Simulation on the influence of different adiabatic length and L-shape structure on pulsating heat pipes with liquid nitrogen

doi:10.16085/j.issn.1000-6613.2025-0070

Abstract

Abstract:

With the rapid advancement of cryogenic technologies, such as high-temperature superconductivity, pulsating heat pipes (PHPs) have attracted significant attentions as highly efficient heat transfer components at liquid nitrogen temperature. For the application scenarios involving longer distances and non-coplanar hot and cold ends, this paper used computational fluid dynamics (CFD) to establish a three dimensional numerical model of the PHP, and the volume of fluid (VOF) method was employed to simulate gas-liquid two-phase flow. A comparative study was first conducted on the thermal performance of PHPs with adiabatic sections lengths of 22mm, 50mm, and 100mm at liquid nitrogen temperature. The results showed that when evaporator and condenser sections remained unchanged, increasing the length of the adiabatic section led to higher thermal conductivity and larger latent heat transfer capacity. Moreover, for the PHP with a 50mm adiabatic section, the operational characteristics of three L-shaped configurations were analyzed. It can be found that the successful startup occurred when the evaporator section was placed horizontally, as well as when the evaporator section and half of the adiabatic section were placed horizontally together. However, when the whole adiabatic section was placed horizontally alongside the evaporator section, the system remained the distribution of gas at bottom and liquid at top, resulting in startup failure. The study provides valuable insights for complex practical environments.

Key words: liquid nitrogen, pulsating heat pipe(PHP), adiabatic section length, L-shape, computational fluid dynamics (CFD)

摘要：

随着高温超导等低温技术的快速发展，脉动热管作为一种高效换热元件在液氮温区的应用逐渐受到关注。对于较长距离和冷热两端不共面的应用背景，本文利用计算流体力学（computational fluid dynamics，CFD）对脉动热管元件建立三维数值模型，并用流体体积（volume of fluid，VOF）方法模拟气液两相流。首先对绝热段长度分别为22mm、50mm和100mm的脉动热管在液氮温区的热性能进行对比研究，结果表明蒸发段和冷凝段长度不变，增加绝热段长度时，其表现出更高的热传导能力，同时潜热传热量也会增大。此外，针对绝热段长度为50mm脉动热管，分析了三种尺寸L形结构的运行特性，发现仅蒸发段水平放置，以及绝热段1/2与蒸发段一起水平放置时可成功启动；但蒸发段和绝热段全部水平放置时，管内始终处于下气上液分布状态，从而未能启动。研究结果为脉动热管在复杂环境中的应用提供了参考。

关键词: 液氮温区, 脉动热管, 绝热段长度, L形, 计算流体力学

CLC Number:

TK172.4

ZHAO Shuyi, ZHAO Hongkun, BU Zhicheng, JIAO Bo. Simulation on the influence of different adiabatic length and L-shape structure on pulsating heat pipes with liquid nitrogen[J]. Chemical Industry and Engineering Progress, 2025, 44(10): 5652-5662.

赵书艺, 赵宏坤, 卜治丞, 焦波. 不同绝热段长度及L形结构对液氮脉动热管影响的模拟[J]. 化工进展, 2025, 44(10): 5652-5662.

