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STUDY ON ACCURATE-HIGH SPEED POWDER CLASSIFICATION SYSTEM CONSIDERING PARTICLE CHARACTERISTICS

考虑颗粒特性的精确高速粉体分级系统研究

基本信息

批准号：
15560156
负责人：
NAKABAYASHI Koichi
金额：
$ 2.37万
依托单位：
AICHI UNIVERSITY OF TECHNOLOGY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2004
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15560156/
关键词：
SMALL PARTICLE CLASSIFICATION EFFECT OF TRUE SPECIFIC GRAVITY EKMAN NUMBER ROSSBY NUMBER FRACTIONALE EFFICIENCY SCALING LAW CENTRIFUGAL EFFECT PARAMETER GRAVITATIONAL EFFECT PARAMETER 重力効果パラメータ粒子特性と分級収率

项目摘要

WE PROPOSE A NEW WET TYPE CENTRIFUGAL CLASSIFICATION SYSTEM TO WHICH A STABLE AND AXISYMMETRIC ALMOST RIGIDLY ROTATING FLOW CAN BE APPLIED. THE CLASSIFICATION SYSTEM HAS DISTINCTIVE FEATURES IN THAT WE CAN ARBITRARY SET THE RATIO OF THE CENTRIFUGAL FORCE TO THE FLUID DRAG ACTING ON PARTICLES AND CAN THEORETICALLY INVESTIGATE THE CLASSIFICATION MECHANISM FROM THE PARTICLE TRAJECTORIES BY NUMERICAL SIMULATION. WE PREVIOUSLY INVESTIGATED RESULTS OF THE CLASSIFICATION PERFORMANCE FOR VARIOUS THROUGH FLOW RATE AND ROTATION RATE, AND CLARIFIED THE DEPENDENCE OF THE SHARPNESS INDEX AND CUT SIZE ON EKMAN AND ROSSBY NUMBERS FOR THE SPHERICAL PARTICLES FROM ONE-MICRON TO SUB MICRON REGIME HAVING TRUE SPECIFIC GRAVITY NEAR ONE. HOWEVER, THE THROUGHPUT IS SMALL FOR THE SYSTEM. INDUSTRIAL NEEDS ALSO DEMAND MORE ACCURATE CLASSIFICATION OF PARTICULATE MATERIALS HAVING VARIOUS SHAPES AND TRUE SPECIFIC GRAVITY MORE THAN TWO. HENCE IN ORDER TO MAKE THIS SYSTEM PRACTICABLE, WE HAVE TO EXTEND THE SYSTEM TO MORE EFFICIENT ONES.THE OBJECTIVE OF THE PRESENT STUDY IS TO DEVELOP THE CLASSIFICATION SYSTEM TO A NEW TECHNIQUE ON THE CLASSIFICATION SYSTEM SATISFYING INDUSTRIAL NEEDS. WE HAVE OBTAINED THE FOLLOWING RESULTS:1. IN ORDER TO CLARIFY A SCALING LAW ON THE GRAVITY FORCE, WE DEFINE CENTRIFUGAL EFFECT PARAMETER Ce, GRAVITATIONAL EFFECT PARAMETER Ge AND PARTICLE REYNOLDS NUMBER Re. AND WE INVESTIGATE THE RELATION BETWEEN THESE PARAMETERS AND THE DIFFERENCE OF FLUID AND PARTICLE VELOCITIES IN THE STEWARTSON LAYER WHICH IS THE MAIN CLASSIFICATION FLOW FIELD.2. WE CALCULATED THE PARTICLE TRAJECTORIES AND THE PROBABILITY DENSITY DISTRIBUTION OF THE PARTICLES BY THE NUMERICAL SIMULATION. AND WE INVESTIGATE THE CLASSIFICATION MECHANISM IN THE EKMAN AND STEWARTSON LAYERS.3. WE TREAT NEW SYSTEM WITH A SIMPLE SHAPE LIKE A DISK-CYLINDER SHAPE AND EVALUATE ITS CLASSIFICATION PERFORMANCE BY NUMERICAL SIMULATION.

本文提出了一种新的湿式离心分级系统，它可以应用稳定的轴对称几乎刚性旋转流。该分类系统的特点是可以任意设定作用于颗粒的离心力与流体阻力之比，并可以通过数值模拟从理论上揭示颗粒的分类机理。本文对不同通流率和转速下的分级性能进行了试验研究，并对真比重接近1的1微米至10微米范围内的球形颗粒，阐明了尖锐度指数和粒度与Ekman数和Rossby数的关系。但是，系统的吞吐量很小。工业上也需要对具有各种形状和真实比重大于2的颗粒材料进行更精确的分类。因此，为了使这一系统实用化，我们必须将这一系统扩展到更有效的系统。本研究的目的是将这一分类系统扩展到一种新的技术，使其能够满足工业需要。我们取得了以下成果：1.为了阐明引力的标度律，我们定义了离心效应参数Ce、引力效应参数Ge和粒子雷诺数Re。并阐明了这些参数与主要分类流场中的Stewart层中流体和颗粒的速度差之间的关系.通过数值模拟计算了颗粒的运动轨迹和概率密度分布。并对Ekman层和Stewart son层的分类机制进行了分析.我们对一个简单的圆盘-圆柱形的新系统进行了处理，并通过数值模拟来验证它的分类性能。