Volume 41,Issue 10,2018 Table of Contents

1 The method of three-line condition numerical simulation of turbocharger performance matching for GDI gasoline engine

LI Zucheng , ZHANG Qing , ZHONG Demei , QU Shangsheng , ZHANG Li , ZHANG Tao

2018, 41(10):1-8. DOI: 10.11835/j.issn.1000-582X.2018.10.001

[Abstract](1019) [HTML](651) [PDF 5.86 M](856)

Abstract:
The traditional research of turbocharger and gasoline engine numerical matching focuses on full load condition, but the reasonable matching for single working condition of full load cannot guarantee reasonable matching of turbocharger and gasoline engine throughout the scope of work. For the limitation of turbocharger and gasoline engine numerical matching on single full load condition, the basic principle of the three-line condition method was introduced. The full load thermodynamic model of direct injection turbocharged gasoline engine was built by using GT-Power software, and the model was extended to part load condition to be applied to the thermodynamic model of the three-line condition method. The thermodynamic model was applied to the matching research of three turbochargers. The results indicate that the three-line condition method can directly reflect the problem of the original turbocharger and engine matching throughout the scope of work, and the matching performance can be improved by using this evaluation method to rematch turbochargers.The method of three-line condition overcomes the limitation of studying only on single full load condition, and provides a numerical evaluation method for the preselection and optimization of turbochargers.

2 Rigid body inertia parameter identification method and experiment for complex structures

LUO Yuan , WANG Pan , DENG Zhaoxiang , YU Feng , LIANG Zhu

2018, 41(10):9-18. DOI: 10.11835/j.issn.1000-582X.2018.10.002

[Abstract](952) [HTML](605) [PDF 4.49 M](1089)

Abstract:
In order to identify the inertia parameters of complex structure rigid body with high efficiency and accuracy, an identification test device was built based on the FRF mass line method. The influence of system stiffness and damping, noise, coordinate error of excitation point and response point, angle error of hammer excitation and sensor installation on the identification accuracy were obtained by multibody dynamics simulation. A rigid body with known inertia parameters was identified by the proposed device and the error was within 5%. It shows that the test device based on the FRF mass line method can identify inertial parameters of complex structure rigid body efficiently and accurately.

3 Concurrent and collaborative development mode of aviation product based on capability maturity model

ZHU Lingzi , WANG Shilong , YANG Bo , TANG Qian , WANG Yankai

2018, 41(10):19-29. DOI: 10.11835/j.issn.1000-582X.2018.10.003

[Abstract](65658) [HTML](2150) [PDF 2.68 M](1792)

Abstract:
One of the main obstacle to the development process of aviation product is that the separation between the design and manufacturing departments together with the one-way serial mode of design-manufacturing leads to the long development cycle and low quality. This paper analyzed the development process of complex aviation products, established the aviation product maturity model, and defines the important links and state nodes of the development process. An aviation product development process controlling technology based on capability maturity model was presented. This technology replaced the original review by maturity calculation, achieving the control of the development process and determining the nodes for manufacturing sector involved in. An evaluation method for aviation product development maturity level based on the two-level fuzzy comprehensive evaluation method was designed to realize the multi-level and multi-factor evaluation of aviation products maturity degree. In order to verify the effectiveness of this method, it was applied to the development process of a type of aviation product. The results show that the manufacturing sector can effectively get involved in advance to implement the concurrent engineering, which is aimed at saving manufacturing cost by shortening the development time, controlling the development costs and improving the quality of products.

4 Research progress on intermetallic compounds and solid solutions of Mg alloys based on first-principlescalculation

LIU Yanglu , LIU Tingting , PAN Fusheng

2018, 41(10):30-44. DOI: 10.11835/j.issn.1000-582X.2018.10.004

[Abstract](1239) [HTML](748) [PDF 3.79 M](1088)

Abstract:
As one of the lightest metal materials, Mg alloys have a broad application prospect, and it has been one of the focuses to develop advanced Mg alloys at present. First-principles calculation provides a cost-effective method for development and design of advanced Mg alloys. Based on first-principles calculation methods, researches on intermetallic compounds and solid solutions of Mg alloys are reviewed. The research work on crystal structure, elastic constant, elastic modulus and generalized stacking fault energy of Mg alloys by first-principles calculation is introduced,and the effects of alloying elements and phase structures on mechanical properties of Mg alloys are also discussed, aiming to to illustrate that the first-principles computation plays an important role in the development of Mg alloys. And we hope that it could provide a theoretical reference for composition design and performance optimization of advanced Mg alloys.

