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High heat flux thermal management through liquid metal driven with electromagnetic induction pump

《能源前沿（英文）》 2022年 第16卷 第3期   页码 460-470 doi: 10.1007/s11708-022-0825-9

摘要： In this paper, a novel liquid metal-based minichannel heat dissipation method was developed for cooling electric devices with high heat flux. A high-performance electromagnetic induction pump driven by rotating permanent magnets is designed to achieve a pressure head of 160 kPa and a flow rate of 3.24 L/min, which could enable the liquid metal to remove the waste heat quickly. The liquid metal-based minichannel thermal management system was established and tested experimentally to investigate the pumping capacity and cooling performance. The results show that the liquid metal cooling system can dissipate heat flux up to 242 W/cm2 with keeping the temperature rise of the heat source below 50°C. It could remarkably enhance the cooling performance by increasing the rotating speed of permanent magnets. Moreover, thermal contact resistance has a critical importance for the heat dissipation capacity. The liquid metal thermal grease is introduced to efficiently reduce the thermal contact resistance (a decrease of about 7.77 × 10−3 °C/W). This paper provides a powerful cooling strategy for thermal management of electric devices with large heat power and high heat flux.

关键词： high heat flux     liquid metal     electromagnetic pump     minichannel heat sink     thermal interface material    

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Review on electromagnetic welding of dissimilar materials

K. SHANTHALA,T. N. SREENIVASA

《机械工程前沿（英文）》 2016年 第11卷 第4期   页码 363-373 doi: 10.1007/s11465-016-0375-0

摘要：

Electromagnetic welding (EMW) is a high-speed joining technique that is used to join similar or dissimilar metals, as well as metals to non-metals. This technique uses electromagnetic force to mainly join conductive materials. Unlike conventional joining processes, the weld interface does not melt, thus keeping the material properties intact. Extremely high velocity and strain rate involved in the process facilitate extending the EMW technique for joining several materials. In this paper, the research and progress in electromagnetic welding are reviewed from various perspectives to provide a basis for further research.

关键词： electromagnetic     welding     impact     dissimilar materials    

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Elliptical lobe shape gerotor pump design to minimize wear

Mohammad Reza KARAMOOZ RAVARI

《机械工程前沿（英文）》 2011年 第6卷 第4期   页码 429-434 doi: 10.1007/s11465-011-0247-6

摘要：

The gerotor pumps are the most important parts of mechanical equipment that have a vast number of applications in industries and automobiles. Because the gerotor pumps cannot be adjusted for wear so it is important to reduce the wear as much as possible. In this paper first mathematical equations for elliptical lobe shape rotors profile and curvature of them have been derived and then Specific flow and wear rate proportional factor (WRPF) have been formulated. To reach the minimum wear in rotors teeth, the ellipse shape factor is changed for each value of number of outer rotor teeth in a feasible range and wear rate proportional factor has been resulted. Also in order to have better comparison specific flow has been presented. The obtained results have been compared with circular pumps with similar geometrical parameters and show the significant improvement in wear of the rotors with negligible changes in the specific flow.

关键词： gerotor pump     elliptical lobe shape pump     wear rate proportional factor (WRPF)     specific flow    

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Extended two-fluid model applied to analysis of bubbly flow in multiphase rotodynamic pump impeller

Zhiyi YU, Guoyu WANG, Shuliang CAO

《机械工程前沿（英文）》 2009年 第4卷 第1期   页码 53-59 doi: 10.1007/s11465-009-0006-0

摘要： This paper presents an extended two-fluid model based on the Navier-Stokes equations and the standard turbulence model, to simulate the three-dimensional air-water bubbly flow in turbo machinery. In the governing equations, the drag force and added mass force are added and the additional source terms arising from fluctuations of gas volume fraction are considered. The discrete equations are solved using a developed two-phase semi-implicit method for pressure-linked equations, consistent (SIMPLEC) algorithm in body-fitted coordinates with a staggered grid system. Simulation is then carried out for the pure liquid flow and air-water two-phase flow with the inlet gas volume fraction being 15% in a multiphase rotodynamic pump impeller and the pump head performance is predicted. Comparison with experimental results shows the reliability and commonality of the numerical model.

