Study On The Effect Of Single Motor Vertical External On The Characteristics Of Cyclone

With the concept of green environmental protection and energy conservation,coal policy has gradually shifted to the direction of optimizing production capacity and improving the quality of supply,and the construction of intelligent coal mine system is also accelerating comprehensively,thus putting forward higher requirements for coal machinery and equipment.As an important part of mine ventilation system,counter rotating axial flow fan is widely used in roadway ventilation because of its compact structure,high pressure rise and good anti wind performance.However,the traditional cyclone fan has not kept up with the pace of technological upgrading,and the disadvantages of poor heat dissipation performance,high noise,inconvenient maintenance are gradually revealed.Therefore,this paper designs a single motor vertical external counter rotating axial flow fan to solve the above problems and provide safety guarantee for the development of intelligent coal mine.Firstly,this paper describes the internal structure and working principle of counter rotating axial flow fan.Takes the FBD No8.0 counter-rotating axial fan as a reference,a counter cyclone driven by a single motor driven by a cross gear box is designed.The simplified model is meshed by ICEM-CFD software,the unstructured grid is selected,and the correctness of the model is tested by grid independence.The differences in efficiency,power,and internal flow loss between the FBD No8.0 counter-rotating fan and the new counter-rotating fan were compared,the results show that the vertical external of single motor has a wider application range for the flow of cyclone,but FBD No8 0 has better performance for cyclone at a flow rate of 800 m~3/min.From the full flow condition,the vertical external of single motor has lower overall entropy output value and less flow loss inside the cyclone.Then,according to the established geometric model,the internal flow of single motor vertical external pair cyclone is studied by FLUENT software,and the internal pressure and velocity distribution are analyzed by steady simulation method.The pressure distribution law is obtained through the cloud characteristics of the impeller,blade surface and different sections.The gas flow is observed according to the velocity distribution cloud and flow trace of the sections before and after the impeller.Changing the speed in the simulation parameters can explore the impact of different speeds on the fan.The results show that the speed regulation has little impact on the efficiency value of the fan,the pressure changes significantly,and the entropy output value of each internal area will also change,but the energy-saving effect is improved and the flow value at the maximum efficiency is changed.Then,the acoustic characteristics of single motor vertical external cyclone are studied.This paper expounds the basic theory of acoustics,summarizes the noise types and prediction models inside the fan.The surface sound power values of the fan under different flow conditions are compared,with emphasis on the noise distribution on the suction surface and pressure surface of the two-stage impeller and the vortex distribution at the inlet and outlet of the impeller.The influence of rotating speed on the noise of impeller surface and inlet section is discussed.The results show that the two-stage impeller is the largest noise generator inside the fan,and the shaft power of the rear stage impeller is also higher than that of the front stage impeller;The noise increases first and then decreases with the speed.Finally,according to GB/T1236-2000“standardized duct performance test for industrial fans”,a test platform for cyclone power performance is built to test the pressure,efficiency,power and other parameters of fans under different flow conditions and different speeds;At the same time,the field industrial test of the cyclone prototype is carried out for the vertical external of single motor,the actual flow,pressure and noise working in the underground roadway are collected,and the real field data are recorded,so as to provide a test basis for subsequent upgrading and optimization.