Volume 36,Issue 7,2013 Table of Contents

1 Analysis on the export characteristics and internal flow of circumferential micro-turbines

TANG Gangzhi , ZHANG Li , DU Baocheng , LIAO Zhaobang

2013, 36(7):1-5. DOI: 10.11835/j.issn.1000-582X.2013.07.001

[Abstract](1944) [HTML](387) [PDF 5.17 M](1326)

Abstract:
Circumferential micro-turbine adapts to miniaturization as it has simple structure. To evaluate and improve the six-blade micro-turbine structure and analyze the influence of tip clearance on the flow, To simulate the output characteristics and gas flow characteristics, a three-dimensional transient numerical simulation model is set up and the output characteristics and gas flow characteristics are simulated. Results show that the six-blade turbine has structural defect. Parts of gas directly exhaust without working because intake port and exhaust have periodic connectivity while running. Simulation results for the improved eight-blade micro-turbine reveal that it hasnt such defects. Then, the effect to pressure drop of tip gap is simulated, and results show that the influence is nonlinear. As the gap is less than 0.01, the pressure drop is very sensitive to the gap. When gap is greater than 0.02, its impact is very small. Simulation and experimental results both show that the output mechanical power of the eight-blade turbine and six-blade turbine increases with the increase of gas flow. The eight-blade turbine mechanical power is 1 355 mW, which is increased 10.5% over the six-blade turbine. The power output start flow of eight-blade turbine is 140 L/h, while that of six-blade turbine is 200L/h. The performance of eight-blade turbine is better than that of six-blade turbine.

2 Study on the effect of cavitation on tribological performances of sliding bearing by CFD Method

MENG Fanming , LONG Tao , GAO Guixiang , CHEN Zhiwei

2013, 36(7):6-11. DOI: 10.11835/j.issn.1000-582X.2013.07.002

[Abstract](1977) [HTML](391) [PDF 6.73 M](1642)

Abstract:
Much attention has been paid to the influence of cavitation on the performance of a sliding bearing, but conventional analysis methods can not exactly describe the influence. Therefore, a reasonable cavitation method is desired, with which tribological performances of the bearing can be improved. Based on the computational fluid dynamics(CFD）and Rayleigh-Plesset(PRE）model, the influence of cavitation is studied by the commercial software CFX module. The numerical results show that both the friction force and the friction coefficient decrease, compared with the corresponding results without the consideration of cavitation effect, which is caused by the reduce in the lubricant viscosity due to the cavitation effect. With the increases in the eccentricity ratio, width diameter ratio and rotating speed, the mean vaporization ratio becomes severer.

3 Adaptive clonal competition algorithm and its application in automatic electroplating production line scheduling

WANG Shilong , LENG Linxia , ZHOU Jie , ZHU Zheqi , LI Shilong

2013, 36(7):12-15. DOI: 10.11835/j.issn.1000-582X.2013.07.003

[Abstract](1947) [HTML](409) [PDF 4.96 M](1477)

Abstract:
Aiming at small batch and multi-type electroplating production scheduling system with flexible process, an adaptive clonal competition algorithm(ACCA）is proposed. The capability of searching the global optimal value and the local optimal value of the new algorithm can be adjusted through the function between the cloning and mutation probability and the number of iterations. Besides, the population diversity of the adaptive clonal competition algorithm can be ensured through the competition mechanism, the elite migration mechanism and the raising new members mechanism. Compared with traditional clonal selection algorithm, adaptive clonal competition algorithm has higher searching ability and faster convergence speed.

4 Numerical calculation and experimental study of mass transfer coefficient of CO2 in circulating water system

YE Chunsong , ZHOU Wei , ZHANG Xian , ZHANG Huiqin , YANG Fan , YANG Hong

2013, 36(7):16-20. DOI: 10.11835/j.issn.1000-582X.2013.07.004

[Abstract](1964) [HTML](290) [PDF 5.19 M](1424)

Abstract:
To moniter the operation condition of circulating water system and realize real-time prediction of the pH variation of circulating cooling water, a mathematic model of pH variation tendency is set up and the mass transfer coefficientof gaseous CO2 is calculated. Then the validity of the model is verified by quasi-dynamic simulation experiment. Results illustrate that circulating water can achieve the gas-liquid equilibrium state after it fully contacts with gaseous CO2 in atmosphere, and the maximum error limit between the theoretical and the measured pH value is only 0.04. The pH variation tendency of quasi-dynamic system is in line with the predicting mathematic model and the A·KG is a constant when temperature(T）and spray flow(Q）are fixed. 10 5·A·KG=0.023 6Q－0.02 gives the relationship between A·KG and Q, when T is 40 ℃.

