Volume 42,Issue 10,2019 Table of Contents

1 Switching control strategy for plug-in hybrid electric vehicles with a reflux power continuously variable transmission

SUN Dongye , FAN Zengyan , CHEN Yuan

2019, 42(10):1-13. DOI: 10.11835/j.issn.1000-582X.2019.10.001

[Abstract](564) [HTML](512) [PDF 5.75 M](913)

Abstract:
Hybrid electric systems with reflux power have two forms during switching. First, the driving mode switching between the power source and the speed control mode switching between the continuously variable transmission (CVT) situation and the power reflux situation. Both of them will cause a sudden change in the output torque of the power coupling system affecting vehicle ride comfort during motion. To solve this problem,we propose a dynamic control strategy for plug-in hybrid electric vehicles (PHEVs) with reflux power by a coordinated control system involving the motor, engine, and clutch to minimize vehicle jerk. The results from MATLAB simulations indicate that the proposed control algorithm can be used to efficiently reduce torque fluctuations and jerk.

2 Light weight design of chassis frame for a soybean harvester

LI Yi , XU Zhongming , ZHANG Lihua , DU Jie , JIANG Yunce

2019, 42(10):14-21. DOI: 10.11835/j.issn.1000-582X.2019.10.002

[Abstract](528) [HTML](509) [PDF 5.42 M](975)

Abstract:
In this paper, the chassis frame of a soybean harvester is taken as an object. Using three-dimensional modeling software Solidworks for the parametric modeling and finite element before the import processing software Hypermesh for the finite element meshing and modal simulation analysis of the chassis frame the modal test of frame samples is conducted to verify the validity of the simulation results.The strength of the chassis under different working conditions is checked and calculated. With the maximum allowable stress of the material taken as constraint when the natural frequency and dynamic load coefficient of the chassis are 2.5, and with the minimum weight of the frame taken as the target, the lightweight optimization design is carried out and the mass of the chassis after optimization is reduced by 16%.

3 Study on the treatment of ethyl mercaptan in exhaust gas by coated nano-tiO₂ photocatalytic technology

LIU Nan , LI Yingying , YANG Hailong , DENG Ruihong , LIU Yang , ZHAO Jihong

2019, 42(10):22-30. DOI: 10.11835/j.issn.1000-582X.2019.10.003

[Abstract](519) [HTML](585) [PDF 3.91 M](838)

Abstract:
With refractory ethanethiol being the target pollutant, the photocatalytic oxidation of the supported nano titanium dioxide is introduced as the treatment technology. Aanatase-type titanium dioxide catalyst with high activity was obtained by calcination at 450℃. The degradation efficiency was investigated under different gas flow rate, light energy density, humidity and oxygen concentration to get the best operating condition of the system. The results showed that the degradation effect of ethylene thiol was negative correlated with the discharge of waste gas. When exhaust gas flow was 0.3 L/min, humidity was 45% and oxygen concentration was 30%, ethyl mercaptan has the best degradation effect. The degradation rate of ethylthiol increases gradually with the increase of light energy density. Taking energy consumption into consideration, the best degradation effect of ethyl mercaptan was achieved when the light energy density was controlled at 7 W/cm².Through significant correlation analysis, we found that there was a significant positive correlation between the concentration of ethyl mercaptan, the density of light energy and the degradation efficiency of ethanethiol, while there was a significant negative correlation between the flow rate of exhaust gas and the degradation efficiency of ethanethiol.

4 Numerical simulation of equal-channel angular pressing process of Ti6Al4V titanium alloy at a right angle and different extrussion speed

JIANG Wenhuan , YANG Huan , WEN Liangying , JIANG Jiahuan , SUNG Paul K-L

2019, 42(10):31-41. DOI: 10.11835/j.issn.1000-582X.2019.10.004

[Abstract](610) [HTML](420) [PDF 13.37 M](1337)

Abstract:
An extrusion process of Ti6Al4V titanium alloy at 900℃ under equal-channel angular pressing (ECAP) at a 90° angle was numerically simulated at a different extrusion speed in the range of 0~5 mm/s by using Deform-3D finite element software. The simulation results show that at the same extrusion speed, the rate of temperature decrease after the sample passes through the corner is reduced; the higher the extrusion speed, the lower the load required for the extrusion process, the smaller the strain accumulation, the lower the equivalent stress, the less the stress concentration phenomenon, and the smaller the temperature drop of the sample in the extrusion process. In this study, the extrusion speed was selected as 5 mm/s.

