基于粉料流动理论的料仓侧形设计及受力分析

介绍了仓内粉体物料流动特性,在此基础上对粉体料仓的侧形设计和仓体结构优化进行了简述,利用Janssen方法,研究分析了典型楔形仓内物料静压力分布,并应用研究结果对某楔形仓受力进行计算。     

环保型散粒体清理机的研发

环保型散粒体清理机采用新颖的设计理念,充分考虑现有散粒体储运清理设备的现状,能轻松地清理大堆散粒物料及仓中物料,残留物料极少,而且具有投资省、能耗低、方便快捷、清洁环保、自行走等特点,大大改变了散粒体人工清理的现状,改善了作业环境,降低了工人的劳动强度。根据样机试验结果分析,完全可以替代现有部分散粒体清理设备。     

悬挂式直线移动螺旋取料机的开发

近年来我国生物质发电项目开始崛起，国内首个生物质能电厂——山东省国能单县生物电厂，已于2005年10月12日开工建设。为了满足破碎后的秸秆从大型矩形料仓底部循环取出的要求，我公司成功开发了悬挂式直线移动螺旋取料机，并在国能单县生物发电厂燃料仓底部安装了2台。     

基于ABAQUS的饲料料仓结构优化设计

饲料料仓是一种常用的饲料存储设备,一般采用钢板焊接及螺钉联接而成。它具有结构简单、制造方便、应用场合多的特点。料仓功用包括对散装物料的接收、贮存、卸出和料位指示等。饲料属于散体,会对所承载的料仓侧壁产生一定压力从而致其变形。为了避免应力过大导致事故,需要可靠的理论分析和正确的计算,并对其进行结构优化设计。     

圆锥形件充液拉深过程中的上限液池压力

圆锥形零件充液拉深过程中存在两种破裂失效形式──侧壁破裂和凸模肩部破裂，理论分析与数值模拟给出了不产生上述破裂的上限液池压力—行程曲线，该曲线表明拉深初期工件在凸模肩部破裂，此后则在侧壁破裂。试验验证了文中提出的数学模型与模拟方法的有效性。     

注气式水下干式仓设计

海洋石油平台的双层保温立管是石油开发中的重要组成部分,由于制造问题多数存在立管外腐蚀情况。通过双层保温立管的内管外腐蚀分析及目前修复方案的弊端,提出一种注气式干式仓立管修复工艺方法。注气式干式仓通过向仓内注入干燥气体观察气体压力与海水压力的变化情况。当气体压力大于海水压力时,海水从干式仓底部排出;当干式仓内压力与干式仓底部海水压力相等时,底部形成气液结合面,在水下形成密闭的干式环境空间。通过建立三维模型,计算了仓内压力变化海水进入干式仓的内部高度,得到了压力变化与进入仓内液面高度的关系,为控制仓内压力提供了理论依据;干式仓的自重与浮力的平衡保证立管不受上拔力或干式仓自重带给立管的重力负荷。同时,通过有限元方法校核了干式仓在海水中承受外压时的强度。所提出的立管维修新方法,可有效解决水下立管干式环境维修难题。     

筒仓仓壁压力计算

分析现有筒仓在物料流动过程中出现结拱、滞流和仓壁开裂等问题的产生原因，对装料压力、卸料压力及其超压原因等进行了系统的分析，并将现今国内外使用的几种典型筒仓设计规范与实验值进行比较，提出了整体流筒仓仓壁压力修正系数的合理取值。     

简仓仓壁压力计算

分析现有筒仓在物料流动过程中出现结拱、滞流和仓壁开裂等问题的产生原因，对装料压力、卸料压力及其超压原因等进行了系统的分析，并将现今国内外使用的几种典型筒仓设计规范与实验值进行比较，提出了整体流筒仓仓壁压力修正系数的合理取值。     

浆体膨胀复合材料储料仓设计与分析

为实现浆体膨胀复合材料自助化制浆装置安全生产与高效制浆,创建了一个包含膨胀复合粉料相关参数的储料仓力学模型,根据充填浆体浓度配比及实际生产的相关要求进行了关键参数设计,确定出了仓体流型、容积、最大半顶角、最小卸料口径。并利用有限元法对储料仓进行结构强度分析,得出其在全载下位于圆柱圆锥连接处的最大应力、应变。工程应用表明,该储料仓可实现混料、储料、卸料等功能,保证了制浆装置的连续制浆与浆体质量,并为储料仓系列化生产提供了理论依据。     

