Thermal Design and Analysis of a radiant Furnace for Uniform Thermal Conditions

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Furnaces play an important role in manufacturing industries. Various types of furnaces are available for numerous heating applications, and also several problems associated with their operations. Non uniform thermal conditions on the load, ineffective heat transfer from heat sources to the load, difficulty in controlling atmosphere inside the furnace, high energy losses, etc., are some of the important problems in furnace operations. Among these problems, difficulty in controlling the thermal conditions (temperature and heat flux distributions) is the most prevalent in many furnaces. Additionally, in solid and liquid fuel combustion furnaces, the major concern is maintaining the controlled environment inside the furnace. For a better thermal control and maintaining a controlled environment, radiant furnaces are the best suited ones. Because of the inherent advantages of the radiant furnaces over the conventional ones, over last two decades the radiant furnaces are gaining popularity in various industrial applications. These applications are not limited to precise heating in laboratories but several industrial heating processes, etc. For the desired post processing results, many industrial heating processes require specific thermal conditions over the region/ part of the system where the heating takes place. In several material heating applications, the uniform thermal conditions are needed. Such cases are found in rapid thermal processing, drying or curing of paints, curing of powder coating, chemical vapor deposition, food processing, material heating for precision heat treatment processes/hot working processes, manufacturing of electronic components, etc. The spatially uniform thermal conditions on the products prevent thermal stresses which avoid structural damage of the products, such as cracking, bending, etc. Furthermore, the desired uniform heating is very much advantageous to achieve the specific metallurgical properties such as the desired microstructure, surface conditions, etc. The non-uniform heating always results in poor quality products.For a given specific application, furnace geometry, properties of the furnace materials, participating medium, location and powers of the heaters, and position of the design object (products) (DO) inside the furnace, are to be properly accounted. For the desired thermal conditions over the specific region (design surfaces) of the system, estimation of thermal boundary conditions in a radiant furnace falls under the purview of inverse boundary design problems. It is well known that, in inverse formulation the computational expense is considerably lower than that of the trial-and-error methods. However, the system of equations defining the inverse problems is ill-posed, and their solution requires a special treatment. Finding the optimal solution for such problems is a challenging task. Apart from the methodologies used for the direct problem, solution of the inverse problem necessitate the use of either regularization or optimization techniques. Due to the increasing relevance in the precision thermal processing, a good number of inverse furnace boundary design problems have been investigated by many researchers. To handle the ill-posed nature of such problems, several regularization and optimization techniques have been proposed. In spite of the inherent advantages such as ease in ha.
Supervisor: S. C. Mishra AND P. Mahanta