微小通道内超临界R134a流动传热特性

doi:10.16085/j.issn.1000-6613.2023-1273

摘要/Abstract

摘要：

超临界有机朗肯循环（supercritical organic Rankine cycle，SORC）是回收中低品位能源较理想的新型动力循环技术之一，而超临界有机工质的传热特性严重影响了系统能效，目前已成为制约有机朗肯循环技术向前发展的瓶颈。基于此，本文实验研究了超临界R134a在2mm微小通道内的流动传热特性，参数范围为：热流密度60~120kW/(m²·s)，质量流速800~3000kg/(m²·s)，压力4.1~5.1MPa，工质进口温度20~100℃，探讨了热流密度、质量流速、压力、流体焓值等参数对传热特性的影响规律。结果表明，传热系数随流体温度的升高先增加后减小，随质量流速的增加而增加，随着热流密度和压力的增加而减小。流体焓值在拟临界值附近出现压降平缓区。根据实验数据拟合得到了微通道内R134a的传热关联式，该关联式预测误差均在±10%之内，具有良好的预测精度。

关键词: 微小通道, 超临界R134a, 流动传热, 有机朗肯循环, 传热关联式

Abstract:

The supercritical organic Rankine cycle (SORC) is an ideal new power cycle technology for recovering energy using supercritical organic Rankine cycle. The energy efficiency of the system is significantly affected by the SORC, the supercritical organic working medium, low grade energy recovery, and the heat transfer characteristics of the supercritical organic working medium. At present, it has become a bottleneck that restrict the development of organic Rankine cycle technology. To address this issue, the experimental studies were conducted on the flow heat transfer characteristics of supercritical R134a in a tiny channel with an inner diameter of 2mm). The parameters considered in the study were as follows: heat flux ranging from 60—120kW/(m²·s), mass flow rate from 800—3000kg/(m²·s), pressure from 4.1—5.1MPa, and working medium inlet temperature from 20—100℃. The effects of heat flow density, mass flow velocity, pressure and fluid temperature on the heat transfer characteristics were discussed. The results showed that the heat transfer coefficient initially increased and then decreased with the increase of fluid temperature. It also increased with the increase of mass flow rate but decreased with the increase of heat flux and pressure. According to the experimental data, a prediction accuracy of ± 10% for R134a in the microchannel was achieved, demonstrating good prediction accuracy.

Key words: micro-channel, supercritical R134a, fluid flow and heat transfer, organic Rankine cycle, heat transfer correlation

中图分类号:

TK124

张巧玲, 马祖浩, 于子元, 刘梓俊, 黄铋匀, 杨振东, 马浩然. 微小通道内超临界R134a流动传热特性[J]. 化工进展, 2024, 43(4): 1667-1675.

ZHANG Qiaoling, MA Zuhao, YU Ziyuan, LIU Zijun, HUANG Biyun, YANG Zhendong, MA Haoran. Convection heat transfer research of supercritical R134a in mini-channel of tube[J]. Chemical Industry and Engineering Progress, 2024, 43(4): 1667-1675.

图/表 14

图1 实验系统图

图2 实验段示意图

表1 实验仪器

参数	范围	精度
高压恒流泵P1000+	0~1000mL/min	±3%
T型热电偶	0~500℃	±0.2℃
T型热电偶丝	0~1000℃	±0.2℃
CX-M5型齿轮流量计	0~1000mL/min	±0.5%
罗斯蒙特3051TG4压力传感器	0~6MPa	±0.075%
罗斯蒙特3051CD3差压变送器	0~20kPa	±0.075%

表2 实验参数不确定度

参数	不确定度
质量流速G/kg·m^-2·s	0.51%
压力p/MPa	0.11%
压差∆p/kPa	0.54%
热流密度q/kW·m^-2	2.13%
内壁温度T_w,in/℃	±0.5℃
换热系数h/W·m^-2·K^-1	7.98%

表3 实验重复性验证

测点	外壁温T_1w,out/℃	外壁温T_2w,out/℃	外壁温T_3w,out/℃
1	48.2	48.2	48.2
2	138.4	138.2	138.2
3	133.9	133.7	133.7
4	153.6	153.7	153.9
5	150.5	151.2	151.0
6	162.9	164.1	163.5
7	159.2	160.1	159.7
8	168.6	169.9	168.9
9	164.7	165.8	164.8
10	178.8	179.7	178.7