Figures/Tables 19

References 42

[1]	AKACHI H. Structure of a heat pipe: US4921041[P]. 1990-05-01.
[2]	ALHUYI NAZARI Mohammad, AHMADI Mohammad H, GHASEMPOUR Roghayeh, et al. A review on pulsating heat pipes: From solar to cryogenic applications[J]. Applied Energy, 2018, 222: 475-484.
[3]	FAZLI Mahyar, ABTAHI MEHRJARDI Seyed ALI, MAHMOUDI Ashkan, et al. Advancements in pulsating heat pipes: Exploring channel geometry and characteristics for enhanced thermal performance[J]. International Journal of Thermofluids, 2024, 22: 100644.
[4]	HAN Xiaohong, WANG Xuehui, ZHENG Haoce, et al. Review of the development of pulsating heat pipe for heat dissipation[J]. Renewable and Sustainable Energy Reviews, 2016, 59: 692-709.
[5]	YANG Chen, TAO Qiuhua, ZHENG Jianwen, et al. Thermal evaluation of photovoltaic panels combined pulsating heat pipe with phase change materials: Numerical study and experimental validation[J]. Energy and Buildings, 2024, 303: 113806.
[6]	MUSHAN Sagar G, DESHMUKH Vaibhav N. A review of pulsating heat pipes encompassing their dominant factors, flexible structure, and potential applications[J]. International Journal of Green Energy, 2024, 21(11): 2559-2596.
[7]	孙芹, 周国庆, 翟万领, 等. 局部多热源下拓扑优化通道平板脉动热管的传热特性[J]. 化工学报, 2025, 76(3):1006-1017.
	SUN Qin, ZHOU Guoqing, ZHAI Wanling, et al. Heat transfer characteristics of flat pulsating heat pipe with topology optimization channel under local multi-heat sources[J]. CIESC Journal, 2025,76(3):1006-1017.
[8]	TSENG Chih-Yung, YANG Kai-Shing, CHIEN Kuo-Hsiang, et al. Investigation of the performance of pulsating heat pipe subject to uniform/alternating tube diameters[J]. Experimental Thermal and Fluid Science, 2014, 54: 85-92.
[9]	TSENG Chih-Yung, YANG Kai-Shing, CHIEN Kuo-Hsiang, et al. A novel double pipe pulsating heat pipe design to tackle inverted heat source arrangement[J]. Applied Thermal Engineering, 2016, 106: 697-701.
[10]	KHANDEKAR Sameer, CHAROENSAWAN Piyanun, GROLL Manfred, et al. Closed loop pulsating heat pipes Part B: Visualization and semi-empirical modeling[J]. Applied Thermal Engineering, 2003, 23(16): 2021-2033.
[11]	MANE Kishor Vishwanath, ALEKSEIK Yevhenii. Comprehensive parametric and design review for reducing pulsating heat pipes dependence on space orientation[J]. Archives of Thermodynamics, 2024: 165-182.
[12]	Jaeyeong JO, KIM Jungho, KIM Sung Jin. Experimental investigations of heat transfer mechanisms of a pulsating heat pipe[J]. Energy Conversion and Management, 2019, 181: 331-341.
[13]	卜治丞, 焦波, 林海花, 等. 脉动热管计算流体力学模型与研究进展[J]. 化工进展, 2023, 42(8): 4167-4181.
	BU Zhicheng, JIAO Bo, LIN Haihua, et al. Review on computational fluid dynamics(CFD) simulation and advances in pulsating heat pipes[J]. Chemical Industry and Engineering Progress, 2023, 42(8): 4167-4181.
[14]	孙芹, 屈健, 袁建平. 等截面和变截面通道硅基微型脉动热管传热特性比较[J]. 化工学报, 2017, 68(5): 1803-1810, 2218.
	SUN Qin, QU Jian, YUAN Jianping. Heat transfer performance comparison of silicon-based micro oscillating heat pipes with and without expanding channels[J]. CIESC Journal, 2017, 68(5): 1803-1810, 2218.
[15]	张东, 侯宏艺, 李庆亮, 等. 非均匀热流密度条件下脉动热管运行特性分析[J]. 华南理工大学学报(自然科学版), 2022, 50(7): 126-135.
	ZHANG Dong, HOU Hongyi, LI Qingliang, et al. Analysis of operation characteristics of pulsating heat pipe under the condition of non-uniform heat flux[J]. Journal of South China University of Technology (Natural Science Edition), 2022, 50(7): 126-135.
[16]	WENG Zhenchuan, DU Juan, JIAO Feng, et al. Experimental investigation on the heat transfer performance of pulsating heat pipe with self-rewetting Fe₃O₄-nanofluid[J]. Case Studies in Thermal Engineering, 2024, 59: 104456.
[17]	包康丽. 热传输距离对不同工作流体脉动热管工作特性影响的研究[D]. 杭州: 浙江大学, 2023.
	BAO Kangli. Study on the effects of heat transfer distance on the operating characteristics of pulsating heat pipe with different working fluids[D]. Hangzhou: Zhejiang University, 2023.
[18]	郭子瑞, 王家伟, 池日光, 等. L形脉动热管电池包的传热性能数值研究[J]. 哈尔滨商业大学学报(自然科学版), 2024, 40(5): 566-571.
	GUO Zirui, WANG Jiawei, CHI Riguang, et al. Numerical study on heat tranfer performance of L-shaped pulsating heat pipe tube battery pack[J].The Journal of Harbin University of Commerce (Natural Sciences Edition), 2024, 40(5): 566-571.
[19]	CZAJKOWSKI Cezary, NOWAK Andrzej I, Przemysław BŁASIAK, et al. Experimental study on a large scale pulsating heat pipe operating at high heat loads, different adiabatic lengths and various filling ratios of acetone, ethanol, and water[J]. Applied Thermal Engineering, 2020, 165: 114534.
[20]	BAO Kangli, ZHUANG Yuan, GAO Xu, et al. Transient numerical model on the design optimization of the adiabatic section length for the pulsating heat pipe[J]. Applied Sciences, 2021, 11(20): 9432.
