不同模型倾角的极小曲面复合相变材料熔化特性分析

以基于片状Diamond和杆状Diamond结构的复合相变储热单元(TPMS-PCM)为研究对象,建立4个模型,分别为不同模型倾角(0°、30°、60°、90°)。通过数值模拟的方法,研究模型倾角对相变储能单元储能性能的影响规律。研究结果表明:基于片状Diamond的相变储能单元自然对流较弱,因此其受模型倾角影响较小;在杆状Diamond中,60°模型融化速度比0°模型提高5.9%。

基于AUV垂直面运动控制的状态增减多模型切换

自主水下机器人(autonomous underwater vehicle,AUV)系统垂直面运动具有强耦合性、非线性等特点导致AUV系统垂直面难以精确控制,且其纵倾角需控制在某一阈值内,以保证系统安全。根据以上控制要求与AUV垂直面运动模型特点,提出将其解耦为深度控制子模型与纵倾角控制子模型,构建AUV系统垂直面运动控制模型集,根据模型集所含两子模型特点,提出了状态变量增减的多模型切换的概念。基于切换系统稳定判据——共同Lyapunov函数法,提出了变加权多模型切换策略,实现了切换过程的稳定性,避免了切换过程的抖动问题。多次湖泊试验证明,加权多模型切换策略避免了由于期望深度变化而造成的执行机构饱和、深度和纵倾角超调量过大等问题,且改善了AUV系统深度运动的静动态控制品质。

固定式光伏发电组件最佳倾角的聚类分析方法

在集中式大型光伏系统工程设计过程中,固定式光伏组件的倾角直接影响着整体光伏组件的IV输出特性,从而直接关系到光伏发电系统的收益。即固定式光伏组件的安装倾角不同,整个光伏系统所接收到的有效太阳辐射量不同,其发电量在一年范围内的差距较大,为此,为有效应对光伏组件安装倾角受限于经纬度、地域环境等多影响因素,追求大型集中式光伏发电系统的经济性,提出了一种考虑区域经纬信息的光伏发电组件最佳倾角聚类分析方法,并在华北地区某174 MW大型光伏电站设计过程中应用,其计算结果与PVsyst软件所计算的结果对比分析,验证了所提算法的有效性。

地震数学模型技术在煤矿采区地震勘探观测系统设计中的应用

根据安徽淮南某煤矿的地质构造特点及煤层赋存形态,在三维地震测区中部选择了一条典型地质剖面,据此建立了陡倾角二维地震数学模型,并从波动方程出发确立了模型的三维地震观测系统。通过对正演模拟得到的炮集记录、叠加剖面、偏移剖面上的波场特征的分析,确定了适合勘探区地质条件的采集和处理方法。对该二维模型数据的处理结果表明,叠后偏移手段不适合陡倾角区煤层地震资料的处理,而叠前时间偏移可有效保证陡倾角勘探区块的地质目标成像。根据陡倾角目的层及逆掩断层区域开展地震勘探的难点问题,提出了适当调整观测系统、提高空间采样密度等措施。根据多年在淮南矿区开展采区三维地震勘探的工作经验,认为该区最佳观测系统为方位角特性好、共面元道集内炮检距分布均匀的八线八炮制束状规则观测系统。

倾角约束下的机器人喷涂效率优化方法研究

喷涂机器人在对工件进行喷涂加工时,常常会受到工作空间和障碍物干涉的限制,导致喷枪无法保持垂直于工件表面的姿态进行喷涂,因此建立了一种以描述喷枪姿态的RPY角为变量的倾角喷涂模型,并提出了涂层厚度约束条件下以喷涂效率为目标的喷涂轨迹优化方法。首先,用种子曲线法生成待加工面上的喷涂轨迹,以涂层厚度均匀性为优化目标,对喷涂轨迹上喷枪的RPY角进行优化,然后以最小涂层厚度为约束,在满足涂层要求的情况下对喷枪的移动速度进行优化,以提高喷涂效率。仿真实验验证了该优化方法的有效性。