5 Fault diagnosis of rotating machinery based on SVM 2PTMC

ZHU Xincai , DENG Xing , ZHOU Xiong , HU Tengfei , GUO Lei

2013, 36(7):21-26. DOI: 10.11835/j.issn.1000-582X.2013.07.005

[Abstract](1851) [HTML](333) [PDF 6.07 M](1720)

Abstract:
A method is proposed to determine the priority class of binary tree SVM. Firstly, the vibration signals of rotating machinery are colleted through a rotating machinery fault experimental platform and data acquisition system. The signals are from 5 different conditions, i.e. rotor normal, rotor unbalance, rotor misalignment, rotor bearing inner ring cracks and rotor bearing outer ring cracks. Then the signals are disposed by zero-mean and the main frequency band of the vibration signals are reconstructed to, extract the dimensionless time domain as characteristic value. Finally, the priority class of SVM 2PTMC can be determined by the correct inspection rate of parallel SVM. Training samples can be completely divided in experiments, which verifies the effectiveness of this method.

6 Characteristic analysis of complex network for customer collaborative innovation network

LI Fei , YANG Yu , XIE Jianzhong , ZHANG Feng , BAO Beifang

2013, 36(7):27-31. DOI: 10.11835/j.issn.1000-582X.2013.07.006

[Abstract](1932) [HTML](653) [PDF 4.80 M](1426)

Abstract:
Customer collaborative product innovation system is a complex collaborative knowledge work network system with multi-agent involved. Aiming at complex characteristics of customer collaborative innovation process, customer collaborative innovation networks(CCIN）is defined, CCIN topology model is proposed and important parameters of CCIN are calculated. In addition, the network structure and characteristics are analyzed. The results show that CCIN has the characteristics of scale-free and small world. The research results provide theoretical basis for the research on mechanisms of knowledge dissemination among agents and dynamical characteristics of network transmission.

7 Analysis and synthesis of time-dependent reliability for integrated steering mechanisms

QIN Fujun , ZHANG Junfu , LONG Jin

2013, 36(7):32-39. DOI: 10.11835/j.issn.1000-582X.2013.07.007

[Abstract](1610) [HTML](364) [PDF 7.49 M](1430)

Abstract:
The steering performance of vehicle is directly affected by the kinematic accuracy of steering trapezoid mechanisms. Considering uncertainties that exist in steering mechanisms, the theory of kinematic time-dependent reliability is adopted to study the analysis and synthesis of the integrated mechanisms. A new method for high accuracy actual steering mechanisms design with the uncertainties is presented. Probabilistic model of kinematic error with dimension random variable is established, and analytical models of up-crossing rate and down-crossing rate for solving the time-dependent reliability of steering mechanisms are derived. A determination model and reliability model for mechanisms synthesis are built, and a numerical example are given to verify the effectively and robustness of time-dependent reliability synthesis method.

8 Design and manufacturing integration support system for sheet metal processing shop of electrical equipment

YIN Chao , JIN Huaijian , LIU Fei

2013, 36(7):40-46. DOI: 10.11835/j.issn.1000-582X.2013.07.008

[Abstract](1880) [HTML](338) [PDF 9.80 M](1232)

Abstract:
Under the mode of customization-oriented multi-varieties and small-batch production, the requirement of design and manufacturing integration exists in sheet metal processing shops, which has the characteristics of great varieties of sheet metals, huge design data and heavy production tasks. To meet the requirement, an integrated operation mode for sheet metal processing shop of electrical equipment is presented. The mode realizes the information sharing and business collaboration from the sheet metal 3D CAD, 2D outspread, process design, optimal sheet metal layout, NC programming to NC machining. The integration framework based on service oriented architecture(SOA), function structure and operation process of the system is constructed. The system has been applied to an electrical equipment manufacturer in Chongqing, and good results are obtained.

