本文選題：筒式冷卻機(jī)　切入點(diǎn)：離散元法　出處：《武漢理工大學(xué)》2014年碩士論文

【摘要】：筒式冷卻機(jī)按筒體形式分為單筒冷卻機(jī)和多筒冷卻機(jī)，冷卻形式主要包括筒體內(nèi)部氣體介質(zhì)對(duì)流的直接冷卻和筒體外部噴射水霧的間接冷卻。針對(duì)后者的冷卻形式，國(guó)內(nèi)外大多數(shù)行業(yè)都是采用冷卻水間接噴淋筒體外壁，甚至是冷卻水直接浸泡筒體的冷卻方式來(lái)達(dá)到冷卻效果。然而，通過(guò)研究國(guó)外先進(jìn)的噴霧冷卻設(shè)備，可以看出，和現(xiàn)有的噴水冷卻設(shè)備相比，在相同的產(chǎn)量要求下，采用噴霧冷卻技術(shù)的冷卻設(shè)備冷卻效率高、占地小、成本低、能源動(dòng)力消耗小，更加節(jié)能環(huán)保。在能源日益緊缺，環(huán)境保護(hù)越來(lái)越受到重視的背景下，噴霧冷卻技術(shù)在工業(yè)領(lǐng)域特別是在機(jī)械和建材行業(yè)有著廣闊的應(yīng)用前景。還原鐵噴霧回轉(zhuǎn)筒式冷卻機(jī)就是一種將冷卻水霧化，直接噴射到筒體外壁，從而間接冷卻筒體內(nèi)部物料的新型節(jié)能環(huán)保冷卻設(shè)備。 由于該筒式冷卻機(jī)采用間接冷卻的冷卻形式，所以冷卻機(jī)內(nèi)顆粒物料的運(yùn)動(dòng)規(guī)律和特性對(duì)冷卻機(jī)設(shè)備設(shè)計(jì)及冷卻效率的提高都有著重要影響。顆粒物料在筒體內(nèi)的流動(dòng)過(guò)程可看作是離散固體的運(yùn)動(dòng)過(guò)程，為了計(jì)算分析其運(yùn)動(dòng)規(guī)律和分布特性，有兩種分析方法：一種是連續(xù)介質(zhì)力學(xué)法，但連續(xù)介質(zhì)機(jī)理過(guò)分依賴(lài)簡(jiǎn)化的、規(guī)定性質(zhì)的本構(gòu)方程，忽略了顆粒個(gè)體的性質(zhì)。另一種是不連續(xù)介質(zhì)力學(xué)方法，比如離散元法（Distinct Element Method）。離散元法是把整個(gè)系統(tǒng)看作由一系列獨(dú)立的顆粒單元組成，每個(gè)單元本身具有一定的幾何和物理特性。PFC（Particle Flow Code）軟件就是利用顯示差分算法和離散元理論開(kāi)發(fā)的微/細(xì)觀力學(xué)程序，從微觀結(jié)構(gòu)角度研究介質(zhì)的基本力學(xué)特性和行為，并認(rèn)為給定介質(zhì)在不同應(yīng)力條件下的基本特征主要取決于粒子之間接觸狀態(tài)的變化，適用于研究顆粒的流動(dòng)問(wèn)題。 本文針對(duì)新型筒式冷卻機(jī)——還原鐵噴霧回轉(zhuǎn)筒式冷卻機(jī)的工況條件，模擬了顆粒物料在筒式冷卻機(jī)內(nèi)的運(yùn)動(dòng)規(guī)律及顆粒間的相互作用。運(yùn)用顆粒流理論和顆粒流分析平臺(tái)，，使用PFC中的內(nèi)置FISH語(yǔ)言編制程序，建立了筒式冷卻機(jī)的橫截面模型，將顆粒處理為二維圓盤(pán)，利用WALL命令建立回轉(zhuǎn)筒體壁面并使其以一定角速度轉(zhuǎn)動(dòng)，從而實(shí)現(xiàn)了對(duì)冷卻機(jī)內(nèi)顆粒物料運(yùn)動(dòng)規(guī)律的動(dòng)態(tài)模擬仿真。模擬中主要針對(duì)筒體轉(zhuǎn)速和筒體內(nèi)部揚(yáng)料板數(shù)量等設(shè)備相關(guān)參數(shù)以及顆粒粒徑、物料填充率等物料相關(guān)參數(shù)的不同，將其與工況狀態(tài)下的顆粒運(yùn)動(dòng)分布規(guī)律進(jìn)行了對(duì)比分析研究。通過(guò)研究，得到了顆粒物料在筒體橫截面內(nèi)的動(dòng)態(tài)運(yùn)行效果，以及單個(gè)顆粒在筒體橫截面上的運(yùn)動(dòng)軌跡曲線。本文研究得出了單個(gè)顆粒的運(yùn)動(dòng)軌跡形狀、工況條件下該設(shè)備內(nèi)的物料休止角以及各因素對(duì)物料運(yùn)動(dòng)規(guī)律的影響。本文對(duì)于以顆粒物料為介質(zhì)進(jìn)行作業(yè)的回轉(zhuǎn)筒式設(shè)備（圓筒冷卻機(jī)、圓筒混合機(jī)、轉(zhuǎn)筒干燥機(jī)和回轉(zhuǎn)窯等）內(nèi)物料運(yùn)動(dòng)規(guī)律的研究具有一定的參考價(jià)值。
[Abstract]:The cylinder cooler can be divided into single tube cooler and multi tube cooler according to the form of cylinder. The cooling forms mainly include the direct cooling of gas convection inside the cylinder and the indirect cooling of spray water mist outside the cylinder.In view of the cooling form of the latter, most industries at home and abroad use the cooling water indirect spray tube outside the wall, even the cooling water directly immersed in the tube to achieve cooling effect.However, by studying the advanced spray cooling equipment abroad, it can be seen that, compared with the existing spray cooling equipment, the cooling equipment with spray cooling technology has higher cooling efficiency, less land occupation and lower cost under the same output requirements.Energy consumption is small, more energy conservation and environmental protection.In the background of energy shortage and environmental protection, spray cooling technology has a broad application prospect in industrial field, especially in machinery and building materials industry.The reductive iron spray rotary cylinder cooler is a new type of energy saving and environmental