检索结果-内蒙古大学图书馆

Journal of Fluids and Structures 2025年 137卷

作者： Yuwen Li Qiang Xu Yeqi Cao Bo Huang Haiyang Yu Liejin Guo State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an 710049 PR China

The investigation of the severe slugging characteristics and its induced vibration is an important basis for effectively avoiding fatigue damage or excessive stress in the offshore riser system. In this paper, a non-invasive optical method is used to study the vibration induced by severe slugging in a pipeline S-shaped riser system. Based on the image data of the gas-liquid interface structure and differential pressure fluctuation, severe slugging is classified into three sub-flow patterns (SS1, SS2, and SS3), and the flow characteristics and dynamic response of the riser are investigated at three sub-flow patterns. The two peaks in the spectral of the riser vibration response correspond to the fluctuation frequency of the differential pressure and the first natural frequency of the riser, respectively, and then a correlation for predicting the response frequency induced by severe slugging is established. The vibration amplitude of the riser is strongly related to the bubble length and the liquid slug velocity in the gas blowdown stage. The in-plane vibration responses of the riser are dominated by the first and second modes. The two modes coexist and switch over time due to the continuous change of slug characteristic parameters.

关键词：

flow and residence time distribution characteristics in continuous hydrothermal reactor under different heating schemes

学校读者我要写书评

暂无评论

Chemical Engineering Science 2025年 316卷

作者： Yi Li Junying Wang Xiaoyu Li Hui Jin State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Shaanxi 710049 PR China

Residence time distribution (RTD) is of significance for reflecting materials or intermediate products dispersion and actual reaction time inside continuous hydrothermal reactors of supercritical water gasification technology. Generally, RTD is strictly related to flow field, which can be affected by wall heating schemes. In order to propose methods to regulating RTD, effects of different heating schemes on flow and RTD characteristics are investigated and compared by numerical simulation. The results indicate that increasing heat flux, interrupting boundary flow by interlace heating, and setting cooling walls can significantly regulate RTD. By analyzing the correspondence of flow and RTD, the mechanisms of increasing materials and intermediate products dispersion can be attribute to the increase of flow instability and the generation of additional vortices. For example, in the cases of present work, the narrow-strip double-vortex generated by mixing between thermal boundary flow and branch flow may significantly increase average residence time and materials distribution range from 10.93 s and 1.00 to 22.83 s and 1.51. In the region above branch inlet without time-averaged vortex structure, the increasing of flow instability caused by wall heating is observed to widen materials distribution range from 0.75 to 0.99. Heating scheme customized according to these mechanisms can regulating RTD as expected, proving the feasibility and significance of regulating RTD by heating schemes.

关键词： Reaction intermediates

Numerical investigation of natural convection characteristics of a heat pipe-cooled passive residual heat removal system for molten salt reactors

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2020年第7期31卷 25-33页

作者： Cheng-Long Wang Hao Qin Da-Lin Zhang Wen-Xi Tian Guang-Hui Su Sui-Zheng Qiu Department of Nuclear Science and Technology Xi’an Jiaotong UniversityXi’an 710049China Shaanxi Key Laboratory of Advanced Nuclear Energy and Technology Xi’an Jiaotong UniversityXi’an 710049China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong UniversityXi’an 710049China

The limited availability of studies on the natural convection heat transfer characteristics of fluoride salt has hindered progress in the design of passive residual heat removal systems(PRHRS)for molten salt *** paper presents results from a numerical investigation of natural convection heat transfer characteristics of fluoride salt and heat pipes in the drain tank of a *** results are compared with experimental data,demonstrating the accuracy of the calculation *** distribution of fluoride salt and heat transfer characteristics are obtained and *** radial temperature of liquid fluoride salt in the drain tank shows a uniform distribution,while temperatures increase with increase in axial height from the bottom to the top of the drain *** addition,natural convection intensity increases with increase in height of the heat pipes in the *** between heat pipes has no obvious effect on the natural convection heat transfer *** study will contribute to the design of passive heat removal systems for advanced nuclear reactors.

