全喂入式胡麻脱粒机的设计与试验

Design and test of full-feed flax thresher

关键词:  胡麻  脱粒机  生物力学特性  模态分析  流场模拟分析  脱粒试验

Key words:  flax  granulator  biomechanical characteristics  modal analysis  wind field simulation analysis  degranulation test

摘要:

针对胡麻籽粒小、茎秆易缠绕、喂入流动性差等特点，采用垂直排列D型纹杆闭式脱粒滚筒和菱形棱角型栅栏式凹板组和的方式，设计一种全喂入式胡麻脱粒机。以陇亚14号胡麻为试验材料，对其茎秆进行生物力学特性试验，运用ANSYS Workbench和Fluent对脱粒机机架和风选系统分别做模态及流场模拟分析，并进行脱粒试验。结果表明：当陇亚14号胡麻中部茎杆含水率为9.43%时，抗拉强度为179.6 MPa，抗弯强度1.79 MPa，剪切强度0.19 MPa；机架前8阶固有频率范围为46.19~257.20 Hz，振幅范围7.53~115.63 mm，在第6阶频率190.46 Hz处出现最大振幅为115.63 mm，在第5阶固有频率190.01 Hz处出现第2大振幅114.99 mm；当脱粒滚筒主轴转速为1 500 r/min时，垂直悬浮筒进口风速达到了6.3~10 m/s，离心风扇径向边缘风速可达50 m/s，垂直悬浮筒进口到离心风扇之间的压强在-500~-1 000 Pa，离心分离筒内壁面压强4 000 Pa，排杂口压强4 799.27 Pa；脱粒时作业机脱净率为98.86%，含杂率2.15%，破碎率0%、夹带损失率0.8%、清选损失率0.27%、飞溅损失率1.8%、未脱净损失率0.09%，总损失率2.97%。该机整体设计符合国家标准要求，满足胡麻脱粒作业需求。

Abstract:

Aiming at the characteristics of small grain,stalk easy winding threshing roller shaft and poor fluidity of flax crop,a full-feed flax thresher composed of vertical arrangement of D-shaped bar closed threshing roller and rhomboid angular raster concave plate was designed.Using the stem of Longya 14 flax as test material,the biomechanical properties of the stem were tested by ANSYS Workbenck and Fluent software to perform modal analysis on the threshing machine frame.The flow field simulation analysis of the wind selection system was carried out and the threshing test to verify the effect of the thresher was conducted.The results showed that when the water content of flax stem was 9.43%,the tensile strength of the middle flax stem of Longya 14 was 179.6 MPa,the flexural strength was 1.79 MPa,and the shear strength was 0.19 MPa.The natural frequency range of the first eight order of the rack was from 46.19 to 257.20 Hz,the amplitude range was from 7.53 to 115.63 mm,the 6th order frequency was 190.46 Hz,the maximum amplitude of the 6th order frequency was 115.63 mm,and the second maximum amplitude of the 5th order frequency was 114.99 mm.When the spindle speed of the threshing roller shaft was 1 500 r/min,the inlet wind speed of the lower part of the vertical suspension tube reaches from 6.3 to 10 m/s,the radial edge speed of the centrifugal fan can reach 50 m/s,and the pressure between the vertical suspension tube and the centrifugal fan was from -500 to -1 000 Pa,the internal wall pressure of centrifugal discharge tube was 4 000 Pa,and the pressure of discharge outlet was 4 799.27 Pa.The stripping test results showed that the whole machine stripping rate was 98.86%,the miscellaneous rate was 2.15%,the breakage rate was 0%,the entrainment loss rate was 0.8%,the clearance loss rate was 0.27%,the splash loss rate was 1.8%,the un-threshing loss rate was 0.09%,and the total loss rate was 2.97%.The overall design of the machine conforms to the national standard requirements and meets the needs of flax stripping operation.