Heat Transfer of Solid Particulate and Gaseous Heat Carrier in an Airlift Apparatus

Abstract

This paper considers the heat transfer process between solid particulates with heat source and gaseous heat transfer carrier in airlift apparatus during the pneumatic transportation. This case has many important practical applications in heat transfer systems where heat is generated within or absorbed by the particulate. Examples of such processes include drying processes, chemically reacting systems, and combustion processes. The two most important parameters in the thermal treatment of solid particulates in this case are the temperatures of solids and the gaseous heat carriers. Traditionally, these temperatures are considered as functions of x-ordinate along the heat transfer duct of the apparatus. Such an approach leads to the subsequent difficulties because it is necessary to solve simultaneously the differential equations of particulates and gaseous heat transfer carrier motion and the equations of heat transfer. This paper considers a deviation from this traditional approach and presents a set of differential equations in which the parameter is a heat transfer surface of the particulates. This approach reduces the number of differential equations describing the process and significantly simplifies the analytical formulation of the problem and hence the solution itself. The provided solutions allow for determining the temperatures of both the solids and the gaseous heat carriers as a function of particulate heat transfer surface. Two specific cases addressed here are heat transfer and heat and mass transfer when heat is generated within or absorbed by the particulates.