页岩气水平井地层倾角随钻监测方法应用研究

由于地震解释精度限制,页岩气水平井钻进过程中常常遇到预测地层深度与倾角与实钻误差较大的情况,故对页岩气水平井进行随钻地层倾角监测,及时根据监测结果进行轨迹调整对于页岩气水平井顺利中靶并长穿优质储层有重要的意义。利用导眼或邻井的自然伽马曲线建立地层对比标志层,在此基础上结合钻井轨迹及预测地层倾角建立地质模型,分析随钻自然伽马曲线变化情况,选择在标志层处、A靶点等控制点进行地层深度和地层倾角的确认,提前预判实际地层的变化,调整钻井轨迹,保证井筒在目标地层中穿行。

InSAR联合矢量倾角分段函数模型计算矿区地表下沉量

针对单轨合成孔径雷达(InSAR)仅能获取沿雷达视线(LOS)向形变和概率积分法(PIM)难以预计沉陷盆地边缘区域下沉量的问题,该文提出了一种由单轨InSAR监测的LOS形变联合移动矢量倾角模型计算矿区地表下沉量的方法。该方法首先在分析下沉盆地地表移动矢量倾角变化特征的基础上,建立主断面上地表点移动矢量倾角的分段函数模型,再结合主断面地表点的LOS向与地表移动矢量的矢量夹角与倾角的函数关系,实现由LOS向形变计算矿区地表下沉量。以马泰壕井田和上湾煤矿的两个工作面为研究对象,采用Sentinel-1A数据和水准实测数据对该方法的可行性和精度进行了验证;结果表明,在沉陷盆地边缘区域,该方法计算的地表下沉量与实测值吻合,两个矿区的监测精度均方根误差(RMSE)都约为5mm,高于InSAR监测精度的19mm,监测精度分别提高了74%和71%。

光学芯轴测量台四点自动调平方法研究

针对Wolter-I型芯轴装调、测量过程中需要多次调平,时刻保持平衡的问题,研究了四点式自动调平方法。从机械、软件两个方面介绍自动调平测量台,分析调平控制机构以及相关软件,用表面轮廓数据采集方法进行数据采集确定倾斜角,对“最高点不动”调平算法进行数学建模,对倾斜角的不同种情况进行仿真计算分析,计算随机产生的倾角对应的支腿移动量。实验结果表明:该方法用5~7次即可达到调平目的,具有较高的检测效率、调平精度和抗倾覆力。

高铁巡检机器人的设计与研究

为了改善高铁维护及巡检劳动条件,设计应用于铁路检修的巡检机器人。首先,对巡检机器人的机械本体进行模块化设计并制作巡检机器人模型样机。其次,构建巡检机器人倾角传感器模型及差速驱动模型,对巡检机器人进行运动学分析,运用PID控制算法来控制巡检机器人在道床上巡检运动。最后,对巡检机器人进行运动调试并进行现场试验,以验证其设计的合理性、运动的稳定性、检修的准确性。

Method to determine installing angle of conical point attack pick

In order to obtain the determining method of the installing angle and decrease the performance indices (cutting force and wearing rate) of the pick, the relationships among the installing angles (impact angle, inclination angle and the skew angle) were studied, and the static model of installing angles of the pick was built. The relationships among the impact angle, the tip angle of pick and the kinematics parameters of the pick were built, too. Moreover, the mechanic models of the maximum clearance angle and the wearing angle of the pick were set up. To research the relationships of the installing angles and the change law of the wearing angle along with the kinematics parameters, the simulation was done. In order to verify the correctness of the models, the cutting experiments were done by employing two picks with different pick tip angles. The results indicate that, the cutting force is the smallest when the direction of the resultant force of pick follows its axis, and the relationship derived among the installing angles should be satisfied. In addition, to decrease the cutting force and the wearing of the pick, the tip angle of pick should not be larger than the half of the difference between the minimum wearing angle and the impact angle of the pick, and the clearance angle must not be less than zero.