5 A new process of vanadium extraction from vanadium-titanium magnetite

LI Dacheng , JI An , HU Meilong

2018, 41(10):45-52. DOI: 10.11835/j.issn.1000-582X.2018.10.005

[Abstract](1444) [HTML](987) [PDF 5.56 M](964)

Abstract:
There are still many utilization problems of vanadium in vanadium-titanium magnetite in our country. Especially for the low-grade ore, the traditional blast furnace-converter process has proved to be more difficult to realize the efficient extraction and utilization of vanadium. Therefore, a new technology was explored for the utilization of vanadium from titanium magnetite. The shaft furnace coal-based reduction and melting separation by electric furnace were used in this process to separate the iron and the vanadium, thus realizing the efficient utilization of the vanadium resources. The optimum processing parameters gained in the experiment are that the shaft furnace coal-based reduction is 11.5 h at 1 050℃, the metallization rate of sponge iron is 93%, and the reduction rate of vanadium can be controlled below 3.5%. Adding 3% borax to the reduction process can increase the metallization rate of sponge iron up to 98.16%. The reduction of the central part of the sample is better than that of the edge part.

6 The preparation and visible light photocatalytic activity of Bi/BiOCOOH composite photocatalyst

DING Zhigang , SHU Youju , DUAN Fang , CHEN Mingqing

2018, 41(10):53-60. DOI: 10.11835/j.issn.1000-582X.2018.10.006

[Abstract](917) [HTML](853) [PDF 8.01 M](905)

Abstract:
BiOCOOH was prepared by solvothermal method, and the Bi/BiOCOOH composite photocatalyst was synthesized by in-situ reduction of BiOCOOH with NaBH₄ aqueous solution as reducing agent. The structure, morphology and optical properties of the prepared photocatalyst were characterized by XRD, FESEM, TEM, DRS and PL. The photocatalytic activity of Bi/BiOOCOOH composite photocatalyst was determined by the degradation of Rhodamine B. The influence of NaBH₄ dosage was investigated. The results indicate that the Rhodamine B can be thoroughly degraded in 50 min when the dosage of NaBH₄ is 25 mg. This can be ascribed to the SPR effect of Bi, which reduces the recombination rate of photogenerated electrons and holes and enhances the absorption of visible light.

7 Electric field analysis of gas insulated 363 kV fast vacuum circuit breaker

AI Shaogui , YU Xiao , HUANG Yongning , YANG Fan , FAN Yiping , DU Wei

2018, 41(10):61-68. DOI: 10.11835/j.issn.1000-582X.2018.10.007

[Abstract](774) [HTML](413) [PDF 3.25 M](723)

Abstract:
Vacuum circuit breakers (VCB) with faster breaking speed can break the short-circuit current in a very short time, which is helpful to reduce the impact of short-circuit current on the power equipment. However, it is difficult to apply single-break VCB to high-voltage grid directly. In this paper, a novel SF₆ gas insulated 363 kV VCB is proposed, which uses the series and parallel structure of 40.5 kV vacuum interrupters. It is able to cut short circuit current in extremely short time by using the operating mechanism based on the eddy current driving principle. For higher voltage level VCB, it is of significance to study its internal electric field. A multi-medium 3D FEM model is established and the single and terminal unit's electric field are determined based on the simplified symmetrical structure. Then the electric field of bus bar, arc extinguish chamber and connecting terminals are analyzed. The results show that, under lightning impulse voltage, the maximum electric field is at the circular bead of connecting terminals and transfer flange, reaching at 28.5 kV/mm and 22.9 kV/mm respectively. The maximum electric field on the surface of the bus bar is 13.4 kV/mm, and electric field inside and outside the vacuum interrupter and other components are in the control range. Connecting terminals radius is optimized and its optimal value is determined to be 12 mm, which provides a reference for the prototype production.

8 Effect evaluation on pressure relief and permeability improvement of hydraulic flushing physical experiment

TAO Yunqi , ZHANG Chaolin , XU Jiang , PENG Shoujian , FENG Dan

2018, 41(10):69-77. DOI: 10.11835/j.issn.1000-582X.2018.10.008

[Abstract](951) [HTML](418) [PDF 6.67 M](923)

Abstract:
Hydraulic flushing technology is one of the most widely used pressure relief and permeability improvement measures and it works well in soft and low permeability coal seams. The physical simulation of hydraulic flushing was determined based on self-developed hydraulic flushing test system, and two CBM drainage tests were conducted before and after hydraulic flushing in order to evaluate its pressure relief and permeability improvement. Equivalent drainage radius and effective drainage time were defined to evaluate the hydraulic flushing technology quantitatively. As a conclusion, the equivalent drainage radius increased to 1.7 times and the effective drainage time reduced to 56% after hydraulic flushing. The results indicate that hydraulic flushing can improve permeability of coal seam and drainage efficiency greatly by increasing the porosity and fissure of coal seam. Therefore, the key of hydraulic flushing technology is how to improve the porosity and fissure of coal seam effectively and stablely.