9 Preparation of a dicyandiamide-contained novel insulation paper and an experiment on the thermal aging characteristics of relevant oil-paper insulations

LIAO Ruijin , ZHANG Fuzhou , YUAN Yuan , ZHANG Shuang , BAI Ge , LIU Tuan

2013, 36(7):47-51. DOI: 10.11835/j.issn.1000-582X.2013.07.009

[Abstract](2181) [HTML](444) [PDF 4.69 M](1870)

Abstract:
In order to study the influence of dicyandiamide added into the insulation paper on the oil-paper insulation during the aging process.The insulation paper containing dicyandiamide and the insulation paper without any stabilizer are prepared. They are immersed in transformer oil separately and placed in the aging chamber with predefined temperature of 130℃ for 31 days to perform thermal aging experiment of oil-paper insulation. The specimens are periodically sampled and some parameters are measured like the degree of polymerization(DP), the breakdown voltage, the nitrogen content, the acidity of insulation oil, and UV-Vis spectrum. The results show that the insulation paper added with dicyandiamide has a distinct anti-aging and anti-breakdown effect and the DP is 58% higher than that of blank sample at the later stage of aging. In the aging process, decline of the nitrogen content of insulation paper is not serious. The oil-paper sample containing dicyandiamide has a far lower value of acidity than that of blank sample, besides the oil color is deeper. Dicyandiamide in the insulation paper improves not only the anti-aging and anti-breakdown properties, but also the performance of oil in the aging process.

10 The progress and trend of research on bifurcation and chaos in H-bridge converter

GUO Ke , ZHOU Lin , LONG Yanping

2013, 36(7):52-60. DOI: 10.11835/j.issn.1000-582X.2013.07.010

[Abstract](2165) [HTML](442) [PDF 8.52 M](1460)

Abstract:
The research actuality of the bifurcation and chaos phenomena in the H-bridge converter is summarized. Two discrete models of the typical H-bridge converter are introduced in detail, and their applicability is also analyzed and assessed. The existing stability analysis approaches and the numerical simulation methods used in the nonlinear study of H-bridge converter are analyzed concretely, and the merits and demerits are also summarized. With the method of Lyapunov exponent, those two discrete models are verified, and the difference between them, which are changeable according to the switching frequency, is analyzed and explained in detail. The application of time-delayed feedback control(TDFC）method and extended time-delayed feedback control method(ETDFC), which are used to control the chaos in H-bridge converter, is introduced, and their superiorities and deficiencies are evaluated. Finally, several future researches on the bifurcation and chaos phenomena of H-bridge converter are proposed, which provides some instructions for follow-up study.

11 Three-dimensional reconstruction of electrical impedance tomography based on corresponding points matching interpolation

HE Wei , NIU Fuli , LI Bing , XU Zheng

2013, 36(7):61-65. DOI: 10.11835/j.issn.1000-582X.2013.07.011

[Abstract](2214) [HTML](319) [PDF 4.79 M](1499)

Abstract:
An interpolation algorithm with corresponding point matching is presented for interpolating two-dimensional reconstructed images of electrical impedance tomography(EIT）to realize three-dimensional reconstruction. The calculation methods of the gradient and its orientation angle have been adjusted according to the characteristic of the EIT data, and the interpolated slice shows good quality. The experimental model is a 2.1 S/m cylinder agar block immersed in a cylindrical water tank. The comparisons of the presented algorithm to the linear interpolation and the shape-based interpolation are made. The results show that corresponding point matching algorithm can ensure both accuracy and computational efficiency, thus the algorithm satisfies the requirements of the real-time EIT monitoring.

12 Dynamic behavior of 500 kV metal oxide arresters with a new type of lead dampers

ZHANG Xuesong , DAI Zebing , CAO Meigen , LU Zhicheng

2013, 36(7):66-73. DOI: 10.11835/j.issn.1000-582X.2013.07.012

[Abstract](2644) [HTML](337) [PDF 8.72 M](1508)

Abstract:
In order to find out dynamic behaviors of the 500 kV zinc oxide arresters with and without a new type of lead damper, the dynamic behavior experiment and finite element analysis are carried out by means of single point input and single point output(SISO）measurement. The results of dynamic behavior experiment show that the primary frequencies of these two structures are between 1 Hz and 10 Hz and the difference between these two primary frequencies is not obvious, indicating that the overall stiffness of the two structures is low. The frequency of these two structures has hardly changed by the lead dampers, but the damping ratio of the arresters with the dampers is increased nearly 3 times, thus the fashion of vibration-reduction control of the dampers is to provide additional damping to the equipments. Owning to increment of damping device with the new type of lead dampers, there is an above reduction of 46% in the maximum stress of bottom porcelain pipe and the new type lead dampers can also decrease the relative displacement at the top of bushing. The results of finite element analysis show that the level modes of the 500 kV zinc oxide arresters with and without the new type of lead dampers are main modes and the vertical modes and torsional modes are not obvious.

