不同含水率苜蓿干草的高密压缩成型特性的试验研究

Experimental Investigation of the Recompression Forming Characteristics of Alfalfa Hay with Different Moisture Contents

为探究含水率对苜蓿干草高密压缩成型特性的影响,基于封闭状态下的干草压缩成型原理,利用压缩装置,以不同含水率8%~20%的苜蓿干草为研究对象,在相同的初始密度、压缩方向和压缩速度条件下进行二次高密压缩试验,获得了不同含水率苜蓿干草的高密压缩特性曲线,并将干草高密压缩过程分为压紧、成型和蠕变3个阶段。试验结果表明:对应相同压缩量的干草成型密度小于300kg/m^(3)时,随着干草含水率的增加干草压力的增幅较小,最大干草压力为1.05MPa;当干草成型密度大于400kg/m^(3)时,含水率对干草压力的影响非常显著,干草压力的最大增幅为120%。

The transportation cost in alfalfa producing areas is high due to lack of recompressing equipment of high density for alfalfa hay. In order to investigate the effects of moisture content on the forming characteristics of alfalfa hay recompressing,compression and analysis were based on the compression forming principle and theory for straws in closed state.Investigating on alfalfa hay recompressing experiment with identical initial densities,compression directions and compression velocity,were conducted by using the compression device designed,the curves of recompression characteristics with different moisture content of the hay were obtained. There is the hay recompression process that can be divided into three stages which were compaction stage,forming stage and creep stage. The results show that the moisture content of hay has smaller effect on the pressure of hay and this pressure value is less than 152 PSI when the straw forming density is less than 300 kg/m^(3);The moisture content of hay have greater effect on the hay pressure and the maximum value of pressure is 688 PSI,when the hay forming density is more than 400 kg/m^(3).