Solid particles during sedimentation separation: formulas for the volume and surface area of spherical particles
Thread Content
【Question】Regarding solid particles during sedimentation and separation: For spherical particles, volume: V=πd3/6 (where d is the diameter of the spherical particle, in meters); surface area: S=πd2; specific surface area (surface area per unit volume of the particle): a=S/V=6/d. Why aren’t the general formulas for the volume and surface area of spheres used?
Because the volume formula for a sphere is 4πd3/3, and the surface area formula is 4πd2. But in the settlement section, the formula becomes. . . The strange one. I don’t understand why that formula has to be used. Could you explain it?
You mean the one above? For the volume of a sphere, the 3 refers to cubic, and the 2 in the case of surface area refers to square; go ahead and calculate it
When converting between radius and diameter, the surface area of a sphere is 4πr2, which is also equal to πd2
The formula for the surface area of a sphere is: S=4πR^2. The formula for the volume of a sphere is: V=(4/3)πR^3
{:3_63:}My IQ! ! ! Everyone, please ignore me. . .
2333 Don’t trust what your eyes see
{:3_63:} I forgot to bring my brain.
Here, d refers to the diameter of the spherical particles. In chemical formulas, the diameter is usually used rather than the radius; in formulas for spheres, r (i.e., the radius) is employed. By substituting d = 2r, you can obtain the formula mentioned above. I understood this only just now as well