橢球形顆粒直線振動(dòng)篩分機(jī)理研究
發(fā)布時(shí)間：2018-12-12 09:36
【摘要】：篩分是各領(lǐng)域中散體料進(jìn)行粒度分級(jí)的主要技術(shù)手段;在各類篩分物料中,橢球形或類橢球形顆粒占較大比例,橢球形顆粒長(zhǎng)直徑遠(yuǎn)大于短直徑的外形特性,導(dǎo)致其篩分特性相對(duì)球形顆粒更為復(fù)雜。目前,對(duì)橢球形顆粒精選篩分,缺乏針對(duì)性篩分機(jī)理及裝置的研究,采用傳統(tǒng)的篩分方法,并以球形顆粒篩分機(jī)理控制參數(shù)進(jìn)行橢球形顆粒篩分,其篩分性能差。為此,本文結(jié)合直線振動(dòng)篩分具有高篩分效率、高生產(chǎn)率,且對(duì)橢球形顆粒篩分適應(yīng)性好的特點(diǎn),提出橢球形顆粒直線振動(dòng)篩分方法,以類橢球形顆粒枸杞為篩分對(duì)象,開展橢球形顆粒直線振動(dòng)篩分機(jī)理研究。主要研究工作內(nèi)容與結(jié)論如下:(1)橢球形顆粒直線振動(dòng)篩分理論研究基于直線振動(dòng)篩分理論,以篩分分離粒度和綜合篩分效率為基礎(chǔ)篩分性能指標(biāo),研究橢球形顆粒直線振動(dòng)篩分過程的顆粒運(yùn)動(dòng)學(xué)特性、透篩特性及其影響因素;結(jié)果表明:篩分分離粒度是一個(gè)區(qū)間范圍?d,顆粒沿篩面方向的相對(duì)速度越大,分離粒度越小;橢球形顆粒物料在篩面上做周期性相對(duì)下滑和相對(duì)上滑移動(dòng),同時(shí),做周期性相對(duì)篩面向上、向下?lián)u擺滾動(dòng),因此,若顆粒垂直篩面方向的跳動(dòng)較大時(shí),不該透篩的較大粒度的橢球形顆粒會(huì)豎直或傾斜穿過篩孔,造成誤篩,使得分離粒度上限值增大,分離粒度區(qū)間?d增大,綜合篩分效率降低。研究了厚層橢球形顆粒直線振動(dòng)分層原理及其影響因素,并設(shè)計(jì)分層性能指標(biāo)檢測(cè)方法,結(jié)果表明:不同粒度顆粒的動(dòng)能差異是形成顆粒分層的主要原因,細(xì)粒或粗粒體積濃度的變化率是檢測(cè)顆粒分層速率的有效可行方法。(2)橢球形顆粒直線振動(dòng)篩分仿真分析利用離散元軟件EDEM,對(duì)單層橢球形顆粒在篩面上的運(yùn)動(dòng)特性進(jìn)行仿真分析,結(jié)果表明:顆粒群在篩面x方向的相對(duì)速度和絕對(duì)速度具有與振動(dòng)篩面相同的周期性;顆粒群相對(duì)速度是時(shí)間的類余弦曲線,平均相對(duì)速度、平均絕對(duì)速度隨著篩分參數(shù)(篩面傾角、振幅、頻率、振動(dòng)方向角)的增大而增大;當(dāng)篩分參數(shù)大于一定值之后,顆粒群出現(xiàn)垂直篩面方向的跳動(dòng),且篩分參數(shù)值越大,跳動(dòng)量越大。對(duì)單層橢球形顆粒篩分分離粒度、綜合篩分效率進(jìn)行仿真分析,結(jié)果表明:篩分分離粒度為一個(gè)范圍(mind~maxd),篩分分離粒度(分離粒度上限maxd、下限mind和中心cd)隨著篩分參數(shù)的增大而減小,隨篩孔直徑增大而增大;驗(yàn)證了?d受顆粒跳動(dòng)的影響,當(dāng)顆粒群在垂直篩面方向上有跳動(dòng)時(shí),?d隨著振幅、頻率和方向角增大而增大,綜合篩分效率降低,篩面傾角在取值范圍內(nèi),因顆粒群垂直篩面方向無跳動(dòng),?d不變,故不影響綜合篩分效率。對(duì)厚層橢球形顆粒直線振動(dòng)分層特性及顆粒運(yùn)動(dòng)動(dòng)能仿真分析,結(jié)果表明:橢球形顆粒振動(dòng)分層過程中,大顆粒與小顆粒垂直篩面方向的動(dòng)能差隨著振幅、頻率、振動(dòng)方向角的增大而增大,篩面傾角對(duì)其影響不大;顆粒分層速率隨著振幅、頻率和振動(dòng)方向角的增大而增大,篩面傾角對(duì)顆粒分層速率影響較小,顆粒分層速率隨時(shí)間的推移越來越小。(3)橢球形顆粒直線振動(dòng)篩分性能試驗(yàn)研究設(shè)計(jì)直線振動(dòng)篩分試驗(yàn)裝置,對(duì)橢球形顆粒枸杞進(jìn)行直線振動(dòng)篩分性能試驗(yàn)及結(jié)果分析。試驗(yàn)結(jié)果驗(yàn)證了單層顆粒篩分中振幅、頻率以及篩面傾角對(duì)篩分分離粒度以及綜合篩分效率的影響規(guī)律;驗(yàn)證厚層篩分中振動(dòng)幅度、振動(dòng)頻率以及篩面傾角對(duì)顆粒分層速率的影響規(guī)律。得到較佳篩分性能參數(shù)為振幅為4mm、頻率為20HZ、篩面傾角為8°時(shí),其篩分效率為93.6%,篩分生產(chǎn)率為1.54t/h。
[Abstract]:The sieving is the main technical means for the particle size grading of the dispersion materials in all fields; in the various screening materials, the ellipsoidal or the like-like particles occupy a larger proportion, the long diameter of the ellipsoidal particle is much larger than the outer shape characteristic of the short diameter, and the screening characteristic is more complex with the spherical particles. At present, the selection and screening of the ellipsoidal particles, the lack of the targeted screening mechanism and the research of the device, the traditional screening method is adopted, and the spherical particle screening is carried out by the spherical particle screening mechanism control parameters, and the screening performance is poor. in ord to solve that problem, the linear vibrating screen is combine to have the characteristics of high screening efficiency, high productivity, and good screening adaptability to the ellipsoidal particle, Study on the mechanism of linear vibrating screen for ellipsoidal particle. The main research contents and conclusions are as follows: (1) The theoretical study of the linear vibrating screen of the ellipsoidal particle is based on the principle of the linear vibrating screen, and based on the screening separation size and the comprehensive screening efficiency as the basic screening performance index, The characteristics of the particle kinematics, the characteristics of the screen and the influencing factors of the elliptic particle linear vibrating screen are studied. The results show that the size of the sieve separation is an