摘要
农业物料的冲击破碎特性对运输、排种和粉碎等机械设备的工作参数设定具有重要参考意义。该研究以玉米籽粒为研究对象,设计并搭建了单颗粒物料冲击破碎试验装置,开展了5种不同含水率(10.86%±0.13%,13.87%±0.18%,17.24%±0.08%、20.23%±0.19%和23.46%±0.23%)玉米籽粒的冲击破碎试验,并以籽粒破碎模式、临界速度和破碎程度表征籽粒的破碎特性。试验结果表明,玉米籽粒的破碎模式可分为未破碎、破裂和破碎3种形式,其中破裂形式包括整体破裂和局部破裂;以碎粒中大颗粒质量与玉米籽粒质量间的比值W界定玉米籽粒的破碎模式,并建立了不同含水率玉米籽粒的W值与冲击速度间的回归模型,模型的决定系数均大于0.92,确定了5种不同含水率(含水率由低到高)玉米籽粒的临界破裂速度分别为11.45、15.54、19.84、30.49和34.28m/s,临界破碎速度分别为19.55、23.75、28.68、42.07和46.79 m/s,表明玉米籽粒的临界破裂速度和破碎速度均随含水率的增加而增加;采用响应曲面法建立了破碎颗粒平均粒径与冲击速度和含水率之间的回归模型,模型的决定系数为0.96,方差分析结果表明冲击速度、含水率及其交互作用对玉米籽粒的破碎程度影响极显著(P<0.01),且破碎程度随冲击速度的提高而增加,随含水率的提高而降低。该研究可为玉米籽粒处理设备的工作参数设定提供参考,并为农业物料颗粒的冲击破碎特性研究提供理论依据和试验方法参考。
Breakage can normally be induced by the impact of granular materials and mechanical equipment on agricultural products during seed discharging,harvesting,transportation,and crushing processes.Some breakage can damage the products,such as seed discharge and transportation,whereas,another breakage can be meaningful,such as crushing.Therefore,it is a high demand to investigate the breakage characteristics of product granules for the decision-making on the operational parameters of agricultural machinery,including the transportation,seeding,and crushing.Taking the maize kernel as the research object,the main purpose of this study is to clarify the influence of moisture content and impact speed on the impact breakage characteristics of products.Five types of maize kernel samples were first prepared with the variable moisture content.An impact testing device was designed for the single particle.A series of impact tests were performed on the maize kernels with five moisture contents.The breakage characteristics of the maize kernel were then characterized,in terms of breakage patterns,the extent of breakage,and the critical impact velocity.The experimental results revealed that the broken particles of maize kernels after breaking were divided into three levels of breakage patterns:the unbroken,rupture,and fragmentation,according to the size and quantity distribution characteristics.Among them,the fracture pattern included the overall and local rupture.The maximum particle mass ratio(W) was defined as the indicator for the breakage patterns of maize kernels,where the W was the mass of the big particle in the broken particles to the mass of the maize kernel.The regression equations were established between the W value and impact velocity of maize kernels with different moisture content,where the coefficients of determination(R2) were obtained all greater than 0.92.The critical rupture velocities of maize kernels with the moisture content from low to high were determined to be 11.45,15.54,19.84,30.49,and 34.28 m/s,respectively,and the critical fragmentation velocities were 19.55,23.75,28.68,42.07,and 46.79 m/s,respectively,according to the regression equations.It indicated that the critical rupture velocity and critical fragmentation velocity of the maize kernel increased with the increase of moisture content.The extent of breakage of maize kernels was characterized by the average particle size of broken particles.The 2FI model regression equation of average particle size was established with the impact velocity and moisture content using the response surface method(RSM),where the R2 was 0.96.In addition,the analysis of variance showed that there was an extremely significant influence on impact velocity,the moisture content of maize kernels,and the interaction on the extent of breakage(P<0.01).The extent of breakage of maize kernels increased with the increase of impact velocity,while decreasing with the increase of moisture content of maize kernels.These datasets can be used to determine the operational parameters of agricultural equipment during granule processing.The finding can also provide a theoretical basis for the impact breakage characteristics of agricultural products.
作者
李洪成
曾荣
杨天圆
牛智有
Li Hongcheng;Zeng Rong;Yang Tianyuan;Niu Zhiyou(College of Engineering,Huazhong Agricultural University,Wuhan 430070,China;Key Laboratory of Agricultural Equipment in Mid-lower Yangtze River,Ministry of Agriculture and Rural Affairs,Wuhan 430070,China)
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2022年第7期29-37,共9页
Transactions of the Chinese Society of Agricultural Engineering
基金
国家重点研发计划项目(2021YFD130003105)。
关键词
玉米
含水率
冲击速度
单颗粒
破碎特性
maize kernel
moisture content
impact velocity
single particle
breakage characteristics