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针对固态含能物料在称重过程中提高自动化程度和称量准确性的需求开展研究,为降低自动输送装填工艺的过程安全风险、提高设备安全控制能力,设计一台失重式气动振动输送装置,采取失重计量的方式,通过安装在秤台上的称重传感器,称重料斗中物料的质量被实时反馈给控制器,控制器通过内部算法得到单位时间内的质量减少量(即实际流量)。根据实际流量与设定流量之间的差值,控制器输出速度信号控制电动机的转速,直线气动振动输送料道将物料以一定速度连续输送,直线气动振动料道通过板簧、振幅、频率的调节,具有良好的线性控制,可以实现固态含能材料的自动安全计量及输送。 相似文献
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《机械制造与自动化》2016,(1):218-222
粉状物料在连续螺旋输送的过程中,物料输送参数在外界扰动和时变效应的影响下会发生很大的变化,采用一般的控制方法很难达到稳定的物料流量。将迭代学习控制算法与传统的PID算法相结合,构成了一种迭代学习PID控制器。针对粉状物料计量系统所存在的问题,给出控制系统结构,并对螺杆输送器的参数进行计算,将该控制器应用其中,采用MATLAB仿真分析,结果表明,该控制器能够自动调节物料输送能力,使控制系统取得满意的控制效果,并且给出了该粉状物料计量系统的控制原理框图,有较好的实际应用价值。 相似文献
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本文以螺旋卸船机的相对旋转式取料装置为研究对象,分析了物料在进料过程中的运动性态与受力性态,提出了判别物料进入取料翼板的条件,导出了物料运动参数的计算方法,进而建立了取料装置充填率的计算模型,它反映出取料装置结构尺寸,取料管转速以及输送段物料运动特性对取料性能的综合影响。本文在一定程度上揭示了当取料管与垂直输送螺旋反向旋转情况下物料运动的规律性,并通过模型试验进行了验证。 相似文献
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The two-dimensional, unsteady, laminar conservation equations for mass, momentum, energy and species transport in the gas
phase are solved numerically in spherical coordinates. This is to study the heat and the mass transfer, and the combustion
around a single spherical droplet. The droplet mass and momentum equations are also solved simultaneously with the gas phase
equations in order to investigate the effects of droplet entrainment in the oscillating flow with and without a steady velocity.
The numerical solution for a single droplet combustion gives the droplet diameter variation as well as the gas phase velocity,
temperature and species concentrations as a function of time. The effects of frequency, amplitude of oscillating flow, velocity
ratio of oscillating flow amplitude to the steady velocity, ambient temperature and initial droplet diameter on the droplet
combustion are also investigated. The droplet burning history is not governed by thed
2-law in the presence of oscillating flow, unlike to the case under quiescent ambient conditions. 相似文献
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为阐明进气方式对气力提升特性的作用规律,以普通河沙模拟井下矿层,利用小型输沙系统实验研究在恒定浸入率和供沙量下气孔数量与进气角度对扬水量、扬沙量及总效率的影响。结果表明:任一进气方式下扬水量、扬沙量及总效率并不随气量值增加呈现单调特性,前两者峰值所处位置大致接近,且较总效率峰值对应点右移。气孔数量和进气角度对扬水量及扬沙量影响较小,对总效率影响程度稍大。就整体而言,对应气孔数量和进气角度分别为4和90°时其扬沙量与总效率较其它进气方式上扬。另外,实验测得最高扬沙效率所对气相佛汝德数大致相同,约为2.5,且最佳扬沙效率所对应的气相佛汝德数随管径递增。 相似文献
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The concentration measurement of pulverized coal in a pneumatic pipeline is a challenging issue in power plant. A thermal probe manufactured with abrasion-proof steel was developed for coal concentration measurement in such a situation. The probe generates 15 W of heat. This method is based on the heat transfer between the thermal probe and the gas–solid two-phase flow. Experiments were conducted in a horizontal pneumatic pipeline to assess the accuracy of the thermal probe, where the gas was air and the solid was pulverized coal with mean diameter of 65 µm. The wall temperature of the thermal probe was found to be dependent on both coal powder concentration and air velocity. A new heat transfer correlation was proposed in terms of the modified Reynolds and Nusselt numbers for the gas–solid two-phase flow across the thermal probe. In the range of coal powder concentration from 0.1 to 0.65 kg/kg, the standard deviation is 0.01 kg/kg for the thermal probe. The thermal probe has potential application for concentration measurement of pulverized coal in the pneumatic pipelines of power plants. 相似文献
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《Measurement》2016
In this paper, an instrumentation system for the measurements of local solid volumetric concentration, local solid velocity, local solid mass flowrate and solid mass flowrate in gas-solid two-phase flow system is developed. It is based on a new type of a Capacitance-Electrostatic sensor (CES). The CES sensor is mainly composed of a capacitance electrode array and two electrostatic electrode arrays. The optimum design of the sensor is achieved by finite element method. The capacitance electrode array is employed to detect the solid distribution over the cross-section of the pipe, and the local solid volumetric concentration measurement is further derived. The electrostatic electrode arrays are used to measure the local solid velocities in conjunction with cross-correlation method. From the local solid velocity and local volumetric concentration, the solid mass flowrate and the local solid mass flowrate can be achieved. The developed system for the local solid volumetric concentration measurement is verified through analogue simulation experiments and static experiments. Finally, the system is employed to measure the local solid volumetric concentration, local solid velocity, local solid mass flowrate and solid mass flowrate on a belt conveyor. The experimental results show that the measurement error of the local solid volumetric concentration measurement results are less than 10.43% for solid local volumetric concentration ranging from 0.02 to 0.56, the standard deviations of the local solid velocity measurement results are less than 0.42 for solid velocity ranging from 3.5 m/s to 15.0 m/s, and the relative error of the solid mass flowrate is within −19.6% to +14.9% for solid mass flowrate ranging from 0.006 kg/s to 0.103 kg/s, indicating that the system is capable of achieving multi-parameters measurement in gas-solid two-phase flow system. 相似文献
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气力输送分支管路流量分配特性的研究 总被引:1,自引:0,他引:1
在水平T形分支管道中,用压缩空气作为输送气体,对不同粒径的砂石进行气力输送试验。分别通过试验和改进型BP神经网络预测两种方法对表观气速和分支管路流量控制阀开度变化时,固相在分支管路中的分配特性进行了研究。结果表明,随着表观气速减小和两分支管路流量控制阀开度差值变大,固相流量在两分支管中的分配产生较大差异。试验值和改进型BP网络预测值的对比结果表明,二者相互吻合较好,说明采用改进型的BP网络来模拟固相在分支管路中的分配特性适应性较好。 相似文献