The Effect of Flame Length on Exterior Heat Exchange in a Glass Melting Furnace with Horseshoe-Shaped Flame

Abstract

The topicality of studying heat and mass exchange in a glass-melting furnace with horseshoe-shaped flame is substantiated. The main requirements on advisable flame length in this type of furnace are formulated. The need for jointly solving the exterior and interior heat-transfer problems is demonstrated. The results of calculating temperatures of the gaseous medium, the roof, and the glass melt surfaces depending on the flame length are given. It is established that based on the set of conditions, the recommended length of the flame can be taken equal to the furnace length. The extent of the intense combustion zone (visible part of the flame) in this case is approximately 0.7 furnace length.At present the main thermal plant for melting container glass is a regenerative tank furnace with a horseshoe-shaped flame. Its design has not undergone significant changes during the past 20 years. At the same time, the engineering and economical parameters of foreign furnaces have reached a rather high level. It is sufficient to note that the efficiency of contemporary furnaces exceeds 50%. This is largely due to the evolutionary upgrade of furnace elements. This primarily concerns the designs of the melting tank, burners, regenerator, etc. A high furnace efficiency implies efficient thermal insulation using high-quality refractories. Furthermore, a high-efficiency furnace requires state-of-the-art control systems and a careful attitude to the quality of initial materials and batch quality.The effect of the majority of the above factors on furnace parameters can be estimated not only qualitatively, but quantitatively as well, including the analysis of the thermal balance items. The design specifics of the main furnace components appear understandable and reproducible. Our knowledge of the glass-melting process and the furnace design appears quite extensive, consequently, we could assume that reaching a high efficiency is just the matter of financial resources. Unfortunately, the actual practice demonstrates that copying a successful furnace design, as a rule, does not produce results adequate to the prototype. The point is that the technical efficiency of a furnace depends on a set of interrelated factors, where the furnace design is only one of significant components. A significant aspect in the performance of a glass-melting flame furnace is setting up heat-transfer processes in the working space and in the melting tank. As the chemical energy of fuel is the main source of heat generation, a rational implementation of the combustion process (the flame) is one of the most essential problems of thermal engineering in glass melting. According to the method of V. G. Lisienko [1], four main parameters of a flame have the most significant effect on heat and mass transfer in the glass-melting furnace, namely the length, the radiation, velocity, and other aerodynamic characteristics of the flame, as well as the flame position with respect to the heated surface (glass melt). The above flame parameters, in turn, are integrated and, ...