基于DEM-BPM-CFD的饲草揉碎机功耗预测模型研究

Power Consumption Prediction Model of Forage Crusher Based on DEM-BPM-CFD Coupling Method

摘要:

饲草揉碎机工作时存在功耗大、生产率低等问题，制约着该类设备向低能耗、绿色化方向发展。为了准确预测饲草揉碎机的功耗情况，进而进行低能耗优化设计，本文基于饲草揉碎机的工作原理与DEM-BPM-CFD耦合方法，将揉碎机消耗能量分为物料与物料、气流、机械结构 （铡刀、锤片以及齿板） 之间相互作用所消耗的能量、使揉碎机内空气具有一定静压和流速所消耗能量、轴承摩擦所消耗能量以及整机振动所消耗能量4部分，并分别建立了各部分能耗以及生产率的数学模型。采用DEM-BPM-CFD耦合方法对饲草揉碎机破碎物料的耗能情况进行数值模拟，并结合功耗试验对所建立的功耗预测模型进行验证。研究结果表明：揉碎机功耗预测模型的理论计算值与功耗实测值相对误差为6.94%，可见饲草揉碎机功耗预测模型基本准确。饲草揉碎机揉碎物料过程中主要能耗为物料与物料、气流、机械结构（铡刀、锤片以及齿板）之间相互作用所消耗的能量，占总能耗3/5以上;其次为使揉碎机内空气具有一定静压和流速所消耗的能量，占总能耗1/4以上;再次为机体振动所消耗的能量，占比接近1/10;占比最小为转子与轴承摩擦所消耗的能量。研究结果可为饲草揉碎机低功耗设计提供基础依据。

Abstract:

The forage crushers have the problems of high-power consumption, low productivity and so on, which restricts the development of this kind of equipment to the direction of low energy consumption and greening. To accurately predict the power consumption of the forage crusher and then optimize the design of low energy consumption, the power consumed by the forage crusher was divided into four parts based on the working principle of the forage crusher and the DEM-BPM-CFD coupling method： the power consumed by the interaction between materials and materials, air flow，and the mechanical structure （cutters, hammers and tooth plate）, power consumption for endowing the air in the forage crusher with static pressure and flow velocity, the power consumed by bearing friction and the power consumption of the whole machine vibration. At the same time, the mathematical models of power consumption and productivity per kW·h of each part were established respectively. The DEM-BPM-CFD coupling method was used to simulate the power consumption of the crushed materials of forage crusher, and the power consumption prediction model was verified by the power consumption test. Results indicated that the relative error between the theoretical calculation value of the power consumption prediction model and the measured value of the power consumption was 6.94 %, which showed that the power consumption prediction model of the forage crusher was basically accurate. The predominant power consumed by the interaction between the materials and the materials, the air flow, and the mechanical structure （cutters, hammers and tooth plate）, constituting more than three-fifths of the total power consumption. The subsequent significant the power consumption for endowing the air in the forage crusher with static pressure and flow velocity, representing over a quarter of the total energy usage. The power consumption of the whole machine vibration accounted for nearly one-tenth of the total power usage, respectively. The smallest proportion was the power consumed by bearing friction. The research result provided a foundation for the design of low-power forage crushers.