Numerical simulation of multi-flow and heat transfer characteristics in heat exchangers with triple-helical baffles

doi:10.11949/j.issn.0438-1157.20160215

Abstract

Abstract:

Triple helical baffle heat exchanger was proposed to arrange more helical baffle in shell side with large helix angle and enhance heat transfer rate. In this paper, the flow characteristics and heat transfer performance of heat exchangers with triple helical baffles were analyzed. The comprehensive performance between single-helical and triple-helical baffle heat exchangers were compared based on the calculating results of pressure drop and heat transfer coefficient when Reynolds number ranges from 1391-4174. The results showed that:heat transfer coefficient and JF factor of triple-helical baffle heat exchangers is 27.9% higher and 13.67% higher than single-helical baffle heat exchanger respectively. Besides entransy dissipation theory was used to analyze the heat transfer performance of triple-helical baffle heat exchanger with different helix angle, and triple-helical baffle with 64.8° got the lowest entransy dissipation rate. The heat transfer rate of central tube and outer tube were compared, outer tube have higher heat transfer rate compared with central tube.

Key words: continuous helical baffles, heat exchanger, triple-helical, entransy dissipation, numerical simulation

摘要：

为了增加大螺旋角下单位长度换热管上螺旋折流板数量提高换热，提出三螺旋折流板导流结构，对设置三螺旋折流板后壳程流体的流动与传热进行了数值模拟，重点考察了Reynolds数Re=1391～4174时的壳程压降及对流传热系数，与设置单螺旋折流板的对比结果表明：三螺旋折流板换热器壳程对流传热系数高27.9%，JF因子高13.67%，综合传热性能更好。在此基础上运用耗散理论分析了三螺旋折流板采取不同螺旋角时对换热效率的影响，发现由传热引起的耗散率随Reynolds数变化规律与壳程对流传热系数随Reynolds数的变化规律类似，相同流量条件下螺旋角为64.8°的换热器耗散率最小。另外，中心换热管与壳壁附近换热管的传热系数比较结果显示，中心管热交换量均低于壳壁附近换热管热交换量。

关键词: 连续螺旋折流板, 换热器, 三螺旋, 耗散, 数值模拟

CLC Number:

TK124

DUAN Zhenya, SHEN Feng, ZHANG Junmei, SONG Xiaomin, CAO Xing. Numerical simulation of multi-flow and heat transfer characteristics in heat exchangers with triple-helical baffles[J]. CIESC Journal, 2016, 67(S1): 232-238.

段振亚, 沈锋, 张俊梅, 宋晓敏, 曹兴. 三螺旋折流板换热器多流路通道流动与传热数值模拟[J]. 化工学报, 2016, 67(S1): 232-238.