关键词： two-fluid model     multiphase rotodynamic pump     SIMPLEC algorithm     numerical simulation    

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R&D of the ground-coupled heat pump technology in China

Nairen DIAO, Ping CUI, Junhong LIU, Zhaohong FANG,

《能源前沿（英文）》 2010年 第4卷 第1期   页码 47-54 doi: 10.1007/s11708-009-0080-3

摘要： The ground-coupled heat pump (GCHP) systems have been identified as one of the best sustainable energy technologies for space heating and cooling in residential and commercial buildings. In this paper, research on and development of the GCHP technology in China are summarized. New models are presented for efficient thermal analysis of ground heat exchangers, of which one- and two-dimensional solid cylindrical source models and their analytical solutions are devised to deal with pile ground heat exchangers. Analytical solutions are also derived for vertical and inclined finite line source models as well as for a groundwater advection model. Explicit solutions of a quasi-three-dimensional model can be used to better evaluate the thermal resistance inside boreholes. Studies on hybrid GCHP systems and the thermal response test in China are also commented.

关键词： ground source heat pump     ground heat exchanger     HVAC     China    

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Evaluation of the performance of a centralized ground-water heat pump system in cold climate region

Shilei LU,Zhe CAI,Li ZHANG,Yiran LI

《能源前沿（英文）》 2014年 第8卷 第3期   页码 394-402 doi: 10.1007/s11708-014-0310-1

摘要： The aim of this study is to evaluate the performance of a centralized open-loop ground-water heat pump (GWHP) system for climate conditioning in Beijing with a cold climate in China. Thus, a long-time test was conducted on a running GWHP system for the heating season from December 2011 to March 2012. The analysis of the testing data indicates that the average heat-pump coefficient of performance (COP) and the COP of the system (COPs) are 4.27 and 2.59. The low value and large fluctuation in the range of COP are found to be caused by the heat transfixion in the aquifer and the bypass in the circulation loop. Therefore, some suggestions are proposed to improve the performance for GWHPs in the cold climate region in China.

关键词： ground-water heat pump (GWHP)     actual coefficient of performance     heat transfixion    

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A valveless piezoelectric pump with novel flow path design of function of rectification to improve energy

《机械工程前沿（英文）》 2022年 第17卷 第3期 doi: 10.1007/s11465-022-0685-3

摘要： Existing valveless piezoelectric pumps are mostly based on the flow resistance mechanism to generate unidirectional fluid pumping, resulting in inefficient energy conversion because the majority of mechanical energy is consumed in terms of parasitic loss. In this paper, a novel tube structure composed of a Y-shaped tube and a ȹ-shaped tube was proposed considering theory of jet inertia and vortex dissipation for the first time to improve energy efficiency. After verifying its feasibility through the flow field simulation, the proposed tubes were integrated into a piezo-driven chamber, and a novel valveless piezoelectric pump with the function of rectification (NVPPFR) was reported. Unlike previous pumps, the reported pump directed the reflux fluid to another flow channel different from the pumping fluid, thus improving pumping efficiency. Then, mathematical modeling was established, including the kinetic analysis of vibrator, flow loss analysis of fluid, and pumping efficiency. Eventually, experiments were designed, and results showed that NVPPFR had the function of rectification and net pumping effect. The maximum flow rate reached 6.89 mL/min, and the pumping efficiency was up to 27%. The development of NVPPFR compensated for the inefficiency of traditional valveless piezoelectric pumps, broadening the application prospect in biomedicine and biology fields.

关键词： composite tube     valveless piezoelectric pump     rectification     energy efficiency    

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Absorption heat pump for waste heat reuse: current states and future development

Zhenyuan XU, Ruzhu WANG

《能源前沿（英文）》 2017年 第11卷 第4期   页码 414-436 doi: 10.1007/s11708-017-0507-1

摘要： Absorption heat pump attracts increasing attention due to its advantages in low grade thermal energy utilization. It can be applied for waste heat reuse to save energy consumption, reduce environment pollution, and bring considerable economic benefit. In this paper, three important aspects for absorption heat pump for waste heat reuse are reviewed. In the first part, different absorption heat pump cycles are classified and introduced. Absorption heat pumps for heat amplification and absorption heat transformer for temperature upgrading are included. Both basic single effect cycles and advanced cycles for better performance are introduced. In the second part, different working pairs, including the water based working pairs, ammonia based working pairs, alcohol based working pairs, and halogenated hydrocarbon based working pairs, for absorption heat pump are classified based on the refrigerant. In the third part, the applications of the absorption heat pump and absorption heat transformer for waste heat reuse in different industries are introduced. Based on the reviews in the three aspects, essential summary and future perspective are presented at last.

