基于数值模拟的燃气工业锅炉热效率预测研究

Research on Thermal Efficiency Prediction of Gas Industrial Boiler based on Numerical Simulation

为解决燃气工业锅炉在工程实际中难以进行热效率测试的问题,本文提出了一种基于数值模拟来预测燃气工业锅炉热效率的方法,可实现任意负荷下锅炉热效率的预测。结果表明:以WNS2-1.25-Q型燃气工业锅炉为例,当锅炉负荷从35%增大至100%时,燃尽室出口烟温从1128.7 K增至1249.0 K,二回程、三回程和节能器烟道对应的高温区域向前延伸。锅炉散热损失随环境温度的升高而减小,随空气流速的升高而增大,且空气流速的影响更显著。额定负荷下该燃气工业锅炉热效率模拟值(94.50%)与实测值(94.04%)偏差为0.49%,表明预测方法可靠。基于模拟结果开发了一款燃气工业锅炉热效率预测软件,拟合得到锅炉热效率与负荷的关系式为y=-0.0015 x^(2)+0.2729 x+81.7813,根据此关系式可便捷预测出任意负荷下的锅炉热效率。这为解决热效率预测问题提供了一种方案,也可指导燃气工业锅炉高效运行和节能改造。

To solve the problem that it is challenging in engineering practice to measure the thermal efficiency of gas-fired industrial boilers,a method based on numerical simulation to predict the thermal efficiency of gas-fired industrial boilers is proposed in this study,which could realize the prediction of boiler thermal efficiency under various loads.Taking the WNS2-1.25-Q gas-fired industrial boiler as an example,the results show that with the boiler load rising from 35%to 100%,the flue gas temperature at the outlet of the burnout chamber increases from 1128.7 to 1249.0 K.The high-temperature regions corresponding to the two-return,three-return,and energy-saving flue extend forward.The heat loss of the boiler decreases with the rise of the ambient temperature while increasing with the increase of the airflow rate.The influence of the airflow rate is more significant.The deviation between the simulated value(94.50%)and the measured value(94.04%)of the thermal efficiency of the gas-fired industrial boiler under rated load is 0.49%,indicating that the prediction method is reliable.Based on the simulation results,a thermal efficiency prediction software for gas-fired industrial boilers is developed.The relationship between boiler thermal efficiency and load is y=-0.0015 x^(2)+0.2729 x+81.7813.According to this relationship,the boiler thermal efficiency under various loads could be easily predicted.This provides a method for solving the problem of thermal efficiency prediction,it can also guide the efficient operation and energy-saving transformation of gas industrial boilers.