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A numerical investigation of the evolution of 2-D disturbances in hypersonic boundary layers and the effect on the flow structure due to the existence of shocklets

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Science China(Physics,Mechanics & Astronomy) 2004年第2期47卷 244-255页

作者： CAO Wei & zhou heng Department of Mechanics,Tianjin University Liu Hui Center of Applied Mathematics,Nankai and Tianjin University,Tianjin 300072,China Correspondence should be addressed to zhou heng(email:hzhou 1 @ ***) Department of Mechanics Tianjin University China Liu Hui Center of Applied Mathematics Nankai China Tianjin University Tianjin China

The evolution of 2-D disturbances in hypersonic boundary layer with Mach number 6,8, and 10 was investigated numerically by three different numerical schemes. At the entrance, second mode T-S waves with different amplitudes were introduced, and the relation between the Mach number and the amplitude of the disturbance when shocklets started to appear was investigated. By comparing the disturbance velocity profiles with those provided by linear stability theory, the effects of shocklets on flow structures were also investigated.

关键词： hypersonic boundary layers, T-S wave, shocklet, direct numerical simulation.

The improvement of turbulence modeling for the aerothermal computation of hypersonic turbulent boundary layers

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Science China(Physics,Mechanics & Astronomy) 2010年第2期53卷 369-379页

作者： DONG Ming & zhou heng Department of Mechanics,Tianjin University,Tianjin 300072,China Department of Mechanics Tianjin University Tianjin China

The engineering computation of turbulent flows is mainly based on turbulence modeling,however,accurate aerothermal computation of hypersonic turbulent boundary layers is still a not well-solved problem. Aerothermal computation for turbulent boundary layers on a supersonic or hypersonic blunt cone with small bluntness is done firstly by using both direct numerical simulation and BL model,and seven different cases are investigated. Then the results obtained by the two methods are compared,and the reason causing the differences is found to be the incorrect assumption in the turbulence modeling that the ratio between eddy heat conductivity and eddy viscosity is constant throughout the whole boundary layer. Based on certain theoretical arguments,a method of modifying the expression of eddy heat conductivity in the region surrounding the peak location of the turbulent kinetic energy is proposed,which is verified to be effective,at least for the seven cases investigated.

关键词： hypersonic turbulent boundary layer aerothermal supersonic cone direct numerical simulation(DNS) BL model coefficient of eddy heat conductivity

The effect of high temperature induced variation of specific heat on the hypersonic turbulent boundary layer and its computation

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Science China(Physics,Mechanics & Astronomy) 2010年第11期53卷 2103-2112页

作者： DONG Ming & zhou heng Department of Mechanics,Tianjin University,Tianjin 300072,China Department of Mechanics Tianjin University Tianjin China

For hypersonic vehicles,as the temperature in its boundary layer usually exceeds 600 K,for which the molecular vibrational degree of freedom is excited,the perfect gas model is no longer *** this paper,the effect of high temperature induced variation of specific heat on the hypersonic turbulent boundary layer of flat plates is investigated by direct numerical simulations with the perfect gas model,*** constant specific heat,as well as with a variable specific heat gas *** comparison of the results from the two gas models has found that the effect of the variation of specific heat on the velocity of the turbulent boundary layers is relatively small,while its effect on temperature,such as the mean temperature,the temperature fluctuations,is *** is also found that the mean specific heat is quite close to the specific heat calculated by using the mean temperature,indicating that it is possible to do turbulence *** modeling is done under the variable specific heat gas model with the mean temperature as the *** feasibility of such consideration is verified by applying the SST model for variable specific heat turbulence computation.

关键词： hypersonic turbulent boundary layer specific heat direct numerical simulation SST model

Discrete element method study of solid descending and residence properties in COREX shaft furnace with center gas supply device

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Journal of Iron and Steel Research International 2019年第7期26卷 669-678页

作者： heng zhou Qin-fu Hou Ming-yin Kou Shun Yao Sheng-li Wu School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing 100083 China Department of Chemical Engineering Monash University Clayton VIC 3800 Australia

Solid descending and residence properties in COREX shaft furnace with a center gas supply device (CGSD) were studied using the discrete element method. Solid flow pattern, residence time distribution, and local solid residence time (SRT) were analyzed. Moreover, the effects of the rotation speed of screws, the radius, and height of CGSD were investigated. The results show that the solid flow is dominantly a plug flow in the shaft furnace with the CGSD. In the upper region of the shaft furnace for gas-solid reduction, uniform distribution of local SRT is observed, which is preferable to match the even gas distribution expected due to the CGSD and slots. For different rotation speeds of the screws, the distribution of solid flow patterns is similar. The averaged residence time, dispersed plug volume fraction, and dead volume fraction decrease with increasing the rotation speed of the screws. The radius of the CGSD affects the solid residence in the shaft furnace. Local SRT above the CGSD increases with the increase in the radius of CGSD, possibly leading to the formation of more agglomerates. Hence, the radius of CGSD should be chosen carefully. The height of CGSD has a minor effect on solid residence in the shaft furnace.

