| The application of gas radiant tube to industrial furnace is economic and appropriate. It can not only reduce the capital construction and running costs, increase production efficiency and lengthen the life of the furnace, but combustion atmosphere and product doesn't contact with heated objects directly. So it will not have an effect on the quality of product. On the contrary, the quality of heated product will be greatly improved, thus it's used widely in the area of metallic heat treatment particularly.This subject develops gas radiant tube that's applicable for medium-temperature industrial drying kiln.Injective gas burner is designed according to the requirements of design parameters. The way of air supply is suction type,natural draft is used and it shows negative pressure in the pipe. Therefore,it is able to save energy during the safe manufacturing. Choosing vycor as the material of radiant tube, no matter whether the uniformity of wall temperature and the corrosivity of combustion products have effects on the life of tube or not.Firstly, conduct a basic experimental study on the thermal performance of gas radiant tube. It focuses on the impact of the three factors(gas consumption, the change of primary air coefficient, adding insert) on the wall temperature of radiant tube and the content of pollutants. Secondly, use burning mathematical model on the basis of the study to do a numerical simulation on the combustion process in gas radiant tube under different conditions. It analyses the thermal performance of gas radiant tube through combustion field of gas and air in the tube(temperature field, concentration field, velocity field of combustion and mass fraction field of combustion product.)Numerical simulation goes from two parts: in line with analysis of variance on the result of quadrate digital test about the thermal performance of gas radiant tube ,the first part finds the significant degree of influence, the three factors—gas consumption, primary air coefficient and controlling device's height of secondary air, have on assessment indicators, as well as the impact of the interaction among all factors on thermal performance. By experimental study of single-factor figures on the thermal performance of gas radiant tube,the second part finds the influence rules of primary air coefficient, gas consumption, air preheating temperature, radiant tube's length and caliber's change on the thermal performance of gas radiant tube(mainly refers to power and efficiency).In order to improve the operational efficiency of gas radiant tube, the last part of this paper optimizes the burner devices. Mainly starting from improving flow patterns and mixing way of gas and air, optimization methods adjusts length and angle on the basis of the original secondary air controlling device. Optimal solution is selected through the comparison in the numerical simulation results of several programs. The purposes of strengthening the mixture of gas and air flow and improving the full extent of gas burning have been achieved.This article conducts a comprehensive study on the thermal performance of radiant tube by numerical simulation and experiment. The most important thing is that it can clearly show temperature field, flow field and component distribution under the burning condition in the radiant tube and enrich our awareness and understanding of the technology about radiant tube combustion. Therefore, using the way of the combination of experimental and numerical simulation can deepen our understanding of the basic phenomenon and process of combustion in gas radiant tube. The research findings will provide theoretical basis and experience on industrialized applications of gas radiant tube. |
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