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October 30,2013
Volume 6,Issue 20
Pages -
Subject Area:Combustion

Title: Analysis of material properties in coupling between THEATRe and MELCOR codes

Authors: SHI Xingwei, CAO Xinrong
PP: 1986-1991
Abstract: The adaptability of material properties often has been emerged from coupling procession between codes because of the property application strongly depends on its utilizing range. In order to solve the problem of the mismatch of material properties in coupling between codes, the properties of coolant, heat structures and core components in THEATRe and MELCOR have been analyzed and compared after studying on the code manual references and the codes. The results show that the properties of coolant and all the core components at high-temperature can not be offered for MELCOR in THEATRe. For meeting with the requirement of the simulation on the beyond design basic accident (BDBA) with coupling between codes, the property tables of coolant and core components at high-temperature need be expanded.
Keywords: nuclear safety; THEATRe; MELCOR; coupling between codes; property

Title: Effect of neutronic feedback on flow instability in parallel channels of the reactor core

Authors: LU Xiaodong, WU Yingwei, QIU Suizheng, SU Guanghui, TIAN Wenxi
PP: 1979-1985
Abstract: Based on parallel multi-channels model, a thermal-hydraulic code for flow instability in parallel channels of the reactor core has been developed. A coupling code has been developed by coupling the thermal-hydraulic code with the DONJON 3D neutron kinetic code. The flow instability for the reactor core is performed using the coupling code. The results show that the disturbed channel and undisturbed channel have the same oscillation amplitude of inlet flow rate with neutronic feedback, a phase difference exists between the inlet flow rate oscillation and the power oscillation in one channel. The flow stability of parallel channels of the reactor core can be stablized by neutronic feedback.
Keywords: nuclear power engineering and technology; neutronic feedback; parallel channel; neutronic-thermohydraulic coupling; flow instability

Title: Study on the develop of the high-power micro-arc oxidation power

Authors: YANG Jing, ZHOU Huiling
PP: 1973-1978
Abstract: The output characteristics of the micro-arc oxidation (MAO) power source is an important fact for the properties of the ceramic coating on the aluminum alloys prepared by MAO. The output parameters of the MAO power source, such as frequency, voltage and the duty, should be set for different processing technologies. According to the working principle of MAO, a power source based on field programmable gate array (FPGA), which could be used for MAO was developed, and the frequency, duty cycle and amplitude could be changed in some extent. This power source could be used for studying MAO technology and exploring the optimal process parameters. The experiment with the MAO power for LY12 aluminum alloy worked very well.
Keywords: power electronics; micro-arc oxidation; pulse power; field programmable gate array

Title: The third generation of GIL using the new environmentally friendly insulation gas

Authors: DENG Yunkun, XIAO Dengming
PP: 1968-1972
Abstract: The paper introduces the advantages and development of gas insulated transmission lines (GIL), also studies the electric insulation performance of CF3I. According to the saturated steam pressure curve and van der Waals equation of CF3I, the relationships between liquefaction temperature of the mixture of CF3I and ideal gases and gas mixture proportion and pressure are given. The new environmentally friendly gas CF3I is proposed to be insulating medium used in GIL. The results show that the third generation of GIL using CF3I which has better comprehensive performance is more environmentally friendly than the first and second generation of GIL.
Keywords: high voltage insulation technology; gas insulated transmission lines; CF3I; environment protection

Title: Pyrolysis process and kinetic analysis of MSW in flue gas

Authors: LIU Liansheng, XU Yan, GOU Xiang, DU Cong
PP: 1960-1967
Abstract: Based on the cycle technology of municipal solid waste (MSW) pyrolysis coupling pyrolysis gas combustion, the thermal decomposition processes of Chinese cabbage, orange peel, paper and plastics were investigated using SDT Q600 thermogravimetric-heat flow system under the air, nitrogen and flue gas atmosphere. The reaction kinetics mechanism and pyrolysis kinetic parameters were analyzed using C-R (Coats-Redfern) method. Compared with nitrogen atmosphere, the mass lose rate of MSW could be improved 10% in flue gas, which was caused by the reduction of CO2+C2CO. So the output of CO was enhanced. The carrier gas compositions had no influences on the pyrolysis of cellulose and hemicellulase in biologic garbage, and the pyrolysis process was dominated by F1 mechanism. However, the pyrolysis of lignine and carbon residue was related to carrier gas compositions. In flue gas, the pyrolysis process of lignine and carbon was dominated by D3 mechanism.
Keywords: combustion; municipal solid waste; pyrolysis; flue gas; nitrogen; pyrolysis kinetic analysis

