检索结果-南通市图书馆

Multi-objective hydraulic optimization and analysis in a minipump

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science Bulletin 2015年第17期60卷 1517-1526页

作者： Bin Duan Minqing luo Chao Yuan xiaobing luo School of Energy and Power Engineering Huazhong University of Science and Technology

Minipump is widely used in microfluidics system, active cooling system, etc. But building a high efficiency minipump is still a challenging problem. In this paper, a systematic method was developed to design, characterize and optimize a particular mechanical minipump. The optimization work was conducted to cope with the conflict between pressure head and hydraulic efficiency by an improved back-propagation neural network （BPNN） with the non-dominated sorting genetic algorithm-II （NSGA-II）. The improved BPNN was utilized to predicate hydraulic performance and, moreover, was modified to improve the prediction accuracy. The NSGA-II was processed for minipump multi-objective optimization which is dominated by four impeller dimensions. During hydraulic optimization, the processing feasibility was also taken into consideration. Experiments were conducted to validate the above optimization methods. It was proved that the optimized minipump was improved by about 24 % in pressure head and 4.75 % in hydraulic efficiency compared to the original designed prototype. Meanwhile, the sensitivity test was used to analyze the influence of the four impeller dimensions. It was found that the blade outlet angle β2 and the impeller inlet diameter Do significantly influence the pressure head H and the hydraulic efficiency η, respec- tively. Detailed internal flow fields showed that the optimum model can relieve the impeller wake and improve both the pressure distribution and flow orientation.

关键词： Minipump Optimization Back-propagation neural network Non-dominated sorting genetic algorithm-II

A novel hydrodynamic suspension micropump using centrifugal pressurization and the wedge effect

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2023年第7期66卷 2047-2058页

作者： XING GuanYing XUE Song HONG Tao ZUO HuaiYu luo xiaobing School of Energy and Power Engineering Huazhong University of Science and TechnologyWuhan 430074China

The micropump is the heart of microfluidics ***,for mechanical micropumps,bearing wear failure has been a major obstacle to performance and *** suspension,which can make the rotating components levitate in liquid without any mechanical friction,is applied to break this *** this paper,a novel kind of hydrodynamic suspension micropump(HSMP) without a grooved thrust bearing is *** on the centrifugal effect,the HSMP uses a rotating rotor to accelerate and pressurize adjacent fluid,and thus reacting forces are generated on the rotor surfaces to levitate *** mechanisms of suspension forces formation,the centrifugal effect and the wedge effect in the liquid films near the rotor are identified using theoretical analysis and *** variation in suspension forces with rotor position is investigated,revealing that the suspension bearings of the HSMP,similar to a spring damper,can self-adjust suspension forces along with a change in rotor ***,the suspension stiffness is positively correlated with the rotating *** HSMP prototype designed herein,whose overall size is only 34 mm × 34 mm × 31 mm,can provide a maximum output performance of3230 mL/min and 96.3 kPa at 20000 r/min,which is manyfold greater than other *** proposed HSMP is demonstrated to be more powerful with a simple structure,high power density,and high reliability.

关键词： hydrodynamic levitation suspension micropump

Experimental and numerical study on a micro jet cooling solution for high power LEDs

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2007年第4期50卷 478-489页

作者： luo xiaobing LIU Sheng JIANG XiaoPing CHENG Ting School of Energy and Power Engineering Huazhong University of Science&TechnologyWuhan 430074China Wuhan National Lab of Optoelectronics Huazhong University of Science&TechnologyWuhan 430074China Institute of Microsytems Huazhong University of Science&TechnologyWuhan430074China

An active cooling solution based on close-looped micro impinging jet is proposed for high power light emitting diodes (LEDs). In this system, a micro pump is utilized to enable the fluid circulation, impinging jet is used for heat exchange between LED chips and the present system. To check the feasibility of the present cooling system, the preliminary experiments are conducted without the intention of parameter optimization on micro jet device and other system components. The experiment results demonstrate that the present cooling system can achieve good cooling effect. For a 16.4 W input power, the surface temperature of 2 by 2 LED array is just 44.2°C after 10 min operation, much lower than 112.2°C, which is measured without any active cooling techniques at the same input power. Experimental results also show that increase in the flow rate of micro pump will greatly enhance the heat transfer efficiency, however, it will increase power consumption. Therefore, it should have a trade-off between the flow rate and the power consumption. To find a suitable numerical model for next step parameter optimization, numerical simulation on the above experiment system is also conducted in this paper. The comparison between numerical and experiment results is presented. For two by two chip array, when the input power is 4 W, the surface average temperature achieved by a steady numerical simulation is 34°C, which is close to the value of 32.8°C obtained by surface experiment test. The simulation results also demonstrate that the micro jet device in the present cooling system needs parameter optimization.

