Features of pipe transportation of paste-like backfilling in deep mine

Based on the pipe transportation of paste-like backfilling system of a certain deep coal mine, its dynamics process was simulated and analyzed. A two-dimensional dynamic model of extraordinary deep and lone pipe was built by GAMBIT, on the basis of which the simulation was done by implicit solver of FLUENT 2ddp. The results show that hydraulic loss of pipe transportation is less than the pressure produced by gravity, which means the backfilling material can flow by itself. When the inlet velocity is 3.2 m/s, the maximum velocity of 4.10 m/s is at the elbow and the maximum velocity in the horizontal pipe is 3.91 m/s, which can both meet the stability requirement. The results of the simulation are proved to be reliable by the residual monitor plotting of related parameter, so it can be concluded that the system of pipe transportation is safe.     

Thermal stress in SiC element used in heat exchanger

1INTRODUCTION Thick walledpipesexperiencinginternalheat flowhavefoundwideapplicationsinindustry,in cludingheatexchanger,furnace,heatpipes,etc.Thethermalstressesinthepipewallareveryim portanttoassessthesizeandmaterialpropertyof thepipe.Somemetallurgicalfurnacesneedalayer offreezingbathforprotectinginnerliningagainst erosionofmeltingbath[1,2].BecauseSiChashigh thermalconductivity,itisusedasinnerliningofmetallurgicalfurnaces,butalotofenergylossisa wasteofresources.Therearethelargethermal gr…     

山区排水管道的设计流速探讨

我国《室外排水设计规范》规定室外金属排水管道最大流速为10m/s,非金属管道为5m/s,然而在实际工程中可以找到一些超过这个规定并且运行良好的工程实例,为此对该规定进行了探讨,并在调研分析的基础上建议室外提高排水管道最大设计流速.     

洪水灾害下管道的力学计算

为了研究流动水动力、浮力、管体以及输送介质重力、土壤地基抗力对管道的共同作用,建立洪水作用下的管道力学分析模型,选用数值分析方法和有限元方法计算了管道的应力及应变。结果表明,两种方法的计算结果较接近。依据该有限元模型,分析了洪水流速和穿越距离对管道应力及应变的影响。结果表明,当流速大于3.0 m/s时,管道应力和应变随流速的增加趋势加大;当穿越距离增加时,堤岸处管道最大应力和轴向应变逐渐增大,但增幅逐渐减小;当穿越距离小于160 m时,河流中部管道的应力和轴向应变随着穿越距离的增加而增大,当穿越距离大于160 m时,应力和轴向应变随着穿越距离的增加而略有减小。对榆⁃济线埋地悬空管道进行了安全评估,结果可知即时应力为178 MPa,悬空管道安全。     

Hydraulic calculation of gravity transportation pipeline system for backfill slurry

Taking cemented coal gangue pipeline transportation system in Suncun Coal Mine, Xinwen Mining Group, Shandong Province, China, as an example, the hydraulic calculation approaches and process about gravity pipeline transportation of backfill slurry were investigated. The results show that the backfill capability of the backfill system should be higher than 74.4 m^3/h according to the mining production and backfill times in the mine; the minimum velocity （critical velocity） and practical working velocity of the backfill slurry are 1.44 and 3.82 m/s, respectively. Various formulae give the maximum ratio of total length to vertical height of pipeline （L/H ratio） of the backfill system of 5.4, and then the reliability and capability of the system can be evaluated.     

Theoretical analysis and numerical computation of dilute solid/liquid two-phase pipe flow

Starting with the kinetic theory for dilute solid/liquid two-phase flow, a mathematical model is established to predict the flow in a horizontal square pipe and the predictions are compared with LDV measurements. The present model predicts correctly two types of patterns of the vertical distribution of particle concentration observed in experiments, and also gives different patterns of the distribution of particle fluctuating energy. In the core region of the pipe, the predicted mean velocity of particles is smaller than that of liquid, but near the pipe bottom the reverse case occurs. In addition, full attention is paid to the mechanism for the vertical distribution of the average properties of particles such as concentration and mean velocity. From the kinetic-theory point of view, the cause of formation for different patterns of the vertical concentration distribution is not only related to the lift force exerted on a particle, but also related to the distribution of particle fluctuating energy.     

