| New energy vehicles lose the coverage of traditional engine noise,and blowers in air conditioning systems become one of the main noise sources,and their performance and noise directly affect the quality of automobiles.Multi-blade centrifugal fan for the core part of the automotive air conditioning blower,the small footprint of space,large air volume and other advantages make it in the air conditioning ventilation and other fields,has obtained a great advantage.However,compared with other types of fan,the overall utilization rate of multi-blade centrifugal fan is low,the overall energy consumption in the automobile air conditioning industry is serious,and the unreasonable design of its structural parameters dominates the performance of the blower.At the same time,because of the periodic rotating parts of centrifugal fan,unreasonable structure will increase the radiation of pneumatic noise,high-level noise environment will greatly affect the ride comfort of the people in the car,and even can pose a threat to health.Therefore,in view of the current problem of outstanding pneumatic noise and low performance of a car air conditioner blower,this paper reduces the pneumatic noise of fan by means of single-influence factor research,global sensitivity analysis,prediction model and multi-objective optimization.First of all,through test and numerical simulation,the pneumatic noise and performance of automobile air conditioning blowers are analyzed,and the numerical simulation model is tested.The analysis shows that the noise of the fan is mainly composed of 43-order pneumatic noise,the fan impeller and the worm tongue are the main noise sources for generating pneumatic noise,and the internal gas reflux of the fan,mutual interference between the components and other factors cause the flow loss is large and the performance is generally low.Areas with strong uneven flow are mainly concentrated near the snail tongue and blades,and the structures with greater influence on fan pneumatic noise and performance are snail tongue,snail tongue gap,blade outlet angle,and worm shell line.Secondly,based on the relevant theoretical formula and numerical simulation results,the influence law of snail tongue radius,snail tongue gap,blade outlet angle and worm shell line on fan pneumatic noise and performance is obtained and analyzed.With the larger radius of the worm tongue,the noise amplitude shows the trend of increasing first and then decreasing,the performance showing the trend of basically unchanged and then increasing;However,the improvement of a single goal often causes different effects of other targets to change,so in the actual engineering design optimization,it is necessary to consider the wind turbine pneumatic noise and performance of the case,the structure parameters of each fan there is a set of optimal values,so that fan noise and performance to achieve the best.The rationality of the calculation results of influencing factors is analyzed,and the variable range is determined for the sensitivity analysis and multi-objective optimization.Then,using the Latin supercube sampling method to randomly sample the sample space of the structural parameters,calculating the corresponding sample points by numerical method,introducing sobol’s global sensitivity analysis method,analyzing the global sensitivity of the above four structural parameters,and obtaining the degree of influence of each parameter on the pneumatic noise and performance of the fan.The degree of influence of each parameter change under the fan noise index is from large to small in order: blade outlet angle,snail tongue gap,snail tongue radius and worm shell line parameters;The effects of interaction caused by simultaneous changes between different parameters on the pneumatic noise and performance of the fan are studied,and the analysis shows that the interaction effect between the tongue radius,the blade outlet angle and other parameters is the greatest,followed by the gap between the worm tongue,and the interaction between the worm shell line and other factors has the least impact on the various target parameters of the fan.Finally,based on the Kriging agent model,90 sets of spatial sample points were used,and the prediction results were consistent with the actual value change trend,and the prediction accuracy of static pressure,efficiency and noise amplitude was higher Among them,the maximum relative error of static pressure value prediction is 1.4%,the average relative error is 1.03%,the maximum relative error of efficiency is 5.8%,the average relative error is 3.7%,and the maximum relative error of noise prediction is 4.6%.The average relative error is 3.3%.Then combined with the predictive model of the fan and the NSGA-III optimization algorithm to carry out multi-objective optimization,the optimization results show that: after the optimization of this method compared with the original fan,the internal flow of the fan,pressure distribution and other aspects of improvement,optimize the pneumatic noise,performance,in which the still pressure and efficiency of the blower increased by 106.3Pa and 4.75 percent,while the noise margin decreased by 4.39 d B.In summary,based on the study of the influence of the main structural factors on the pneumatic noise and performance of the blower,this paper introduces Sobol’ global sensitivity method to analyze the effect of the interaction between the parameters and parameters on pneumatic noise,static pressure value and efficiency,and establishes a pneumatic noise and performance prediction model of automotive air conditioner blower based on the Kriging agent model,combined with the prediction model and NSGA-III algorithm.A multi-objective optimization method for pneumatic noise and performance of blowers is proposed,which is of some guiding significance for the noise improvement and pneumatic performance optimization of automobile air conditioning blowers in engineering practice. |
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