表4 实验数据处理

参数	公式
电加热效率η	$η = M H b, o - H b, i U I$
热流密度q/kW·m^-2	$q = U I η π d L$
质量流量G/kg·s^-1	$G = ρ V A = 4 ρ V π d 2$
流体焓值H_b/kJ·kg^-1	$H b = H b, i + x L (H b, o - H b, i)$
内壁温度T_w,in/℃	$T w, i n = T w, o u t - d i n 2 q λ w d o 2 d o 2 - d i n 2 l n d o d i n - 12$
平均换热系数h/W·m^-2·K^-1	$h = q T ¯ w, i n - T ¯ b$
浮升力数	$B u J = G r b R e 2$ $G r b = g (ρ b - ρ w) d 3 ρ b v b 2$

表4 实验数据处理

参数	公式
电加热效率η	$η = M H b, o - H b, i U I$
热流密度q/kW·m^-2	$q = U I η π d L$
质量流量G/kg·s^-1	$G = ρ V A = 4 ρ V π d 2$
流体焓值H_b/kJ·kg^-1	$H b = H b, i + x L (H b, o - H b, i)$
内壁温度T_w,in/℃	$T w, i n = T w, o u t - d i n 2 q λ w d o 2 d o 2 - d i n 2 l n d o d i n - 12$
平均换热系数h/W·m^-2·K^-1	$h = q T ¯ w, i n - T ¯ b$
浮升力数	$B u J = G r b R e 2$ $G r b = g (ρ b - ρ w) d 3 ρ b v b 2$

图3 流体焓值对传热系数的影响

图4 质量流速的影响（实心为上壁面，空心为下壁面）

图5 压力的影响

图6 热流密度的影响（空心为上壁面，实心为下壁面）

图7 实验段外壁温沿程分布（实心为上壁面，空心为下壁面）

图8 R134a流动特性变化规律

表5 已有典型关联式总结

传热关联式	公式形式	适用工质
Kang关联式	$N u = 0.0244 R e 0.762 P r b 0.552 ρ w ρ b 0.0293$	R134a
Jackson & Hall关联式	$N u = 0.0183 R e 0.82 P r b 0.5 c p c p b n r w r b 0.3$	水和CO₂
Bishop关联式	$N u = 0.0069 R e 0.9 P r b 0.5 ρ w ρ b 0.43 1 + 2.4 D x$	水和CO₂

表5 已有典型关联式总结

传热关联式	公式形式	适用工质
Kang关联式	$N u = 0.0244 R e 0.762 P r b 0.552 ρ w ρ b 0.0293$	R134a
Jackson & Hall关联式	$N u = 0.0183 R e 0.82 P r b 0.5 c p c p b n r w r b 0.3$	水和CO₂
Bishop关联式	$N u = 0.0069 R e 0.9 P r b 0.5 ρ w ρ b 0.43 1 + 2.4 D x$	水和CO₂

