下运带式输送机磁流变制动技术研究

发布时间：2018-06-13 07:03

本文选题：下运带式输送机 + 磁流变制动器　；参考：《太原科技大学》2017年硕士论文

【摘要】：在下运带式输送机的制动系统中,采用传统摩擦制动或液压制动会存在“热衰退”、制动尖叫、制动闸瓦磨损严重、制动力矩不能连续调控等问题。而磁流变制动器作为一种新型的线控制动器,可以极好的弥补这些缺点,其具有能耗低、制动时间短、部件磨损小、制动力矩可调可控、便于集成新型控制技术等优点,这些优点十分契合下运带式输送机的制动需求。针对这一问题,本文对传统单线圈混合式磁流变制动器进行改进,设计了一种双线圈旁置式新型磁流变制动器,并将其应用到小型下运带式输送机的制动系统中,以达到在增大磁流变制动器制动力矩的同时实现轻量化设计的目的。首先从微观角度对磁流变制动器的制动机理进行了数值模拟,搭建了磁流变液中磁性颗粒的动力学仿真模型,研究了磁流变液体积分数和磁场强度对其成链微观结构的影响,对磁性颗粒在磁场作用下的剪切过程进行了数值模拟。其次以某小型下运带式输送机为例,计算了该下运带式输送机所需制动力矩,根据所需制动力矩,设计了一种双线圈旁置式磁流变制动器。基于Herscher-Bulkley模型,推导了双线圈旁置式磁流变制动器的力矩模型,并提出了相应的磁路设计方法。同时为了提高双线圈旁置式磁流变制动器制动力矩,实现轻量化设计的目的,提出了一种基于有限元分析和多目标遗传算法的联合优化设计方法。利用该方法得到了磁路结构的Pareto非劣解集,并选用组合赋权法对Pareto非劣解进行选优,得到了制动器最佳的磁路结构参数。最后通过对磁流变液的Bingham模型进行修正,得到磁流变液的等效表观粘度,并将其作为联系磁场、流场、温度场的重要中间变量。另外,建立了双线圈旁置式磁流变制动器的运动学方程,基于麦克斯韦方程、Navier-Stokes连续性方程、共轭传热方程,采用序贯耦合法建立了磁流变制动器的磁流固热多物理场耦合仿真模型,得到了双线圈旁置式新型磁流变制动器在下运带式输送机非制动工况下的稳态温度分布,以及制动工况下的磁场分布、流场分布、瞬态温度场分布。结果表明所提出的双线旁置式新型磁流变制动器可以满足小型下运带式输送机的制动要求。本论文的研究可以为磁流变制动器的结构设计、磁路设计以及优化分析提供参考,同时也能为下运带式输送机的制动方式提供了一种新的选择方案。
[Abstract]:In the braking system of belt conveyor, the traditional friction brake or hydraulic brake will have some problems, such as "heat decline", brake scream, brake shoe wear and brake torque can not be controlled continuously. As a new type of wire brake, magnetorheological brake can make up for these shortcomings. It has the advantages of low energy consumption, short braking time, small wear of parts, controllable braking torque, and easy to integrate new control technology. These advantages are in line with the brake requirements of the belt conveyor. To solve this problem, this paper improves the traditional single-coil hybrid magnetorheological brake, designs a new type of double-coil side-mounted magneto-rheological brake, and applies it to the braking system of a small down-load belt conveyor. In order to achieve the purpose of lightweight design while increasing the braking torque of Mr brake. Firstly, the braking mechanism of magneto-rheological brake is numerically simulated from the microscopic point of view, and the dynamic simulation model of magnetic particles in the magnetorheological fluid is built, and the effects of the integral number and magnetic field intensity of the magnetorheological fluid on the chain microstructure are studied. The shear process of magnetic particles under the action of magnetic field is numerically simulated. Secondly, the braking torque of a small down belt conveyor is calculated. According to the required braking moment, a magnetic rheological brake with two coils is designed. Based on the Herscher-Bulkley model, the torque model of the double-coil side-mounted magneto-rheological brake is derived, and the corresponding magnetic circuit design method is proposed. At the same time, in order to improve the braking torque of the double-coil side-mounted magnetorheological brake and realize the lightweight design, a joint optimization design method based on finite element analysis and multi-objective genetic algorithm is proposed. By using this method, the Pareto noninferior solution set of magnetic circuit structure is obtained, and the optimal magnetic circuit structure parameters of the brake are obtained by selecting the Pareto noninferior solution by using the combinatorial weighting method. Finally, by modifying the Bingham model of MRF, the equivalent apparent viscosity of MRF is obtained, which is regarded as an important intermediate variable of magnetic field, flow field and temperature field. In addition, the kinematics equation of the double-coil side-mounted magneto-rheological brake is established. Based on Maxwell's equation, the Navier-Stokes continuity equation and the conjugate heat transfer equation are established. The simulation model of magneto-fluid-solid-heat multi-physical field coupling of magneto-rheological brake was established by sequential coupling method. The steady state temperature distribution of a new type of magneto-rheological brake with two coils was obtained under the non-braking condition of the belt conveyor. And the distribution of magnetic field, flow field and transient temperature field under braking condition. The results show that the new type of magnetorheological brake can meet the brake requirements of small downloadable belt conveyors. The research in this paper can provide a reference for the structure design, magnetic circuit design and optimization analysis of the MRF brake, and also provide a new option for the braking mode of the downward belt conveyor.
【学位授予单位】：太原科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TH222

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