Pulverized Coal Boiler Thermal Processes More Than Numerical Analysis Of Coupled With The Double Of The Temperature Field Simulation Method Of Research

Thermal process of pulverized coal boiler influences directly its technological and economic index, such as thermal efficiency, life span of boiler, and so on. However, at present on-line monitoring technology for thermal process isn't ripe yet, and temperature distribution represents thermal process comprehensively. So a multi-couple simulation on thermal process and two-stage numerical simulation has been studied, which made it feasible to monitor temperature field on-line. This is of important theoretical and practical meaning for optimizing operation parameters, making boiler running steady and safely with high-efficiency.In this paper, multi-fields couple simulation methods for turbulent gas-particle flows in the process of pulverized coal combustion was described systematically, including velocity field, temperature field, concentration field, heat-releasing field in combustion, and so on. And a two-stage simulation method for solving the problem of multi-fields couple models' lowering rank and linear operation was discussed in detail. On the basis of analyzing results of thermal synthetic measurement, reference work condition and relative work conditions were determined.The main work and innovations of the paper are as follows:(1) Coupling simulation of multi-field for many work conditions (including measured work condition, average work condition, reference work condition, relative work conditions) was carried out using commercial software CFX-4.3. The results show that if excess air coefficient is too large, it will lead to the phenomenon of part high-temperature in the center of furnace, and it was certified by numerical calculation;(2) Temperature field in the furnace was calculated by two-stage simulation. That is coefficient matrixes, which influence temperature field, was got by results of multi-couple simulation, by which temperature distribution was got with change of operation parameters. The results were compared with the results of multi-couple, and its reliability was verified indirectly. Tow-stage simulation supplies valid measures for on-line monitoring temperature distribution in thefurnace;(3)The effect of boiler structure's asymmetry on results of two-stage simulation was analyzed and calculated at first time. The conclusions are got that asymmetry of boiler's structure would impact the symmetry of temperature distribution. So in order to improve the accuracy of two-stage simulation's results, the effect of asymmetry of boiler's structure should be considered.