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畢業(yè)論文外文翻譯
畢業(yè)設(shè)計(jì)（論文）題目
PYB1200彈簧圓錐破碎機(jī)的結(jié)構(gòu)設(shè)計(jì)
翻譯題目
煤的沖擊式破碎機(jī)的分形特征
學(xué) 院
信息與工程學(xué)院
專 業(yè)
機(jī)械設(shè)計(jì)制造及其自動(dòng)化
姓 名
馮艷
班 級 學(xué) 號
10082338
指導(dǎo)教師
李兵
湖州師范學(xué)院畢業(yè)論文外文翻譯
煤的沖擊式破碎機(jī)的分形特征
機(jī)械與電氣工程學(xué)院
中國礦業(yè)大學(xué)，中國礦業(yè)大學(xué)
徐州，中國
摘要：煤的沖擊式破碎機(jī)的粒度分布的分形表達(dá)是根據(jù)分形理論構(gòu)建。正交試驗(yàn)是通過煤的破碎機(jī)沖擊粉碎設(shè)備的大小和分布進(jìn)行線性擬合，在雙對數(shù)坐標(biāo)分析。結(jié)果表明，回歸曲線在雙對數(shù)坐標(biāo)中是直的并且線性回歸是有利的。分形理論對煤的沖擊式破碎機(jī)的分布規(guī)律是合適的。其中影響煤炭的分形維數(shù)的因素，沖擊的速度是顯著的，材料的硬度是第二，沖擊頻率是非常小的;分形維數(shù)隨著煤硬度和沖擊速度的增加而減小。
關(guān)鍵詞：沖擊式破碎機(jī)，分形特性;正交實(shí)驗(yàn);粒度分布
1. 介紹
隨著采礦和煤層夾矸開采的日益機(jī)械化，原料煤的質(zhì)量隨大矸石混入煤中含量的增加而下降。煤矸石大量進(jìn)入選煤影響選煤效率，提高制備成本。同時(shí)，煤矸石在制備后被堆放在地面，成為環(huán)境污染的危險(xiǎn)源。從地下煤矸石中分離不僅可以提高原煤質(zhì)量，降低制備成本，而且還可以提供材料，并且煤矸石可以充填地下[1-2]。煤矸石的沖擊碰撞是有效的分離的煤矸石和地下巖石的破碎的統(tǒng)計(jì)特性，它可以用分形維數(shù)的方式來描述[3-4]。因此，煤和煤矸石的破碎分形分布的研究可以給矸石分離提供理論支持。
一些學(xué)者在國內(nèi)外主要探討了巖石材料在沖擊載荷受損的情況下粒度分布的研究的部分分形特征，巖石材料在一般機(jī)械破碎損壞的分形特征還沒有得到充分的討論。對巖石碎片裝上uiaxial壓縮試驗(yàn)的分形特征進(jìn)行了研究參考文獻(xiàn)[5，6]，對巖石破碎耗能的分形模型中提供了旋轉(zhuǎn)鉆井在參考文獻(xiàn)[7]，分形的割煤的分布規(guī)律字符大小，研究了參考[8]。對煤矸石的沖擊式破碎機(jī)的分形特征的對比研究，是罕見的。因此，煤的沖擊式破碎機(jī)的分形特征是本文根據(jù)沖擊試驗(yàn)研究的。
2. 粒度分布分形模型
有許多模型是對對粒徑分布規(guī)律的研究，松香Rammler（RR）和蓋茨戈丹 - 舒曼模型和Weibull分布的分布規(guī)律的研究是常用的[9-10]。用分形維數(shù)描述看似隨意的粒度分布是在過去的幾十年中巖石粒度分布研究領(lǐng)域的一個(gè)重大進(jìn)展[11,12]。分形維數(shù)的定義如下[13]：
(1)
式中：
x：松散煤體特征尺度；
F: 煤炭墜毀的特征尺度大于或等于x的量;
c:比例常數(shù);
D:為分形維數(shù)。
煤顆粒的密度分布函數(shù)可以通過分形維數(shù)的推導(dǎo)可以得到
(2)
從公式2得到的顆粒的質(zhì)量，其尺寸大于X的質(zhì)量
(3)
XMAX是粒度最大的粒子，長度單位是毫米，密度單位是，g/mm3分別是粒子的形狀因子。
質(zhì)量累積速率，其尺寸大于X從公式3得到。
(4)
質(zhì)量累積速率，其尺寸小于x可以從公式4可以得到
(5)
粒度大小分布分形維數(shù)（D）可以通過線性回歸在雙對數(shù)坐標(biāo)系中計(jì)算。
分形維數(shù)的物理意義（D）表示如下：大量的分形維數(shù)的表示有許多和小碎片，少量的分形維數(shù)表明有越來越大的碎片，因此，分形維數(shù)（D）能夠在特定的加載模式作為破碎特性指標(biāo)[14]。
3. 實(shí)驗(yàn)
(1) 實(shí)驗(yàn)設(shè)備
該裝置由輸送帶，溜槽，高速帶加速器，加壓裝置和粉碎板，它是如圖1所示的。煤是通過將沿滑槽皮帶高速帶加速器進(jìn)行的，而煤是固定的加壓裝置。在高速下破碎板的沖擊會(huì)影響煤的。高速帶加速器的速度是通過變頻器調(diào)整以獲得不同的沖擊速度。
圖1 實(shí)驗(yàn)裝置布裝圖
1破碎板；2壓裝置；3高速帶加速器；4槽；5輸送帶
(2) 實(shí)驗(yàn)方法
煤樣來自山東靚裝煤炭進(jìn)出口公司，山東大柳煤礦總公司，徐州夾河煤礦公司和他們的普氏硬度分別為0.84，1.54,2.42。將煤篩選出從50毫米150毫米篩分成9個(gè)樣品并且獲得的平均值。每個(gè)樣品有200公斤的重量。用正交試驗(yàn)法是直接用沖擊式破碎機(jī)進(jìn)行的。
煤的硬度，沖擊速度，沖擊頻率設(shè)置為因素，每個(gè)因素有三個(gè)水平。它的因素和水平如表1所示。
表1因素水平
測試序號.
硬度(A)
(f)
沖擊速度(B)(m/s)
沖擊頻率(c)
水平
1
0.84
6
1
2
1.54
8
2
3
2.42
10
3
實(shí)驗(yàn)是根據(jù)所定義的因子水平下的正交表L9（34）進(jìn)行的。
(3) 實(shí)驗(yàn)結(jié)果及分析
正交試驗(yàn)的結(jié)果示如表2所示。
表2 實(shí)驗(yàn)結(jié)果
NO.
A
B
C
累積百分比(%)
50mm
70mm
90mm
110mm
130mm
150mm
1
0.84
6
1
43.6
59.5
72.3
87.2
93.1
100
2
0.84
8
2
64.9
79.6
93.7
100
100
100
3
0.84
10
3
73.4
87.1
97.5
100
100
100
4
1.54
6
2
23.6
37.9
52.1
77.4
91.2
100
5
1.54
8
3
54.2
71.3
83.1
91.6
95.8
100
6
1.54
10
1
51.2
60.7
72.5
83.7
96.1
100
7
2.42
6
3
16.2
30.8
48.7
70.3
86.3