关键词： passive characteristics pipes

Numerical Simulations on Hybrid Thermal Management of Mini-Channel Cold Plate and Pcm for Lithium-Ion Batteries

学校读者我要写书评

暂无评论

SSRN 2024年

作者： Liu, Yang Zhou, Zhifu Wu, Wei-Tao Wei, Lei Li, Yang Liu, Xinyu Huang, Heng Li, Yubai Song, Yongchen Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education Dalian University of Technology Dalian116024 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi’an710049 China School of Mechanical Engineering Nanjing University of Science and Technology Nanjing210094 China Department of Mechanical and Energy Engineering Southern University of Science and Technology Shenzhen518055 China

In this study, a novel battery thermal management system (BTMS), combining phase change material (PCM) and mini-channel cold plates (MCPs), was modeled and analyzed. First, the effects on single cell cooling using MCPs and PCM alone are investigated at different coolant rates, temperatures, and PCM thicknesses. Then, the hybrid thermal management system (HTMS) is developed with the aim of reducing the cooling load of the PCM through hybridization with MCPs and the optimal combination of them is investigated. At the end of this work, the thermal performance of a battery pack with a hybrid thermal management structure has been analyzed, where the cold plate can take away the heat from the PCM to restore its thermal storage capacity. The results show that the combination of 3 channel and 10 mm PCM with 0.1 m/s coolant velocity and 20°C coolant temperature is the quit suitable regarding the cooling performance. Under 2C discharging rate, this design reduces the maximum battery temperature to 40°C, which is 32.5% lower, and the average temperature to 35℃, which is 41% lower than it without cooling. The study's findings offer potential new strategies and predictions for hybrid thermal management that utilize MCPs and PCM. © 2024, The Authors. All rights reserved.

关键词： Lithium-ion batteries

Investigations on affinity law under gas-liquid conditions in multistage radial and mixed-flow multiphase pumps

学校读者我要写书评

暂无评论

国际流体工程（英文）

国际流体工程（英文） 2024年第1期1卷 52-66页

作者： Liang Chang Chenyu Yang Xiaobin Su Xiaoyu Dai Qiang Xu Liejin Guo State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an 710049China

Affinity laws have been widely used in pump design and simulation under high-temperature and corrosive *** applying such laws,it is possible to shorten development cycles and reduce test ***,current applications of affinity laws are still limited to liquid *** this paper,expressions for affinity laws and their applicability are investigated for multistage radial and mixed-flow multiphase pumps under gas-liquid conditions.A high-pressure(30 MPa)gas-liquid experimental platform is constructed,and three-stage and 25-stage radial pumps and a 15-stage mixed-flow pump are investigated,with specific speeds of 107 and *** gas compressibility taken into account,the gas-liquid two-phase flow rate,head,and power,and the corresponding dimensionless hydraulic coefficients,are defined for multiphase *** deterioration of gas-liquid pressurization performance is found to be divided into three processes with different dynamic mechanisms,corresponding to three flow *** inlet gas volume fraction of pump is used to judge dynamic *** the same inlet gas volume fractions λ1=λ2,when the gas-liquid flows in two pumps have the same flow pattern,dynamic similarity will be *** affinity law that is established shows good applicability to the three-stage radial multiphase pump,with goodness of fit R2 larger than 0.9 for the two-phaseΨm-Φm andΠm-Φm performance ***,experimental results indicate that the affinity law also has good applicability to multiphase pumps with different stage numbers and blade structures under gas-liquid conditions.

关键词： conditions radial affinity gas-liquid investigations mixed-flow multiphase multistage pumps under

Numerical Simulations for Comparison of Cold Plate Cooling and Hfe-7000 Immersion Cooling in Lithium-Ion Battery Thermal Management

学校读者我要写书评

暂无评论

SSRN 2024年

作者： Liu, Xinyu Zhou, Zhifu Wu, Wei-Tao Wei, Lei Hu, Chengzhi Li, Yang Huang, Heng Li, Yubai Song, Yongchen Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education Dalian University of Technology Dalian116024 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi’an710049 China School of Mechanical Engineering Nanjing University of Science and Technology Nanjing210094 China Department of Mechanical and Energy Engineering Southern University of Science and Technology Shenzhen518055 China