interval range. d, the greater the relative speed of the particles in the direction of the screen surface, the smaller the separation particle size, If the direction of the vertical screen of the particles is large, the spherical particles of the larger particle size of the screen not to be passed through the sieve are vertical or inclined to cause a false screen, so that the upper limit value of the separation particle size is increased, and the particle size range is separated. and d is increased, and the comprehensive screening efficiency is reduced. The principle of linear vibration of thick-layer ellipsoidal particle and its influencing factors are studied, and the test method of layered performance index is designed. The results show that the difference of the kinetic energy of different particle size particles is the main reason for the formation of the particles. The rate of change in the volume concentration of fine or coarse particles is an effective and feasible method for detecting the rate of particle delamination. (2) The dynamic characteristics of the single-layer ellipsoidal particle on the screen surface were simulated and analyzed by using the discrete element software EDEM, and the results showed that the relative velocity and absolute velocity of the particle group in the x-direction of the screen surface had the same periodicity as the vibrating screen surface. the relative speed of the particle group is the cosine curve of the time, the average relative speed, the average absolute speed is increased with the increase of the sieving parameters (screen inclination, amplitude, frequency, vibration direction angle), and the larger the sieving parameter value, the larger the jump amount. The results show that the separation size of the sieve is a range (mind.to maxd), the size of the separation and separation (the upper limit of the separation particle size maxd, the lower limit mind, and the center cd) decreases with the increase of the screening parameters. Increase with the diameter of the mesh; verified? d is affected by the particle run-out, when the particle swarm has a run-out in the direction of the vertical screen surface? d With the increase of the amplitude, frequency and direction angle, the comprehensive screening efficiency is reduced, and the inclination of the screen surface is in the range of value. and d, so the comprehensive screening efficiency is not affected. The results show that the difference of the kinetic energy of the large particle and the small particle in the plane of the vertical screen increases with the increase of the amplitude, frequency and vibration direction in the process of the vibration of the ellipsoidal particle. The influence of the angle of the screen surface is not large; the particle layer rate is increased with the increase of the amplitude, the frequency and the vibration direction angle, the influence of the inclination of the screen surface on the layer rate of the particles is small, and the layering rate of the particles is smaller and smaller over time. (3) The design of the linear vibrating screen sub-test device for the ellipsoidal particle linear vibrating screen is carried out, and the test of the linear vibrating screen and the result analysis of the ellipsoidal granular medlar are carried out. The influence of the amplitude, frequency and the angle of the screen on the separation size of the screen and the efficiency of the comprehensive screening is verified by the test results, and the influence of the vibration amplitude, the frequency of the vibration and the angle of the screen surface on the rate of the granular layer is verified. The screening efficiency was 93.6% and the screening rate was 1.54t/ h.
