唐箕に関する実験的基礎研究 (第1報)
羽根の取付角度と風速分布との関係
1955 年 16 巻 3-4 号 p. 143-146
詳細
1955 年 16 巻 3-4 号 p. 143-146
As the first trial of fundamental experimental analysis of winnower, the author measured the velocity and its distribution at exit, changing the fixed angle of fan plate (θ) at seven kinds and revolution (n) at five kinds. Outer diameter of fan is constantly 380mm.
The study reported in this paper has led to the following general conclusions;
1. Relation between velocity distribution of wind and fixed angle of plate is shown in Fig. 2, (a) to (g). At large angles of plate and high revolutions, velocity distribution shows very turblent state, air flow becomes unsteady.
2. At backward angles, lateral veolcity distribution curves show concave, but conversely, they show convex upward at forward angles. Under v=6m/sec at θ=0° and backward 20°, velocity distribution is, averaged and ideal for actual work.
3. Speaking about vertical distribution, lower velocities are larger than upper ones at backward, but they are opposit at forward.
4. Mean velocity of whole section (vm) don't change so plainly against angle of plate as shown in Fig. 3 (A), but proportional to revolution. Fig. 3 (B) shows the proportional constant (a) which defined by equation (3). In this experiment, mean value of vm of seven fixed angles is nearly equal to 0.01 namely vm is about one hundredth of revolution. (n) under error of 7 to 8 per cent.
5. From 2 to 4 discribed above, we can say that (i) fixed angle of plate has influence upon velocity distributions, but (ii) doesn't influence mean velocity of whole section. Quantity of air discharged is not changed by angle of plate.
6. Power consumed by air resistance of plates doesn't change so widely by angle, but as shown in Fig. 3 (C), it increases rapidly against revolution.
