonance region, however, as its deformation and stress are small, and the stress is far less than the impeller fatigue limit, so the fatigue damage of impeller will not occur, and its work is safe.