基于离散元法的螺旋进料器物料流动特性分析

发布时间：2018-08-24 21:21

【摘要】：针对附属于给定机型颗粒成型机上的螺旋进料器,对玉米秸秆粉料在进料器内的流动特性进行了模拟分析。利用离散元分析软件EDEM,创建了螺旋进料器部件的几何模型,并对玉米秸秆粉料颗粒接触模型和颗粒生成方法进行了研究,通过离散元模拟获得了现有工况下螺旋进料器工作时的粉料流动状态。采用HERTZ-MINDLIN无滑移接触模型,取重力加速度为9.81m·s~(-2),设置接触参数并生成了秸秆颗粒25000个进行仿真模拟。结果表明:在T=13.80~14.30s阶段为一典型的出料波动周期。出料过程中粉料呈浪涌流动状态的不连续脉动流;进一步分别针对颗粒密度、粒径大小、壁面摩擦因数、螺距、螺旋叶片内径参数进行了流态和速度的影响因素分析。颗粒密度分别取40,80,120kg·m~(-3)时,出料所需时间分别为21.37,17.68,15.01s;粒径分别取为2,1.8,1.6mm时,出料所需时间分别为17.68,18.06,19.37s;壁面静摩擦因数分别取为0.58,0.48,0.38时,出料所需时间分别为17.68,16.03,15.84s;螺旋叶片内径分别取为50,60,70mm时,在整个模拟时长20s内出料的平均流量分别为16.73,12.61,8.96g·s~(-1)。其中颗粒密度越大,粒径越大,则出料速度越快,但对粉料流态无明显影响;壁面摩擦因数越小、螺距越大、螺旋叶片内径越小,则出料口流速越快,流场分布越宽,落料范围越大,流态越剧烈。本研究可为适用于生物质颗粒成型机的螺旋进料器的设计和改进提供参考。
[Abstract]:In this paper, the flow characteristics of corn straw powder in the feed unit are simulated and analyzed for the screw feeder attached to a given type of particle forming machine. Using discrete element analysis software EDEM, the geometric model of screw feeder components was established, and the contact model of corn straw powder particles and the method of particle formation were studied. Through discrete element simulation, the powder flow state of the screw feeder working under the existing working conditions is obtained. The HERTZ-MINDLIN non-slip contact model was adopted and the gravity acceleration was 9.81m s ~ (-2). The contact parameters were set and 25000 straw particles were generated for simulation. The results show that the fluctuation period of discharge is typical at the stage of TX 13.80 ~ 14.30s. The discontinuous pulsating flow of powder in surge flow state during discharging process was further analyzed according to particle density, particle size, wall friction factor, pitch and inner diameter of spiral blade. When the particle density is 40,80120kg m ~ (-3), the discharge time is 21.37m ~ (- 3), the discharge time is 17.6818kg / m ~ (-3), when the particle diameter is 2 ~ 1.81.6mm, the discharge time is 17.68m ~ (-1) 18.06m ~ (-3), the wall static friction coefficient is 0.580.480.38, the discharge time is 17.68 ~ 16.0315.84s, and the inner diameter of the spiral blade is 506060mm / 70mm, respectively, when the particle density is 40 ~ (80) kg / m ~ (-3), the discharge time is 21.37 ~ (m ~ (-3) and the diameter of the spiral blade is 5060m ~ (70) mm, respectively. The average discharge rate in 20 s is 16.73% 12.61% 8.96 g s ~ (-1), respectively. The larger the particle density and the larger the particle size, the faster the discharge speed, but the less the wall friction coefficient, the larger the pitch, the smaller the diameter of the spiral blade, the faster the outlet velocity and the wider the flow field distribution. The larger the blanking range is, the more intense the flow pattern is. This study can be used as a reference for the design and improvement of screw feeder for biomass pellet molding machine.
【作者单位】：沈阳农业大学工程学院;重庆大学动力工程学院;
【基金】：国家自然科学基金项目(51405311)
【分类号】：TQ021.1

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