Numerical simulation of the influence factors for rotary kiln in temperature field and stress field and the structure optimization

Abstract

With the development of metallurgical industry and the improvement of kiln technology, the processing properties of kiln equipment are being paid more attention. The rotary kiln is one of the most representatives of the furnace equipment; higher requirements of the rotary kiln are put forward in response to the call of the national energy saving and emission reduction. That is, the new designed equipment has the characteristics of the optimal energy consumption and stable performance. In order to analyze the energy consumption of the rotary kiln, it is necessary to study the heat transfer process of the rotary kilns. The three-dimensional numerical model of the rotary kiln is set up by using the finite element technology. After analyzing the data, it is found that different thicknesses of the kiln crust and different working conditions have certain influence on the rotary kiln’s temperature field and stress field. After analyzing the result of the simulation, the temperature of the rotary kiln’s outer wall has an approximate linear relationship with the thickness of the kiln crust. Changing the thickness of the kiln crust will not only alter the value of the maximum stress but also have influence on the position of maximum stress. The increase in the thickness of the kiln crust can reduce the extreme value of stress. When the wind speed of induce fan inside the kiln is larger, the temperature of each layer will be relatively high as well, and the temperature curve is softer, and the temperature variation is more stable. It has also been found that when the comprehensive coefficient of heat exchange outside the kiln surface is larger, the thermal stress created by the body of kiln is smaller. The phenomenon of excessive thermal stress can be improved by changing the outer surface ventilation conditions of the rotary kiln. In order to ensure that the high temperature of the kiln wall has no influence on working wheels, and make sure the temperature of the kiln wall is well-distributed along the length direction of the kiln, the thickness of the kiln crust along the length direction is changed, and the structure of the cylinder with wheels on it is altered. After further numerical simulation, the optimized thickness of the kiln crust and kiln structure is found, and the above problem is solved effectively. The results can reduce the inputs of rotary kiln design and the production costs. It can also reduce energy consumption, and some guidance is given on the production process of kilns.