13 Technology and performance of stearic acid SAMs on pure magnesium

QIAO Liying , GAO Jiacheng , WANG Yong , XIE Fengyu , HU De

2013, 36(7):74-78. DOI: 10.11835/j.issn.1000-582X.2013.07.013

[Abstract](2081) [HTML](411) [PDF 4.87 M](1089)

Abstract:
The surface-treatment of self-assembled monolayer(SAMs）of stearic acid on pure magnesium is studied to improve the bioactivity and corrosion resistance of pure Mg. Three pre-treatment methods(HCl-NaOH treatment, alkali-heat treatment and heat treatment）are used before SAMs treatment is carried out in stearic acid. The orthogonal test is performed to select the best pre-treatment method, concentration of solution and soaking time. The electrochemical properties of samples with different pre-treatment are tested. The water contact angles of samples with and without SAMs treatment are studied. Samples are also immersed in simulated body fluid(SBF), the pH varieties of the solution and the concentration of Mg ion in SBF is tested to evaluate the corrosion resistance of SAMs, and surface morphology and composition analysis of samples are characterized by the scanning electron microscope with energy dispersive spectrometer(SEM-EDS). The results show that the sample with heat pre-treatment soaked into 0.5 mol/L stearic acid/ethanol solution for 1.5 hours has the best corrosion resistance. SAMs change the hydrophilic nature of samples and the contact angle with water significantly increases. Also SAMs decrease the corrosion rate of magnesium and samples with SAMs show better bioactivity than untreated magnesium.

14 Effects of Cu content on the microstructure and mechanical properties of AZ61 alloy

ZHANG Dingfei , DAUN Zuoheng , ZHANG Hongju , QI Fugang

2013, 36(7):79-84. DOI: 10.11835/j.issn.1000-582X.2013.07.014

[Abstract](2177) [HTML](448) [PDF 7.13 M](1377)

Abstract:
Microstructures and mechanical properties of AZ61 with Cu addition are investigated by optical microscope（OM），X-ray diffraction analysis（XRD），differential thermal analysis（DSC），scanning electron microscopy(SEM) and energy spectrum analysis（EDS）.The results show that some ternary AlCuMg phases are observed along the grain boundaries and between dendrites in AZ61-xCu alloys, and they can refine the microstructure of as-cast alloys. Meanwhile, with the addition of Cu，the quantity and the size of β-Mg17Al12 decrease. As Cu content increasing, the strength of as-extruded alloys increase first and then decrease.The elongation has no obvious decrease until Cu content reaches 1.5%. AZ61-1Cu alloy has optimum combination mechanical properties,with σ0.2=230 MPa,σb=321 MPa and δ=9.7%,respectively.When Cu content is 1.5%, the coarse AlCuMg phase splits the matrix and deteriorates mechanical properties.

15 Control model for secondary cooling of continuous casting based on compensation temperature of the difference between liquidus and solidus

LIU Qing , LIU Xiaoshan , ZHANG Xiaofeng , JU Qiping , XIE Feiming , WANG Bin , LI Hongwei , LU Xinchun

2013, 36(7):85-92. DOI: 10.11835/j.issn.1000-582X.2013.07.015

[Abstract](2072) [HTML](425) [PDF 7.69 M](1152)

Abstract:
During continuous casting process, the composition of molten steel often varies with different heats, which leads to the big fluctuation of billet surface temperature when the traditional parameter water control model is applied to control the process. Additionally, it is difficult to keep the temperature at the straightening point of the billet within a reasonable range. Given above consideration, a new control model for secondary cooling of continuous casting based on compensation temperature of the difference between liquidus and solidus has been presented. Meanwhile, the temperature field of the billet is simulated with both the parameter water control model and the new secondary cooling control model, and the results indicate that the new control model for secondary cooling of continuous casting could perform better when it is used to control the surface temperature at straightening points of billet, thereby ensuring the quality of the billet.