100
8
2.42
8
1
30.5
43.9
65.1
76.1
93.7
100
9
2.42
10
2
53.3
64.8
79.7
87.3
100
100
斜率（b）和相關(guān)系數(shù)（R2）可根據(jù)線性擬合曲線和分形維數(shù)（D）可以用b相應(yīng)地計(jì)算得到。分形維數(shù)（D）的視覺正交實(shí)驗(yàn)分析，以找出影響分形維數(shù)的主次因素分析。分析的結(jié)果示于表3中。
表3 實(shí)驗(yàn)結(jié)果分析
序號
A
B
C
D
R2
1
0.84
6
1
2.23
0.982
2
0.84
8
2
2.44
0.983
3
0.84
10
3
2.59
0.945
4
1.54
6
2
1.53
0.987
5
1.54
8
3
2.45
0.952
6
1.54
10
1
2.36
0.990
7
2.42
6
3
1.31
0.989
8
2.42
8
1
1.88
0.985
9
2.42
10
2
2.34
0.993
K1
7.26
5.07
6.47
K2
6.34
6.77
6.31
K3
5.53
7.29
6.35
R
1.73
2.22
0.16
在表3中，每個(gè)因子（KI）的效果值是各因素的分形維數(shù)在i層的總和;范圍（R）是各因素的效應(yīng)值的最大值和最小值的相減得到的，R是測量分形維數(shù)的波動(dòng)的關(guān)鍵指標(biāo)。其范圍是較大的因素的多元化對分形維數(shù)更大的影響力。
可以從結(jié)果中可以看出，其中影響煤的分形維數(shù)的因素，沖擊的速度是顯著的，材料的硬度是第二和沖擊頻率非常小，隨著煤的硬度的增加的分形維數(shù)是降低的而沖擊速度的增加分形維數(shù)是增加的。
4. 結(jié)論
(1) 分形理論是適用于煤的沖擊式破碎機(jī)的分布規(guī)律。
(2) 其中影響煤炭的分形維數(shù)的因素，沖擊的速度是顯著的，材料的硬度是第二和沖擊頻率是非常小的。
(3) 煤的硬度增加分形維數(shù)減少，而沖擊速度的增加而增加。
致謝
作者非常感謝國家自然科學(xué)基金重點(diǎn)項(xiàng)目（項(xiàng)目編號：50834004）。
參考文獻(xiàn)
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From: Li Jian ping;Zhang Jia-jia;Du Chang-long/Consumer Electronics, Communications and Networks (CECNet), 2011 International Conference on
Fractal Character of the Impact Crusher of Coal
LI Jian-ping, ZHANG Jia-jia, DU Chang-long
College of Mechanical and Electrical Engineering
China University of Mining and Technology,CUMT
Xuzhou,China
Abstract:Fractal expression of the size distribution of impact crusher of coal is built according to fractal theory. Orthogonal experiment is carried out by impactive crush equipment and size distribution of the crusher of coal is linear fitted and analyzed in double logarithmic coordinates. The results indicate that regression curve in double logarithmic coordinates is straight and linear regression is favorable. The fractal theory is suitable for the distribution discipline of the impact crusher of coal. Among the factors which affect the fractal dimension of coal, the speed of impact is notable, hardness of materiel is secondly and impact frequency is very little; fractal dimension decreases with the increases of hardness of coal and increases with the increases of impact speed.
Key words:impact crusher; fractal properties; orthogonal experiment; size distribution
I. I NTRODUCTION
With the increasing mechanization of mining and the exploitation of coal seam with dirt band, the quality of raw coal decreases as the increases of the content of large gangue mixed in the coal. The large number of gangue goes into the coal preparation that affects the efficiency of coal preparation and increase the cost of preparation. Meanwhile the gangue is stacked on the ground after preparation, which becomes the hazard sources of environmental Pollution. The separation of gangue from coal underground can not only improve