关键词： COREX shaft furnace Solid residence time Discrete element method Center gas supply device Solid descending

Development and application of coke oven gas spraying on sinter bed

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Journal of Iron and Steel Research International 2020年第6期27卷 617-623页

作者： He-ping Li Sheng-li Wu Zhi-bin Hong heng zhou Ming-yin Kou School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing100083China Ironmaking Plant Shanghai Meishan Iron and Steel Co.Ltd.Nanjing210039JiangsuChina

The Shanghai Meishan Iron and Steel Co., Ltd. has a large supply of coke oven gas (COG) and has the potential to develop and apply the spraying of COG on the surface of a sinter bed. The effects of the amount of COG, the spraying time, and the spraying distribution with the process on the quantity and quality indexes of sinter were investigated in the laboratory experi-ments. The results showed that the COG spraying can improve the sinter indexes to a large extent if appropriate parameters were used. It was found that an appropriate amount of COG, a relatively long spraying time, and a decreasing distribution of the COG amount with the spraying process all help to obtain a better performance for sinter quantity and quality indexes. When the COG spraying was applied to the No. 3 sintering machine, the sinter tumbler index increased by 0.45%, the overall finished product rate increased by 0.72%, the solid fuel consumption decreased by 4.06kg/t, the reducibility increased by 3.89%, and the cost of iron decreased by 5.29 CNY/t, and the CO2, SO2 and Nox emissions also decreased, thus proving the feasibility of this technology. Therefore, COG spraying provides a new way to improve sinter and also decrease the energy consumption and pollution.

关键词： Coke oven gas spraying Sinter index Spraying distribution High quality Low energy consumption Low pollution

INSTABILITY WAVES IN THE WALL REGION OF A TURBULENT BOUNDARY LAYER ON A FLAT PLATE

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Acta Mechanica Sinica 1989年第1期5卷 11-19页

作者： zhou heng (Department of Mechanics,Tianjin University,Tianjin,China) Department of Mechanics Tianjin University Tianjin China

Coherent structures and the bursting phenomena in the wall region of a turbulent boundary layer play a very important role in determining the characteristics of the boundary layer. Yet the nature and the origin of the coherent structures are unclear until *** this paper, nonlinear stability calculations for the wall region of a turbulent boundary layer have been *** was found that there do exist instability waves which may be responsible for the coherent structures.

关键词： coherent structures instability wave turbulent boundary layer

Effect of cross-section shape of rotating chute on particle movement and distribution at the throat of a bell-less top blast furnace

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Particuology 2019年第3期17卷 194-206页

作者： Mingyin Kou Jian Xu Shengli Wu heng zhou Kai Gu Shun Yao Bingjie Wen School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing 100083 China Department of Metallurgical Engineering College of Materials Science and Engineering Chongqing University Chongqing 400044 China

Rotating chutes are widely used to control the burden distribution and enhance the gas distribution in a blast *** chute cross-section shape has a significant effect on the particle movement and ***,this study developed a three-dimensional model of a blast furnace top with rotating chute using the discrete element *** effect of different chute shapes on the particle movement and radial burden distribution was then *** results showed that the burden stream height at the chute discharge agrees well with the burden stream thickness at the burden surface.A semicircular chute had the largest main striking point,where the chute discharge joins the burden surface,and trapezoidal and rectangular chutes had successively smaller *** semicircular chute helped to obtain a uniform radial size *** trapezoidal chute helped form an aggregated burden stream at low rotating speeds,while the rectangular shape chute achieved this at higher rotating speeds and different chute angles.

关键词： Blast furnace Chute shape Burden size segregation Discrete element method

Influence of Burden Distribution on Temperature Distribution in COREX Melter Gasifier

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Journal of Iron and Steel Research International 2013年第3期20卷 30-35页

作者： HAN Li-hao LUO Zhi-guo zhou Xiao-lei zhou heng ZOU Zong-shu ZHANG Yu-zhu School of Materials and Metallurgy Northeastern University College of Metallurgy and Energy Hebei United University

The temperature distribution of COREX melter gasifier was studied by using a two-dimensional 1/30 scale thermal dynamic model.A set of operating conditions,such as radial distribution of direct reduction iron（DRI） to lump coal and coke volume ratio,coke charging location,coke charging amount and coke size,were taken into *** results show that the temperature near the wall region decreases with the decrease of the radial distribution of DRI to lump coal and coke volume *** temperature with central coke charging is higher than that without central coke ***,the temperature significantly increases with the increase of central coke charging *** the increase of intermediate coke charging amount,the temperature near the wall region decreases while the temperature in the intermediate region *** temperature increases with the increase of coke size whether charging central coke or intermediate coke.

关键词： burden distribution temperature distribution central coke charging intermediate coke charging COREX melter gasifier

Effect of screw casing structure on descending of burdens in COREX shaft furnace

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Journal of Iron and Steel Research International 2017年第1期24卷 18-26页

作者： Zi-long Qiu Zhi-guo Luo heng zhou Ren Chen Feng Wang Zong-shu Zou College of Metallurgy Northeastern University College of Metallurgy Engineering Liaoning Institute of Science and Technology

COREX shaft furnace（SF）is a typical screw feeder with a storage container coupled with eight screw casings and *** structure of screw casing plays an important role in the moving behavior of burdens,stress distribution,abrasive wear of screws,and energy consumption during the operation of ***,a three-dimensional semi-cylindrical model of actual size of COREX-3000 SF was established based on discrete element method to investigate the influences of screw casing *** results show that the increase in the gap between the outside of screw flight and screw casing is beneficial for the smooth operation of SF,resulting in uniform descending velocity along the radius of SF in the lower part,decreasing the size of recirculation region,and alleviating stress concentration in the screw ***,raising the gap appropriately is also beneficial to weaken screw abrasive wear,decrease energy consumption,and then prolong the service life of the ***,enlarging the gap also leads to more undesired high temperature reduction gas into the SF from melter gasifier,thereby deteriorating the operation of ***,an ideal distance exists between the outside of the screw flight and the screw casing,which is suggested to be equal to the average of particle diameter.

关键词： COREX shaft furnace Screw casing structure Discrete element method Recirculation structure Screw abrasive wear