夹套式上升管内荒煤气对流辐射传热的计算  

Heat Transfer of Convective Radiation from Flue Gas in Jacket-type Riser Tube

作　　者：黄海清 邹声华[1] 沈毅 赵勇 HUANG Haiqing;ZOU Shenghua;SHEN Yi;ZHAO Yong(School of Civil Engineering,Hu’nan University of Science and Technology,411201,Xiangtan,China;Hu’nan Hualing Energy Saving and Environmental Protection Technology Limited Company,411100 Changsha,China)

机构地区：[1]湖南科技大学土木工程学院,411201湖南湘潭 [2]湖南华菱节能环保科技有限公司,411100长沙

出　　处：《煤炭转化》2020年第1期89-96,共8页Coal Conversion

基　　金：国家自然科学基金资助项目(51274098,51134005);湖南省战略性新兴产业科技攻关与重大科技成果转化专项项目(2017GK4013)

摘　　要：通过理论推导和数值计算,分析了荒煤气在上升管内流动的对流传热和辐射传热问题。基于热平衡方程推导得到上升管内荒煤气流动传热微分方程,考察荒煤气进口温度、内壁面发射率、对流传热系数和斯坦顿数对上升管内壁面温度变化和荒煤气出口温度的影响。采用Matlab软件编制四阶Runge-Kutta计算程序求解,得出上升管内壁温度沿轴线方向的变化曲线和荒煤气的平均传热系数,荒煤气在夹套式上升管中的平均传热系数为30 W/(m^2·K)~36 W/(m^2·K),将此计算结果与他人的成果进行对比,吻合较好,误差为10%左右。结果表明:辐射传热过程主要受内壁面发射率和荒煤气进口温度的影响,内壁面发射率越大,辐射传热量越大;流体速度对对流传热的影响很大,随着流速的增加,对流传热量增大;焦炉在一个炼焦周期内,应该合理控制荒煤气的流量,可避免上升管内壁焦油的凝结;在设计上升管时,增大内壁面的发射率,可以提高上升管的传热效率。The convective and radiative heat transfer processes of flue gas flowing in the riser tube were analyzed via theoretical analysis and numerical simulation. Based on the thermal balance equation, the heat transfer differential equation of the gas flow in the rising tube was derived, the effects of the flue gas inlet temperature, inner surface emissivity, convection heat transfer coefficient and the Stanton number on the temperature variation of the rising tube inner wall and flue gas outlet temperature. By using the fourth-order Runge-Kutta calculation program that was compiled in the Matlab software, the average heat transfer coefficient of the rising tube inner wall along the axis direction and the average heat transfer coefficient of the flue gas in the jacket-type rising tube are 30 W/(m^2·K) and 36 W/(m^2·K), respectively. Compared with the model in the literature, the results are better matched and the error is reduced to 10% by using the developed program in the present study. The results show that the radiation heat transfer process is mainly affected by the internal wall emission rate and the inlet temperature of flue gas, the larger the emission rate of the inner wall, the greater the radiation transfer heat is, and the more dependent on the flow rate of the heat transfer process is. With the increasing flow rate, the heat to spread also increases. During a coking cycle, the flow rate of raw gas should be reasonably controlled to avoid the tar condensation on the inner wall of rising tube. With respect to the design of the rising tube, increasing the emission rate of the surface of the inner wall can improve the heat transfer efficiency of the rising tube.

关 键 词：上升管 荒煤气 数值计算 RUNGE-KUTTA法 传热 

分 类 号：TQ546[化学工程—煤化学工程]