Title: Design and reduction of multi-objective controller for the active suspension

Authors: JIANG Chenglin, ZHENG Ling, LI Yinong
PP: 1953-1959
Abstract: To improve the riding comfort and handling stability performance of vehicle, a multi-objective and mixed H2/generalized H2 output controller is devised for an active suspension system by using seven degree-of-freedom full-car model. Then the optimal Hankel-norm reduction method is utilized for the designed high-order controller. The simulation results demonstrate that the reduced-order controller obtains a better performance of riding comfort while guaranteeing handling stability performance.
Keywords: instrument and meter technology; active suspension; multi-objective output controller; optimal Hankel-norm reduction; controller reduction; simulation

Title: Numerical analysis of mold filling process for extrusion machine beam casting

Authors: SHI Yanguo, LIU Zhenhua, ZHANG Qingling, LI Min, WANG Lujun
PP: 1947-1952
Abstract: In this paper, the extrusion machine front beam casting filling process was analyzed, and a reasonable step gating system was designed. Firstly, according to the shape of the size of the beam casting, a reasonable step gating system was designed. Then, the flow field analysis of the initial process was simulated using the finite element software PROCAST, and the initial process scheme was optimized. At the same time, the flow field of optimized process solutions were simulated. Finally, hydraulics models of the initial process and the optimization process were built, and the two kinds of process of liquid steel flow state were analyzed. The analysis showed that the optimal casting filling process was smooth, and did not produce defects easily.
Keywords: technology and equipment of casting; large steel casting; filling; step gating system

Title: Study on high power pulsed MIG welding inverter power supply

Authors: WU Kaiyuan, LI Huajia, CHENG Jia, HUANG Xi
PP: 1941-1946
Abstract: A novel high power pulsed metal inert-gas (MIG) welding inverter power supply based on digital signal processor (DSP) was introduced in this paper. In order to meet the requirements of the pulsed waveform modulation of pulsed MIG welding, according to the modulation principle of pulse power supply, a pulse width modulation (PWM) waveform which used in full-bridge inverter was produced based on DSP. The proposed pulsed MIG welding inverter power supply was tested on the external characteristics, the dynamic characteristics and high power output. The results indicated that the novel pulsed MIG welding inverter power supply possessed excellent dynamics and static characteristics and reliably high power output performance, which can meet the requirements of pulsed MIG welding well.
Keywords: technology and equipment of jointing; pulsed metal inert-gas welding inverter power supply; high power; digital signal processor control

Title: Study of energy saving control technology on paver engine

Authors: LIU Jie, LIU Zhigang, WU Yongping
PP: 1936-1940
Abstract: Based on the analysis of the property of paver engine, we found that when paver keeping constant traveling velocity, the load change could cause the change of engine power output. If we did not change the throttle opening size, the fuel efficiency would reduce greatly. To solve the above problems, a throttle control system with fuzzy PID control method was proposed. With the help of Matlab, the throttle control system was modeled. Simulation results showed that the system of fuzzy PID control technology could output the required values of the throttle opening, thus reduced the fuel consumption rate.
Keywords: mechanical dynamics and vibration; paver; engine; throttle opening size; fuzzy PID; fuel consumption

Title: Effect of milling cutter s rotational speed on surrounding air flow field

Authors: ZOU Lintao, ZHANG Song, YAN Xufan, MAN Jia
PP: 1931-1935
Abstract: In the present research, the effect of rotational speed on the fluid dynamics of the milling cutter s surrounding air flow filed under minimum quantity lubrication (MQL) cutting condition is carried out by means of computational fluid dynamics (CFD) technology. Firstly, the geometric model for the analysis region is established and the governing equations and boundary conditions of the finite element model are determined. Secondly, the fluid dynamics of the milling cutter s surrounding air flow filed under different rotational speeds are investigated. The analysis results indicate that the milling cutter rotating at high speed can generate a closed ‘ring’ zone surrounding the cutting tool, and the radius of the closed ‘ring’ will increase with the increase of the rotational speed. In addition, the air pressure at the tool/workpiece contact area will increase when the milling cutter rotates at high speed. As a result, the closed ‘ring’ zone surrounding the milling cutter and the increased pressure at the tool/workpiece interface both obstruct the way of the cutting medium towards the cutting zone, and thus weaken the cooling and lubrication effects of the oil-air mixture.
Keywords: technology and equipment of machinery manufacture; computational fluid dynamics; minimum quantity luburication; air field; rotational speed; pressure

