ANALOGIES BETWEEN THE TRANSIENT MOMENTUM AND ENERGY EQUATIONS OF PARTICLES

Analytical forms of the rectilinear equation of motion and energy equa tion of particles, droplets or bubbles have been developed for very lo w Reynolds and Peclet numbers. Some of the early work on the two equat ions is briefly explored and recent advances are presented in more det ail. Particular emphasis is placed on the analogies and similarities b etween the momentum and energy equations, and the ways the similaritie s have been utilized in practice. The creeping Bow assumption, oil whi ch most of the known analytical forms are based, is critically examine d. The semiempirical and empirical versions of the momentum and energy equations, which are widely used in engineering practice, are also pr esented, as well as a numerical method to deal with the history terms. Implicit assumptions on the use of the empirical equations are expose d. An erroneous result pertaining to the droplet hows, and a paradox r elated to the typical history terms are examined, and their rectificat ion is pointed out. Recent results on the motion and heat transfer al finite Reynolds and Peclet numbers are also exposed. Tn this case, the momentum and thermal wakes around the particle play an important role in the momentum and energy transport process. Copyright (C) 1996 Else vier Science Ltd.