5 Effects of sulfur on smelting Panzhihua titanium concentrate to produce titanium slag

ZHAO Qing'e , LYU Xuewei

2019, 42(10):42-49. DOI: 10.11835/j.issn.1000-582X.2019.10.005

[Abstract](690) [HTML](387) [PDF 3.88 M](961)

Abstract:
According to relevant surveys, S content of Panzhihua titanium concentrate is as high as 1.55%. We studied the effects of sulfur on the smelting of titanium slag in Panzhihua titanium concentrate. The results show that smelting Panzhihua titanium concentrate to produce titanium slag, the S content of the by-product semi steel is higher, and the C content is lower. Furthermore, the temperature of molten metal increases by an amplitude of 70℃ to 150℃, and the power consumption per ton slag increases by nearly 20 kW·h. By comparison, producing titanium slag by smelting titanium concentrate after oxidative desulfurization can reduce the content of S and eliminate the influence of S on the smelting process. Therefore, pre-oxidation is an effective way to produce titanium slag with high-sulfur titanium concentrate.

6 Research progress on electrolytic processes in molten salt to prepare titanium

MA Tongxiang , YANG Yu , LIU Pengjie , LYU Xuewei , HU Meilong

2019, 42(10):50-56. DOI: 10.11835/j.issn.1000-582X.2019.10.006

[Abstract](701) [HTML](2073) [PDF 897.39 K](1881)

Abstract:
Preparation of titanium metal by electrolytic process in molten salt has been the crucial process for the development of titanium industry to explore and seek breakthroughs. In recent years, the molten salt electrolysis process has attracted great attention of resrarchers worldwide. In this work, the development and research progress of electrolytic processes in molten salt are analyzed including FFC Cambridge process, OS process and USTB process, and the differences of them related to the process, mechanism and characteristics are discussed, on the basis of which their advantages and disadvantages are compared. Finally, the problems in industrialization of the electrolytic processes are also discussed.

7 Experimental study on applying titanium-containing concentrate to Angang steel pelletization

REN Wei , LI Jinlian , LIU Peijiang , ZHANG Liguo , WANG Liang , HAN Ziwen , ZHANG Shengfu

2019, 42(10):57-64. DOI: 10.11835/j.issn.1000-582X.2019.10.007

[Abstract](473) [HTML](489) [PDF 24.82 M](829)

Abstract:
In order to explore the feasibility of adding titanium concentrate to Angang Karala concentrate for pelletizing, the effects of bentonite ratio, titanium concentrate ratio and roasting temperature on the properties of titanium-bearing pellets were investigated. The results show that the qualified green pellets could be prepared with 5% to 25% titan magnetite and 1.3% to 1.5% bentonite in terms of mass fraction. The roasting temperature and the mass faction of titanomagnetite played an important role in the compressive strength of the finished ball. As the roasting temperature increased, the compressive strength first increased and then decreased, reaching the maximum value at about 1 200℃. From the perspective of mineralogical phase, the mechanism of relatively low roasting temperature of titanium-bearing pellets as well as the difference between their strength and that of ordinary ones was studied by means of polarization microscope, SEM, EDS and EPMA. It is found that titanium-bearing pellets have low roasting temperature due to the formation of ilmenite at 1 150℃, which could provide intensity in the pellets. Furthermore, the oxidative recrystallization at high temperature is poor. Compared with the ordinary pellets which have a large number of fine and uniform magnetite grains, the ilmenite in the titanium-bearing pellets is large, resulting in their weak oxidative recrystallization, and their strength is lower than that of the ordinary pellets.

8 Effects of aluminum on the carbothermic reduction of vanadium-titanium magnetite concentrate and melting separation

LI Jie , KOU Luyao , YANG Li , HU Tu , ZHANG Zimu

2019, 42(10):65-72. DOI: 10.11835/j.issn.1000-582X.2019.10.008

[Abstract](566) [HTML](403) [PDF 11.89 M](881)

Abstract:
The effect of aluminum powder on the carbothermal reduction process of vanadium-titanium magnetite concentrate was studied. The results show that the addition of aluminum powder can promote the rate of carbothermic reduction of vanadium-titanium magnetite concentrate. During the reduction process, aluminum powder replaces carbon as a reductant to participate in the reduction reaction, which releases a large amount of heat to cause local high temperature around it, thereby promoting the progress of the carbothermic reduction reaction and promoting the accumulation of new metal iron. The addition of 1% aluminum powder can slightly improve the separation of slag and metal; when the amount of aluminum powder added is more than 2%, the fluidity of the slag becomes difficult due to the formation of TiC, and the separation effect of slag and metal is deteriorated.

9 Behavior of Fe in pipeline magnesium electrolysis process

MA Shangrun , ZHU Fuxing , LI Kaihua

2019, 42(10):73-81. DOI: 10.11835/j.issn.1000-582X.2019.10.009

[Abstract](485) [HTML](704) [PDF 5.22 M](1098)

Abstract:
The behavior of Fe in pipeline magnesium electrolysis was studied by means of electrochemical workstation, gas-cooled cathode and molten salt comprehensive analyzer. The results show that Fe is liable to cause current loss and magnesium loss. The current density, cell voltage, electrode material, reaction time, electrolyte temperature and electrolyte disturbance are the main factors affecting the purification of Fe. The purifying rate of Fe increases with the increase of cell voltage (lower than the decomposition voltage of MgCl₂), current density and reaction time, the purifying rate of Fe at graphite electrode is better than that at carbon steel electrode, and the purifying rate of Fe is the best when the electrolyte temperature is 725℃±5℃. In industrial production, by installing graphite DC electrode in the cell and controlling the voltage of graphite electrode within 6 V to 8 V, the purification rate of the cell can be improved. After industrial experiments, the impurity Fe in the electrolyte dropped from 0.028 9% to 0.009 1%, and the purification effect was obviously improved.