深海卧管⁃悬链线立管系统管内流动特性分析

为探究深海卧管⁃悬链线系统内立管管内流动特性,针对南海某油气田,通过数值模拟分析了管径、卧管入口处总流量、含水率（质量分数）和出口压力对管内流动特性参数的影响规律。结果表明,以管内流动状态发生转变的位置为界限,各影响因素对管内流动状态参数的影响表现出不同的变化规律,但是管内沿程温度分布基本不受相关因素的影响;4个因素对管内流动特性参数的影响存在明显的阶段性：管径的影响分为D=0.06～0.12 m和D=0.12～0.50 m两个阶段,卧管入口处总流量的影响分为Q=0.001～0.030 m3/s和Q=0.100～0.300 m3/s两个阶段,含水率的影响分为w=10%～25%和w=25%～30%两个阶段,出口压力的影响分为0～5.0、5.0～7.0 MPa和7.0～10.0 MPa三个阶段。     

高速列车随机激振载荷无砟轨道路基的动应力分布规律

相较于传统的列车轨道路基整体耦合三维有限元模型，提出一种优化处理列车荷载的方法，基于多体系统动力学理论建立列车轨道垂向耦合模型，并通过数值计算得到考虑了轨道随机不平顺条件下的轮轨激振载荷，随后利用二次开发子程序将轮轨载荷导入无砟轨道路基天然地基土非线性数值分析三维有限元模型，在此基础上研究分析高速移动荷载作用下路基的动应力分布规律。研究结果表明：采用的车辆荷载处理方法在保证计算精度的前提下代替车辆不平顺轨道路基地基整体耦合振动模型，降低了建模及计算时间成本；竖向动应力沿横向分布规律，在轨道结构中数值较大，路基基床内远小于轨道结构中的数值，基床表层及基床底层底面出现"马鞍形"分布；沿竖向分布，随着深度的增加，竖向动应力逐渐减小，在基床表层内的衰减率较大，甚至超过50%；沿纵向分布，在各结构层内产生了与转向架数目相等的应力峰值数目，列车运行过程中轨道及路基动应力的变化可以看作是反复的加、卸载过程；列车移动速度对路基动力响应影响作用明显，时速由200 km/h增长到350 km/h时，各结构层动应力幅值增长均超过30%。     

低速冲击下C型冷弯薄壁钢构件动力响应分析

为了研究C型冷弯薄壁钢构件在横向冲击荷载作用下的动力性能,本文选用两组共12个冷弯薄壁槽钢梁构件进行冲击试验,并将试验构件的变形模式和试验测得的位移极值与ANSYS/LS-DYNA有限元模拟所得的结果进行对比分析,结果表明：两者的构件变形模式相似,位移极值差值均在8.0%以内,表明ANSYS/LS-DYNA有限元模型能够准确有效的模拟该构件的动力响应结果。采用该数值模型依次分析了不同冲击参数（密度、速度和角度）对C型冷弯薄壁槽钢梁构件的变形模式和动力性能的影响。结果表明：当冲击物密度在2000-8000kg/m3内以2000 kg/m3的增量增大时,构件冲击力最大增加25.5%,竖向位移最大值为20.30mm,应变能稳定值所占峰值的比例基本保持在60.0%左右;当冲击物速度在3-9m/s内以3m/s的增量增大时,构件冲击力最大增幅为79.1%,竖向位移最大值为26.78mm,应变能稳定值所占峰值的比例基本保持在60.0%左右;当冲击物冲击角度由30°增加到90°,构件冲击力最大增幅为41.4%,竖向位移最大值为20.09mm,应变能稳定值所占峰值的比例在60.0%-70.0%之间。因此,冲击物密度、速度与冲击角度的改变,对构件的变形和破坏程度均有影响,但冲击速度的改变对构件变形程度的影响最为显著。     

高精度MFL—PIG地面标记系统的设计

管道漏磁通检测系统（MFL—PIG）是目前国内外使用最广泛的管道内检测设备．地面标记系统（AGM）作为管道漏磁通检测系统的重要组成部分,是消除检测器里程累积误差、精确定位管壁缺陷的重要保障．针对里程轮机械结构误差及PIG在行进过程中的翻转、里程轮打滑失效等因素,采用高精度的时钟作为共同时间基准,设计了高精度MFL—PIG新型地面标记系统．采用该地面标记系统的MFL—PIG对管道缺陷的定位误差小于1m．现该系统已通过中国石油天然气管道局管道技术公司的可靠性试验．并成功应用于陕京二线永清—采玉段天然气管道的现场检测．     