【學(xué)位授予單位】：江蘇大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TH237.6
本文編號(hào)：2374341
[Abstract]:The sieving is the main technical means for the particle size grading of the dispersion materials in all fields; in the various screening materials, the ellipsoidal or the like-like particles occupy a larger proportion, the long diameter of the ellipsoidal particle is much larger than the outer shape characteristic of the short diameter, and the screening characteristic is more complex with the spherical particles. At present, the selection and screening of the ellipsoidal particles, the lack of the targeted screening mechanism and the research of the device, the traditional screening method is adopted, and the spherical particle screening is carried out by the spherical particle screening mechanism control parameters, and the screening performance is poor. in ord to solve that problem, the linear vibrating screen is combine to have the characteristics of high screening efficiency, high productivity, and good screening adaptability to the ellipsoidal particle, Study on the mechanism of linear vibrating screen for ellipsoidal particle. The main research contents and conclusions are as follows: (1) The theoretical study of the linear vibrating screen of the ellipsoidal particle is based on the principle of the linear vibrating screen, and based on the screening separation size and the comprehensive screening efficiency as the basic screening performance index, The characteristics of the particle kinematics, the characteristics of the screen and the influencing factors of the elliptic particle linear vibrating screen are studied. The results show that the size of the sieve separation is an interval range. d, the greater the relative speed of the particles in the direction of the screen surface, the smaller the separation particle size, If the direction of the vertical screen of the particles is large, the spherical particles of the larger particle size of the screen not to be passed through the sieve are vertical or inclined to cause a false screen, so that the upper limit value of the separation particle size is increased, and the particle size range is separated. and d is increased, and the comprehensive screening efficiency is reduced. The principle of linear vibration of thick-layer ellipsoidal particle and its influencing factors are studied, and the test method of layered performance index is designed. The results show that the difference of the kinetic energy of different particle size particles is the main reason for the formation of the particles. The rate of change in the volume concentration of fine or coarse particles is an effective and feasible method for detecting the rate of particle delamination. (2) The dynamic characteristics of the single-layer ellipsoidal particle on the screen surface were simulated and analyzed by using the discrete element software EDEM, and the results showed that the relative velocity and absolute velocity of the particle group in the x-direction of the screen surface had the same periodicity as the vibrating screen surface. the relative speed of the particle group is the cosine curve of the time, the average relative speed, the average absolute speed is increased with the increase of the sieving parameters (screen inclination, amplitude, frequency, vibration direction angle), and the larger the sieving parameter value, the larger the jump amount. The results show that the separation size of the sieve is a range (mind.to maxd), the size of the separation and separation (the upper limit of the separation particle size maxd, the lower limit mind, and the center cd) decreases with the increase of the screening parameters. Increase with the diameter of the mesh; verified? d is affected by the particle run-out, when the particle swarm has a run-out in the direction of the vertical screen surface? d With the increase of the amplitude, frequency and direction angle, the comprehensive screening efficiency is reduced, and the inclination of the screen surface is in the range of value. and d, so the comprehensive screening efficiency is not affected. The results show that the difference of the kinetic energy of the large particle and the small particle in the plane of the vertical screen increases with the increase of the amplitude, frequency and vibration direction in the process of the vibration of the ellipsoidal particle. The influence of the angle of the screen surface is not large; the particle layer rate is increased with the increase of the amplitude, the frequency and the vibration direction angle, the influence of the inclination of the screen surface on the layer rate of the particles is small, and the layering rate of the particles is smaller and smaller over time. (3) The design of the linear vibrating screen sub-test device for the ellipsoidal particle linear vibrating screen is carried out, and the test of the linear vibrating screen and the result analysis of the ellipsoidal granular medlar are carried out. The influence of the amplitude, frequency and the angle of the screen on the separation size of the screen and the efficiency of the comprehensive screening is verified by the test results, and the influence of the vibration amplitude, the frequency of the vibration and the angle of the screen surface on the rate of the granular layer is verified. The screening efficiency was 93.6% and the screening rate was 1.54t/ h.
【學(xué)位授予單位】：江蘇大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TH237.6
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