武夷岩茶摇青机离心风机优化设计与试验

Optimization Design and Experimental Validation of Centrifugal Fan for Wuyi Rock Tea Shaking Machine

摘要:

为提升武夷岩茶摇青机用离心风机性能，通过多目标遗传算法对离心风机叶轮进行优化设计与试验验证。首先，针对38组设计样本，采用拉丁超立方设计方法对叶轮叶片数量、叶轮内外径比、叶片进口安装角、叶片出口安装角、叶片折弯半径和叶片进口直径进行优化；然后通过NSGA-Ⅱ多目标算法对构建的最小二乘回归（Least squares regression, LSR）与移动最小二乘法（Moving least square method, MLSM）响应面模型进行求解，得到风机风量与风机效率最优时的Pareto解集，并进行Spearman变量相关性分析；最后通过CFD数值仿真与试验，验证了优化设计方法对实际设备摇青效果提升的有效性。结果表明：叶片进口安装角和出口安装角对风机风量影响最大，叶轮内外径比和叶片出口安装角对风机效率的影响最大，达到高相关程度；最优参数组合为叶片数量19、叶轮内外径比0.67、叶片进口安装角73.86°、叶片出口安装角128.74°、折弯半径25.28mm、叶片进口直径24.95mm；相较于原型风机，优化后风机风量增加381.22m3/h，风机效率提高4.33个百分点，叶梗、叶片平均走水分别提高2.05、3.15个百分点，做茶感官审评平均得分91.4，验证了风机优化设计对整机茶叶摇青品质的提升。

关键词:武夷岩茶摇青机;离心风机;叶轮;优化设计;试验

Abstract:

In order to improve the performance of centrifugal fan for Wuyi rock tea shaking machine, the centrifugal fan impeller was optimally designed and experimentally verified by multi-objective genetic algorithm. Firstly, for the 38 groups of design samples, the Latin hypercube design method was used to optimize the number of impeller blades, the inner and outer diameter ratio of the impeller, the inlet mounting angle of the blades, the outlet mounting angle of the blades, the bending radius of the blades, and the inlet diameter of the blades. Then, the constructed least squares regression (LSR) and moving least square method (MLSM) response surface models were solved using the NSGA-Ⅱ multiobjective genetic algorithm, the Pareto solution set for the optimal relationship between fan airflow and fan efficiency can be obtained, and Spearman variable correlation analysis can be conducted. Finally, the effectiveness of the optimized design method in improving the shaking effectiveness of the actual equipment was verified through CFD numerical simulation and experiments. The results showed that the blade inlet mounting angle and outlet mounting angle had the greatest effects on the fan airflow, the impeller inner and outer diameter ratios and the blade outlet mounting angle had the greatest effects on the efficiency of fan, reaching a high degree of correlation.The optimal parameter combinations were as follows: the number of blades was 19, the ratio of the inner and outer diameters of the impeller was 0.67, the installation angle of the blade inlet was 73.86°, the installation angle of the blade outlet was 128.74°, the bending radius was 25.28mm and the blade inlet diameter was 24.95mm. Compared with the prototype fan, the optimized fan air volume was increased by 381.22m3/h, the efficiency of fan was increased by 4.33 percentage points, the average water loss of the stem and leaves increased by 2.05 and 3.15 percentage points, respetively, and the average score of the sensory review of the tea was 91.4 points, which verified that the optimized design of the fan improved the quality of the whole machine for tea shaking.

Key words:Wuyi rock tea shaking machine;centrifugal fan;impeller;optimized design;experiment