关键词： high power LEDs closed system micro impinging jets thermal management

Increasing operational stability of journal bearing in hydraulic suspension micro-pump by herringbone grooved structure

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2024年第3期67卷 853-862页

作者： HONG Tao XING GuanYing ZUO HuaiYu XUE Song luo xiaobing State Key Laboratory of Coal Combustion School of Energy and Power EngineeringHuazhong University of Science and TechnologyWuhan 430074China

The operational stability of radial journal bearings is the bottleneck that limits the reliability of hydraulic suspension micropump. Due to self-excited vibrations, the whirl amplitude of the plain journal bearing(PJB) is large at high rotational speeds,which will accelerate wear failure. It has been proven that employing herringbone grooved journal bearing(HGJB) is an effective method to reduce the whirl amplitude and improve operational stability. However, enhancing the stability of journal bearings in micro-pumps by herringbone grooved structures has rarely been studied, and its effect needs to be verified. We validated the mechanism of the stability improvement with the CFD method and compared the dynamic characteristics of HGJB and PJB by rotor dynamics evaluation and experiment. The experimental results show that under the same conditions the whirl amplitude of the HGJB decreases by 29.61% in the x direction and by 24.09% in the y direction compared with that of the PJB. This study reveals the effect of the herringbone grooved structure on the operational stability of bearings and may provide guidance for the reliability improvement of hydraulic suspension micro-pump.

关键词： journal bearing herringbone groove hydrodynamic effect micro-pump

Atom substitution of the solid-state electrolyte Li_(10)GeP_(2)S_(12)for stabilized all-solid-state lithium metal batteries

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第1期88卷 28-38,I0002页

作者： Zijing Wan Xiaozhen Chen Ziqi Zhou Xiaoliang Zhong xiaobing luo Dongwei Xu State Key Laboratory of Coal Combustion School of Energy and Power EngineeringHuazhong University of Science and TechnologyWuhan 430074HubeiChina

Solid-state electrolyte Li_(10)GeP_(2)S_(12)(LGPS)has a high lithium ion conductivity of 12 mS cm^(-1)at room temperature,but its inferior chemical stability against lithium metal anode impedes its practical *** all solutions,Ge atom substitution of the solid-state electrolyte LGPS stands out as the most promising solution to this interface problem.A systematic screening framework for Ge atom substitution including ionic conductivity,thermodynamic stability,electronic and mechanical properties is utilized to solve *** fast screening,an enhanced model Dop Net FC using chemical formulas for the dataset is adopted to predict ionic ***,Li_(10)SrP_(2)S_(12)(LSrPS)is screened out,which has high lithium ion conductivity(12.58 mS cm^(-1)).In addition,an enhanced migration of lithium ion across the LSr PS/Li interface is ***,compared to the LGPS/Li interface,LSrPS/Li interface exhibits a larger Schottky barrier(0.134 eV),smaller electron transfer region(3.103?),and enhanced ability to block additional electrons,all of which contribute to the stabilized *** applied theoretical atom substitution screening framework with the aid of machine learning can be extended to rapid determination of modified specific material schemes.

关键词： Atom substitution Solid-state electrolyte Machine learning Stabilized interface

Spatiotemporal Modulation of Thermal Emission from Thermal-Hysteresis Vanadium Dioxide for Multiplexing Thermotronics Functionalities

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 2021年第12期38卷 21-27页

作者： Guanying Xing Weixian Zhao Run Hu xiaobing luo School of Energy and Power Engineering Huazhong University of Science and TechnologyWuhan 430074China

Taking heat positively as the information carrier,thermotronics can exempt the long-lasting thermal issue of electronics fundamentally,yet has been faced with the challenging multiplexing integration of diverse ***,we demonstrate a spatiotemporal modulation platform to achieve multiplexing thermotronics functionalities based on the thermal-hysteresis vanadium dioxide,including negative-differential thermal emission,thermal diode,thermal memristor,thermal transistor,and *** physics behind the multiplexing thermotronics lies in the thermal hysteresis emission characteristics of the phase-changing vanadium dioxide during the spatiotemporal *** present spatiotemporal modulation is expected to stimulate more exploration on novel functionalities,system integration,and practical applications of thermotronics.