关键词： absorption     heat pump     heat transformer     waste heat     working pair    

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Radial electromagnetic type unbalance vibration self-recovery regulation system for high-end grinding

《机械工程前沿（英文）》 2023年 第18卷 第3期 doi: 10.1007/s11465-023-0763-1

摘要： Modern rotating machines, which are represented by high-end grinding machines, have developed toward high precision, intelligence, and high durability in recent years. As the core components of grinding machine spindles, grinding wheels greatly affect the vibration level during operation. The unbalance vibration self-recovery regulation (UVSRR) system is proposed to suppress the vibration of grinding wheels during workpiece processing, eliminating or minimizing the imbalance. First, technical principles and the system composition are introduced. Second, the balancing actuator in the UVSRR system is analyzed in detail. The advanced nature of the improved structure is presented through structure introduction and advantage analysis. The performance of the balancing actuator is mutually verified by the theoretical calculation of torque and software simulation. Results show that the self-locking torque satisfies the actual demand, and the driving torque is increased by 1.73 times compared with the traditional structure. Finally, the engineering application value of the UVSRR system is verified by laboratory performance comparison and actual factory application. The balancing speed and effect of the UVSRR system are better than those of an international mainstream product and, the quality of the workpieces machined in the factory improved by 40%.

关键词： UVSRR system     radial electromagnetic type     vibration suppression     performance simulation     engineering application    

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design of novel proton-pump inhibitors with reduced adverse effects

Xiaoyi Li, Hong Kang, Wensheng Liu, Sarita Singhal, Na Jiao, Yong Wang, Lixin Zhu, Ruixin Zhu

《医学前沿（英文）》 2019年 第13卷 第2期   页码 277-284 doi: 10.1007/s11684-018-0630-3

摘要： The development of new proton-pump inhibitors (PPIs) with less adverse effects by lowering the pKa values of nitrogen atoms in pyrimidine rings has been previously suggested by our group. In this work, we proposed that new PPIs should have the following features: (1) number of ring II= number of ring I+ 1; (2) preferably five, six, or seven-membered heteroatomic ring for stability; and (3) 1

关键词： proton-pump inhibitor     adverse effect     pharmacological mechanism     toxicological mechanism     pKa calculation    

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Analytical model and finite element computation of braking torque in electromagnetic retarder

Lezhi YE,Guangzhao YANG,Desheng LI

《机械工程前沿（英文）》 2014年 第9卷 第4期   页码 368-379 doi: 10.1007/s11465-014-0314-x

摘要：

An analytical model has been developed for analyzing the braking torque in electromagnetic retarder by flux tube and armature reaction method. The magnetic field distribution in air gap, the eddy current induced in the rotor and the braking torque are calculated by the developed model. Two-dimensional and three-dimensional finite element models for retarder have also been developed. Results from the analytical model are compared with those from finite element models. The validity of these three models is checked by the comparison of the theoretical predictions and the measurements from an experimental prototype. The influencing factors of braking torque have been studied.

关键词： electromagnetic retarder     magnetic field distribution     magnetic circuit     finite element method    

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aerogels decorated with multi-walled carbon nanotubes: preparation, characterization, and application for electromagnetic

Jian LI,Caichao WAN

《农业科学与工程前沿（英文）》 2015年 第2卷 第4期   页码 341-346 doi: 10.15302/J-FASE-2015082

摘要： Electromagnetic wave pollution has attracted extensive attention because of its ability to affect the operation of electronic machinery and endanger human health. In this work, the environmentally-friendly hybrid aerogels consisting of cellulose and multi-walled carbon nanotubes (MWCNTs) were fabricated. The aerogels have a low bulk density of 58.17 mg·cm . The incorporation of MWCNTs leads to an improvement in the thermal stability. In addition, the aerogels show a high electromagnetic interference (EMI) value of 19.4 dB. Meanwhile, the absorption-dominant shielding mechanism helps a lot to reduce secondary radiation, which is beneficial to develop novel eco-friendly EMI shielding materials.

关键词： cellulose aerogels     carbon nanotubes     electromagnetic interference shielding     composites    

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Efficiency characteristics of piezostack pump for linear actuators

Junwu KAN, Kehong TANG, Chenghui SHAO, Guoren ZHU, Taijiang PENG,

《机械工程前沿（英文）》 2009年 第4卷 第4期   页码 407-414 doi: 10.1007/s11465-009-0049-2

摘要： A piezostack pump for linear actuators is presented and studied in terms of mechanical energy efficiency (MEE), energy conversion efficiency (ECE) and design method. MEE is defined as the ratio of the output mechanical energy to that converted from input electrical energy, and ECE is the ratio of output mechanical energy to input electrical energy. The analysis results show that both MEE and ECE decrease with the increase of stiffness of the chamber diaphragm (), which is a function of the radius ratio (rigid disk radius to chamber radius). There is respective optimal external load () for them to achieve peak value for a given piezostack with blocked force () and stiffness (). The optimal force ratio (/) is a constant of 0.5 for maximum MEE, and between 0.57 and 0.5 for maximum ECE. Considering the deflection of the pump chamber and dynamic response of the piezostack, the stiffness ratio (/) should be limited between 0.3 and 1, and the relative radius ratio is between 0.7 and 0.8. With the increase of the radius ratio in the range, the maximal MEE decreases from 0.38 to 0.25, and the peak ECE decreases from 0.20 to 0.14.

