Experiment 2 Unit Op

Experiment 2: Measurement of equivalent radius, bulk density and solid density of granular materials.

Objective:
To measure the equivalent radius, bulk density and solid density of granular materials.

Materials:
Red beans, green beans and ground nuts.

Apparatus:
100mL measuring cylinder, 50mL measuring cylinder, analytical balance and cooking oil.

Procedure:

Results:
Table 2.1: Data of equivalent radius, solid density, bulk density and porosity of granular materials. nj Red beans
Green beans
Ground nuts
Weight of 400 beans, M (kg)
38
22
144
Volume of 400 beans + void spaces, V (ml)
48
26
232
Initial reading of cylinder V1 (ml)

300
300
300
Final reading of cylinder V2 (ml)
285
290
210
Volume of void spaces, v=v1-v2 (ml)
15
10
90
(V-v) x 10-6 m3
3.3 x 10-5
1.6 x 10-5
1.42 x 10-4
Equivalent radius, r (mm)
2.70 x 10-3
2.1216 x 10-3
4.3925 x 10-3
Solid density, ρs (kg/m3)
1151515.2
1375000
1014084.5
Bulk density , ρb (kg/m3)
791666.7
846153.8
620689.7
Porosity, ɛ
0.3125
0.3846
0.3879

Discussion: In this experiment, we have to measure the equivalent radius, bulk density and solid density of granular material. Granular materials are composed of grains or particles solids with interstitial spaces which is spaces between the particles. If the grains are small enough, the material is a powder. The solid density is the density of the material in the grains. It is important as it will determine whether the material will float or sink in water which the particle may or may not contain air. The bulk density is an important property, especially for storage and transportation rather than a separation process. It is defined as the mass divided by the total volume occupied by the material. This total volume includes air trapped between the particles. The volume fraction trapped between the particles is known as the porosity. The equivalent radius for ground nuts (4.3925 x 10-3) is higher than green beans (2.1216 x 10-3) and red beans (2.70 x 10-3). The size increase as the equivalent radius increase. Then, the solid density of the ground nuts is the lowest compared to green beans and red beans. The bulk density of the ground nut (620689.7) is the lowest compared to red beans (791666.7) while the highest is green beans (846153.8). As the amount of bulk density decrease, the porosity will be increase. The ground nuts resulting the highest porosity which is 0.3879.
References:

References: