bluuebunny/crossref_metadata_2025 huggingface dataset:
Manufacture of a Scanning Magnet Power Supply Used in Industrial Radiation Accelerator
Authors: Yu Cheng Da , Li Gang , Li Zhi Qiang , Wang Yong Feng
Published: June 2012

The design of a scanning magnet power-supply used in a 10MeV industrial radiation accelerator is presented in this paper. The consideration of linear magnetic field current and the principle of triangle wave modulator are included. In addition, the control system based on single chip and its anti-jamming scheme in industrial circumstance are also introduced. The scanning magnet power-supply can produce continuous triangle waveform current. The frequency can be adjusted by step length of 1Hz ranged from 20Hz to 50Hz, and the peak-to-peak current is 20A.
The Modeling and Control Study of VSC-MTDC System
Authors: Ye Peng , Yuan Lin , Guan Duo Jiao , Xu Xing Wei , Hou Kai Yuan
Published: June 2012

VSC-Multi-Terminal Direct Current(VSC-MTDC) system is much more controllable and economic. In this paper, the mathematical model for the VSC-MTDC system is set up. Base on this model, the multi-terminal constant DC voltage control scheme with an offset component was developed for MTDC system in the distribute network. Decoupling linear PI controllers are applied for the independent control of active and reactive power. Constant DC and AC voltage controller is implemented respectively for source side and loads side for the high quality power supply. Simulation results show that the control scheme is very effective. With the proposed control strategies, dynamic process of the system can be controlled effectively. What is more, the control law is not complex and it is in the local mode. All of these merits make the control strategy very practical.
On Piezoelectric Harvesting Technology
Authors: Shang Guang Qing , Tao Yi Yi , Li Zhi Rong , Sun Chun Hua
Published: June 2012

In recent years, significant progress has been made with in-deep application of piezoelectric harvesting energy technology. To make the technology development more convenient, a comprehensive review on application of piezoelectric harvesting technology is made in the paper. Piezoelectric harvesting devices as power source from vibration, human motion and so on are expounded. The technology would bring fast increasing in systems of micro wireless sensor, integrated systems and self-power MEMS.
2-Staged Reconstruction Optimization for High Voltage Distribution Network Based PSO Algorithm
Authors: Yuan Gui Hua , Li Lin , Li Jun , Hu Zhi Jian , Li Xiao Bo , Zhang Cheng Xue
Published: June 2012

High voltage distribution network is an important link between transmission and middle voltage distribution network. If a high voltage distribution network fault occurs, the economy and reliability of the whole city distribution system will be seriously affected. To solve this problem, a traditional reconstruction optimization model is improved and a 2-staged reconstruction optimization model is proposed based on an improved particle swarm optimization (PSO) algorithm. The first stage reconstruction only considers the economic goal and the second stage reconstruction needs consider the boundary constrains. The 2-staged method considers the economic benefit and the voltage quality simultaneously. It can achieve the multi goals: meeting actual boundary operation conditions, optimizing the combination of network losses and the number of operation switching. The fault isolation and reconfiguration of an actual distribution network system in Dezhou power grid were simulated. Simulation results validate the rationality and feasibility of the proposed method
Preparation and Properties of Super Insulation Material SiO2 Aerogel
Authors: Ni Xing Yuan , Wang Ji Chao , Liu Guang Wu , Zhang Zhi Hua , Shen Jun , Zhou Bin , Wu Guang Ming
Published: June 2012

Nano-porous monolithic SiO2 aerogel as insulation material was prepared from silicon alkoxide as the precursor materials, followed by ethanol supercritical drying in this paper. In order to improve the mechanical properties of silica aerogel monoliths, the ceramic fibers were mixed in the pure aerogel, or integrating inorganic fiber materials as skeleton materials with low thermal conductivity supporting. Instron 5566, 5500R Material Testing Machine was used to measure the mechanical intensity. SEM was used to characterize the morphology of the silica aerogel monoliths. The thermal properties of the silica aerogels were determined by using the Hot Disk device. The results show that new type composite materials had a low effect on the thermal conductivities of the silica aerogel monoliths, but improved the mechanical intensity clearly. It made a great progress in the practical application of the SiO2 aerogel monoliths.
The Application of High Voltage Variable Frequency Technology in the Induced Draft Fan of Power Plant
Authors: Li Feng Xia
Published: June 2012

This article researches the variable frequency technology of the power plant boiler induced draft fan, and to explain the conversion principle of the high voltage inverter frequency, through the analysis and calculation, it is known that the high voltage inverter power saving rate has reached 60%, and both save energy and reduce the loss.
Calculation of Performance for Brushless Doubly-Fed Machine as Generator Based on Finite-Element Model
Authors: Cheng Yuan , Wang Xue Fan
Published: June 2012

For Brushless Doubly-fed Machine(BDFM), the main feature of field is that there are two kinds of magnetic fields differing in pole number in the machine’s iron circuit and the two fields have the same order of magnitude. Hence, it is difficult to calculate the machine’s performance accurately using conventional analytic method. In this paper, the author constructed one finite-element model of BDFM, and analyzed the machine’s performance using transient solver. The author also compared the finite-element method with experiment and conventional analytic method. Because taking into account the saturation, the results of finite-element method are closer to the measurements than that of conventional analytic method. The validity of model is verified.
Research on the Flow Characteristics of Forced Circulation Evaporative Cooling System of Stator in Turbo-Generator
Authors: Dong Hai Hong , Ruan Lin
Published: June 2012

The forced circulation evaporative cooling system of stator in turbo-generator is a new cooling system under study, with the advantages of high-security, high efficiency and energy-saving. In this paper, an experiment table of this new cooling system with single hollow conductor was established. The flow characteristics of coolant in hollow conductor were analyzed and discussed by theoretical simulating and experimental researching. The results show that with the volume flow of coolant increasing, the variation tendencies of total flow resistance in hollow conductor and Xe are not monotonic and the prediction precision of total flow resistance in hollow conductor is satisfying with maximum relative error less than 10%. The length of subcooled flow boiling region in hollow conductor is relative long and can not be ignored. The conclusions in this paper can provide the theoretical and experimental basis for the further study of this new cooling system.
The Analyse of High-Power Density and High-Efficiency PMSM
Authors: Zhang Bing Yi , Wang Sen , Feng Gui Hong
Published: June 2012

This paper attempts to present an optimal design strategy and characteristics of high-power permanent magnet synchronous motor(PMSM). The structures of rotor lamination, calculation of Air-gap Length, how temperature influences the performance of the motor and the calculation of Xad、Xaq under the equivalent direct axis are presented.
Speed Sensorless Vector Control System of Induction Motor
Authors: Wang Hong Yu , Cai Wen Long , Hou Cheng Wei
Published: June 2012

This paper introduces a vector control system for speed sensorless induction motor drive, which we have recently developed. In the introduce vector control system, one induction motor’s rotor speed estimation method based on model reference adaptive identification theory is proposed. The induction motor speed identification system based on the proposed method can estimate the rotor speed of the induction motor. The speed sensorless vector control system based on proposed method in this paper was built with Simulink blocks in Matlab platform. The simulation results indicate that the proposed method could operate stably in whole range of speed with preferable identification precision of rotor speed.
Research of One-Step Commutation Strategy in Matrix Rectifier
Authors: Liu Xiao , Zhang Qing Fan , Hou Dian Li
Published: June 2012

Due to the absence of natural free-wheeling paths, the commutation in matrix rectifiers is much more complicated than in the other kinds of AC-DC converters. In this paper, based on the measurement of the output current direction and the signs of the input line-to-line voltages, a new one-step commutation strategy is applied in the design of matrix rectifier. Experimental results show that the new method is valid and feasible, founding a basis of further practical application.
Research on Control Scheme of Subspan Oscillation in 6-Bundle Transmission Line
Authors: Liu Long , Cao Zhi Quan , Zhu Kuan Jun , Di Yu Xian , Si Jia Jun , Cao Kai
Published: June 2012

In this paper, penalty function method is applied for the 6-bundle spacer optimal arrangement to inhibit subspan oscillation. Based on the arrangement, 3-bundle spacers are installed in 6-bundle transmission lines. Analysis of aerodynamic variation of conductor and damping effect of the control scheme is conducted by the foundation of finite element model. Besides, assessment is carried out with transmission line on-line monitoring system to prove the efficiency.
TTSP-Based Study on Residual Life Prediction of Shipboard Cable
Authors: Wei Yi , Liu Yan Cheng , Liu Yu Dong , Wang Chuan
Published: June 2012

In this paper, TTSP is used to demonstrate that the aging characteristic quantity at high temperature accords with that at low temperature, and to predict the residual life of shipboard cable. The aging process of cable is described based on second order dynamic model. The method is proved effective by the experimental data, and provides theoretical bases for residual life of cable and cable anti-aging study under the influence of multi-factors.
A Study on Copper Alloy C194 Lead Frame Grain Size Correlation to the Mechanical Properties Variations in Microelectronic Assembly Line
Authors: Amirul Abd Rashid , Mahani Yusoff
Published: June 2012

Copper alloy C194 lead frame occasionally has been observed creates non-sticking defect at wire bond process in typical microelectronic assembly line. The effect was significantly assessed as process variation during die attach. In this study, microstructure and mechanical properties of copper alloy lead frames were investigated. The copper alloy lead frames were selected from different batches in the production line that produced sticking (typical performance) and non-sticking defect. The micro structural and structural properties were investigated by means of optical microscopy (OM) and X-ray diffraction (XRD), respectively. The hardness and tensile strength were also determined. The result revealed that non-sticking lead frame has larger grain size of 43.8 nm than typical performance lead frame. Due to lower dislocation density, tensile strength and hardness of typical lead frame with smaller grain size were higher than that of defect lead frame. Elongation of defect lead frame was reached above 10% as compared to typical performance lead frame groups with the value below 4%.
Experimental Investigation of Electrical Conductivity of Liquid Desiccant Solution
Authors: Cheng Qing , Zhang Xiao Song
Published: June 2012

Liquid desiccant cooling system is a novel air conditioner with good energy saving potential, which should be a promising choice to meet the needs of cooling and moisture loads. Among all regeneration methods, ED regeneration method should be a promising choice for liquid desiccant cooling system. In this paper, systematic experiments were carried out to investigate the electrical conductivity of desiccant solution. Experimental data of electrical conductivity of desiccant solution is acquired in the experiment, which will be greatly helpful to the energy analysis of ED regeneration system. The experimental results show that the energy consumption in the concentrated chambers is more than others for ED regeneration system cells. Moreover, increasing the temperature of desiccant solution may be a measurement to reduce the energy consumption of ED regeneration system.
Research of SVC Control System Based on Real-Time Operation System for Wind Farm
Authors: Liu Jin , Zhong Ze Yu
Published: June 2012

Wind power generation was developed rapidly in China. And many wind farms are configured Dynamic Static Var Compensators (SVCs) as reactive power compensator, which can meet the dynamic demands of the reactive power compensation for the wind farm. The paper put forward a coordination control strategy of reactive power for wind farm based on embedded real-time operation system in DSP, and by using LabVIEW to realize PC management and network communication management, and provides the research foundation for coordination and the optimal control of reactive power in large wind farm.
Research on Power Factor Control Strategy of AC-AC Converter Based on Power Balance
Authors: Xiao Yong Tao , Chen Bao Hua
Published: June 2012

Power balance control strategy is applied to a novel AC-AC converter. The simulated model was established based on the power balance. The paper analyzed the input/output characteristics of AC-AC converter under different power factor. The results show that decoupling the active and reactive current, the power factor can be regulated under power balance control, and it is able to avoid the phase-shifting from the input filter. And in inverter stage, the system applies the complex vector model control to obtain the better dynamic performance and stronger robustness.
Studying the Effects of Adsorption Heat on Nitrogen Adsorption in a Single Pellet
Authors: Liu Xiang Jun , Wang Dan Li , Liu Ying Shu
Published: June 2012

A physical model of a 5A zeolite pellet considering its micro-structure is established. Mathematical models to describe the mass and heat transfer process occurred inside the pellet are proposed. Two adsorption processes, including an isothermal and an adiabatic process are comparatively studied. The N2 adsorption properties on 5A zeolite pellet at different thermal conditions are compared. The effects of adsorption heat on adsorption capacity, adsorption rate and adsorbent equilibrium time are revealed.
Analysis and Controlling Method of Pump Vaporization in Heat Supply Network
Authors: Guo Xiao , Sun Xiao
Published: June 2012

The cavitation in pump is an important factor impacts the operating safety of the pump, and against the cavitation occurrence, this paper chooses the SM253-640 centrifugal water pump as the study object to analysis the reason and the harm caused by cavitation. And this paper showed how to line-pump cavitation, especially, while the flow rate of the medium is very small and the temperature is high. The safety operating interval of the pump was analyzed in this paper, and showed how to avoid the pump cavitation and improve the pump working efficiency, to ensure the safety and economic operation of the heat supply network.Introduction
Application of High Temperature Heat-Pipes Leading Structure on the Capsule Type Re-Entry Vehicle
Authors: Sun Jian , Liu Wei Qiang
Published: June 2012

The leading structure of circumferential embedded high temperature heat-pipes in sidewall is considered as thermal protection system to prevent capsule type re-entry vehicle from the serious aerodynamic heating. It can lighten thermal load of windward and make good use of the endothermic capability of low temperature leeward. By means of fluid structure interaction method, we calculate the temperature distribution of capsule under given conditions and the maximum sidewall temperature decreases by 8.45%. The transfer of heat from windward to leeward is achieved, the windward of the thermal load is weakened and the ability of thermal protection is strengthened. The influence of structure parameters of heat-pipe-cooled capsule, flying attributes and materials attributes of coating to thermal protection effect are discussed in this paper to provide some references for the selection of leading structure and materials.
Experimental Study on the Nozzle of High-Pressure Fog Cooling Systems in Greenhouses
Authors: Zhao De Ling , Shao Xiao Hou
Published: June 2012

This paper describes a designed new nozzle and provides experimental studies on the nozzle used in high-pressure fog cooling system in Greenhouses. Fogging droplet sizes of the nozzle is measured by MPA Malvern Particle Analyzer. The diameter of droplet sizes (VMD, Dv10, Dv50, Dv90) which is 500 mm far from the nozzle is measured and analyzed when the pump pressure is 2, 3, 4, 5, 6,7MPa.The experimental results shows: the nozzle has fine fogging performance, and its droplet sizes (VMD) are small and less than 30 microns when operating pressure is more than 5MPa.
Field Testing of Water Source Heat Pump Systems in Chongqing of China
Authors: Bai Xue Lian , Liu Ning Yi , Cheng Ke Hui , Liu Yi Cheng
Published: June 2012

As an application technology of renewable energy resource, water source heat pump (WSHP) has been paid more attention on. WSHP have been practiced especially for saving building energy consumption in Chongqing of China since there is abound water resources. However, it was found that some systems were not operated very well without achieving expected energy efficiency. Taking three real projects which use WSHP for heating and cooling of buildings in Chongqing city to test in field, key parameters were measured and operation performances were analyzed. The influences of water temperature and partial load ratio on system energy efficiency were studied. Based on existing problems, strategies for improving system energy performance are suggested from aspects of design and operating. Dynamic load hourly simulation plays a key role to determine appropriately the size and the form of system. More efforts have to be put on water pumps arrangement to save energy consumed for water transportation which accounts for large part of system energy. The temperature difference and water quality of water source should be controlled according actual operating conditions. The integrated systems and operation strategies under partial load are also beneficial for efficiency improvement.
Heat Transfer Correlation in Small Channels
Authors: Wei Hui Ming , Zhang Xuan , Liu Tai Li
Published: June 2012

In this study, a study on heat transfer is performed for water upward flow in small channels to provide a systematic database for low pressure and mass flow velocity conditions. An empirical correlation on heat transfer in small channels for predicting the average Nusselt number has been derived by using Genetic Algorithm (GA).
Medium-Sized Ground Source Heat Pump Incubator Design and Research of Condenser
Authors: Lin Jun , Li Shuang , Hu Ying Ning , Liu Jing Sheng , Wu Jie Wen
Published: June 2012

Based on kind of medium-sized ground source heat pump incubator condenser’s design and research, incubator can get good uniformity temperature filed. Incubation experiments showed that the incubator reached the national key performance indicators. Compared with the traditional way of heating incubation, the experiment got a high rate of hatchability and child health. Energy saving effect is remarkable and achieve good social and economic benefits.
Status and Prospect of Large-Scale Circulating Fluidized Bed Boiler
Authors: Ma Da Fu , Hao Xiao Hong
Published: June 2012

The paper is focused on the present situation and the development of large-scale circulating fluidized bed (CFB) boilers. Several developed technology of CFB such as supercritical and ultra supercritical pressure CFB boilers for power plants, oxy-fuel CFB boiler for CO2 capture and high-density circulating fluidized bed gasifier for advanced IGCC/IGFC are introduced in this paper.
Study on Energy Characterization Method of Friction Sensitivity about High-Burning Rate Solid Propellant
Authors: Chu Hua , Huang Ting , Wang Guo Juan , Guo Fei Ge
Published: June 2012

The energy characterization method of friction sensitivity about high-burning rate solid propellant, which identified by 50% explosion probability was studied, and it was verified in the practical application. This method solved the problems about the conventional test methods can not be compared with similar formulations friction degree.
The Design of Thermal Generating Unit Controller Based on New Energy Balance
Authors: Qi Hui , Zhu Long Ji , Yang An , Zang Qiang
Published: June 2012

Firstly, the limitation of using simplified model to design thermal generating unit controller is discussed. For the simplified model, the dynamic of the synchronous generator is neglected, and thus it is not valid in the emergency state of power systems. Secondly, the integral model of thermal generating unit is constructed, which consists of the models of boiler, turbine and synchronous generator. Compared with the simplified model, the integral model can accurately describe the rotor storage characteristic of thermal generating unit. Thirdly, a new energy balance controller is designed based on the constructed integral model. In the new controller the derivative of rotor speed is feed-forwarded, and thus the controller can respond to the energy imbalance more quickly, and the dynamic of steam pressure can be enhanced obviously. Finally, the simulation results also demonstrate the validity of the proposed controller.
Thermal Energy Harvesting From Automotive Waste Heat
Authors: Ismail Meor Mohd Rizal , Wira Jazair Yahya , Abu Aminuddin , Zainul Abidin Mohd Azman
Published: June 2012

The objective of this study was to determine the best method for waste thermal energy recovery from internal combustion engine (ICE). There are several technologies that can be used to accomplish this objective such as turbocharger, combined turbines, Stirling engine, Seebeck effect and Rankine cycle. Two elements that need to be taken into consideration in order to choose the best technology for waste heat recovery system are the complexity of the system and the method to utilize waste heat energy from engine. After a reviewing some of past research work, it was determined that Rankine cycle appears to be one of the best technology to recover waste heat from ICE. Improved design in Rankine cycle configuration and selection of the highest evaporation enthalpy working fluid are said to be necessary. This study finally proposed that future related research should focus on recovering waste heat from the engine waste heat (engine block) only. This is predicted to give an additional power output of approximately 10%.
Thermodynamic Models and its Application for Open Feedwater Heaters under Transient Conditions
Authors: Guo Xi Yan , Li Ai Juan , Xu Hui , Fu Peng
Published: June 2012

The aim of this paper is to find the energy distribution principle of open feedwater heaters under transient conditions. Taking a heater as the example and employing the first and second law of thermodynamics, thermodynamic models for vapor-liquid, mixture-liquid and liquid-liquid heaters were established and applied. And its energy distribution is obtained. The results indicate that that some error occurs when models for steady conditions are used at transient states. And the drain-cooler section has the largest error. The major factor is the exergy stored in exothermic fluid.
Numerical Simulation of Thermal Environment in High Heat Tunnel
Authors: Che Qiang
Published: June 2012

With the increasing depth of coal mining, problems of high temperature thermal damage in mine become more and more serious. A high heat tunnel thermal environment case is numerical simulated in the presented work, PMV (Predicted Mean Vote) indices are using to predict the thermal comfort of environment, velocity field, temperature field and PMV values field in high heat tunnel had been obtained. The simulation results indicated while the inlet air velocity is 0.7 m/s, the temperatures in most tunnel area are below 26 °C and the thermal environment conforms to the Coal Mine Safety Regulation in China.
Study of Forming & Exfoliation Mechanism of Oxide Skin in High-Temperature Tube of Supercritical Boiler
Authors: Cheng Ming Tao
Published: June 2012

In recent years, with the rapid development of supercritical units also brings some serious problems, for example, due to the oxide skin exfoliation of boiler tube caused many boiler tube explosion accidents. Aiming at this problem, the paper first introduced commonly used steel and its resistance to steam oxidation, and then the metal oxide skin formation and exfoliation mechanism is studied. These findings have a certain reference value for the power plant safe and economy operation.
Application of Matrix Analysis in Multiple Index Orthogonal Test Design
Authors: Wei Xiao Ling , Li Xiao Rui , Wang Jie Hua , Chen Zhi Wen
Published: June 2012

In Multiple Index Orthogonal Test Design, the key question is how to determine the influence degree of each test index on the whole test results and according to the influence degree to get test data calculation and eventually gain the optimal plan to achieve the purpose of orthogonal test design. A method of matrix analysis is introduce in this article, with which the weighs of the factors and levels having influences on the tests’ results can be calculated, and then the optimal plan of multiple index orthogonal test and the important order of the factors’ influences on the tests’ index values can be determined according to the weights. Using this method to carry out the test analysis of the passing performance of the swamp bulldozer, the optimal scheme selection problem of Multiple Index Experiment of the Orthogonal Test can be solved, and obtains feasible experimental results .
Application of Similarity Modeling in Failure Prognostic System
Authors: Lv Yu Kun , Chang Shuai , Yang Jiao
Published: June 2012

Based on similarity modeling, the failure prognostic system is rooted in mass of historical data that can provide easy and rapidly implementary and reliable failure prognostic system for power plant .The system can find equipment fault symptom before fault formation, so measures can be taken in advance to avoid the occurrence of failure. In this paper, the similarity theory, modeling and applications of failure prognostic systems are described detially. The prognostic example of a power plant in Shanxi is used to demonstrate that the system can detect abnormal changes of equipment in a timely manner, and the prognostic effect is achieved .
Application of the Wind-Water Combined Slag Coolers in CFB Boilers
Authors: Li Zhi Gang , Chen Jin Li , Li Jing Ji
Published: June 2012

At present, there have been a lot of accidents happened in the wind-water combined slag coolers of the Circulating Fluidized Bed (CFB) boiler power plants, which usually caused the low-load or even stop of the units along with great financial losses. Comprehensively considering the actual conditions of the domestic CFB boiler power plants, the theoretical analysis and thermodynamic calculation were conducted aiming to solve the specific problems found in the operation. There were new designs and retrofitting measures in the integral structure and some key components, such as the slag inlet-tube. The operation effect of the slag coolers, i.e. the stability and heat-recovery efficiency etc., were significantly improved by retrofitting the devices.
CFD Simulation of a SCWO Reactor Containing a Hydrothermal Flame
Authors: Zhou Lu , Wang Shu Zhong , Ma Hong He
Published: June 2012

A supercritical water oxidation (SCWO) reactor containing a hydrothermal flame as heat source is simulated by computational fuild dynamics (CFD) simulation. Methanol solution and oxygen are fed separately into the reactor as fuel and oxidizer, and at the same time the cold waste water is also fed into the reactor. The combustion of methanol is simulated by the eddy dissipation concept (EDC) model with an Arrhenius law kinetic. This simulation is conducted to study the behavior of the hydrothermal flame at different inlet fuel temperatures and the relationship between the ignition temperature and methanol mass fraction.
Numerical Investigation on Primary Atomization of the Fuel Spray in Diesel Engines
Authors: He Zhi Xia , Tian Li Li , Liu Ju Yan
Published: June 2012

In addition to the aerodynamic effects, turbulence and cavitation play an important role on the primary atomization. Different spray breakup models were analysized and evaluated though simulation of spray with them and then a new model of coupling the nozzle cavitating and turbulence flow to the spray primary breakup was put forward. The numerical simulation results with all these different spray primary breakup models were comparied with the experimental data and then the new model were proved to be much better. The study may effectively help establish the accurate spray breakup model.
Study on Control System of Turbine Speed of 600MW Ultra-Supercritical Unit
Authors: Ding Da Ye , Yu Shao Juan , Li Chen
Published: June 2012