关键词： piezostack actuator     piezostack pump     mechanical efficiency     energy conversion efficiency (ECE)    

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Design and analysis of linear oscillating motor for linear pump application-magnetic field, dynamics

Zongxia JIAO,Tianyi WANG,Liang YAN

《机械工程前沿（英文）》 2016年 第11卷 第4期   页码 351-362 doi: 10.1007/s11465-016-0407-9

摘要：

A linear oscillating motor is an electromagnetic actuator that can achieve short-stroke reciprocating movement directly without auxiliary transmission mechanisms. It has been widely used in linear pump applications as the source of power and motion. However, because of the demand of high power density in a linear actuation system, the performance of linear oscillating motors has been the focus of studies and deserves further research for high power density. In this paper, a general framework of linear oscillating motor design and optimization is addressed in detail, including the electromagnetic, dynamics, and thermal aspects. First, the electromagnetic and dynamics characteristics are modeled to reveal the principle for optimization. Then, optimization and analysis on magnetic structure, resonant system, and thermal features are conducted, which provide the foundation for prototype development. Finally, experimental results are provided for validation. As a whole, this process offers complete guidance for high power density linear oscillating motors in linear pump applications.

关键词： linear oscillating motor     linear pump     magnetic field     motor optimization    

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A solar assisted heat pump drying system for grain in-store drying

Haifeng LI, Yanjun DAI, Jianguo DAI, Xibo WANG, Lei WEI,

《能源前沿（英文）》 2010年 第4卷 第3期   页码 386-391 doi: 10.1007/s11708-010-0003-3

摘要： For grain in-store drying, a solar assisted drying process has been developed, which consists of a set including a solar-assisted heat pump, a ventilation system, a grain stirrer, etc. In this way, low power consumption, short cycle time and water content uniformity can be achieved in comparison with the conventional method. A solar-assisted heat pump drying system has been designed and manufactured for a practical granary, and the energy consumption performance of the unit is analyzed. The analysis result shows that the solar fraction of the unit is higher than 20%, the coefficient of performance about system (COP) is 5.19, and the specific moisture extraction rate (SMER) can reach 3.05 kg/kWh.

关键词： solar energy     heat pump     airflow     in-store drying    

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标题 作者 时间 类型 操作

High heat flux thermal management through liquid metal driven with electromagnetic induction pump

期刊论文

Review on electromagnetic welding of dissimilar materials

K. SHANTHALA,T. N. SREENIVASA

期刊论文

Elliptical lobe shape gerotor pump design to minimize wear

Mohammad Reza KARAMOOZ RAVARI

期刊论文

Extended two-fluid model applied to analysis of bubbly flow in multiphase rotodynamic pump impeller

Zhiyi YU, Guoyu WANG, Shuliang CAO

期刊论文

R&D of the ground-coupled heat pump technology in China

Nairen DIAO, Ping CUI, Junhong LIU, Zhaohong FANG,

期刊论文

Evaluation of the performance of a centralized ground-water heat pump system in cold climate region

Shilei LU,Zhe CAI,Li ZHANG,Yiran LI

期刊论文

A valveless piezoelectric pump with novel flow path design of function of rectification to improve energy

期刊论文

Absorption heat pump for waste heat reuse: current states and future development

Zhenyuan XU, Ruzhu WANG

期刊论文

Radial electromagnetic type unbalance vibration self-recovery regulation system for high-end grinding

期刊论文

design of novel proton-pump inhibitors with reduced adverse effects

Xiaoyi Li, Hong Kang, Wensheng Liu, Sarita Singhal, Na Jiao, Yong Wang, Lixin Zhu, Ruixin Zhu

期刊论文

Analytical model and finite element computation of braking torque in electromagnetic retarder

Lezhi YE,Guangzhao YANG,Desheng LI

期刊论文

aerogels decorated with multi-walled carbon nanotubes: preparation, characterization, and application for electromagnetic

Jian LI,Caichao WAN

期刊论文

Efficiency characteristics of piezostack pump for linear actuators

Junwu KAN, Kehong TANG, Chenghui SHAO, Guoren ZHU, Taijiang PENG,

期刊论文

Design and analysis of linear oscillating motor for linear pump application-magnetic field, dynamics

Zongxia JIAO,Tianyi WANG,Liang YAN

期刊论文

A solar assisted heat pump drying system for grain in-store drying

Haifeng LI, Yanjun DAI, Jianguo DAI, Xibo WANG, Lei WEI,

期刊论文