Abstract
These fundamental experiments were conducted to design the casing most effectively fitted to the plate fan of the threshing machine.
The results were as follows:
(1) The required power is shown in Fig. 2 (a). The forward tilted blade fan is higher than the backward. (2) Mean wind velocity V=a⋅n, here n is r. p. m. of fan rotor, a is constant, which is shown in Table 2. (3) Overall efficiency of the forward tilted angle high. The highesteff iciency are obtained at 0° and +22° tilted blade angle, respectively at the two and four blades.
(4) The vertical distribution of wind velocity, such as shown in Fig. 3 (a), is lower at upside rather than downside. (5) The horizontal distribution of wind velocity is shown in Fig. 3 (b). It is similar to the w-type and V-type, respectively at Casing I and II. (6) In the case of casing I, the rates of wind velosity deviation are respectivel 9-11% at two blades fan, 7-9% at four blades fan, and it is 2-3% lower than in the casing II. It is found from Fig. 4 that minimum rates occurs at about 0°-+22°tilted blade angle.
