HEAT TRANSFER OF PARTICLES IN PNEUMATIC ESCALATOR

Abstract

Pneumatic escalator is examined as to its heat transfer characteristics with particles. Change in particle temperature in the horizontal direction of overall particle flow is measured by a radiation thermometer. An experimental equation of particle temperature is made under various operating conditions such as air flow rate, particle feed rate and inlet air temperature. An apparent coefficient of heat transfer based on particle temperature alone is evaluated by heat balance and rate of heat transfer between particles and air or wall surfaces.
As a result, it is found that Nusselt''s number increases with particle Reynolds number, particle concentration and average temperature of air within each sectionalized cell and with decreasing particle size. Thus, a pneumatic escalator could suitably be designed and utilized for continuous and simultaneous heating operations on the basis of the heat transfer data obtained.