本文選題：卸料斗幾何參數(shù) + 微粒流��； 參考：《天津商業(yè)大學(xué)》2015年碩士論文

【摘要】：在工業(yè)生產(chǎn)和散裝物料(如黃沙、煤炭以及糧食顆粒等)運(yùn)輸和卸料的過(guò)程中,進(jìn)行自由下落運(yùn)動(dòng)的散料微粒流到處可見(jiàn)。微粒流在自由下落過(guò)程中由于受重力、浮力、顆粒之間摩擦阻力以及顆粒與環(huán)境空氣之間作用力的影響,會(huì)導(dǎo)致環(huán)境空氣被卷吸到微粒流束流場(chǎng)中形成微粒羽流。微粒羽流在自由下落過(guò)程中,當(dāng)散料碰到底端接收裝置時(shí),由于下落散料的沖擊力,促使散料粉塵逃逸到周圍環(huán)境空氣中造成環(huán)境污染,給工作人員的身心健康帶來(lái)巨大的損害。本課題跟蹤國(guó)際前沿、針對(duì)生產(chǎn)實(shí)際應(yīng)用,以卸料斗自身結(jié)構(gòu)為研究對(duì)象,運(yùn)用EDEM顆粒元軟件與Fluent軟件對(duì)散狀物料經(jīng)卸料斗自由下落時(shí)與環(huán)境空氣之間的耦合規(guī)律以及卸料斗幾何參數(shù)、顆粒物料物性參數(shù)之間的關(guān)系進(jìn)行數(shù)值模擬；在自由下落微粒流與環(huán)境空氣關(guān)系的多功能實(shí)驗(yàn)平臺(tái)上,通過(guò)改進(jìn)卸料斗結(jié)構(gòu)(卸料斗的傾斜角度a、卸料斗的初始下落口徑D),對(duì)微粒流在環(huán)境空氣中自由下落時(shí)的產(chǎn)塵量G進(jìn)行實(shí)際測(cè)量,以期獲得產(chǎn)塵量G最小的卸料斗。通過(guò)數(shù)值模擬和實(shí)驗(yàn)研究得出如下結(jié)論：(1)數(shù)值模擬結(jié)果表明：a)卸料質(zhì)量流量Ws隨著傾斜角度(?)、內(nèi)摩擦系數(shù)μ、壁摩擦系數(shù)μW不斷增加而減小。當(dāng)53°(?)≤55°時(shí),卸料質(zhì)量流量Ws隨卸料斗傾斜角度a的增加減少的幅度較大；而當(dāng)55°(?)≤60°時(shí),卸料質(zhì)量流量Ws隨卸料斗傾斜角度a的增加的減少的幅度較小。在本課題的研究范圍內(nèi)卸料質(zhì)量流量Ws與內(nèi)摩擦系數(shù)μ之間的關(guān)系表達(dá)式為：Ws=195.83×exp[0.095/(μ+0.176)],在本課題的研究范圍內(nèi)卸料質(zhì)量流量Ws與壁摩擦系數(shù)μs之間的關(guān)系表達(dá)式為：Ws=322.5-416.3μw736.2μw2-638.6μw3+211.4μw4。b)計(jì)算區(qū)域內(nèi)的顆粒濃度、微粒流流速v隨初始下落口徑D的增加而不斷增大；在初始下落口徑為0.0lm時(shí),顆粒濃度最小,而當(dāng)初始下落口徑D為0.03m時(shí),顆粒濃度最大。在微粒下落的初始階段,微粒流流速v隨著下落高度h的增加而增加,當(dāng)下落高度h增長(zhǎng)到某一定值時(shí),微粒流流速v趨于穩(wěn)定；微粒流流速v隨著初始下落口口徑D的增加而增加,當(dāng)初始下落口徑D為0.0lm時(shí),微粒流速Vmax為2.28m/s,初始下落口徑D為0.03m時(shí),微粒流速Vmax為3.5 m/s。c)計(jì)算區(qū)域內(nèi)顆粒的擴(kuò)散半徑隨微粒密度ρp的增加而逐漸減小。在微粒下落的初始階段,微粒流流速v隨著下落高度h的增加而增加,當(dāng)下落高度h增長(zhǎng)到某一定值時(shí),微粒流流速v趨于穩(wěn)定；微粒流流速v隨著微粒流密度ρp的增加而增加,當(dāng)微粒密度ρp為790kg/m3時(shí),微粒流速vmax為1.21 m/s,微粒密度ρp為2590 kg/m3時(shí),微粒流速Vmax為2.83m/s。d)計(jì)算區(qū)域內(nèi)顆粒的擴(kuò)散半徑隨微粒粒徑dp的增大而不斷減小,顆粒的停留時(shí)間t隨之減�。划�(dāng)微粒粒徑dp為186.42×10-6m時(shí),顆粒與環(huán)境空氣的混合程度較好,顆粒在計(jì)算區(qū)域的停留時(shí)間較長(zhǎng),擴(kuò)散半徑也較大,相反在微粒粒徑dp為767.13×10-6m時(shí),顆粒在計(jì)算區(qū)域的停留時(shí)間較短,擴(kuò)散半徑也較小。在微粒下落的初始階段,微粒流流速v隨著下落高度h的增加而增加,當(dāng)下落高度h增長(zhǎng)到某一定值時(shí),微粒流流速v趨于穩(wěn)定；微粒流流速v隨著微粒粒徑dp的增加而增加,當(dāng)微粒粒徑dp為186.42×106m時(shí),微粒流速Vmax為1.01 m/s,微粒粒徑為767.13×106m時(shí),微粒流速Vmax為2.54 m/s。(2)實(shí)驗(yàn)研究結(jié)果表明：各種結(jié)構(gòu)(傾斜角度)的卸料斗都有其合理的使用范圍,在工程實(shí)際應(yīng)用中要根據(jù)物料的特性選用合適結(jié)構(gòu)的卸料斗,如使得黃沙微粒流產(chǎn)塵量G最小的卸料斗角度為58°、玉米微粒流產(chǎn)塵量G最小的卸料斗角度為57°,而二氧化硅微粒流產(chǎn)塵量G最大的卸料斗角度為54°(3)通過(guò)實(shí)驗(yàn)數(shù)據(jù)與模擬數(shù)據(jù)的對(duì)比分析,發(fā)現(xiàn)微粒流在下落過(guò)程中速度的實(shí)驗(yàn)結(jié)果與模擬結(jié)果基本吻合,因此,實(shí)驗(yàn)研究與數(shù)值模擬計(jì)算均可以用來(lái)研究卸料斗結(jié)構(gòu)對(duì)自由下落微粒流流場(chǎng)特性以及產(chǎn)塵量G的影響規(guī)律。(4)采用數(shù)學(xué)的方法,運(yùn)用π定理以及多元線性回歸分析的方法對(duì)大量的實(shí)驗(yàn)數(shù)據(jù)進(jìn)行線性擬合,最終得出自由下落微粒流產(chǎn)塵量G與微粒流的質(zhì)量流量Mρ、初始下落口徑D、下降高度h、微粒密度ρp、微粒粒徑dp、空氣密度ρa(bǔ)及卸料斗的傾斜角度a之間經(jīng)驗(yàn)公式：G=2.28e20.D1.55648.dp-0.30275.h1.85923.ρp1.31621.ρa(bǔ)-1.31621.α-7.05575
