Influence Of Fluid Operating Conditions On Surge Of Centrifugal Fan

Surge is a common failure during the operation of a centrifugal fan,which seriously affects the safety and reliability of the fan operation.The actual operating conditions of the centrifugal fan are usually different from the standard operating conditions at the time of production design,which makes the performance of the centrifugal fan greatly change compared with the standard design performance during use.Therefore,the influence of fluid conditions on the centrifugal fan surge is studied,which has certain guiding significance for the rational selection of centrifugal fan models and the selection of proper maintenance and control measures.The subject takes the LKFB-A-355 centrifugal fan as the research object.The Fluent software in the ANSYS Workbench 16.0 software platform was used to simulate the internal flow field of a centrifugal fan under different fluid conditions.The results show that when the temperature of the suction gas of the centrifugal fan increases or the inlet pressure decreases,the overall pressure-flow performance curve shifts to the lower left and the peak point also shifts to the lower left and the efficient work area becomes narrower.The static pressure at the outlet of the centrifugal fan is the same.When the centrifugal fan suction gas temperature is higher or the inlet pressure is lower,the amplitude of the volume flow fluctuation during surge is larger and the frequency is lower.And the greater the return flow rate in the centrifugal fan flow path,the more serious the phenomenon that the low velocity zone and the vortex structure block the flow channel.Based on numerical simulation results of internal flow field in centrifugal fans.Static Structural software in the ANSYS Workbench 16.0 software platform was used to perform one-way fluid-solid coupling analysis of the fan impeller.The results show that when the centrifugal fan changes from the design condition to the surge condition,the von-Mises equivalent stress due to the force of the impeller,the maximum position is transferred from the junction between the blade trailing edge and the front disc hub move to the middle position of blade leading edge,great changes have taken place.The static pressure at the outlet of the centrifugal fan is the same,the suction gas temperature of the centrifugal fan increases or the inlet pressure decreases.When the centrifugal fan surges,the values of the von-Mises effective stress and the?₁ equivalent stress caused by the internal force of the impeller decrease,but not obvious.