The development of ultra-supercritical units is feasible choice of energy utilization ratio in China, its stability and economy rely on control system of turbine mightily. The control system of 600MW turbine is widely used currently, according to the non-linear time-varying excitation control system of turbine speed, the speed of turbine is employed as the feedback variable, a controller combined with a PID feedback loop control system is designed, analyzed and studied respectively from theory and emulation. The simulation results shows that PID feedback control has good effects in inhibiting interference andstabilizing system. Put forward strategy that can control the speed of turbine on this basis in order to achieve the goal of turbine’s fast tracking and stability control.
Study on Optimal Load for Hydraulic Control System of Continuously Variable Transmission
Authors: Kuo Kei Lin
Published: June 2012

In recent years, the main research focus for vehicle transmission systems has been the development of the Continuously Variable Transmission (CVT). CVTs can provide passengers with greater comfort, reduce energy consumption, and offer better transmission efficiency. CVT systems achieve the desired gear ratio by adjusting the hydraulic pressure on the rear and front pulleys using a solenoid valve. Our study aims to increase the efficiency of an existing CVT system, without reducing its performance. In this study have modified the CVT so that we can independently control the external and internal axes electronically. The speed of the hydraulic pump in the gearbox is not affected by the engine speed. In this way, In this study can achieve the lowest possible hydraulic pressure. In our study, In this study use the visual programming language LabVIEW as the human-machine interface for the monitoring program. In addition, a data acquisition system is used to collect experimental parameters, record data in real time, and perform data consolidation. Our system uses varying loads in order to evaluate the improvement in transmission efficiency over many operating conditions. Through the use of solenoids valves acting together, the pipeline hydraulic pressure can be varied. The widths of the front and rear pulleys are thus changed to achieve the goal of continuous variation. Under different loads, the relationships between the measured efficiency and the hydraulic pressure on the rear and front pulleys are used to verify and confirm the increase in efficiency achieved by controlling the hydraulic pressure.
The Simulation Study on the Combustion Characters of Cold Starting in a Common Rail Diesel Engine
Authors: Zheng Qing Ping , Zhang Jie Zhong , Li Bo
Published: June 2012

The simulation results shows that pilot injection, intake preheating, main injection advance angle have a big impact on ignition performance of diesel engine. After using pilot injection, the average cylinder pressure and temperature, and the accumulated heat release increased, ultimately the fuel efficiency had been improved. By using the intake preheating, combustion efficiency had been improved for combustible mixture gas formed easily and combustion conditions significantly improved in cylinder. Besides, an appropriate main injection advance angle could improve the combustion of ignition delay period and increased the engine power and fuel efficiency.
Experimental Investigation on Stall Separation Control on NACA0015 Airfoil by Steady Plasma Aerodynamic Actuation
Authors: Sun Min , Yang Bo , Li Jian Min , Lei Ming Kai
Published: June 2012

Experimental investigation was performed to study the influence law of the free-stream speed, angle of attack and actuation voltage on the control effectiveness of NACA0015 airfoil stall separation suppression by steady plasma aerodynamic actuation. It is found that plasma actuation can effectively suppress flow separation on the airfoil at free-stream speeds in the range from 20 m/s up to 65 m/s. When the speed is 25m/s, the stall angle will be delayed by 3°, lift coefficient will increase and drag coefficient will decrease by 10.4% and 28.9% respectively. Moreover, Experimental results indicate that the threshold voltage increases with the increasing free-stream speed and attack angle. Meanwhile, both of smoke flow visualization and flow control experiments were carried out, conclusions show that the direction of induce flow has little effect on plasma flow control effectiveness, which means that momentum transferring is not the basic cause of active flow control of plasma aerodynamic actuation.
Application of New Type Gas-Solid Two Phase Flow Pipeline Average Velocity Measurement System
Authors: Sun Bao Min , Zhao Yong Gang , Liu Zhi Qiang , Zhu Ye Wei , Zhao Zhi Yong , Gao Jun , Liu Xiao Xia
Published: June 2012

In order to measure average velocity of Gas-Solid Two Phase Flow in pipelines real time and accurate, to develop the gas-solid two-phase flow average velocity meter based on direct measurement method and the secondary system. The paper introduces the working principle of the system and analyzes the factors that affect the accurate measurement. To further study the performance and continuous improve its structural design, an aerodynamic testing system was established. The device performance tests were carried out. In addition, the cold and hot industrials test were carried out in the industrial field.Practical application and test results showed that the device performance is well to achieve the industrial pipeline gas-solid two-phase flow average velocity long-term, stable and accurate measurement, and measurement error <2%.It has many features: simple structure, reliability, small flow resistance, easy installation, low maintenance costs, long life, a short straight pipe required. It can measure the gas-solid two-phase flow average velocity with high or low concentrations, and suitable for round, rectangular cross-section pipe installation. The measuring device has been used in dozens of power plant boiler, and a national invention patent and significant economic and social benefits to be achieved.
The Analysis and Implementation of the Double-Line Maximum Power Point Tracking Method
Authors: Cheng Zhao Liang , Liu Shu Qin , Yu Wen Tao , Weng He Zhang , Zhang Wen Shan
Published: June 2012

