本文選題：自由下落 + 顆粒流��； 參考：《西安建筑科技大學(xué)》2017年碩士論文

【摘要】：工業(yè)生產(chǎn)過程中,散狀物料輸送、轉(zhuǎn)運(yùn)是粉塵擴(kuò)散的重要來源,研究該過程中的產(chǎn)塵機(jī)理對控制粉塵,確保生產(chǎn)安全、人員健康有著重要意義。為了研究散狀物料的粒徑對其自由下落過程中的粉塵逃逸的影響,選取工業(yè)生產(chǎn)中常用的二氧化硅物料進(jìn)行分析。五組物料的中位徑分別為:82.5μm、145.8μm、209.5μm、245.1μm、314.5μm。本文以粒徑為重要變量之一,研究了在物料粒徑、下落高度、出流口徑三個(gè)變量作用下散狀物料自由下落過程的產(chǎn)塵規(guī)律。分別以地面、水面為接觸面,將總產(chǎn)塵分為下落時(shí)逃逸的一次塵和碰撞時(shí)產(chǎn)生的二次塵兩部分。在用產(chǎn)塵率描述單位質(zhì)量物料產(chǎn)塵量大小的基礎(chǔ)上,引入粒度產(chǎn)塵率以描述物料某一粒徑范圍顆粒的成塵比例�；诖死碚�,本文以0-10μm顆粒為對象,探究了物料粒徑、下落高度、出流口徑對該粒徑范圍內(nèi)產(chǎn)塵率、粒度產(chǎn)塵率的作用。并根據(jù)不同粒徑顆粒對人體的危害程度,將0-10μm顆粒分為八個(gè)粒徑范圍,主要針對其中六個(gè)范圍的產(chǎn)塵規(guī)律進(jìn)行分析,得到物料粒徑、下落高度、出流口徑對不同粒徑范圍顆粒的粒度產(chǎn)塵率的影響,為日后降低通風(fēng)系統(tǒng)能耗、提高除塵系統(tǒng)效率提供有效的理論依據(jù)。研究結(jié)果表明,對粒徑范圍0-10μm的顆粒,粒度產(chǎn)塵率隨下落高度、物料中位徑的增大而增大,隨出流口徑的增大而減小。較之二次粒度產(chǎn)塵率和總粒度產(chǎn)塵率,一次粒度產(chǎn)塵率受下落高度和物料中位徑的影響最小。下落高度增大時(shí),4.7-10μm顆粒占產(chǎn)塵的百分比增大,1.1-4.7μm顆粒占產(chǎn)塵的百分比減小。三個(gè)影響因素中,下落高度對一次粒度產(chǎn)塵率的影響最大,物料中位徑與下落高度兩個(gè)因素對二次粒度產(chǎn)塵率的影響基本相當(dāng)。對比不同顆粒粒徑范圍的粒度產(chǎn)塵率可知,物料中位徑對1.1-2.1μm顆粒的粒度產(chǎn)塵率影響較大,下落高度對3.3-4.7μm顆粒的粒度產(chǎn)塵率影響較大,而出流口徑對9.0-10.0μm、5.8-9.0μm顆粒的粒度產(chǎn)塵率影響較大。本文分析了物料粒徑、下落高度、出流口徑對散狀物料自由下落過程產(chǎn)塵的影響,并對三個(gè)因素與產(chǎn)塵率、粒度產(chǎn)塵率之間的關(guān)系做了深入分析,其結(jié)論對粉塵控制提供了一定的理論基礎(chǔ)。
[Abstract]:In the process of industrial production, the transportation and transportation of bulk materials is an important source of dust diffusion. It is of great significance to study the mechanism of dust production in the process of controlling dust, ensuring the safety of production and the health of personnel. In order to study the influence of particle size on the dust escape in the free falling process, the silica materials commonly used in industrial production were selected for analysis. The median diameters of the five groups were: 1: 82.5 渭 m, 145.8 渭 m, 209.5 渭 m, 245.1 渭 m, 314.5 渭 m, respectively. Taking particle size as one of the important variables, this paper studies the law of dust production in the free falling process of loose material under the action of three variables: particle size, falling height and outlet diameter. Taking the surface and water surface as contact surfaces, the total dust production can be divided into two parts: the primary dust escaped when falling and the secondary dust produced during collision. On the basis of describing the dust production rate per unit mass material, the particle size dust production rate is introduced to describe the dust-forming ratio of a certain particle size range of the material. Based on this theory, the effects of particle size, falling height and outlet diameter on dust yield and particle size in the range of 0-10 渭 m particle size were investigated. According to the harm degree of different particle size to human body, the 0-10 渭 m particle is divided into eight particle size ranges. The dust production law of six range is analyzed, and the particle size and falling height are obtained. The influence of outlet diameter on the dust production rate of different particle size ranges provides an effective theoretical basis for reducing the energy consumption of ventilation system and improving the efficiency of dust removal system in the future. The results show that the dust yield increases with the drop height, the median diameter of the material increases, and decreases with the increase of the outlet diameter for the particles with the particle size ranging from 0 to 10 渭 m. Compared with the secondary particle size and the total particle size dust yield, the primary particle size dust yield is the least affected by the falling height and the median diameter of the material. When the falling height increases, the percentage of 4.7-10 渭 m particles in dust production increases and the percentage of 1.1-4.7 渭 m particles decreases. Among the three influencing factors, the falling height has the greatest influence on the dust yield of primary particle size, while the two factors of the medium diameter and falling height of the material have the same effect on the dust yield of the secondary particle size. Compared with the different particle size ranges, the median diameter of the particle has a great effect on the particle size of 1.1-2.1 渭 m, and the falling height has a great effect on the particle size of 3.3-4.7 渭 m. However, the diameter of outlet flow has a great effect on the particle size yield of 9.0-10.0 渭 m ~ (5.8 ~ 9.0 渭 m) particles. In this paper, the influence of particle size, falling height and outlet diameter on dust production in the free falling process of bulk materials is analyzed, and the relationship between three factors and dust production rate of particle size is deeply analyzed. The conclusion provides a theoretical basis for dust control.
【學(xué)位授予單位】：西安建筑科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：X964

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