9 Numerical simulation of stoping sequence among ore block based on pressure arch theory

ZHANG Deming , WANG Hao , BIAN Jiwei , LI Hongpeng

2018, 41(10):78-89. DOI: 10.11835/j.issn.1000-582X.2018.10.009

[Abstract](650) [HTML](649) [PDF 8.12 M](886)

Abstract:
Rational stoping sequence can effectively improve the stress distribution state of rock mass and ensure the stability of the stope. To determine a reasonable stoping sequence among ore block of Xingqiao Mine -300 m middle section, three schemes of stoping sequence among ore block were put forward according to mine existing conditions, including parallel stoping, Pin-pillar stoping and inverted Pin-pillar stoping, and by Midas finite element software, the numerical simulation models of the shemes were established. Considering the tensile stress, compressive stress and displacement, pressure arch theory was applied to analyze the simulation results. The results show that after the excavation of the ore body, the pressure arch will be formed around the goaf, and with the increase of the goaf, the outer boundary of the pressure arch moves to the deep part of the rock mass; during Pin-pillar stoping process, central part and both sides of goaf form a larger arch to bear its own and overlying rock load. The maximum tensile stress and compressive stress are respectively 2.288 MPa and 23.24 MPa with a maximum displacement of 55.71 mm, which are smaller than those of the other two options. In contrast, the program is more reasonable. The mining practice shows that the production process of Pin-pillar stoping sequence applied in the mine has achieved good economic and social benefits.

10 Study on application of salt hydrates phase change materials in solar melting ice and snow experimental system

ZHENG Taojie , CHEN Zhili

2018, 41(10):90-102. DOI: 10.11835/j.issn.1000-582X.2018.10.010

[Abstract](767) [HTML](357) [PDF 14.45 M](1047)

Abstract:
A solar melting ice and snow experimental system combined with phase change materials was fabricated and the effect of phase change materials on the system efficiency and the water production was studied under the conditions of "quick start", "energy supplement", "fluctuation" and "energy absorption". Based on the addition of the phase change material and process optimization in the experimental system, the differences in water production and energy consumption before and after the system improvement were compared and studied. The results show that the salt hydrates phase change materials can effectively control the temperature in the range of 3℃ to 5℃, and have good energy storage, release performance and anti-fluctuation ability, which can meet the temperature control requirements under various situations. By adding phase change materials and adopting optimized flow design, the experimental system can increase the water production by 11.4% and decrease the power consumption by 9.4% in the full simulation experiment, which can realize the efficient use of energy under different conditions and reduce the labor cost.

11 Reduction and adsorption of Cr (Ⅵ) in wastewater by Tieguanyin tea stalk

XIANG Wenying , XIE Bingbing , HU Juntao , ZHANG Qiang

2018, 41(10):103-116. DOI: 10.11835/j.issn.1000-582X.2018.10.011

[Abstract](873) [HTML](471) [PDF 6.68 M](929)

Abstract:
A series of single factor experiments were employed to study the effect of a novel adsorbent, Tieguanyin tea stalk, for the reduction of the high toxic heavy metal Cr (Ⅵ) to Cr (Ⅲ) which is low toxic even nontoxic. Two adsorption isotherm models and two adsorption kinetic models were used to simulate the experimental data. The characterization methods, SEM, BET, FTIR and XPS were employed to discuss the reduction and adsorption mechanism. The results show that the bigger tea stalk diameter, the more dosing quantity or pH ≤ 11, the higher removal rate of Cr (Ⅵ); The influence of the coexisting ions Ca (Ⅱ) and Ni (Ⅱ) to adsorption of Cr (Ⅵ) by tea stalk are weak. The Freundlich isotherm model and the Pseudo-second-order model fit closely to the experimental data. Tieguanyin tea stalk, Pu'er tea stalk and Tieguanyin tea stalk modified by maldehyde show better performance than activated carbon under certain conditions. The characterization results show that the reduction and adsorption plays important roles on the removal efficiency of Cr (Ⅵ) in water by tea stalk, and the functional groups of the hydroxyl, amino and acyl are involved in the reduction and adsorption of Cr (Ⅵ) by tea stalk.

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