作　　者： ; ; (丁小江）;

机构地区： 广东工业大学材料与能源学院

出　　处： 《化工学报》 2004年第11期1764-1767,共4页

摘　　要： 根据缩放管管内湍流对流换热的场协同控制机理 ,提出一种强化缩放管管内湍流对流换热的改型结构 ,即保持肋高和肋距不变的前提下 ,采用平直连接收缩段和扩张段的方式 ,延长收缩段的长度 ,相应缩短扩张段的长度 ,增强管内速度场与温度梯度场的协同作用 .模拟计算的结果表明 ,这种新的结构可优化缩放管中速度场与热流场的协同关系 ,提高Nusselt数 4 6 7%～ 8 34% ,但同时也增大了阻力 7 87%～ 15 2 2 % (Re=1 5×10 4～ 5× 10 4) .与惯用的优化缩放管结构 (收缩段为扩张段 2倍 )相比较 ,改型后的缩放管的Webb性能因子 η=1 0 0 8～ 1 0 6 . According to the physical mechanism of the field synergy that controls the turbulent fluid heat transfer in the converging-diverging tube, an enhanced heat transfer structure is proposed here, that is to extend the converging section length as far as possible while retaining the optimal rib height and pitch and the tube diameter obtained by Мигай.A numerical study has been carried out to investigate the heat and flow characteristics of the converging-and-diverging tube with different converging length ratio.The results of numerical study indicate that increasing the converging length ratio can augment the synergy effect of the velocity and heat flux vector fields.Additionally, different types of way how to joint the converging section with diverging one are compared and the jointed convexly way is found to be the best among them.Therefore a developed geometry configuration is presented in the paper.A 4.67%—8.34% increase of Nusselt number is observed and a 7.87%—15.22% increase of friction factor is detected for the developed configuration (Re=1.5×10 4—5×10 4).Finally, Webb’s comparison method is adopted to evaluate the combined performance of the developed tube.The performance evaluation factor of the developed tube is η=1.008—1.06 against theReynolds number in the range of 1.5×10 4—5×10 4 as compared with the optimal configuration proposed by Мигай, whose converging length is twice the diverging length.

关 键 词： 缩放管 结构优化 换热 流动阻力

领　　域： [动力工程及工程热物理]