燃气辐射管换热器的结构优化与数值模拟

为解决W型燃气辐射管换热器排烟温度高的问题,设计了三种改进换热器性能的结构,采用ANSYS FLUENT软件进行数值模拟,得到了不同结构换热器的性能参数,如烟气出口温度、空气预热温度、压力损失、各换热面换热量和有无折流板的热阻变化.结果表明,中心空气管由一根φ79 mm粗管改为六根φ33 mm细管后换热量增加了57.6%,增设烟气双行程后换热量提高20.7%.增设密封折流板和多孔折流板后换热量分别增加了5.7%和5.3%,空气和烟气之间的热阻都降低了20%左右.多孔折流板的烟气压力损失比密封折流板低47.4%.

Structural optimization and numerical simulation of gas-fired radiant tube heat exchangers

In order to solve the problem of high exhaust gas temperature in W-shaped gas-fired radiant tubes, three kinds of structures were designed to improve the heat exchanger performance. Numerical simulation was carried out by using ANSYS FLUENT software. The performance parameters of heat exchangers with different structures were obtained, such as exhaust gas outlet temperature, preheated air temperature, pressure loss, heat flux in each surface, and heat resistance change with and without baffles. It is shown that the quantity of heat exchange increases by 57.6% after the central air tube changes from one tube of φ79 mm to six tubes of φ33 mm and by 20.7% through adding a double trip of exhaust gas. After inserting the sealed baffle and porous baffle, the quantity of heat exchange increases by 5.7% and 5.3% respectively, and the thermal resistance between air and exhaust gas decreases both by about 20%. The pressure loss of the porous baffle is lower by 47.4% than the sealed-baffle.