不同含水率蚯蚓粪颗粒物料流动性研究  

Flow properties of vermicompost particle with different moisture contents

作　　者：林嘉聪[1,2] 罗帅 袁巧霞[1,2] 曹红亮 Lin Jiacong;Luo Shuai;Yuan Qiaoxia;Cao Hongliang(College of Engineering,Huazhong Agricultural University,Wuhan 430070,China;Key Laboratory of Agricultural Equipment in Mid-lower Reaches of the Yangtze River,Ministry of Agriculture and Rural Affairs,Wuhan 430070,China)

机构地区：[1]华中农业大学工学院,武汉430070 [2]农业农村部长江中下游农业装备重点实验室,武汉430070

出　　处：《农业工程学报》2019年第9期221-227,共7页Transactions of the Chinese Society of Agricultural Engineering

基　　金：中央高校基本业务科研经费(2662016PY108);公益性行业(农业)专项(201303091);湖北省自然科学基金(2017CFB159)

摘　　要：蚯蚓粪是有机固体废弃物经蚯蚓过腹处理后排出的特殊物料,由于含水率高达 40%~60%的同时又能够保持散体细小颗粒的状态,导致流动性参数难以通过常规测试手段得到。为给蚯蚓粪收集、分离、运输等不同阶段机械化作业提供有效的运动摩擦参数,探究含水率变化对蚯蚓粪颗粒流动性参数的影响。研究通过堆积角试验与离散元仿真(Discreteelement method,DEM)堆积角虚拟试验相结合的方法,从数值上量化分析了基于牛粪转化后不同含水率 25%~65%蚯蚓粪物料的滚动摩擦参数与物料黏结能力。结果表明,显著影响蚯蚓粪堆积角的因素为蚯蚓粪-蚯蚓粪滚动摩擦系数,蚯蚓粪-不锈钢滚动摩擦系数,蚯蚓粪的 JKR 表面能(Johnson Kendall Roberts surface energy)。随着含水率的增加,蚯蚓粪-蚯蚓粪的滚动摩擦系数由 0.135 下降至 0.110,蚯蚓粪-不锈钢滚动摩擦系数由 0.116 下降至 0.102,两者呈现小幅度下降,内摩擦角由 45.81°降至 26.10°,而 JKR 表面能由 0.179 J/m2增加至 0.345 J/m2,增幅显著。含水率低于 50%时,随着含水率增加,物料滚动摩擦系数减小,内摩擦角减小,一定程度上有利于物料滚动流动;含水率超过 50%时,由于表面能增高,内聚力增大,蚯蚓粪物料之间易发生物料黏结团聚,一定程度上又会阻碍蚯蚓粪的翻滚运动。The earthworm processing of waste is recognized as a very sustainable approach for management of organic wastes. The vermicompost resulted from this procession has been proved to be practical and useful in farming, substrate nursery, gas absorbent etc. However, this technology has been widely adopted to treat different organic waste material. Most of scientific investigation in vermicompost concentrates on its nutrient characteristics and microorganism rather than physical properties. The flow ability is key factor for the mechanized operation of vermicomposting. The basic parameters like rolling friction coefficient and surface energy are needed for the equipment design, material calculation, and vermicompost product manufacture. The moisture content of vermicompost can reach 40%-50% under natural condition, even with high moisture content, the vermicompost can still keep the granular condition. Flow parameters, such as friction coefficient, cannot simply test though the normal physical method. In order to provide the quantized flow parameters of vermicompost for mechanization, in this study, vermicompost transformed from pure cow dung by the worm procession was used. The experiments were undertaken in condition of different moisture contents, changing from 25%-65%. The friction coefficient and surface energy were investigated by the method of pile angle simulation and calibration using discrete element method (DEM). First, Plackett-Burman (PB) design was conducted to select the impacted physical frictional parameter factors that have significant influence on pile angle. Then, the steep climbing test was conducted to shorten the parameter ranges from the maximum range of PB design. According to the result of steep climbing test, the response surface methodology (RSM) was carried out to build the model which can reflect the relationship between pile angle and friction coefficients. Besides, for explaining the flow ability of vermicompost in further, the direct shearing test was applied to calculate the internal f

关 键 词：粪 含水率 蚯蚓粪 摩擦系数 流动性 黏结性能 离散元 

分 类 号：S216[农业科学—农业机械化工程] S3[农业科学—农业工程]