[Abstract]:In the process of transportation and unloading of industrial and bulk materials, such as sand, coal, and grain particles, free falling particles are seen everywhere. The influence of gravity, buoyancy, friction resistance between particles and the force between particles and ambient air during the free falling process leads to the environment. The air is absorbed into the flow field of particles to form a particle plume in the flow field of particles. In the process of free fall, the particle plume will cause environmental pollution in the ambient air, resulting in great damage to the physical and mental health of the workers. The international frontier, aiming at the practical application of production, takes the self structure of the hopper as the research object, and uses the EDEM particle element software and Fluent software to simulate the relationship between the free falling of the discharge hopper and the ambient air when the discharge hopper is free and the relation between the geometric parameters of the hopper and the physical parameters of the granular material. On the multi-functional experimental platform of the relation between the particle flow and the ambient air, by improving the structure of the hopper (the tilt angle of the hopper a, the initial drop diameter of the hopper D), the actual measurement of the dust amount G when the particle flow is freely falling in the ambient air is carried out in order to obtain the least dusts with the dust amount of G. The numerical simulation and experimental study are obtained. The following conclusions are as follows: (1) the numerical simulation results show that the discharge quality flow Ws decreases with the increasing of the angle (?), the internal friction coefficient and the wall friction coefficient mu W. When the 53 degree (?) less than 55 degrees, the discharge quality flow Ws decreases with the increase of the a of the hopper angle a; and the discharge quality flow Ws is unloaded when the discharge quantity is less than 60 degrees. The decreasing amplitude of the increase of the hopper inclination angle a is smaller. The relation expression between the discharge mass flow Ws and the internal friction coefficient um is Ws=195.83 x exp[0.095/ (mu +0.176) in the research scope of the subject. The relation expression between the discharge mass flow Ws and the wall friction coefficient mu s is: Ws=322.5-416 in the scope of the study. The particle concentration in the region is calculated by.3 mu w736.2 w2-638.6 mu w3+211.4 mu w4.b. The particle flow velocity V increases with the increase of the initial drop diameter D, and the particle concentration is the smallest when the initial falling aperture is 0.0lm, while the particle concentration is the largest when the initial falling aperture D is 0.03m. The particle flow velocity is v along with the initial phase of the particle drop. When the falling height of H increases, the particle flow velocity V tends to be stable when the falling height of H increases to a certain value, and the particle flow velocity V increases with the increase of the initial drop aperture D. When the initial drop aperture D is 0.0lm, the particle velocity Vmax is 2.28m/s, the initial falling diameter D is 0.03m, the particle velocity Vmax is 3.5 The diffusion radius of the inner particles gradually decreases with the increase of the particle density of P P. In the initial stage of the particle drop, the flow velocity V increases with the increase of the drop height h. When the drop height h increases to a certain value, the particle flow velocity V tends to be stable; the particle flow velocity V increases with the increase of the micro particle