核桃物料空气动力学特性研究与壳仁风选设备优化

Research on aerodynamic characteristics of walnut materials and optimization of shell-kernel air separation device

壳仁分选是核桃破壳取仁的重要环节,是核桃进行精深加工的基础。为探索风选技术在核桃壳仁分选领域的可行性,通过理论计算与试验研究对核桃物料的空气动力学特性进行了研究,并在此基础上设计了一种核桃壳仁风选设备,运用单因素试验和响应面试验对该设备的工作参数进行优化。结果表明:核桃壳仁混合物料中仅有碎仁与1/2壳的悬浮速度范围有少量重叠区域,同等级核桃壳、仁具有不同的悬浮速度范围,通过控制气流速度可实现核桃壳仁分离;核桃壳仁风选设备的工作参数对清选率的影响由大到小依次为入料口高度、喂料速度、风机频率,最佳工作参数组合为喂料速度5kg/min、风机频率46Hz、入料口高度34mm,在此条件下清选率为99.32%,损失率为1.03%。综上,运用风选法进行核桃壳仁分离具有可行性,通过参数优化可提升风选设备的分选效果。

Shell-kernel sorting constitutes an essential link in the process of cracking walnuts to retrieve the kernels and serves as the foundation for the in-depth processing of walnuts.To investigate the feasibility of air separation technology in the domain of walnut shell-kernel sorting,the aerodynamic characteristics of walnut materials was explored by theoretical calculations and experimental research,and on this foundation,a walnut shell-kernel air separation device was designed.The working parameters of this device were optimized by single factor experiment and response surface methodology.The results indicated that within the mixed material of walnut shells and kernels,there was only a minor overlap in the suspension speed range between crushed kernels and 1/2 shells.Walnut kernels and shells of the same grade exhibited varying ranges of suspension speeds.By regulating the airflow speed,separation of walnut kernels from shells could be achieved.The influence of the operational parameters of the walnut shell-kernel air separation device on the cleaning rate was ranked in descending order as follows:height of the input port,feed rate,and fan frequency.The optimal operational parameter combination was obtained as follows:feed rate 5 kg/min,fan frequency 46 Hz,and input port height 34 mm.Under these conditions,the cleaning rate and the loss rate were 99.32%and 1.03%,respectively.In conclusion,using the air separation method for walnut shell and kernel separation is feasible,and the sorting efficiency of the air separation device can be enhanced by optimizing parameters.