Application of ultrasonic in strength measurement of similar materials of limestone

Similar materials such as cement, gypsum and sand are options for simulating limestone characteristic. A series of reasonable proportions are chosen to do similar experiments of Karst roof based on the proportions testing of small samples indoors. Applying on ultrasonic, the velocities of transverse wave and vertical wave of similar samples have been inspected with the sound wave instrument. Dynamic modulus of elasticity and Poisson’s ratio of the samples have been educed. According to the testing data, the relationship between the transverse wave and vertical wave velocity, compressive strength and anti-bend strength are analyzed. It has been proved that the vertical wave velocity is better for reflecting compressive strength and anti-bend strength of similar materials than the transverse wave velocity. The vertical wave velocity increases with the strength and dynamic modulus of elasticity. Foundation item: Project(200020) supported by the Communication Department of Hunan Province, China     

Measurements of in situ stress and mining-induced stress in Beiminghe Iron Mine of China

In order to obtain the distribution rules of in situ stress and mining-induced stress of Beiminghe Iron Mine, the stress relief method by overcoring was used to measure the in situ stress, and the MC type bore-hole stress gauge was adopted to measure the mining-induced stress. In the in situ stress measuring, the technique of improved hollow inclusion cells was adopted, which can realize complete temperature compensation. Based on the measuring results, the distribution model of in situ stress was established and analyzed. The in situ stress measuring result shows that the maximum horizontal stress is 1.75–2.45 times of vertical stress and almost 1.83 times of the minimum horizontal stress in this mineral field. And the mining-induced stress measuring result shows that, according to the magnitude of front abutment pressure the stress region can be separated into stress-relaxed area, stress-concentrated area and initial stress area. At the −50 m mining level of this mine, the range of stress-relaxed area is 0–3 m before mining face; the range of stress-concentrated area is 3–55 m before mining face, and the maximum mining-induced stress is 16.5–17.5 MPa, which is 15–20 m from the mining face. The coefficient of stress concentration is 1.85. Foundation item: Projects(10702072, 10632100) supported by the National Nature Science Foundation of China     

建筑排水横管中固体物移动速度的研究

本研究通过摄像法测定不同坡度、不同排水量时塑料排水横管中模拟固体物的移动速度，并分析了模拟固体物的运动规律和可能发生沉积的条件，确定了影响模拟固体物运动速度的主要因素，为排水横管的合理设计提供了有关数据。     

流量差异和管径突变对立管流动状态的影响

为探究深海T型管流量差异和管径突变对立管管内流动特性参数的影响,以南海某油气田为研究对象,通过数值模拟的方法进行了研究。结果表明,立管管内流动状态受到水平管段内总流量影响,与其分支管段流量的关系不明显;当水平管段管径保持不变的条件下,在立管直径DC为0.03 m、0.06～0.12 m和0.24 m时,立管相关参数的变化规律不同;当立管管径发生突变时,管内流动参数的变化主要与其最小管径有关。     

Designing for Long Campaign Life Blast Furnace (1) --The Mathematical Model of Temperature Field for Blast Furnace Lining and Cooling Apparatus and New Concept of Long Campaignship Blast Furnace Cooler Design

The physical and mathematical model of temperature field for blast furnace stave coolers was established. The computation results show that the heat resistance of 2-6 mm water scale within the cooling pipe is about 7%-20% of the total heat resistance of cooling stave body, as for drilling duct type, the heat resistance of 2-6 mm water scale is about 88%-98% of the total heat resistance. Using drilling duct or full cast pipe can eliminate gas clearance and coating layer between pipes and cast iron body and reduce the heat resistance of the cooler sharply and improve the coefficient of heat transfer to a great extent. The water velocity within coolers can be kept at the 1evel of 0.5- 1 .5 m/s, the higher water velocity can not decrease the hot surface temperature, but can increase energy consumption for cooling water.     