density p p, when the particle density is density. When the p p is 790kg/m3, the particle velocity Vmax is 1.21 m/s, the particle density p p is 2590 kg/m3, the particle velocity Vmax is 2.83m/s.d). The particle diffusion radius decreases with the increase of particle size DP, and the retention time t decreases with the particle size. When the particle size DP is 186.42 * 10-6m, the mixing degree of particles with ambient air is more than that of the ambient air. Well, the retention time of the particles in the calculation area is longer and the diffusion radius is larger. On the contrary, when the particle size DP is 767.13 x 10-6m, the retention time of the particles in the calculated area is shorter and the diffusion radius is smaller. The velocity V of the particle flow increases with the increase of the falling height h in the initial stage of the particle drop, and when the falling height h increases to a certain value, the particle flow velocity is increased to a certain value. When the particle flow velocity V tends to be stable, the particle flow velocity V increases with the increase of the particle size DP. When the particle size DP is 186.42 x 106m, the particle velocity Vmax is 1.01 m/s and the particle size is 767.13 x 106m, and the particle velocity Vmax is 2.54 m/s. (2). The experimental results show that all kinds of structure (inclined angle) discharge hoppers are all reasonable. In the application range, in the practical application of the project, the proper structure of the discharge hopper should be selected according to the material characteristics. For example, the angle of the minimum discharge bucket of the G of the yellow sand particles is 58, the angle of the minimum unload hopper of G for the corn particle miscarriage is 57 degrees, and the maximum hopper angle of the silica particle miscarriage dust is 54 degrees (3) through the experimental number (54 degrees). According to the comparison and analysis of the simulated data, it is found that the experimental results of the velocity of the particle flow are basically consistent with the simulation results. Therefore, both the experimental and numerical simulation can be used to study the effect of the structure of the hopper on the flow field characteristics of free falling particles and the effect of the dust production G. (4) the method of mathematics and the application of the PI theorem are used. And the method of multivariate linear regression analysis is linear fitting for a large number of experimental data. Finally, the mass flow of free falling particles G and particle flow mass flow M rho, initial drop diameter D, drop height h, particle density p p, particle size DP, air density rho A and tilt angle a of discharging hopper: G=2.28e20.D1.5 5648.dp-0.30275.h1.85923. P p1.31621. P a-1.31621. alpha -7.05575
【學(xué)位授予單位】：天津商業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：X513

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 郭一;陳玉成;;基于經(jīng)濟(jì)視角的霧霾天氣分析及治理研究[J];環(huán)境科學(xué)與管理;2015年01期

相關(guān)博士學(xué)位論文 前3條

1 肖國(guó)先;料倉(cāng)內(nèi)散體流動(dòng)的數(shù)值模擬研究[D];南京工業(yè)大學(xué);2004年

2 楚錫華;顆粒材料的離散顆粒模型與離散—連續(xù)耦合模型及數(shù)值方法[D];大連理工大學(xué);2006年

3 劉洪濤;氣固兩相流中微細(xì)顆粒沉積與擴(kuò)散特性的數(shù)值研究[D];重慶大學(xué);2010年

，

本文編號(hào)：1904854