ABSTRACT

This chapter outlines transport processes and transport properties such as relaxation times and introduces diffusivities of a single particle in a flowfield. It shows that particulates of different sizes will have different dynamic response characteristics in mass, momentum, energy, and charge transfers even when they are constituted of similar materials. The heat and mass transfer of a fluid sphere moving in a continuous fluid medium are affected by the motion inside the sphere. Bubble growth occurs in a liquid by adiabatic expansion or compression as the pressure of the system changes as well as via cooling or heating of the liquid. A drag force arises due to electrostatic interaction on a sphere moving through a highly ionized gas. A sphere of radius 'a' acquires negative charges because of the greater velocities of electrons. The factors which influence the motion and drag coefficient of a solid particle are velocity gradient, pressure gradient, temperature gradient, nonuniform radiation, and concentration gradient.