移动荷载作用下加筋路堤和轨道系统的三维动力响应

用解析法研究了加筋路堤上轨道系统在移动荷载作用下的三维动力响应问题。基于Biot多孔弹性介质的波动理论,建立了加筋路堤轨道系统分析模型。将钢轨简化为无限长弹性Euler梁,将枕木简化为连续质量块,将加筋路堤作为一横观各向同性层来考虑,将下卧土体考虑为由Biot波动方程描述的饱和半空间。联立轨道系统、加筋路堤和下卧土体的动力方程,在Fourier变换域内求解荷载作用下钢轨位移和土体位移的表达式,将求得的表达式进行Fourier逆变换得到其在时域里的表达式。研究了列车移动速度、加筋路堤层的厚度、荷载幅值大小和加筋率等对路堤及轨道系统动力响应的影响。计算结果表明,钢轨竖向变形随着速度的增大呈现先增大后减小的趋势;加筋路堤上的钢轨竖向变形显著小于同厚度下未加筋路堤上的钢轨竖向变形;钢轨竖向变形随着荷载幅值的增大而增大;随着加筋率的增大而减小。     

煤矿井筒保温全风量送风系统设计及热管阻力的优化研究

为了探究热管换热单元阻力特性和优化井筒保温全风量送风系统设计,建立了热管单个模块阻力分析模型,分析了不同并联模块的阻力特性,在此基础上提出了热管阻力平衡计算方法;同时分析了不同工况下,井筒不同进风口进风量的规律。结果表明：通过改变管排数量,风速分布较原设计更加均匀,阻力减少。最大风速差由2.1 m/s降低至1 m/s内,系统风速不平衡率由80%降低至20%以下。全风量送风系统运行过程中,密闭性是决定新风风道进风量的最主要因素;当辅助风道开启时,进风风量可达2 600 m³/min,占总进风量比例26.8%。     

FEM modeling for 3D dynamic analysis of deep-ocean mining pipeline and its experimental verification

3D dynamic analysis models of 1000 m deep-ocean mining pipeline, including steel lift pipe, pump, buffer and flexible hose, were established by finite element method (FEM). The coupling effect of steel lift pipe and flexible hose, and main external loads of pipeline were considered in the models, such as gravity, buoyancy, hydrodynamic forces, internal and external fluid pressures, concentrated suspension buoyancy on the flexible hose, torsional moment and axial force induced by pump working. Some relevant FEM models and solution techniques were developed, according to various 3D transient behaviors of integrated deep-ocean mining pipeline, including towing motions of track-keeping operation and launch process of pipeline. Meanwhile, an experimental verification system in towing water tank that had similar characteristics of designed mining pipeline was developed to verify the accuracy of the FEM models and dynamic simulation. The experiment results show that the experimental records and simulation results of stress of pipe are coincided. Based on the further simulations of 1 000 m deep-ocean mining pipeline, the simulation results show that, to form configuration of a saddle shape, the total concentrated suspension buoyancy of flexible hose should be 95%?105% of the gravity of flexible hose in water, the first suspension point occupies 1/3 of the total buoyancy, and the second suspension point occupies 2/3 of the total buoyancy. When towing velocity of mining system is less than 0.5 m/s, the towing track of buffer is coincided with the setting route of ship on the whole and the configuration of flexible hose is also kept well.     

输流管道流固耦合非线性动力学分析

利用有限元软件，采用ALE法对输流管道流固耦合非线性动力学特性进行计算分析．得到耦合处及其附近流体各向速度随时间变化曲线，在某一时刻管内任意横截面处的速度分布和管子在垂直流速方向上的振型，及管子在耦合作用下的振动频率．为提高设计阶段对振动特性预测的精度、保证管路系统的运行可靠性提供了参考．     

Airflow characteristics by air curtain jets in full-scale room

A new air distribution pattern, air curtain jet ventilation was presented. The ventilation or airflow patterns and the air velocity produced by air curtain jet were investigated in detail. To identify the airflow characteristics of this novel air curtain jet ventilation system, a full-scale room was used to measure the jet velocity with a slot-ventilated supply device, with regards to the airflow fields along the vertical wall as well as on the horizontal floor zones. The airflow fields under three supply air velocities, 1.0, 1.5 and 2.0 m/s, were carried out in the full-scale room. The experimental results show the velocity profiles of air distribution, the airflow fields along the attached vertical wall and the air lake zones on the floor, respectively. The current experimental research is helpful for heating, ventilation and air conditioning (HVAC) engineers to design better air distribution in rooms.