the quality of raw coal, decrease the cost of preparation, but also provide materials to the gangue filling underground[1 ?2]. The impactive crash of coal and gangue is a effective way to separate gangue from coal underground and the statistical characteristics of rock crash can described by fractal dimension[3 ?4]. Therefore the research of fractal fragmentation distribution of coal and gangue can provide the gangue separation with theoretical support.
Scholars at home and abroad mainly probe into the fragments fractal character of rock material damaged under Blast loading for the research of size distribution of particle, fractal character of rock material damaged under general mechanical disruption has not be discussed adequately. The fractal character of rock fragment loading on uiaxial compressive test was studied in reference [5, 6], fractal model for consuming energy on rock fragmentation is provided in rotary drilling in reference [7], fractal character of the distribution law of the cutting coal size was studied in reference [8]. Research of the fractal character of the impact crusher of coal and gangue is rare in contrast. Therefore, fractal character of the impact crusher of coal is researched according to impactive experimentation in this paper.
II. FRACTAL MODEL OF SIZE DISTRIBUTION
There are many models which study on the distribution law of particle size, Rosin-Rammler (R-R) and Gates-Gaudin-Schuhmann model and Weibull distribution are in common use[9-10]. Using fractal dimension to describe the seemingly haphazard size distribution is a significant progress in the field of research on size distribution of rock in the last decades[11,12]. Fractal dimension was defined the as follows[13]
(1)
Were x is characteristic scale of crashed coal; F is amount of crashed coal that characteristic scale is greater than or equal to x; c is constant of proportionality; D is fractal dimension.
Density distribution function of coal particles can be got by the derivation of fractal dimension
(2)
Mass of particle whose size is greater than x was obtained from Eq.2
(3)
Were xmax is the size of the biggest particle, mm; is density, g/mm3; is the shape factor of particle.
Mass accumulation rate whose size is greater than x was obtained from Eq.3
(4)
Mass accumulation rate whose size is less than x can be got from Eq.4
(5)
Fractal dimension of size distribution (D) can be calculated by linear regression in double logarithmic coordinate system.
Physical meaning of fractal dimension (D) is expressed as follows: The large amount of fractal dimension indicates there are many and small fragments, the small amount of fractal dimension indicates there are less and big fragments, Therefore, fractal dimension (D) can be used as fragmentation characteristic index under specific loading mode [14].
