Numerical simulation for volatile organic compound removal in rotating drum biofilter

Rotating drum biofilters (RDBs) could effectively remove volatile organic compounds (VOCs) from waste gas streams. A mathematical model was developed on the basis of mass transport and mass balance equations in an RDB,the two-film theory,and the Monod kinetics. This model took account of mass transfer and biodegradation of VOC in the gas-water-biofilm three-phase system in the biofilter,and could simulate variations of VOC removal efficiency with a changing specific surface area and porosity of the media due to the increasing of biofilm thickness in the biofilter. Toluene was used as a model VOC. This model was further simplified by introducing a coefficient of the gas velocity and ne-glecting the water phase due to the complexity of operating conditions. The equations for the biofilm phase,gas phase,and biofilm accumulation in this model were solved using collocation method,ana-lytic method,and the Runge-Kutta method separately. A computer program was written down as MATLAB to solve this model. Results of numerical solutions showed that toluene removal efficiency in the RDB increased and reached the maximum values of 97% on day 4 after the startup,and then de-creased and remained at 90% after 5 more days of operation. Toluene concentration was high at the outermost layer where more than 70% toluene was removed,and was low at the innermost layer where less than 10% toluene was removed. The dynamic removal efficiencies from this model correlated reasonably well with experimental results for toluene removal in a multi-layered RDB.     

储纬器定长方法的探讨

文章分析了IWF8407和ROJ—Elf两种储纬器的定长方法 ,提出了在不改变储纬鼓直径条件下提高引纬定长精度的三种方法 ,可供开发设计新型储纬器时参考。     

鼓式制动器接触分析

通过建立鼓式制动器的理论模型，并运用工程分析软件ANSYS对摩擦衬片和制动鼓之间的摩擦接触进行分析，得出接触压力的分布行性及制动器的应力分布场，强化了理论设计。结果表明这一方法对于鼓式制动器的分析计算有很高的精度。     

基于BP神经网络的煤层硬度多等级识别方法

针对煤层硬度识别方面存在的问题,提出一种基于BP神经网络算法的煤层硬度多等级识别方法,将煤层硬度划分为6个等级进行识别.以采煤机截割电机和牵引电机的定子电流信号及调高油缸压力信号作为识别信号,利用小波包分解提取各个信号的特征量,并将其作为神经网络的输入样本进行训练和测试.经过实验,在仿真数据条件下本文提出的煤层硬度多等级识别方法对硬度等级的识别准确率为96.7%,在实机数据条件下识别准确率为93.3%,验证了该煤层硬度识别方法的有效性,为采煤机自适应截割过程煤层硬度高精度识别奠定了理论基础.     

鼓式制动器效能因数的计算研究

双向自增力鼓式制动器受力复杂,影响因素较多,制动效能因数的计算比较困难。该文通过建立双向自增力鼓式制动器力学模型,用２种方法分别对其效能因数进行了计算,同时,通过台架试验测试了该制动器的制动力矩,以获得其效能因数,并对计算结果和试验结果进行对比分析。结果表明,所建立的双向自增力鼓式制动器力学模型基本与实际相符,计算方法准确简单。     

Classification by Neural Net of a Particle Stream in an Eddy Current Drum Separator

At present, eddy current separation is primarily used for the recovery of non‐ferrous metals from industrial waste (e. g. car scrap), rather then the recovery of similar metals from domestic waste. This is due to the complexity of domestic waste and to the difficulties in its characterisation. This work approached the problem in order to study the possibility of developing and implementing the control system of an eddy current drum separator, based on image analysis of the fed stream. The investigated control sets settled the working parameters of the device (i. e. belt and drum speed and splitter position) according to the data supplied by a control model based on a neural net. The goal was to establish the critical parameters that can lead the neural net to a proper classification of the input stream, starting from selected OWF (organic wet fraction of the waste) and shredded particles. After experimental tests, carried out under different conditions (belt and drum speed) and on particles of different materials, morphological (area, diameter, minor and major axis, aspect), optical (metal particles surface response to the lighting system) and trajectory (second‐order curve) parameters are extracted by image analysis of the scene. In order to achieve a proper classification, the most important parameters were area and trajectory parameters. Better classification results were obtained taking into account a special feature, ECD (eddy current dimension), extracted after image analysis.     

采煤机滚筒截割记忆程控误差的灰预测

根据采煤工作面设备配套条件和采煤机工作循环特点,分析了记忆程控滚筒调高的采样、控制环节误差产生的原因,论述了可靠预测采样控制的精度及误差的修正,以再现上一截割循环顶底板的变化序列曲线.通过对正弦函数型的参考序列曲线和比较序列曲线关联度计算分析,研究了灰预测关联度的几种方法特征,给出了适合采煤机滚筒记忆程控特点的关联度预测方法,满足记忆程控的指令宏观再现控制要求.     

铲斗装载机鼓轮曲面的特性研究

正位鼓轮曲面的形状对矿用铲斗式装载机的工作性能、生产率和使用寿命都有直接的影响。通过对六种不同的鼓轮曲面所进行的模拟分析，得出了相应的铲斗提升过程的运动参数及其变化情况，在此基础上，研究了各种鼓轮曲面的特征。分析表明：鼓轮曲面的空间曲线为直线形的方案是比较合理的。     

转鼓分流分相式气液两相流体流量测量技术研究

提出了一种分流分相式气流两相流体流量计，其采用转鼓作为分配器，从被测的两相流体中成比例地分流出约20％的气流混合物，并应用分离法分别测量出其中的气相和液相流量，然后根据比例关系确定被测两相流体的各相总流量，理论分析和实验结果都证明，分流系数等于分流通道数与总通道数的比值，而与流型无关，实验中出现的流型包括分层流，波状分层流和环状流，在实验范围内，流量测量的平均误差小于5％，实验结果与表明，转鼓运动间隙是影响实际分流系数稳定性的主要因素，转鼓的加工精度愈低，运动间隙过大，则分流系数的稳定性和测量精度就愈低。     

鼓槌形状与击鼓过程力学特性分析

用力学理论分析鼓槌击鼓的过程,对鼓槌的不同形状和质量分布进行讨论,得出了鼓槌的最佳握点及形状。