Dragload and Downdrag Performances of Inclined Pile Group Embedded in Consolidating Soil

The performance of inclined pile group embedded in consolidating soil under surcharge load was investigated by experiment in comparison with vertical pile group and single pile under the same conditions; dragload, downdrag, and layered soil settlement were measured. A three-dimensional numerical model was built via FLAC3D software, and verified by the experimental results. Influence factors, such as consolidation time, pile spacing, and pile tilt angle were analyzed. The results show that dragload of inclined pile group increases with the increase of consolidation time and pile spacing or the decrease of pile tilt angle. Downdrag of inclined pile group increases with the increase of consolidation time, pile spacing and pile tilt angle.

Electric field distribution in 75 kA drained aluminum reduction cell

Current distribution in a drained aluminum reduction cell is critical due to its influence on the current efficiency, electrolysis stability, anodes and cathodes integrity. A finite element model was developed to simulate the electric field in a 75 kA drained aluminum reduction cell. The current distribution and influences of the cathode inclination angle and anode-cathode distance (ACD) were studied. The results show that relatively large horizontal current density appears in the aluminum film, and the maximum value reaches 600 kA/m2. As the cathode inclination angle increases from 2° to 15°, the maximum current density of the metal pad increases by 15%, while the maximum current density of the aluminum-wettable coating layer decreases by 27%. The influence of the ACD on the current distribution is not obvious.

倾斜摄影技术在水利工程中的应用研究

以某大型水库调蓄枢纽工程为研究对象,通过理论解析的方法推导了基于无人机倾斜摄影的倾角数学模型,并分析了无人机倾斜摄影技术的数据采集及实景模型的重构过程,研究无人机倾斜摄影技术的测绘精度。结果表明,基于无人机倾斜摄影技术构建的水利调蓄枢纽工程以及地形地物的实景模型,纹理清晰、三维效果显著、地形地物区分明显,能够真实反映实际物体;基于无人机摄影技术地物测绘解算结果和地面近景摄影图像技术的地物测绘精度成果对比表明,无人机倾斜摄影在水利枢纽工程基本地形图测绘中具有适用性,解译精度高。

Maximum heat transfer capacity of high temperature heat pipe with triangular grooved wick

A mathematical model was developed to predict the maximum heat transfer capacity of high temperature heat pipe with triangular grooved wick. The effects of the inclination angle and geometry structure were considered in the proposed model.Maximum heat transfer capacity was also investigated experimentally. The model was validated by comparing with the experimental results. The maximum heat transfer capacity increases with the vapor core radius increasing. Compared with the inclination angle of0°, the maximum heat transfer capacity increases at the larger inclination angle, and the change with temperature is larger. The performance of heat pipe with triangular grooved wick is greatly influenced by gravity, so it is not recommended to be applied to the dish solar heat pipe receiver.

Deformation study of bicrystalline and nano-polycrystalline structures using phase field crystal method

Deformation behaviors of bicrystalline and nano-polycrystalline structures of various tilt angles and inclination angles in two dimensions are investigated in detail using a two-mode phase field crystal model.The interaction between grain boundary(GB)and dislocation is also examined in bicrystals and nano-polycrystals that both contain asymmetric and symmetric tilt GBs,with energy analysis being carried out to analyze these processes.During deformation simulations,we assume the volume of each simulation cell at every time step is coincident with that of the initial state just before deformation.Our simulation results show that the behaviors of symmetric and asymmetric GBs in bicrystals and nano-polycrystals differ from each other depending on tilt angle and inclination angle.A new dislocation emission mechanism of interest is observed in bicrystals which contain low angle symmetric tilt GBs.Low angle GB has a higher mobility relative to high angle GB in both bicrystalline and nano-polycrystalline structures,as does asymmetric GB to symmetric GB.The generation,motion,pileup and annihilation of dislocations,grain rotation and grain coalescence are observed,which is consistent with the simulation results obtained by molecular dynamics.These simulation results can provide strong guidelines for experimentation.