Optimization Of The Impeller Of A Cross-flow Air Curtain And Its Internal Flow Analysis

Air curtain machine is a kind of air supply machinery used to isolate indoor and outdoor air,which is widely used in industrial production and daily life.With the transformation of the economic structure to high-quality development,people have increasingly higher requirements on the air volume and noise quality of the cross-flow air curtain machine.The design tends to be specialized.Therefore,for a certain type of cross-flow air curtain machine,combined with numerical calculation,experiment and optimization algorithm to pursue the large air volume of the air curtain machine under fixed specifications as the goal,a more complete impeller optimization route and implementation process are established.Changing the number of blades,inner and outer circumferential angles,chord length,camber,placement angle,and impeller placement position makes the fan’s internal flow condition improve and the air volume increases significantly.The main research content of the paper:(1)The CFD numerical calculation is performed on the cross-flow air curtain model and compared with the performance test experimental results.The flow error is less than 4% under both working conditions to verify the reliability of the numerical method.The analysis of the flow field of the prototype revealed that there was a vortex zone on the upper left side of the impeller,the left side of the volute tongue,and the position inside the impeller near the volute tongue.There were a few vortexes in the lobes near the vortex zone.(2)A fourth-order Bezier curve fitting model based on the parameterized cross-flow fan blade profile is established,and the impeller is generated by MATLAB programming.On this basis,the number of blades of the cross-flow impeller was studied.The results showed that too many or too few blades will have a negative impact on the performance of the fan.When the number of blades is too small,the functional capacity decreases and the cascade consistency is low,and obvious blades will appear.The channel vortex obstructs the flow;when the number of blades is too large,the cascade consistency is large,which causes blockage to the overall flow.When the blade is 33,the flow rate of the fan is the largest.Compared with the prototype,the flow blockage is improved in the high-end.The maximum flow is increased by 2.5%,and the low-end is increased by 3.4%.(3)Based on the optimal number of blades,a multi-island genetic algorithm optimization model of cross-flow fan blade parameters was established,and the five sets of parameters of inner and outer circumferential angles,chord length,curvature,and placement angle were optimized to obtain the optimized The combination of impeller parameters weakens the blade vortex inside the fan,narrows the eccentric vortex range,and increases the flow rate;the maximum flow rate is increased by 4.3% in high-end and 3% in low-end.(4)On the basis of algorithm optimization,the influence of the position of the impeller in the structure of the wind curtain machine on the flow and flow field is studied.The analysis found that the eccentric installation mainly affects the impulse intake angle of impeller,and the optimization space is limited.The optimization results show that compared with the results before the eccentricity,the vortex area on the upper left side of the fan impeller is reduced.The increased volute gap leads to an increase in the eccentric vortex range.The fluid in the jet area is weakened by the back plate.Traffic increased slightly.After optimization,the maximum flow of the fan is increased by 1% in high-end and 1.1% in low-end.This article establishes a comprehensive optimization path for the impeller of the cross-flow air curtain machine,which ultimately increases the maximum flow rate of the prototype in the high-end position by 8% and the maximum flow rate in the low-range position by 10%;compared with the internal flow of the prototype,after the series optimization The main vortex area of the fan has been reduced,the number of blade vortexes at the inlet is reduced,the flow distribution in the mainstream area and the jet area is more uniform,the flow loss is reduced,and the optimization effect is remarkable.