Title: Welding technology of CKD9A locomotive bogie frame

Authors: XU Jian
PP: 1926-1930
Abstract: In this paper, the welding technology of CKD9A locomotive bogie frame (including side-beam) exporting to Turkmenistan was analysized. According to the service environment, structure characteristics and material characteristics of the locomotive, the technological parameters of the frame assembly capacity, artificial semi-automatic CO2 welding process parameter and manipulator automatic welding process parameters were initially set. These were validated by actual trial production, which made the model frame production smoothly. Therefore, this research can provide a reference value for other models.
Keywords: mechanical manufacturing and automation; bogie frame; assembling; welding

Title: Modeling and simulation of the feed servo system of blisk grinding and polishing machine tool

Authors: XU Yicheng, ZHANG Lei, LU Lei, ZHANG Fuqing
PP: 1918-1925
Abstract: The mathematical model for the feed servo system of blisk grinding and polishing machine tool was established by using the linearization method. The control system was modeled and simulated by Matlab. The virtual prototype model of the machine tool was also developed. The mechanical system and control system were united by using the ADAMS/Controls module, which realized the mechatronics system united simulation. According to the simulation results, the output response time of the system was not only short and non-overshoot, but with good performance of trajectory tracking as well. And the effectiveness of the mathematical model had been testified by the simulation analysis, which offered a foundation for designing and debugging the feed servo system of machine tool.
Keywords: mechanical manufacturing and automation; feed servo system; Matlab; ADAMS; united simulation

Title: Influence of vibration on machining distortion in high-speed milling aeronautical monolithic components

Authors: SONG Qinghua, AI Xing
PP: 1911-1917
Abstract: Based on the stability lobe diagram of two degrees of freedom (DOF) milling system obtained by using the numerical method, two kinds of cutting conditions (stable and unstable) are selected to perform the cutting tests of aeronautical monolithic components. Cutting distortion and secular distortion are measured and analyzed by using the MISTRAL 775 coordinate measuring machine (CMM), respectively. Influences of chatter on machining distortion are investigated. Machining-induced residual stresses are also simultaneously measured by using the XStress 3000. It is shown that, both cutting distortion and secular distortion are smaller in stable case; in unstable case, cutting distortion is also smaller, while secular distortion is very large, and torsion occurs in the workpiece end with larger box. Machining-induced residual stress is one of the most important factors yielding machining distortion. Therefore, workpieces need to be machined in stable conditions for subsequent assembly tasks, especially aeronautical monolithic components.
Keywords: mechanical manufacturing and automation; high-speed milling; chatter; aeronautical monolithic component; machining distortion

Title: Three-dimensional finite element simulation of cutting temperature during milling of titanium alloy

Authors: YONG Yong, LI Ming
PP: 1901-1910
Abstract: A finite element model of helix double-edge cutting was developed to study the ending milling process of titanium alloy Ti6Al4V. To improve the accuracy of finite element simulation, a new method to construct material constitutive model was adopted, and the adiabatic shear model was also applied. Three-dimensional numerical simulation of cutting temperature was carried out with major and minor cutting edge, and cutting temperature curves during milling process were obtained. The analysis indicated that the highest cutting temperature lied in tool-chip interface and was more close to cutting edge; moreover, the temperature was higher in tool face than tool flank. The semi-artificial thermo-couple cutting temperature experiment was improved by substituting constantan band for constantan wire. With the new cutting temperature experiment, the cutting temperature curves during milling process were obtained. A good agreement between simulation and experimental value was achieved, which proved that the finite element model presented in this paper was correct, and cutting temperature could be predicted by using this model. This work lays the foundation for milling parameter optimization and provides a new way to control machining distortion caused by thermal stress for titanium alloy aviation monolithic component.
Keywords: mechanical manufacturing and automation; titanium alloy; milling process; double-edge cutting; cutting temperature; finite element simulation

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