On Computer Simulation Of Temperature For The Preheating Section Of Tunnel Kiln

Temperature difference from top to bottom in preheating zone of tunnel kiln is the biggest obstacle for rapid firing, energy saving. In order to enhance the design of tunnel kiln efficiency and improve the quality of furnace operation and the quality of ceramic products and production.We use three-dimensional numerical simulation to study the temperature field and velocity field in preheating zone of tunnel kiln by computer and research how the thermostat burner and other operation parameters effect them. Thus the structure of Preheating zone settings and process parameters are optimized.With similar experimental conditions, the simulation experiment results show that: Flame quantity, flame speed, flame temperature, and the arrangement of thermostat burner have a significant influence of the temperature difference from top to bottom in materials area of tunnel kiln. The temperature difference of material zone in preheating zone of tunnel kiln is decreasing when the ratio (1.5～10%) ,velocity (60～110m/s) and temperature (0～500K) of flame gas injected are increasing if the thermostat burner's other operation parameters fixed. Burner thermostat suitable arrangement is staggered.The speed of flowing smoke will infection thermal efficiency if it is too high or too slow.There is a little temperature difference when the speed of flowing smoke is 0.5～1.0m/s. The temperature difference is increasing gradually when the temperature of flowing smoke is increasing between 673～1473K. The temperature difference in tunnel kiln from top to bottom is increasing obviously when the flowing smoke temperature is higher than 1073K.The appropriate ratio of interspace is in the range of 0.208～0.408 on condition that we maintain the temperature and the velocity of stack gas unchanged. Appropriate density of material can decrease the temperature difference from top to bottom in tunnel kiln, and the product's quality and output can be improved.Kiln car with the heat changing effects the temperature difference from top to bottom in kiln very obviously. With the heat of the kiln car has decreased (from 100% to 25%), the kiln temperature from 37K down to 12K. Temperature difference in kiln is decreasing when the heat with kiln cars reduced.Cold wind injected can decrease the temperature difference from top to bottom in tunnel kiln. The temperature difference is decreasing in kiln when the temperature of cold wind sprayed at the range of 0～250K.Cool wind injected from the top of kiln is very helpful to temperature uniformity.