[21]	FONSECA Luis Diego, PFOTENHAUER John, MILLER Franklin. Short communication: Thermal performance of a cryogenic helium pulsating heat pipe with three evaporator sections[J]. International Journal of Heat and Mass Transfer, 2018, 123: 655-656.
[22]	FONSECA Luis Diego, PFOTENHAUER John, MILLER Franklin. Results of a three evaporator cryogenic helium Pulsating Heat Pipe[J]. International Journal of Heat and Mass Transfer, 2018, 120: 1275-1286.
[23]	Niti KAMMUANG-LUE, SAKULCHANGSATJATAI Phrut, TERDTOON Pradit. Thermal performance of various adiabatic section lengths of closed-loop pulsating heat pipe designed for energy recovery applications[J]. Energy Reports, 2022, 8: 731-737.
[24]	SUKCHANA Thanaphol, JAIBOONMA Chaiyun. Effect of filling ratios and adiabatic length on thermal efficiency of long heat pipe filled with R-134a[J]. Energy Procedia, 2013, 34: 298-306.
[25]	GAN Zhihua, SUN Xiao, JIAO Bo, et al. Experimental study on a hydrogen closed loop pulsating heat pipe with different adiabatic lengths[J]. Heat Transfer Engineering, 2019, 40(3/4): 205-214.
[26]	白雪玉. 部分水平结构脉动热管的性能研究[D]. 天津: 天津大学, 2018.
	BAI Xueyu. Investigation of pulsating heat pipe with partial horizontal structure[D]. Tianjin: Tianjin University, 2018.
[27]	CZAJKOWSKI Cezary, NOWAK Andrzej I, Sławomir PIETROWICZ. Flower Shape Oscillating Heat Pipe—A novel type of oscillating heat pipe in a rotary system of coordinates—An experimental investigation[J]. Applied Thermal Engineering, 2020, 179: 115702.
[28]	CHEN Yang, HE Yongqing, ZHU Xiaoqin. Flower-type pulsating heat pipe for a solar collector[J]. International Journal of Energy Research, 2020, 44(9): 7734-7745.
[29]	Kritsada ON-AI, Niti KAMMUANG-LUE, TERDTOON Pradit, et al. Implied physical phenomena of rotating closed-loop pulsating heat pipe from working fluid temperature[J]. Applied Thermal Engineering, 2019, 148: 1303-1309.
[30]	LIU Ying, BAO Kangli, YAN Yuhao, OUYANG Hongshen, HAN Xiaohong. Investigation on the influence of different heat transmission distances on thermo-hydrodynamic characteristics of pulsating heat pipes[J]. Applied Thermal Engineering, 2023, 234: 1359-4311.
[31]	FONSECA Luis Diego, MILLER Franklin, PFOTENHAUER John. Experimental heat transfer analysis of a cryogenic nitrogen pulsating heat Pipe at various liquid fill ratios[J]. Applied Thermal Engineering, 2018, 130: 343-353.
[32]	BRUCE Romain, BARBA Maria, BONELLI Antoine, et al. Thermal performance of a meter-scale horizontal nitrogen pulsating heat pipe[J]. Cryogenics, 2018, 93: 66-74.
[33]	LI Yi, WANG Qiuliang, CHEN Shunzhong, et al. Experimental investigation of the characteristics of cryogenic oscillating heat pipe[J]. International Journal of Heat and Mass Transfer, 2014, 79: 713-719.
[34]	SAGAR Kalpak R, NAIK H B, MEHTA Hemantkumar B. Numerical study of liquid nitrogen based pulsating heat pipe for cooling superconductors[J]. International Journal of Refrigeration, 2021, 122: 33-46.
[35]	SAGAR Kalpak R, NAIK H B, MEHTA Hemantkumar B. CFD analysis of cryogenic pulsating heat pipe with near critical diameter under varying gravity conditions[J]. Theoretical Foundations of Chemical Engineering, 2020, 54(1): 64-76.
[36]	LI Sizhuo, BU Zhicheng, FANG Tiegen, et al. Experimental study on the thermo-hydrodynamic characteristics of a nitrogen pulsating heat pipe[J]. International Communications in Heat and Mass Transfer, 2023, 146: 106920.
[37]	李思卓. 液氮温区脉动热管流动特性及传热机理研究[D]. 杭州: 浙江大学, 2023.
	LI Sizhuo. Study on flow characteristics and heat transfer mechanism of pulsating heat pipe at liquid nitrogen temperature range[D]. Hangzhou: Zhejiang University, 2023.
[38]	卜治丞, 李思卓, 焦波, 等. 不同冷凝段温度下液氮脉动热管可视化实验研究[J]. 化工学报, 2023, 74(12): 4892-4903.
	BU Zhicheng, LI Sizhuo, JIAO Bo, et al. Visualization study on a nitrogen pulsating heat pipe under different condenser temperatures[J]. CIESC Journal, 2023, 74(12): 4892-4903.
[39]	BU Zhicheng, LI Sizhou, ZHAO Shuyi, et al. Thermo-hydrodynamic analysis of a nitrogen flat-plate pulsating heat pipe using CFD modeling and visualization experiments[J]. International Communications in Heat and Mass Transfer, 2024, 159: 108029.
[40]	何欣. 超临界管径脉动热管单向循环流动下理论及实验研究[D]. 大连: 大连海事大学, 2024.
	HE Xin. Theoretical and experimental research on unidirectional circulating flow in supercritical oscillating heat pipe[D]. Dalian: Dalian Maritime University, 2024.
[41]	孙潇. 液氢温区脉动热管高效传热理论及实验研究[D]. 杭州: 浙江大学, 2021.
	SUN Xiao. Study on efficient heat transfer performance of pulsating heat pipe at liquid hydrogen temperature range[D]. Hangzhou: Zhejiang University, 2021.
[42]	YE Mengting, XIANG Daoping, GUI Ziyu. Thermal conductivity enhancement of epoxy by a 3D Si₃N₄ crystal rod/grain skeleton fabricating from photovoltaic silicon waste[J]. Ceramics International, 2024, 50(24): 53780-53789.