In this work, fluorinated liquids can be used as a new immersion coolant for effective battery thermal management (BTM) because of their insulating and non-flammable inert characteristics. In this research, the liquid chosen for immersion cooling is HFE-7000, characterized by a boiling point of 34°C. The analysis of bubble kinetics is employed to investigate the heat transfer mechanism in two-phase immersion cooling by examining the behavior of bubbles during the boiling process. The square ternary Li-ion batteries are subjected under loads of 2C and 3C cooled by immersion cooling and a mini-channel cold plate as a comparison. It turns out that immersion liquid cooling modules offer superior thermal performance. Under constant current (CC), the peak temperature is reduced by 4.89°C and 9.31°C compared with the mini-channel cold plate cooling (CPC). Under dynamic load conditions, the maximum temperature rise of the battery is reduced by 29.89% and 43.89% compared to CPC. As a passive heat dissipation method, two-phase immersion cooling reduces the design requirements for active control. Also, it delivers an efficient battery thermal management system (BTMS) designed for upcoming electric vehicles (EVs). © 2024, The Authors. All rights reserved.

关键词： Lithium-ion batteries

Zero-Energy Nonlinear Temperature Control of Lithium-Ion Battery Based on a Shape Memory Alloy

学校读者我要写书评

暂无评论

SSRN 2024年

作者： Li, Yang Bai, Minli Zhou, Zhifu Wu, Wei-Tao Wei, Lei Hu, Chengzhi Liu, Xinyu Gao, Shuai Li, Yubai Song, Yongchen Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education Dalian University of Technology Dalian116023 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'An710049 China School of Mechanical Engineering Nanjing University of Science and Technology Nanjing210094 China Department of Mechanical and Energy Engineering Southern University of Science and Technology Shenzhen518055 China

Improving the poor performance of lithium-ion battery (LIB) in extreme temperatures is essential to promoting electric vehicles (EVs) into wider application. The most severe challenge for the existing battery thermal management systems (BTMSs) is to overcome the contradiction between excellent heat dissipation at high temperatures and effective insulation at low temperatures. Here, we propose a zero-energy nonlinear temperature control strategy based on thermal regulator. The designed thermal regulator based on shape memory alloy (SMA) can switch the heat flux on the battery surface according to its temperature without any power supply or logic control and provide the desirable thermal functions. This thermal regulator increases the battery capacity by 55.44% in the cold environment of -20℃ compared to the baseline BTMS with superior heat dissipation. Simultaneously, it can limit the battery peak temperature to near the FS49 boiling point (49℃) in the hot environment of 45℃ to ensure safety. Furthermore, we demonstrate that the thermal regulator enables thermal runaway to be effectively suppressed inside the battery, reducing the emission of combustible or toxic gases by 72.26%, which is reported for the first time. Finally, we simplify the design of the thermal regulator from the perspective of system integration and demonstrate the feasibility of the thermal regulator at the battery pack level. © 2024, The Authors. All rights reserved.

关键词： Lithium-ion batteries

Transient Cooling Performance of R134a Flash-Evaporation Spray Enhanced by Cold Air Jet: A Novel Heat Transfer Enhancement Method in Laser Dermatology

学校读者我要写书评

暂无评论

SSRN 2022年

作者： Li, Bufa Wang, Junfeng Tian, Jiameng Chen, Bin Xu, Haojie School of Energy and Power Engineering Jiangsu University Zhenjiang212013 China State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Shaanxi Xi’an710049 China

Nevus of Ota is a dermal hyperplastic pigmented disease with a morbidity rate of 0.1%–0.6% in the Asian population. Laser surgery with the assistance of cryogen spray cooling (CSC) is a potential clinical treatment for nevus of Ota. However, for Asians with high melanin content, it is necessary to enhance cooling capability without the increment of refrigerant amount. In this study, a R134a flash-evaporation cryogen spray cooling coupled with cold air jet (CSC-CAJ) was developed to improve the cooling capacity. Epoxy resin was employed as a skin phantom to investigate the heat transfer characteristics of CSC-CAJ with different air jet parameters. Air jet parameters of CSC-CAJ are recommended to be T a = -7 °C, V a = 3 m 3 /h Z a = 10 mm and Φ a = 30°. Compared to CSC, CSC-CAJ could reduce the minimum surface temperature from -39 °C to -42.1 °C, and the average value of convection heat transfer coefficient ( h ) of CSC-CAJ could increase from 8 W/(m 2 ·k) to 12.9 W/(m 2 ·k) or 61.3% for the recommended parameters. The liquid film residence time ( τ ) decreases from 301 ms to 234 ms or 23.3%. In addition, based on the visualization observation and surface heat transfer measurement, the frost formation phenomenon on the surface and the heat transfer enhancement mechanisms are well understood. Four modes, including Leidonfrost mode, no runoff mode, runoff mode and evaporation mode, are proposed to describe the four stages of CSC-CAJ. A non-dimensional correlation of normalized Nusselt number ( Nu *) and time ( t *) is summarized. The primary heat transfer enhancement mechanism of CSC-CAJ is found to be the increase in cryogen evaporation rate and the ratio of heat removal from the phantom surface to phase change latent heat. © 2022, The Authors. All rights reserved.

