The Numerical Simulation Of Tunnel Kiln Internal Temperature Fired Honeycomb Ceramic

Tunnel kiln as a modern ceramic thermal equipment, has been widely used in the firingof porcelain, building and sanitary porcelain, electrical porcelain, and other functionalceramics. Furnace structure whether simple or complex, can be divided into preheating zone,firing zone and cooling zone according to the products in the kiln temperature change. But thelength of each section has a large difference because products, kiln structure, firing andworking system are different. There is a significant influence to temperature, pressure andatmosphere system for kiln structure, burner distribution and combustion process parameters.If the kiln structure and operating parameters are unreasonable, it affects the quality ofproducts, reduces production efficiency and the heat energy utilization, resulting in energywaste and environmental pollution.By the numerical simulation of tunnel kiln, we can optimize the kiln structure, burningsetup, loading models and NO_Xpollutant, which provide theoretic foundation for improvingkiln and reducing pollutant.According to the real structure of tunnel kiln in a famous honeycomb ceramic company,we established the models and meshed the models with Tet/Hybrid grids. By using thestandard k-model, non-premixed combustion model and DO radiation model, combinedwith the actual measured data, we simulate the inner temperature filed in the condition ofno-load, load, loading model and NO_Xoutput, which analyses how the changes of thermalparameters affect the temperature uniformity and NO_Xoutput in kiln.The results show that:(1) When the fuel inlet velocity and air inlet velocity were15m/sand3m/s respectively, the temperature difference was minimum about44K. And kiln carwas8layers, each layer has six shelf plates and the spacing between shelf plates was60mm,each shelf plate was placed six honeycomb ceramics.(2) With FERRO27#, shrinkage andwater absorption of products, we could get that simulation results were closed to actualtemperature. Using the design of simulation, product qualified rate of more than98%.(3)With FLIR, we can get entire plane temperature distribution and different position of heat leak,the results were more closer to the actual temperature.(4) Upper NO concentration was higherthan the bottom’s, if we increased the flue gas flow appropriately, the concentration of NOcould effectively reduce.