III. E XPERIMENTATION
A. Device of experimentation
The device consists of feeding belt, chute, high-speed belt accelerator, pressing device and crush plate, which is shown in Fig.1. Coal is carried by feeding belt along the chute to the high-speed belt accelerator, while the coal is fixed by pressing device. Coal impacts the crush plates at high speed. The speed of high-speed belt accelerator is adjusted by inverter in order to get different impact speed.
Fig.1 Layout of experimental device
1 crush plate; 2 pressing device; 3 high-speed belt accelerator; 4 chute; 5 feeding belt
B. Experimental methods
The coal samples came from Shandong Liangzhuang Coal Corporation, Shandong Daliu Coal Corporation, Xuzhou Jiahe Coal Corporation and their Protodikonov's hardness are 0.84, 1.54,2.42 respectively. The coal is screened out from 50 mm to 150 mm by sieve and nine samples are obtained on average. Each of the samples is 200Kg weight. Orthogonal test is carried out using directly impact crusher machine.
Hardness of coal, impact speed, impact frequency are set as the factor and each factor has three level. The factors and levels are shown in Table 1.
T ABLE 1 LEVELS OF FACTORS
Test No.
Hardness(A) (f)
Factor impact speed(B)(m/s)
Impace frequency(c)
level
1
0.84
6
1
2
1.54
8
2
3
2.42
10
3
Experiment was conducted under orthogonal table L9 (34) according to the levels of factors defined.
C. Experimental results and analysis
Results of orthogonal experiment are shown in Table 2.
T ABLE 2 E XPERIMENTAL FINDINGS
NO.
A
B
C
Cumulative percentage(%)
50mm
70mm
90mm
110mm
130mm
150mm
1
0.84
6
1
43.6
59.5
72.3
87.2
93.1
100
2
0.84
8
2
64.9
79.6
93.7
100
100
100
3
0.84
10
3
73.4
87.1
97.5
100
100
100
4
1.54
6
2
23.6
37.9
52.1
77.4
91.2
100
5
1.54
8
3
54.2
71.3
83.1
91.6
95.8
100
6
1.54
10
1
51.2
60.7
72.5
83.7
96.1
100
7
2.42
6
3
16.2
30.8
48.7
70.3
86.3
100
8
2.42
8
1
30.5
43.9
65.1
76.1
93.7
100
9
2.42
10
2
53.3
64.8
79.7
87.3
100
100
Slope (b) and correlation coefficient (R2) can be got according to linear fitting curve and fractal dimension (D) can be calculated by b correspondingly. Fractal dimension (D) is analyzed by visual analysis of orthogonal experiment in order to find out the Primary and secondary factors that affect the fractal dimension. Result of analysis is shown in Table 3.
T ABLE 3 ANALYSIS OF EXPERIMENTAL FINDINGS
NO.
A
B
C
D
R2
1
0.84
6
1
2.23
0.982
2
0.84
8
2
2.44
0.983
3
0.84
10
3
2.59
0.945
4
1.54
6
2
1.53
0.987
5
1.54
8
3
2.45
0.952
6
1.54
10
1
2.36
0.990
7
2.42
6
3
1.31
0.989
8
2.42
8
1
1.88
0.985
9
2.42
10
2
2.34
0.993
K1
7.26
5.07
6.47
K2
6.34
6.77
6.31
K3
5.53
7.29
6.35
R
1.73
2.22
0.16
In Table 3, effect value of each factor ( ki) is the sum of fractal dimension of each factor under level i ; range ( R ) is the subtraction of the max and minimum of the effect value of each factor, R is the key index to measure the fluctuation of fractal dimension. The diversification of the factor whose range is bigger has a bigger influence on fractal dimension.
It can be seen from the results that among the factors which affect the fractal dimension of coal, the speed of impact is notable, hardness of materiel is secondly and impact frequency is very little; Fractal dimension decreases with the increases of hardness of coal and increases with the increases of impact speed.
IV. CONCLUSION
1) The fractal theory is suitable for the distribution discipline of the impact crusher of coal.
2) Among the factors which affect the fractal dimension of coal, the speed of impact is notable, hardness of materiel is secondly and impact frequency is very little.
3) Fractal dimension decreases with the increases of hardness of coal and increases with the increases of impact speed.
ACKNOWLEDGEMENTS
The authors gratefully acknowledge the Major Project of National Natural Science Foundation (Project No. 50834004).
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From: Li Jian ping;Zhang Jia-jia;Du Chang-long/Consumer Electronics, Communications and Networks (CECNet), 2011 International Conference on