protection cooling equipment which atomizes the cooling water directly into the outer wall of the cylinder and indirectly cools the inner materials of the cylinder.Due to the indirect cooling of the cooler, the movement and characteristics of the particles in the cooler have an important effect on the design of the cooler equipment and the improvement of the cooling efficiency.The flow process of granular material in the cylinder can be regarded as the motion process of discrete solid. In order to calculate and analyze its motion law and distribution characteristic, there are two analytical methods: one is continuum medium mechanics method.However, the continuum mechanism relies too much on the simplified constitutive equations with specified properties and neglects the properties of the particles.The other is discontinuous Element method, such as discrete element method.The discrete element method regards the whole system as a series of independent particle units. Each unit has certain geometric and physical properties. The software PFCU Particle Flow Code is a micro / meso-mechanics program developed by using the display difference algorithm and discrete element theory.The basic mechanical properties and behaviors of the medium are studied from the point of view of microstructure, and it is considered that the basic characteristics of a given medium under different stress conditions mainly depend on the change of the contact state between particles, and are suitable for studying the flow problem of particles.In this paper, according to the working conditions of a new type of cylinder cooler, the movement law of particle material and the interaction between particles in the cylinder cooler are simulated.Based on the particle flow theory and particle flow analysis platform, the cross section model of the cylinder cooler is established by using the built-in FISH language in PFC. The particles are treated as two dimensional disks.The wall surface of the rotary cylinder was built by WALL command and rotated at a certain angular speed, so that the dynamic simulation of the motion law of the particle material in the cooler was realized.In the simulation, the parameters such as rotating speed of the cylinder and the quantity of the lifting plate inside the cylinder, as well as the particle size, the filling rate of the material and so on, are different.The distribution of particle motion is compared with that under working condition.The dynamic running effect of granular material in the cross section of the cylinder and the trajectory curve of a single particle in the cross section of the cylinder are obtained.In this paper, the trajectory shape of a single particle, the angle of repose of the material in the equipment and the influence of various factors on the moving law of the material are obtained.This paper has a certain reference value for the study of the movement law of the materials in the rotary drum type equipment (cylinder cooler, cylinder mixer, rotary dryer and rotary kiln, etc.) in which the particle material is used as the medium.
【學(xué)位授予單位】：武漢理工大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類(lèi)號(hào)】：TB657

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