10 The discussion of theoretical method and result evaluation of regional geo-hazard trend forecasting

WEN Mingsheng , CHEN Chunli , XU Wei , FANG Zhiwei , LIU Yanhui

2019, 42(10):82-91. DOI: 10.11835/j.issn.1000-582X.2019.10.010

[Abstract](446) [HTML](661) [PDF 14.65 M](1113)

Abstract:
In this paper, trend forecasting of geo-hazards of China in 2017 was carried out based on the dangerous parameter of geo-hazard forecasting theory. The profile, type and spatial distribution characteristics were forecasted. The trend forecasting result showed that 7 190 geo-hazards would happen all over the country in 2017, primarily in northwestern and northeastern Yunnan, southern and northeastern Sichuan, northwestern and eastern Guizhou, southern Chongqing, part of northern Guangdong, western and southeastern Hunan, southern Jiangxi, and western Fujian, etc. Comparison with the actual situation of geo-hazards in 2017 indicates that the forecasting of total quantity and landslide quantity are highly acceptable with errors less than 5%. The incidence of geo-hazards is high in the areas with very high potential risk (LevelⅠ) or high potential risk (Level Ⅱ), and low in the areas with moderate potential risk (Level Ⅲ) or low potential risk (Level Ⅳ), proving that the forecasting is in good agreement with the the actual situation as a whole. But the forecasting in the areas (Level I) is not accurate enough because the geo-hazard incidence in the areas (LevelⅡ) is higher than that in the areas (Level I). The result of geo-hazard trend forecasting provides support and decision-making reference on disaster prevention and reduction for the government departments concerned.

11 Computer-aided optimization algorithm for solving transportation problems based on table-manipulation principle

SHEN Ling , ZENG Qiang , CHANG Menghui

2019, 42(10):92-105. DOI: 10.11835/j.issn.1000-582X.2019.10.011

[Abstract](662) [HTML](708) [PDF 1.40 M](1033)

Abstract:
Aimed at getting the optimal solution of transportation problems, a computer-aided optimization algorithm based on table-manipulation principle is proposed. In the algorithm, the minimum element method is used to get an initial basic feasible solution;the potential method is adopted to get the array of check numbers and the recursive process is applied to get the closed loop array. Then the adjusting quantity is got according to the closed loop array and basic feasible solution, a new feasible solution is got after the feasible solution is adjusted according to the closed loop array and adjusting quantity, and the While loop is used to get the optimal solution until the minimum check number is not less than 0. After the While loop exits, if there are one or more 0 check numbers in the array of check numbers, one 0 check number is selected randomly to get a random optimum solution through above process. Case study shows that by the proposed computer-aided optimization algorithm, the computerization of the table-manipulation process is realized, thus improving the calculation efficiency and ensuring calculation accuracy.

12 Control of overlying strata migration by shallow isolated coal pillars and their reasonable setting-up

SHI Xiuchang

2019, 42(10):106-114. DOI: 10.11835/j.issn.1000-582X.2019.10.012

[Abstract](501) [HTML](474) [PDF 5.66 M](912)

Abstract:
In order to reveal the control effect of overlying strata movement by isolated coal pillars during mining along inclined direction in western shallow working face, Daliuta coal mine is taken as engineering background, the control effect of overlying strata collapse, movement and deformation by isolated coal pillars and the characteristics of stress change in mining face are analyzed by using similar material simulation test method, and the rational setting of coal pillars is determined. The results show that in the direction of mining area inclination, each working face will form an independent caving zone with isolated coal pillars between them, which effectively separates the lateral penetration and vertical expansion of the caving space in adjacent working faces and divides off the settlement curve of overlying strata on adjacent working faces; the caving height of overlying strata is closely related to the mining length of working face inclination not filled with coal pillars. The collapse height of overburden rock decreases when sublevel mining is more fully exploited. In the process of coal seam mining, the No.1^# to No.4^# pillar with a width of 30 m is in a stable state, but the safety of No.3^# and No.4^# pillars is low. The reasonable pillar widths of No. 2^-2 and 5^-2 coal seam are 18.6 m and 24.5 m, respectively. The optimum offset of upper and lower coal pillars is 95.5 m to avoid the concentrated stress of pillars and control the uniform settlement of the surface.

Home

Volume 42,Issue 10,2019 Table of Contents

Current Issue

Volume

Issue

Most Read

Most Cited

Most Downloaded