关键词： hysteresis thermal vanadium

Analysis of elliptical thermal cloak based on entropy generation and entransy dissipation approach

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2019年第8期28卷 364-368页

作者： Meng Wang Shiyao Huang Run Hu xiaobing luo China-EU Institute for Clean and Renewable Energy Huazhong University of Science and TechnologyWuhan 430074China School of Energy and Power Engineering Huazhong University of Science and TechnologyWuhan 430074China

In this work,we designed the elliptical thermal cloak based on the transformation *** local entropy generation rate distribution and entransy dissipation rate distribution were obtained,and the total entropy generation and entransy dissipation of different types of elliptical cloaks were *** used entropy generation approach and entransy dissipation approach to evaluate the performance of the thermal cloak,and heat dissipation analysis was carried out for models with different ***,the optimized elliptical thermal cloak with minimum entropy generation and minimum entransy dissipation is found,and some suggestions on optimizing the structure of elliptical thermal cloak were given.

关键词： metamaterials thermal conductivity entropy

FUZZY NEURAL NETWORK FOR MACHINE PARTS RECOGNITION SYSTEM

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2003年第3期16卷 334-336页

作者： luo XiaobinYin GuofuChen KeHu xiaobing luo YangInstitute of CAD&CAM,Sichuan University,Chengdu 610065, China Institute of CAD&CAM Sichuan University Chengdu 610065

The primary purpose is to develop a robust adaptive machine parts recognitionsystem. A fuzzy neural network classifier is proposed for machine parts classifier. It is anefficient modeling method. Through learning, it can approach a random nonlinear function. A fuzzyneural network classifier is presented based on fuzzy mapping model. It is used for machine partsclassification. The experimental system of machine parts classification is introduced. A robustleast square back-propagation (RLSBP) training algorithm which combines robust least square (RLS)with back-propagation (BP) algorithm is put forward. Simulation and experimental results show thatthe learning property of RLSBP is superior to BP.

关键词： Fuzzy neural network Image processing RLSBP algorithm Machine partsclassification

Status and prospects for phosphor-based white LED packaging

在线全文

学校读者我要写书评

暂无评论

Frontiers of Optoelectronics 2009年第2期2卷 119-140页

作者： Zongyuan LIU Sheng LIU Kai WANG xiaobing luo Institute for Microsystems School of Mechanical Science and Engineering Huazhong University of Science and Technology Division of MOEMS Wuhan National Laboratory for Optoelectronics College of Optoelectronic Science and Engineering Huazhong University of Science and Technology School of Energy and Power Engineering Huazhong University of Science and Technology

The status and prospects for high-power,phosphor-based white light-emitting diode(LED) packaging have been presented. A system view for packaging design is proposed to address packaging issues. Four aspects of packaging are reviewed: optical control, thermal management, reliability and cost. Phosphor materials play the most important role in light extraction and color control. The conformal coating method improves the spatial color distribution(SCD) of LEDs. High refractive index(RI) encapsulants with high transmittance and modified surface morphology can enhance light ***-phosphor-based packaging can realize the control of correlated color temperature(CCT) with high color rendering index(CRI). Effective thermal management can dissipate heat rapidly and reduce thermal stress caused by the mismatch of the coefficient of thermal expansion(CTE). Chip-on-board(CoB) technology with a multilayer ceramic substrate is the most promising method for high-power LED packaging. Low junction temperature will improve the reliability and provide longer *** processes, precise fabrication and careful operation are essential for high reliability LEDs. Cost is one of the biggest obstacles for the penetration of white LEDs into the market for general illumination *** production in terms of CoB, system in packaging(SiP), 3D packaging and wafer level packaging(WLP) can reduce the cost significantly, especially when chip cost is lowered by using a large wafer size.

关键词： light-emitting diode (LED) packaging phosphor silicone optical thermal reliability cost