First this paper analyzes the model structure and the output characteristics of the photovoltaic (PV) module, and then we get the output characteristic curve using the parameter sheet. In this paper a simple, quick, and low cost Double-line MPPT ( maximum power point tracking) method and an simple temperature compensation method are proposed after analyzing and comparing the cell’s output features in terms of irradiance and temperature environment changes .The detailed process of the theoretical derivation and the simulation in MATLAB are provided. At last, the paper introduces the control strategy of the Double-line MPPT method. We conclude that Double-line MPPT method is Low-Complexity, easier to realize , faster without oscillation compared with other methods ,it can be used in low power PV system.
The Temporal Evolution of Particle Population Involving Simultaneous Coagulation, Diffusion Deposition, Gravity Sedimentation and Ventilation in the Fixed Space
Authors: Fu Juan , Ning Zhi , Song Yun Chao , Lv Ming
Published: June 2012

The dynamic behavior of small particles in fixed spaces is of interest in various fields of science and engineering. In the paper, a population balance equation for particles in fixed space is established to describe the dynamic behavior of system involving simultaneous coagulation, diffusion deposition, gravity sedimentation and ventilation. Related Parameters are decided by experiments for the convenience of achieving numerical solution of the equation. Finally, the temporal evolution of particles population in fixed space is simulated and discussed under different conditions.
Transient Analysis of Supercritical Water-Cooled Reactor with Main Feed-Water Parameter Changing
Authors: Chen Juan , Zhou Tao , Luo Feng , Wang Han Ding
Published: June 2012

Based on a transient analysis code that developed with coupled neutron and thermal hydraulic calculation model for supercritical water reactor, the transient characteristics under feed-water parameter changing is detailed analyzed, including temperature decreasing, flow-rate decreasing and pressure increasing. The results show that, if no control system action given, flow rate or temperature decreasing would lead to the increase of main steam temperature and decrease of core power, but pressure increasing shows a little influence. If control systems are put into operation, transient characteristics will be obviously changed but finally recovered to normal level. As the same changing percentage 3% is selected, main steam temperature during pressure decreasing transient can reach its highest level in 510.9°C, and return to normal at the time of 90s. But for feed-water temperature decreasing transient, main steam temperature shows an obvious fluctuation during its adjustment and returns to normal until 170s from 503°C. In addition, compared with the results calculated by non-coupling calculation model, main steam temperature calculated by above coupling model shows a smaller deviation but a little longer time needed for returning to its normal value.
A Design of Online Leak Sealing Clamp for the Flange with Defects
Authors: Yang Xiao Hui , Tai Jian Xin , Lv Rui Dian , San Lai Min
Published: June 2012

The injecting online leak sealing technology is an emergency repair technique widely applied in process industry, which can remove the leakages of the devices, flanges, pipes and valves, with safe, reliable, economic and efficient. In a variety of online leak sealing operations, the work to handle flange leakages accounts for about 90% of the entire workload. This is because most of flanges in actual production have the installing and machining defects, such as uneven clearance, eccentric, reducing, etc. Aimed at those flanges with defects, to ensure the seal effect, the online leak sealing clamp must be machined and installed precisely, which will increase the difficulty of operation. Thus, on the basis of comparing advantages and disadvantages of the existing enhanced seal clamps, a new design has proposed to solve the problem of flange leakage, especially for the flange with defects, which can reduce the difficulties of operation while ensuring the sealing effect.
Analysis of the Evaporating Characteristics of the Grooved Micro Heat Pipe with Alkali Metals as Working Fluid
Authors: Yu Lei , Liu Wei Qiang
Published: June 2012

This paper has built a mathematical model for the evaporating characteristics of the grooved micro heat pipe’s thin film region and computed them in a specific working condition. The evaporating model of Wayner was employed in this mathematical model. The results from computation showed, for the H2O and NH3 as working fluid, at the beginning of the thin film region, the heat flux raised rapidly to a peak value and then declined to almost 0 also rapidly in a very short distance. Differently, for the Na and K as working fluid, the heat flux raised quickly but declined slower. Therefore, the alkali metals working fluids had larger area of high heat flux covered. The results indicated that the alkali metals working fluid has better evaporating characteristics for the high-temperature heat pipe than normal working fluids.
A Zero-Dimensional Model to Predict the Performance of the Claw Type Vacuum Pump
Authors: Lu Jau Huai , Chen Hsueh Hsuan , Hsu Tsang Lin , Guo Ci Liang , Yeh Jung Feng
Published: June 2012

A new type of mechanical vacuum pump is introduced in this paper. It is composed of two conjugated rotors spinning in opposite directions. The shape of rotor looks like a claw, and it is called a claw vacuum pump. A zero dimensional model was used in this paper to analyze the performance of this vacuum pump. The whole system was decomposed into five subsystems. Each subsystem has its own values in temperature, pressure and mass. The pressure variations and the temperature variations as well as the work required to complete the whole cycle were calculated with this model. It was found that the major leakage route is from exit port to chamber. The averaged outlet temperature may reach 483K. However, inner leakage may ease the problem of high temperature flow.
Impact Of Diffuser Width On The Performance Of AP1000 Reactor Coolant Pump
Authors: Yuan Dan Qing , Yan Hua , Wang Pei Pei
Published: June 2012

