Hot air Generator, Using a Natural Convection Flow in a Heated Channel

Abstract

Hot air producing is one of the most important engineering applications in recent years. It is a technique used in various thermodynamic systems, such as home heating systems, food dryers. One of the main problems impeding the spread of hot air producing technology is the lack of homogeneity of the heat flow coming from hot air generators as well as an inadequate flow rate. The most of the existing hot air generators require to be supported by systems that can increase the low volumetric flow and the air temperature of these generators, through increasing the speed of the flow of air emitted or lifting the drawer Heat, which contributes to raising the overall cost. However, to improve the thermal and dynamic quality of the hot air flow produced by the generator, a numerical investigation of the free convection flow inside two different configurations is presented in this thesis. The primary objective of this work is to predict the behavior of the flow inside tow configurations, the first one consists of a vertical cylinder with heated walls, and the second configuration is an open-ended vertical cylinder with a hot disc placed at the entrance (configuration A, configuration B). This work characterizes through the examination of this flow, the variables that control an air emission with high flow rate and a high and homogeneous temperature to represent the appropriate criteria that should be respected to obtain a hot air generator overcoming the previously mentioned constraints. Furthermore; the results of this work show the influence of Rayleigh number and the shape of the generator on the flow.