Question

Tranport Phenomena

Settling of ceramic particles in water. Small and relatively uniform titanium oxide particles can be made by precipitation from a solution. Here we will study how fast the particles sink through solution so the particles can be collected from the bottom of the container 1- Derive an expression for the terminal rising/sinking velocity of a sphere in a fluid, starting from the friction factor definition for flow past a sphere, the weight and buoyancy force, and the relation between f and Re in Stokes Flow 2- Consider a uniform suspension of approximate spheres of titanium oxide (p 3850 kg/cm3) in water. If the water is 10 cm deep, above what diameter do all of the spheres reach the bottom within 1 minute? 3- Is Stokes flow is a valid assumption for (Q2)? Why?

Answer 1