16 Analysis on the adsorption corrosion behavior of two kinds of azole drugs on 45 steel surface analysis

FAN Zhaoting , ZHANG Shengtao , LIU Jia , YIN Linliang

2013, 36(7):93-97. DOI: 10.11835/j.issn.1000-582X.2013.07.016

[Abstract](2134) [HTML](410) [PDF 5.23 M](1291)

Abstract:
The adsorption behavior of different concentrations of sulfamethoxazole and tinidazole on 45 steel surface is analyzed by establishing a Temikin isotherm equation-based segmentation adsorption model, when they are used as corrosion inhibitors in 3% HCl solution. Adsorption parameters obtained by the model show their corrosion inhibiting performance increase first and then decrease as their concentrations increase. And the main reason is the intermolecular hydrophobic attractive force in high concentration range of inhibitor is stronger than the electrostatic repulsion, and then hydrophobic aggregation happens, resulting in the decrease of adsorption performance on the surface of 45 steel.

17 An analysis on the energy of coal and gas outburst process

JIANG Yongdong , ZHENG Quan , LIU Hao , SONG Xiao

2013, 36(7):98-101. DOI: 10.11835/j.issn.1000-582X.2013.07.017

[Abstract](2097) [HTML](491) [PDF 5.63 M](1186)

Abstract:
Based on the hypothesis of the synthetic coal and gas outburst operating, we study the work done by elastic energy of coal mass and methane expansion energy in the coal and gas outburst process through theory and experiment. By using MTS815 rock mechanics test system, the triaxial compression test of the coal sample is carried out under different confining pressures and the power function relation between coal bodys elastic energy per unit volume and body stress is worked out. It shows there is a linear relation between methane expansion energy and methane pressure obtained by testing methane expansion energy under different moisture contents, different methane pressures and different compactness of coal mass, with the help of self-developed methane expansion energy testing device. The temperature change in the system is about 1 ℃ when methane does work in expansion. The result also shows that it could be regard as an isothermal process during coal and gas outburst. The results from experiment do great help in researching the mechanism of coal and gas outburst and establishing energy criterion.

18 Analysis on weakening hard rock used by long-hole presplitting blast in fully mechanized coal face with water-gel explosive grain

HUANG Wenyao , MU Chaomin , ZONG Qi , FU Jugeng , WU Hongbo , TU Min

2013, 36(7):102-107. DOI: 10.11835/j.issn.1000-582X.2013.07.018

[Abstract](1979) [HTML](313) [PDF 6.63 M](1198)

Abstract:
Aimed to the hard rock fault in rock path of the coal working faces and the low efficiency of rock breaking directly by coal cutter，the long-hole presplitting blast is done by self-made water-gel explosive grain of long-range booster, numerical simulation and design of reasonable blasting parameters. The results show that the long-range booster water-gel explosive has high reliability and when the blasting hole diameter is 75 mm, the diameter of charge is 63 mm, the radius of crushing zone is 0.4-0.5m and the radius of cracks is 0.5-1.0 m. When the distance between neighboring blasting hole is about 1.6-2.2 m, the damage cracks are future extended after long-hole blasting, it satisfies the requirement of rock breaking used by coal cutter, which ensures that the fully mechanized coal face passes through the hard fault of rock successfully.

19 Influence of obstacles on the parameters of flame front in gas explosion

XIE Beijing , FU Yukai , XU Xiaoxuan

2013, 36(7):108-113. DOI: 10.11835/j.issn.1000-582X.2013.07.019

[Abstract](2162) [HTML](369) [PDF 6.00 M](1131)

Abstract:
The temperature, ion current, overpressure and photoelectric signal of flame front at the same cross-section in square tube of laboratory simulation of tunnel are recorded by homemade thermocouple, homemade ion probe, pressure transducer and photoelectrical transducer at the same time. The parameters changes of flame front with the same gas concentration of 10.17% are compared with obstacles or without obstacles. The results show that, when the obstacles exists, the value of temperature is slightly lower, the temperature is from 1 303.7 ℃ down to 1 234.4 ℃ by close to ignition position and from 1 198.7 ℃ down to 902.5 ℃ away from ignition position. The value of ion current is slightly higher and the double peak values occur obviously in the signals of ion current, the peak value of ion current is from 1 46.25 nA up to 160 nA in the vicinity and from 432.5 nA up to 605 nA in the distance. The precursor compression wave in flame propagation tube is appeared ahead to further promote the gas explosion process in DDT. Therefore, roadway should minimize the presence of obstacles.