References 22

[1]	LUTCHA J, NEMCANSKY J. Performance improvement of tubular heat exchangers by helical baffles[J]. Trans. Inst. Chem. Eng., 1990, 68:263-267.
[2]	陈亚平. 适合于正三角形排列布管的螺旋折流板换热器[J]. 石油化工设备, 2008, 37(6):1-5. CHEN Y P. A novel helix baffled heat exchanger suitable for tube bundle arrangement with equilateral triangles[J]. Petro-Chemical Equipment, 2008, 37(6):1-5.
[3]	文键, 杨辉著, 杜冬冬, 等. 螺旋折流板换热器换热强化的数值研究[J]. 西安交通大学学报, 2014, 48(9):43-48. WEN J, YANG H Z, DU D D, et al. Numerical simulation for heat transfer enhancement of a heat exchanger with helical baffles[J]. Journal of Xi'an Jiaotong University, 2014, 48(9):43-48.
[4]	曹兴. 连续与搭接螺旋折流板换热器理论分析与实验研究[D]. 济南:山东大学, 2012. CAO X. Theoretical analysis and experiment study of shell-and-tube heat exchanger with continuous helical baffles and overlapped helical baffles[D]. Jinan:Shandong University, 2012.
[5]	杜文静, 王红福, 曹兴, 等. 新型六分扇形螺旋折流板换热器壳程传热及流动特性[J]. 化工学报, 2013, 64(9):3123-3129. DU W J, WANG H F, CAO X, et al. Heat transfer and fluid flow on shell-side of heat exchangers with novel sextant sector helical baffles[J]. CIESC Journal, 2013, 64(9):3123-3129.
[6]	YANG J F, ZENG M, WANG Q W. Numerical investigation on shell-side performances of combined parallel and serial two shell-pass shell-and-tube heat exchangers with continuous helical baffles[J]. Applied Energy, 2015, 139:163-174.
[7]	YANG J F, ZENG M, WANG Q W. Numerical investigation on combined single shell-pass shell-and-tube heat exchanger with two-layer continuous helical baffles[J]. International Journal of Heat and Mass Transfer, 2015, 84:103-113.
[8]	WANG Q W, ZENG M, TING M, et al. Recent development and application of several high-efficiency surface heat exchangers for energy conversion and utilization[J]. Applied Energy, 2014, 135:748-777.
[9]	KRAL D, STEHLIK P, VANDERPLOEG H J, et al. Helical baffles in shell-and-tube heat exchangers (I):Experimental verification[J]. Heat Transfer Engineering, 1996, 17(1):93-101.
[10]	JAFARI M R, SHAFEGHAT A. Fluid flow analysis and extension of rapid design algorithm for helical baffle heat exchangers[J]. Applied Thermal Engineering, 2008, 28(11/12):1324-1332.
[11]	ZHANG J F, HE Y L, TAO W Q. 3D numerical simulation on shell-and-tube heat exchangers with middle-overlapped helical baffles and continuous baffles(Ⅰ):Numerical model and results of whole heat exchanger with middle-overlapped helical baffles[J]. International Journal of Heat and Mass Transfer, 2009, 52(23/24):5371-5380.
[12]	ZHANG J F, HE Y L, TAO W Q. 3D numerical simulation on shell-and-tube heat exchangers with middle-overlapped helical baffles and continuous baffles (Ⅱ):Simulation results of periodic model and comparison between continuous and noncontinuous helical baffles[J]. International Journal of Heat and Mass Transfer, 2009, 52(23/24):5381-5389.
[13]	陈亚平, 董聪, 林丽, 等. 螺旋折流板换热器在发电厂应用的可行性[J]. 锅炉技术, 2014, 45(3):1-5. CHEN Y P, DONG C, LING L, et al. The application of helical baffles heat exchanger in power plant[J]. Boiler Technology, 2014, 45(3):1-5.
[14]	MOVASSAG Z S, TAHER F N, RAZMI K, et al. Tube bundle replacement for segmental and helical shell and tube heat exchangers:performance comparison and fouling investigation on the shell side[J]. Applied Thermal Engineering, 2013, 51(1/2):1162-1169.
[15]	李斌, 陶文铨, 何雅玲. 螺旋折流板换热器螺距计算的通用公式[J]. 化工学报, 2007, 58(3):587-590. LI B, TAO W Q, HE Y L. Determination of helical lead distance of shell-and-tube heat exchanger with helical baffles[J]. Journal of Chemical Industry and Engineering(China), 2007, 58(3):587-590.
[16]	王福军. 计算流体动力学分析[M]. 北京:清华大学出版社,2004:113-143. WANG F J. Analysis of Computational Fluid Dynamics[M]. Beijing:Tsinghua University Press, 2004:113-143.
[17]	ZHANG J F, LI B, HUANG W J, et al. Experimental performance comparison of shell-side heat transfer for shell-and-tube heat exchangers with middle-overlapped helical baffles and segmental baffles[J]. Chemical Engineering Science, 2009, 64(8):1643-1653.
[18]	KAYS W M, LONDON A L. Compact heat exchangers[J]. Journal of Applied Mechanics, 1964, 27(2):460-470.
[19]	过增元, 梁新刚, 朱宏晔.——描述物体传递热量能力的物理量[J]. 自然科学进展, 2006, 16(10):1288-1296. GUO Z Y, LIANG X G, ZHU G Y. Entransy-a new physical parameter to describe heat transfer ability[J]. Progress in Natural Science, 2006, 16(10):1288-1296.
[20]	董永申, 王定标, 向飒, 等. 倾斜螺旋片强化的套管换热器数值模拟[J]. 浙江大学学报, 2015, 49(2):309-314. DONG Y S, WANG D B, XIANG S, et al. Numerical simulation of double-pipe heat exchanger enhanced by oblique helical fins[J]. Journal of Zhejiang University, 2015, 49(2):309-314.
[21]	许伟峰, 王珂, 靳遵龙, 等. 螺旋折流板换热器局部流场和温度场的数值研究[J]. 机械工程学报, 2015, 51(10):152-159. XU W F, WANG K, JIN Z L, et al. Numerical study on local flow field and temperture field of helical baffles heat exchanger[J]. Journal of Mechanical Engineering, 2015, 51(10):152-159.
[22]	WU J, GUO Z Y. Application of entransy analysis in self-heat recuperation technology[J]. Industrial & Engineering Chemistry Research, 2014, 53(3):1274-1285.