关键词： Evaporation

Numerical Study of High-Energy Spark Ignition Characteristics in a Scramjet Combustor

学校读者我要写书评

暂无评论

SSRN 2024年

作者： Gao, Ziyan Zhang, Meng Zhang, Zhibo Wu, Yun Zheng, Xing Miao, Huifeng National Key Lab of Aerospace Power System and Plasma Technology Xi’an Jiaotong University Xi’an710049 China State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong Universiy Xi’an710049 China National Key Lab of Aerospace Power System and Plasma Technology Air Force Engineering University Xi’an710038 China Shaanxi Key Laboratory of Environment and Control for Flight Vehicle School of Aerospace Engineering Xi’an Jiaotong University Shaanxi 710049 China

Reliable ignition is a fundamental prerequisite for the scramjet engines. In order to improve the reliability of ignition, further enhance the application of spark ignition in engineering, and improve the ignition ability in the field of supersonic combustion, an innovative long electrode distance high-energy spark igniter (LHSI) system was proposed by our research team. To reveal the instantaneous ignition characteristics of the LHSI, a simulation model of the LHSI is established and verified by experiments. Based on this, the formation and development of the initial fire core of vaporized kerosene and the ignition characteristics of LHSI in a scramjet combustor were simulated and compared with the conventional high-energy spark igniter (HSI). The analysis revealed that the success of the cavity ignition is greatly influenced by the local equivalent ratio of the initial flow field and the penetration depth of the initial flame core. Meanwhile, the fore recirculation zone of the cavity plays a key role in stabilization and development of the initial fire core. Compared with the HSI, the LHSI can produce initial flame core with higher penetration and greater size, which is the main reason for why LHSI has a broader ignition boundary. © 2024, The Authors. All rights reserved.

关键词： Ignition

Curvature Adaptive Voxel-Based Monte Carlo Method with Application for Customized Retinal Laser Surgery

学校读者我要写书评

暂无评论

SSRN 2024年

作者： Zhang, Hao Li, Dong Chen, Bin Zhang, Hanfeng Liang, Yao Zheng, Yuping Wang, Guoxiang State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China Department of Ophthalmology 2nd affiliated hospital Medical School Xi’an Jiaotong University Xi’an710049 China Department of Mechanical Engineering The University of Akron AkronOH44325 United States

Accurate prediction of light propagation and energy deposition in biological tissues is crucial for the success of laser-based medical treatments. We propose a novel Curvature Adaptive Voxel-based Monte Carlo method (CAVMC) to correct for light reflection and refraction at curved interfaces by introducing coordinate transformation with an artificial surface parallel to the curved interface. This approach achieves an optimal balance between simulation accuracy and efficiency. Our study demonstrates that for small optical mismatches, the relative error can be reduced significantly, with the energy deposition error dropping from 34.7% to 6.6%. For large optical mismatches, CAVMC substantially improves accuracy, reducing computational errors by more than 50%. We validated CAVMC in a customized retinal laser therapy scenario for diabetic retinopathy, demonstrating its ability to accurately predict laser energy deposition and thermal effects, which is crucial for avoiding tissue damage during treatments. The efficiency and accuracy of the CAVMC method make it valuable for personalized retinal laser surgery and potentially other medical applications. Overall, CAVMC offers a robust tool for simulating light propagation in heterogeneous biological tissues, enhancing the precision and safety of medical treatments. © 2024, The Authors. All rights reserved.

关键词： Laser surgery