In this experiment, the effects of apparatus factors, such as the base ring diameter, the pouring rate,
etc. on the angle of repose φ
r of the poured powder have been studied.
By using the apparent fraction of the void ε
_??_ of the poured powder and its adhesion property, the authors have tried to explain the dependency of φ
r on the apparatus factors.
In this case, the apparatus factors for the angle of repose of the poured powder are as follows:
(1) The base ring diameter
Dr (mm)
(2) The pouring rate
Q (g/min)
(3) The spatter height
Hs (mm)
(4) The base ring height
hr (mm)
Magnesium hydroxide, garnet, talc, artificial stone (white marble), glass bead, and lycopodium were used as sample powder.
The results obtained are summarized as follows:
(1) As
Dr increases, φ
r of all sample powder decreases and ε
_??_ of talc, glass bead, and artificial stone decreases, but ε
_??_ of lycopodium, garnet, and magnesium hydroxide is constant.
(2) As
Q increases, φ
r and ε
_??_ of all sample powder decrease.
(3) As
Hs increases, φ
r of magnesium hydroxide and artificial stone increases, and φ
r of lycopodium decreases, but ε
_??_ of all these powder decreases.
(4) As
hr increases, in the case of the artificial stone, φ
r and ε
_??_ take the maximum value and then they decrease again.
For the dependency of φ
r on these apparatus factors, the following are matters of great importance.
(1) Packing of the poured powder by its own weight.
(2) Break down of the top of the heap of the poured powder by falling powder.
(3) The pile up effect on the top of the heap of the poured powder by its adhesion property.
(4) In fine powders their coagulated secondary particles moved as flowing units through the spatter, but, in the case of the large
Hs, these coagulated particles were broken into primary particles during the falling.
抄録全体を表示