外圆车抛一体装置及仓内粉尘压力密度监控系统研究

传统的靶材加工需要使用车床和抛光机，加工效率不高，而靶材生产剩余粉尘遗留喷涂仓中，会对喷涂质量产生很大的影响，只采用负压方式吸尘无法满足仓内压力要求，需要研发新型的靶材加工装置和密度监控系统。外圆车抛一体装置抛光机构将抛光机构整合到普通车床上，采用公用床身和导轨系统，前方设置有靶管，靶管的前方设有车削机构，可满足不同粗细的靶管抛光需要。BP-PID控制器可输入实时压力值、粉尘密度值等参数，采用BP神经网络对参数进行处理，输出频率控制值与风门开度进行干扰补偿，可优化喷涂仓压力，具有很高的实用价值。     

非牛顿介质中图形化表面对减阻效果的影响

为研究图形化表面在非牛顿介质中对减阻效果的影响,在微摩擦试验机(UMT)上进行了销盘润滑实验。实验中在硅片的表面刻蚀了纵向和横向2种沟槽以形成不同的表面图形。实验表明,与光滑表面相比,当剪切速率处于牛顿流动区时,沟槽具有一定的减阻效果;而当剪切速率处于剪切稀化区时,沟槽表面的阻力上升;并且横向沟槽表面的阻力总是大于纵向沟槽表面的阻力。流体数值计算的结果表明,横向沟槽侧壁的压差阻力和纵向沟槽侧壁的粘性阻力无法完全补偿沟槽底面上的阻力损失,因而产生了减阻效果。     

氧化铝料箱排气管冒料分析及对策

针对电解槽氧化铝料箱排气管“冒料”现象，从料箱和下料器结构、工作过程及工作条件等方面分析，找出“冒料”原因，采取措施，取得了明显的效果。     

PIV measurements in a turbulent wall jet over a backward-facing step in a three-dimensional,non-confined channel

A study of a turbulent wall jet over a backward-facing step is especially of interest because it shows a rich phenomenon flow and a mechanism to alter the flow characteristics downstream of the step. However, studies on this flow configuration are rare. In this paper, we considered this flow configuration in a non-confined channel as the specific engineering applications of electrical rotating machines and alternator that can be found in modern wind generators of the power production industry and automobile engines. The turbulent wall jet over a backward-facing step in a non-confined wind tunnel had the jet Reynolds number of 24,100 and the step Reynolds number of 11,900. Particle image velocity (PIV) and stereoscopic PIV measurements were performed along the central plane and several cross-stream planes. Numerical simulation of the test configuration was conducted by solving the three-dimensional Reynolds Averaged Navier–Stokes (RANS) equations with the second-order closure Reynolds stress model (RSM). The mean flow fields and second-order statistical moments from the RSM simulation were compared to results that were obtained through the PIV and stereo-PIV experiments. The mean reattachment length obtained from the current configuration was much shorter than those from the backward-facing step in the plane channel. The stereo-PIV measurements in the cross-stream planes revealed a high three-dimensionality of the flow, a high population of streamwise vortice in the upper region, near the side walls and the corners formed by the side walls and the bottom wall. The obtained results also confirmed the presence of the wall-jet formation on the bottom wall.     

Modified Building Structure for Tire Bead

This new utility model is related to a modified tire bead building structure which mainly consists of a major body and a few pieces of components to form the tire bead. The outside of the main body is an combined open space. The two side walls and the bottom of the combined space forms a straight angle or an obtuse angle, so it facilitates for mold stripping after the main body is formed. The assembly is curving and a complete circle can be formed by several assemblies. The outside of the assembly is corresponding to the combined space and its inner side is formed a channel. A few curving assemblies could be applied to the combined space of the main body to form acomplete tire bead body. After assembly, the bead could be put into the tire body from this channel.     