图9 Nuexp与已有传热关联式对比

参考文献 32

1	孙铭泽, 马宁, 李浩然, 等. 中低温超临界CO₂及其混合工质布雷顿循环热力学分析[J]. 化工学报, 2022, 73(3): 1379-1388.
	SUN Mingze, MA Ning, LI Haoran, et al. Thermodynamic analysis of Brayton cycle of medium and low temperature supercritical CO₂ and its mixed working medium[J]. CIESC Journal, 2022, 73(3): 1379-1388.
2	李子航, 王占博, 苗政, 等. 亚临界有机朗肯循环系统工质筛选及热经济性分析[J]. 化工学报, 2021, 72(9): 4487-4495.
	LI Zihang, WANG Zhanbo, MIAO Zheng, et al. Working fluid selection and thermo-economic analysis of sub-critical organic Rankine cycle[J]. CIESC Journal, 2021, 72(9): 4487-4495.
3	韩中合, 杜燕, 王智. 有机朗肯循环低温余热回收系统的工质选择[J]. 化工进展, 2014, 33(9): 2279-2285.
	HAN Zhonghe, DU Yan, WANG Zhi. Medium selection of organic Rankine cycle(ORC) in low temperature waste heat[J]. Chemical Industry and Engineering Progress, 2014, 33(9): 2279-2285.
4	高天泽. 跨临界压力下碳氢化合物传热特性实验研究[D]. 大连: 大连理工大学, 2021.
	GAO Tianze. Experimental study on heat transfer characteristics of hydrocarbons at trans-and supercritical pressures[D]. Dalian: Dalian University of Technology, 2021.
5	崔亚林, 王怀信. R134a超临界压力下管内换热特性实验研究[J]. 中国电机工程学报, 2018, 38(8): 2376-2383, 2547.
	CUI Yalin, WANG Huaixin. In-tube convection heat transfer research of R134a under supercritical pressures[J]. Proceedings of the CSEE, 2018, 38(8): 2376-2383, 2547.
6	CHENG X, YANG Y H, HUANG S F. A simplified method for heat transfer prediction of supercritical fluids in circular tubes[J]. Annals of Nuclear Energy, 2009, 36(8): 1120-1128.
7	JONATHAN Fewster. Mixed forced and free convective heat transfer to supercritical pressure fluids flowing in vertical pipes[D]. Manchester, North West England, UK: University of Manchester, 1976.
8	SHEN Zhi, YANG Dong, WANG Siyang, et al. Experimental and numerical analysis of heat transfer to water at supercritical pressures[J]. International Journal of Heat and Mass Transfer, 2017, 108: 1676-1688.
9	WANG Han, BI Qincheng, YANG Zhendong, et al. Experimental and numerical investigation of heat transfer from a narrow annulus to supercritical pressure water[J]. Annals of Nuclear Energy, 2015, 80: 416-428.
10	BISHOP A A, SANDBERG R, TONG L. Forced-convection heat transfer to water at near-critical temperatures and supercritical pressures[C]. Joint Meeting of the American Institute of Chemical Engineers and the British Institution of Chemical Engineers, United States, 1964.
11	JACKSON J D. Consideration of the heat transfer properties of supercritical pressure water in connection with the cooling of advanced nuclear reactors[C]. Pacific Regional Nuclear Energy Conference, 2002.
12	YANG Zenan, LUO Xiaobo, WANG Ge, et al. Numerical study on the effects of supercritical CO₂-based nanofluid on heat transfer deterioration[J]. Numerical Heat Transfer A: Applications, 2022, 82(5): 193-216.
13	YUN Rin, HWANG Yunho, RADERMACHER Reinhard. Convective gas cooling heat transfer and pressure drop characteristics of supercritical CO₂/oil mixture in a minichannel tube[J]. International Journal of Heat and Mass Transfer, 2007, 50(23/24): 4796-4804.
14	GU Hongfang, LI Hongzhi, WANG Haijun, et al. Experimental investigation on convective heat transfer from a horizontal miniature tube to methane at supercritical pressures[J]. Applied Thermal Engineering, 2013, 58(1/2): 490-498.
15	JIANG Peixue, ZHAO Chenru, SHI Runfu, et al. Experimental and numerical study of convection heat transfer of CO₂ at super-critical pressures during cooling in small vertical tube[J]. International Journal of Heat and Mass Transfer, 2009, 52(21/22): 4748-4756.
16	DANG Chaobin, HIHARA Eiji. Numerical study on in-tube laminar heat transfer of supercritical fluids[J]. Applied Thermal Engineering, 2010, 30(13): 1567-1573.
17	DANG Chaobin, HIHARA Eiji. In-tube cooling heat transfer of supercritical carbon dioxide. Part 1. Experimental measurement[J]. International Journal of Refrigeration, 2004, 27(7): 736-747.