20 Preparation and applications of inorganic polymer composite flocculant poly aluminum ferric sulfate

ZHENG Huaili , CHEN Wenyuan , ZHANG Zhi , SUN Yongjun , GUAN Qingqing , LIU Liwei , LU Wei , ZHENG Xiaokai

2013, 36(7):114-120. DOI: 10.11835/j.issn.1000-582X.2013.07.020

[Abstract](2400) [HTML](277) [PDF 7.48 M](1281)

Abstract:
Industrial by-products FeSO4·7H2O is taken as raw material, concentrated nitric acid as strong oxidant and aluminum sulfate as additive to produce poly aluminum ferric sulfate(PAFS）flocculants, which is applied to the removal of organic humic acid. The study includes the reaction temperature, reaction time, Al/Fe molar ratio and basicity(OH/Fe). Infrared spectroscopy and scattering electron are used to characterize the structure of the PAFS. The results show that the product have the best coagulation effect when reaction temperature, reaction time, Al/Fe molar ratio and basicity(OH/Fe）are 60～80℃, 30～50 min, 1∶9 and 0.3 respectively. Infrared spectroscopy analysis shows the products structure and scattering electrons analysis suggests a large surface area and a strong condensed state for PAFS. The removal rate of humic acid is 94.72% when the dosage of PAFS is 3.36 mg /L, pH value is 7, rapid stirring speed is 350 rpm, fast mixing time is 2.0 min, the slow stirring speed is 40 rpm and slow stirring time is 12 min.

21 Effects of Scenedesmus quadricauda on the growth of Microcystis aeruginosa under fluid motion

LI Lin , ZHU Wei

2013, 36(7):121-126. DOI: 10.11835/j.issn.1000-582X.2013.07.021

[Abstract](1980) [HTML](623) [PDF 5.96 M](1400)

Abstract:
In order to reveal the effects of competition of other algae and Microcystis on growth of Microcystis under flow condition before the formation of algal blooms, and the growth of Microcystis aeruginosa is affected by Scenedesmus quadricauda under flow conditions, experiments are conducted by plexiglass ring groove in axenic laboratory. The competition relationship affected by competition parameters, density and specific growth rate of Microcystis are analyzed. The results show that the Microcystis aeruginosa adaptability on flow water is reduced under the competition between Scenedesmus quadricauda and Microcystis aeruginosa, namely, the optimal flow rate in simple and mix culture are 35 cm/s and 5 cm/s respectively. The exponential growth time of Microcystis aeruginosa under mix culture are longer than under simple culture. Microcystis aeruginosa growth are stimulated and its specific growth rate increase by Scenedesmus quadricauda at flow rate from 0 to 25 cm/s, contrary to these results at 35 cm/s. The growth of Scenedesmus quadricauda is slightly inhibited by Microcystis aeruginosa in control group and treatment groups during the experiment.

22 Interval local orthogonal element-free Galerkin method for the plane with cracks

ZHOU Liming , MENG Guangwei , LIU Xinhui , ZHOU Zhenping

2013, 36(7):127-132. DOI: 10.11835/j.issn.1000-582X.2013.07.022

[Abstract](1906) [HTML](319) [PDF 5.95 M](1103)

Abstract:
In order to solve the problem that some structural parameters have errors or uncertainties which are caused by manufacture, installation, measurement or computation in structural analysis and design, an interval local orthogonal element-free Galerkin method(ILOEFGM）is proposed. Based on the interval mathematics, inner product space, perturbation theory, element-free Galerkin method(EFGM）are employed to deduce ILOEFGM equilibrium equations, and the parameter perturbation of interval number is used to solve the ILOEFGM equilibrium equations. As an application of the method, a numerical example based on the problem for plane with cracks is given. The calculated results show that the method is effective.

Home

Volume 36,Issue 7,2013 Table of Contents

Current Issue

Volume

Issue

Most Read

Most Cited

Most Downloaded