For the problem of incapable to determine the width of spherical diffuser, four groups of spherial diffusers with different width were designed by using the speed coefficient method. Numerical investigation of internal flow in the nuclear coolant pumps with these diffusers was made based on ANSYS-CFX software. Aimed at the efficiency, ditribution of pressure and velocity vector on the meridian plane of each volute scheme was analysised emphatically. By comparing the performance curves of the coolant pumps predicted by the numerical simulation, we can draw that the head and efficiency of pump decreased as the increasing of diffuser width and performanced worst at the width of d=1.7R, then the performance no longer changes when diffuser width continue to reduce.
Numerical Simulation of Crossing Shock Waveturbulent Boundary Layer Interaction
Authors: Kong Wei Xuan , Zeng Peng , Yan Chao , Zhao Rui
Published: June 2012

Numerical simulations have been captured for 3-D crossing shock wave/turbulent boundary layer interactions generated by 15-deg sharp fins mounted symmetrically on a flat plate at mach8.3. The full Reynolds-averaged Navier-Stokes equations are solved with high-resolution implicit finite-volume scheme. Turbulence closure is achieved with Spalart-Allmaras(SA), Wilcox’ k-ω and Menter’s Shear Stress Transport (SST) models. Complex crossing shock wave interactions, flowfield structures including the boundary-layer separation, centerline vortex, vortex interaction and entrainment flow have been revealed. Comparisons for profiles of the velocity vector, pressure and heat transfer distribution have been observed between calculated results and experimental measurements. Behavior of turbulence models in the complex flow have been pointed out. SST shows better performance in calculating the pressure and the velocity vector and all turbulence models over-predicted heat transfer coefficient.
Study on a Special Association Polymer Gel Applied in Vicious Lost Circulation in Crushed Zones
Authors: Wang Ping Quan , Nie Xun Yong , Zhang Xin Min , Luo Ping Ya , Bai Yang
Published: June 2012

Vicious or severe loss mainly refers to total or complete lost circulation which occurs in fractured or cavity formation and requires repeated particulate materials or cementing slurry sealing，which is a major technical problem accompanied by drilling engineering. The special gel is an association polymer with good rheology property designed to cure severe lost circulation, which can form a type of reversible supramolecular structure(dynamic physical molecular network, rather than chemical cross-linking) by the intermolecular force of supramolecular. The gel has good shear-thinning property which can provide the gel be pumped and flow in pipes easily and flow with high viscosity and resistance in the zone porous. And the gel has visible viscoelasticity that the gel have high displacement efficiency to cut off the connection between the formation fluid and the drilling fluid in borehole. And the gel is hard to be diluted by formation fluids for its apparent viscosity and strong cohesive force. Therefore, the gel is potential to control severe lost circulation accompanying with water zones or overflow and loss coexist. In field application, the gel was successful to deal with several severe loss complexities in Sichuan and Changqin oil fields in China.
Selection of Cd-Excluder Rice in Shenyang Region of China for Food Safety
Authors: Zhan Jie , Wei Shu He , Niu Rong Cheng
Published: June 2012

It is one of very important technologies of phytoremediation using low accumulative plant especially excluder crop to safely product food in contaminated soil. In order to identify some excluder crop cultivars, a pot experiment was conducted to compare Cd accumulation differences among of 26 normal and 4 hybrid rice cultivars (Japonica) in Shenyang region of China for food safety aim. The results showed that only Cd concentration in brown rice of Shendao 4 among of 30 rice cultivars was lower than 0.2 mg kg-1 (agricultural trade standard of non-pollution food for rice of China, NY 5115-2008) at a lower level of Cd exposure spiked at 2.5 mg kg-1. When soil Cd spiked at 5 mg kg-1, Cd concentration in brown rice of Shendao 4 was lower either compared to other cultivars, and its enrichment factors (EFs) and translocation factors (TFs) were lower than 1.0 and 0.5, respectively. Furthermore, the yields of grains and the biomasses of aboveground of Shendao 4 didn’t decrease significantly compared to the control (p<0.05), indicating it was a Cd-excluder cultivar. This is a new and important found in Northeast China rice production and may have an important interest in exploring crop exclusion mechanism.
A Preliminary Study on the Warning Appraisal of Eco-Environment in the Wujiang Valley
Authors: Su Wei Ci , Yi Wu Ying
Published: June 2012

In this paper, the principles and standards of eco-environmental warning assessment were discussed, and the warning types of eco-environment were also stated, meanwhile, the indexes and models of eco-environmental warning appraisal were established. Finally the eco-environmental warning assessment results of 39 countries (or cities, district, special district) in Wujiang River watersheds were showed in this paper. By means of the Delphi, build judgment matrix.，work out the largest eigenvalves and eigenvectors by product method, determinate the weight and calculate out the quality scores of each evaluation index and ecological environment system. The results showed: the change speed and change trend among different counties at different stages showed relatively large difference. The eco-environmental quality of Anshun, Pingba, Longli, Guiding and Shibing county was much better and more stable than other counties. It will be based for the development and harness of Wujiang valley.