18	YOON Seok Ho, KIM Ju Hyok, HWANG Yun Wook, et al. Heat transfer and pressure drop characteristics during the in-tube cooling process of carbon dioxide in the supercritical region[J]. International Journal of Refrigeration, 2003, 26(8): 857-864.
19	冯龙龙, 钟珂, 张羽森, 等. 水平管内R1234yf的流动沸腾换热特性[J]. 化工进展, 2022, 41(7): 3502-3509.
	FENG Longlong, ZHONG Ke, ZHANG Yusen, et al. Flow boiling heat transfer characteristics of R1234yf in horizontal microchannel[J]. Chemical Industry and Engineering Progress, 2022, 41(7): 3502-3509.
20	杨梦, 张华, 秦延斌, 等. 混合制冷剂R134a/R1234yf(R513A)与R134a热力学性能对比及实验[J]. 化工进展, 2019, 38(3): 1182-1189.
	YANG Meng, ZHANG Hua, QIN Yanbin, et al. Thermodynamic performance comparison and experimental study of mixed refrigerant R134a/R1234yf(R513A) and R134a[J]. Chemical Industry and Engineering Progress, 2019, 38(3): 1182-1189.
21	DOBSON M K, CHATO J C. Condensation in smooth horizontal tubes[J]. Journal of Heat Transfer, 1998, 120(1): 193-213.
22	TANG Liangyou, OHADI Michael, JOHNSON Arthur T. Flow condensation in smooth and micro-fin tubes with HCFC-22, HFC-134a and HFC-410 refrigerants. Part Ⅱ: Design equations[J]. Journal of Enhanced Heat Transfer, 2000, 7(5): 311-325.
23	CAVALLINI A, CENSI G, DEL COL D, et al. Experimental investigation on condensation heat transfer and pressure drop of new HFC refrigerants (R134a, R125, R32, R410A, R236ea) in a horizontal smooth tube[J]. International Journal of Refrigeration, 2001, 24(1): 73-87.
24	JIANG Peixue, ZHAO Chenru, LIU Bo. Flow and heat transfer characteristics of R22 and ethanol at supercritical pressures[J]. The Journal of Supercritical Fluids, 2012, 70: 75-89.
25	KANG Kyoung-Ho, CHANG Soon-Heung. Experimental study on the heat transfer characteristics during the pressure transients under supercritical pressures[J]. International Journal of Heat and Mass Transfer, 2009, 52(21/22): 4946-4955.
26	姜文全，李琳，杨帆，等. 变物性比下无量纲力对超临界压力甲烷混合对流换热影响[J]. 中国石油大学学报（自然科学版）， 2022, 46(3): 140-147.
	JIANG Wenquan, LI Lin, YANG Fan, et al. Effects of dimensionless forces on mixed convection heat transfer of supercritical pressure methane under variable thermophysical property ratio[J]. Journal of China University of Petroleum(Edition of Natural Science), 2022, 46(3): 140-147.
27	宿诗雨，姜文全，李琳，等. U形竖管内超临界甲烷传热异常行为机理研究[J]. 推进技术， 2023, 44(11): 175-182.
	SU Shiyu, JIANG Wenquan, LI Lin, et al. Mechanism analysis of abnormal heat transfer behavior of supercritical methane in a u-tube [J]. Journal of Propulsion Technology, 2023, 44(11): 175-182.
28	李辉，汝卓霖，邹正平，等. 微小尺度通道内超临界甲烷传热特性研究[J]. 南京航空航天大学学报， 2021, 53(4): 513-520.
	LI Hui, RU Zhuolin, ZOU Zhengping, et al. Investigation on heat transfer characteristic of supercritical methane in a microtube[J]. Journal of Nanjing University of Aeronautics & Astronautics, 2021, 53(4): 513-520.
29	谷家扬，陈代飞，魏世松，等. 流道截面形状对超临界甲烷在微通道中流动换热特性影响研究[J]. 舰船科学技术， 2023, 45(13): 53-58.
	GU Jiayang, CHEN Daifei, WEI Shisong, et al. Flow channel cross section shape for supercritical methane in microchannels Study on the influence of flow heat transfer characteristics[J]. Ship Science and Technology, 2023, 45(13): 53-58.
30	孙会芹，韩昌亮，李泽宇，等. 水平圆管内超临界甲烷非均匀流场的对流传热特性[J]. 哈尔滨理工大学学报， 2021, 26(3): 51-57.
	SUN Huiqin, HAN Changliang, LI Zeyu, et al. Non-uniform flow field of convection heat transfer characteristics of supercritical methane in a horizontal tube[J]. Journal of Harbin University of Science and Technology, 2021, 26(3): 51-57.
31	PIORO Igor L, KHARTABIL Hussam F, DUFFEY Romney B. Heat transfer to supercritical fluids flowing in channels—Empirical correlations (survey)[J]. Nuclear Engineering and Design, 2004, 230(1/2/3): 69-91.
32	XIAO Runfeng, TIAN Gui, CHEN Liang, et al. A dimensionless correlation to predict the onset of heat transfer deterioration of supercritical fluids in upward circular tubes[J]. Nuclear Engineering and Design, 2022, 392: 111763.

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