Method for determining the angle of repose - Database & Sql Blog Articles

The determination method of the angle of repose is defined as:

The fluidity of the powder cannot be expressed by a single characteristic value, and the angle of repose is often used.

Angle of repose

) said.

Usually refers to the maximum angle formed by the free slope of the powder accumulation layer and the horizontal plane.

Method for determining the angle of repose

There are two methods for determining the angle of repose: the injection method and the discharge method.
(1)

Injection method: The powder is slowly added from above the funnel, and the material leaking from the bottom of the funnel forms a tilt angle of the conical stack on the horizontal surface.
(2)

Discharge method: adding powder to the cylinder

container

Inside, the bottom surface of the cylinder is kept horizontal, and when the powder flows out from the center hole of the simple bottom, the reverse conical residual powder deposit formed in the cylinder

Tilt angle

.

Both tilt angles are angles of repose, sometimes tilting

Method for determining the angle of repose

The actual laboratory testing method:

(3)

Tilt method

Will be fitted

1/3

The rectangular container of the bulk material is inclined or the cylindrical container is fluctuated. The angle formed by the surface of the object after rest is the angle of repose, and the angle of repose is determined by the injection method, and the device is given a bottom diameter as shown in the figure.

D

,Minute

Do not measure

H

Angle of repose

a=arctg(2H/D)

.

(1) Two funnels are fixed on the iron stand

,

Funnel staggered

,

Contact the lower end of one funnel with the inside of another funnel

,

Put an inverted watch glass under the funnel

,

Slowly pass the powder through the upper funnel

,

Buffer through the lower funnel

,

Slowly stacked on the watch glass

,

Finally, determine the height of the powder accumulation

,

Divided by the radius of the watch glass

(

The diameter is generally

6.5CM), using the formula

α

=

Arc tg H/R

α is the angle of repose.

(2) Using the funnel method

,

Although every measurement has an error

,

But the results still have some reference value.

.

The funnel was placed a distance above the horizontal paper and the powder was added to the funnel to allow the powder to flow freely from the bottom of the funnel until the leaked powder showed a cone. And observe the sharpest angle that can be formed

(

Must be the largest acute angle

).

Then take measurements

:

The diameter of the cone is

2R

, height is

H

The angle of repose is the angle between the slope of the cone and the horizontal plane.

α

:

α

=

Arc tg H/R

α

The smaller, the better the liquidity. Generally considered

α

Less than

30

Degree, can flow freely. in

30

with

40

Between degrees is also possible

,

But more than

40

It’s not ok

.