贯流风机结构参数优化组合研究

Optimum Combination of Structure Parameters of Cross Flow Fans

利用计算流体力学对叶片扭曲角为30°的贯流风机三维内部流场进行了数值模拟,并研究了各个结构参数(蜗壳间隙、蜗舌间隙、叶片内圆周角、叶片外圆周角、叶片数、叶轮内外径之比和叶片扭曲角)对贯流风机性能(出风口体积流率)的影响。采用正交试验设计方法,确定了上述7个结构参数的最优组合,并得到在定叶轮外径和转速下,结构参数最优组合为:蜗壳间隙εc为1 mm、蜗舌间隙εt为2 mm、叶片内圆周角α为90°、叶片外圆周角β为20°、叶片数n为30、叶轮内外径之比γ为0.75、叶片扭曲角θ为90°,优化后贯流风机出风口体积流率比优化前提高了25.2%。在贯流风机性能参数检测台上,试验测试了在定叶轮外径和不同叶轮转速下,优化后与优化前贯流风机出风口平均风速大小。试验结果表明优化后出风口平均风速比优化前增大了4.6%,试验结果和理论计算结果基本吻合。

The three-dimensional internal flow field of cross flow fans with 30° twisted blade was simulated with computational fluid dynamic （CFD） method. The influence of each structure parameters （volute case gap, volute throat gap, internal circumferential angle of the blade, external circumferential angle of the blade, blade numbers, the ratio of internal diameter to external diameter of the impeller or twisted angle of the blade） on the volume flow rate of the cross flow fan outlet was numerically researched. The optimal combination of seven structural parameters with the optimal performance of the cross flow fans was obtained by the orthogonal design method. Under the constant impeller external diameter and rotating speed, the optimal combination of structural parameters are as follows ： volute case gap 6°is 1 mm, the volute throat gap 8, is 2 mm, the internal circumferential angle of the blade αis 90°, the external circumferential angle of the blade β is 20°, the blade numbers n is 30, the ratio of internal diameter to external diameter of the impeller 3° is 0.75, and the twisted angle of the blade θ is 90°. It is obtained that the volume flow rate of the outlet of the optimized cross flow fan was increased by 25.2%. By means of the detection device of cross flow fan＇ s performance parameters, the air outlet average velocities of the optimized and original cross flow fans were experimentally tested under the constant impeller external diameter and different impeller rotating speeds. The experimental result showed the air outlet average velocities of the optimized cross flow fan were increased by 4.6%. The theoretical calculation results were consistent with the experimental test results.