文献	工质	蒸发段长度（L_e）	绝热段长度（L_a）	冷凝段长度（L_c）	加热功率	热阻最低工况
Czajkowski等^[19]	水	265mm	500mm 750mm 1000mm	355mm	0~2kW	Q<2kW，R_min：L_a=1000mm
Bao等^[20]	水	60mm	60mm 120mm 180mm 240mm	60mm	20~80kW	Q<25W，R_min：L_a=240mm
Fonseca等^[21-22]	氦	30mm	300mm 1000mm	90mm	0~3W	Q<0.26W，R_min：L_a=1000mm
Kammuang等^[23]	R123	150mm	300mm 450mm	355mm	5000~35000W/m²	Q=Q，R_min：L_a=300mm
Sukchana等^[24]	R123	100mm	300mm 500mm 700mm	100mm	2~10kW/m²	q=5.92kW/m²，R_min：L_a=300mm
Gan等^[25]	液氮	60mm	100mm 500mm	60mm	2~5W	Q<1.5W，R_min：L_a=100mm

文献	工质	蒸发段长度（L_e）	绝热段长度（L_a）	冷凝段长度（L_c）	加热功率	热阻最低工况
Czajkowski等^[19]	水	265mm	500mm 750mm 1000mm	355mm	0~2kW	Q<2kW，R_min：L_a=1000mm
Bao等^[20]	水	60mm	60mm 120mm 180mm 240mm	60mm	20~80kW	Q<25W，R_min：L_a=240mm
Fonseca等^[21-22]	氦	30mm	300mm 1000mm	90mm	0~3W	Q<0.26W，R_min：L_a=1000mm
Kammuang等^[23]	R123	150mm	300mm 450mm	355mm	5000~35000W/m²	Q=Q，R_min：L_a=300mm
Sukchana等^[24]	R123	100mm	300mm 500mm 700mm	100mm	2~10kW/m²	q=5.92kW/m²，R_min：L_a=300mm
Gan等^[25]	液氮	60mm	100mm 500mm	60mm	2~5W	Q<1.5W，R_min：L_a=100mm

径向网格数	热阻R/K·W^-1
4×6=24	1.10716
6×9=54	1.15657
8×12=96	1.13118
4×6=24	1.14657

径向网格数	热阻R/K·W^-1
4×6=24	1.10716
6×9=54	1.15657
8×12=96	1.13118
4×6=24	1.14657

轴向网格高度/mm	热阻R/K·W^-1	网格数量
0.2	1.09172	142954
0.4	1.07485	254251
0.6	1.10632	336652
1	1.13012	396522
1.5	1.42852	563652
2.0	1.51969	618632