Heat transfer and friction characteristics in steam cooled rectangular channels with rib turbulators

We studied the heat transfer and friction characteristics in steam-cooled rectangular channels with rib turbulators on W side or H side walls in the Reynolds number (Re) range of 10000-80000. Each of the test channels was welded by four stainless steel plates to simulate the actual geometry and heat transfer structure of blade/vane internal cooling passage. The length of the channel L was 1000 mm, the cross section of the channel was 40 mm × 80 mm, and the pitch-to-rib height ratio p/e was kept at 10. The channel blockage ratio (W/H) was 0.047. Results showed that the Nusselt number (Nu) distributions displayed different trends at the entrance region with the increase of Re for the rib turbulators on the W side walls. The heat transfer performance of the rib turbulators on the H side walls was about 24-27% higher than that on the W side walls at the same pumping power. In addition, semi-empirical correlations for the two cases, rib turbulators on W side walls and rib turbulators on H side walls, were developed based on the heat transfer results, which could be used in the design of the internal cooling passage of new generation steam-cooled gas turbine blade/vane.     

水平槽道内几种周期性结构的传热与流动研究

采用数值模拟方法,对流体在不同周期性结构二维水平槽道内的传热性能与流动特性进行研究。分析不同雷诺数条件下,布置于槽道下壁面的障碍块表面时均努塞尔数Nu及表面摩擦因数μ的变化规律。计算结果表明,当障碍块之间量纲一距离分别为0.50和0.25、雷诺数Re=1 000时;槽道上、下壁面均布置障碍块的传热性能较仅在槽道下壁面布置障碍块的传热性能有了显著提高,前者比后者的传热性能分别提高393%和574%。当雷诺数Re=500、障碍块之间量纲一距离为0.50时,对在槽道中间设置一斜板与不设置斜板两种情况进行比较后发现,设置斜板的槽道比不设置斜板的槽道传热性能提高27.1%。当在下壁障碍块右上角处放置一小圆柱体后发现:传热性能并未得到有效提高,但流动摩擦因数有所减小,从而使得输送流体的泵功降低。     

复杂腔槽五轴数控加工的干涉检查及修正算法研究

针对复杂腔槽多轴数控加工的干涉问题进行了分析研究,进而给出腔槽侧面及底面无干涉刀位的计算方法。对于开口槽侧面边缘处的加工,通过检验侧面边缘与刀轴的干涉而确定粗加工走刀终止条件;对于腔槽底面加工,提出了刀具与底面及相临侧面间干涉的定量计算,并在此基础上根据干涉量一次性修正刀位,生成无干涉的合理刀位。     

Numerical study on the motion of azimuthal vortices in axisymmetric rotating flows

A rich phenomenon in the dynamics of azimuthal vortices in a circular cylinder caused by the inertial oscillation is investigated numerically at high Reynolds numbers and moderate Rossby numbers. In the actual spin-up flow where both the Ekman circulation and the bottom friction effects are included, the first appearance of a seed vortex is generated by the Ekman boundary-layer on the bottom wall and the subsequent roll-up near the corner bounded by the side wall. The existence of the small vortex then rapidly propagates toward the inviscid region and induces a complicated pattern in the distribution of azimuthal vorticity, i.e. inertial oscillation. The inertial oscillation however does not deteriorate the classical Ekman-pumping model in the time scale larger than that of the oscillatory motion. Motions of single vortex and a pair of vortices are further investigated under a slip boundary-condition on the solid walls. For the case of single vortex, repeated change of the vorticity sign is observed together with typical propagation of inertial waves. For the case of a pair of vortices with a two-step profile in the initial azimuthal velocity, the vortices’ movement toward the outer region is resisted by the crescent-shape vortices surrounding the pair. After touching the border between the core and outer regions, the pairt vortices weaken very fast.     

Electron microscope image contrast with double beam illumination from crystal supports

When a cluster of atoms on the bottom side of a crystal is viewed in the vicinity of a bend contour, a double image of the cluster is formed. The crystal acts as a beam splitter so that an object on the bottom of the crystal is illuminated by two coherent but non-parallel electron waves. The possibility of using double beam illumination to enhance the contrast of amorphous phase objects is discussed. Experimental results are presented for the image contrast of clusters formed by evaporating gold and aluminium on to the bottom side of graphite and silicon crystals.