Studies on the fitting angle and number of wings at the winnowing fan

Abstract

In order to investigate the influence of the fitting angle of winnower wings, in the theoretical study the potential equation was fixed by the conformal representation which in gained by using, at first, the vortical flow gusted out of the part near the foot of the runner and then the circulation round the wings. And in the results of culculation through these equation in the case of the dimensions of the sample winnowing fans used in the rice huller, we found the potential velocity about 10m/s and rapider air velocity was required at the angle which inclines to the rotating direction of blowing blades. (say+wing) In the practical study, when we measured the wind velocity, those practical values obtained were the same as the above-mentioned value theoreticalley calculated. The most efficacy of the sections wind velocity-distribution according to various fitting angles was found in the case of 0° by the method of scoring marks. Comparison by the separation is generally made by the gathering quantity, consisting of paddy, crashed rice and husk, at the Second Mouth and Third Mouth of wind flow outlet of winnowing fan; and we found +11° the most efficient of all the cases in the experiment.
In conclusion, + angle wings were very useful owing to rapid wind velocity, hence we should use them at the range of 0°-+30° As for the number of winnowing fan wings, three leaves in proved to be the most efficient through our experiment.