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叶片式抛送装置抛送机理研究与参数优化
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摘要
叶片式抛送装置由于具有结构简单、工作可靠、容易调整维修、输送能力强以及制造成本低等优点,因此应用范围非常广泛。叶片式抛送装置存在的主要问题是抛送功耗大,抛送效率低且容易堵塞。论文针对目前国内外对物料抛送机理研究中存在的不足,通过理论分析、计算机仿真模拟以及试验研究对物料的抛送机理进行了研究。在此基础上,对叶片式抛送装置的结构及运动参数进行了优化。
     (1)采用计算流体力学软件FLUENT对不同参数叶片式抛送装置的气流流场进行了三维数值模拟,获得了气流流场的基本特征。通过与气流流场试验研究结果比较表明,利用FLUENT对叶片式抛送装置气流流场进行模拟分析的结果是正确的。研究发现,气流流场的分布影响物料的抛送和所消耗功率,且抛送叶轮转速越高,出料直管处的气流速度越大,平均抛送距离越远。在此基础上,对抛送叶轮的叶片数、叶片倾角以及圆形外壳出口处的圆弧半径进行了优化。优化结果为:4叶片、圆形外壳、后倾10°叶片更有利于抛送,且出口处圆弧半径不宜太大。
     (2)采用理论分析、虚拟样机技术与高速摄像技术相结合的方法对物料沿抛送叶片的运动规律进行研究,获得了对物料抛送及所消耗功率起决定作用的物料抛出角和物料离开抛送叶片时速度的变化规律及影响因素,并得到物料的最佳抛出角范围为80o ~130o。建立了物料沿抛送叶片运动的ADAMS模型,为了综合考虑物料间的相互作用以及气流对物料的作用引入当量摩擦系数,通过与高速摄像试验数据进行回归分析计算得到当量摩擦系数的值,进而对ADAMS模型进行了修正。
     (3)通过高速摄像研究表明,在抛送叶片带动物料运动过程中,部分物料沿叶片滑移到叶片末端后离开叶片;另一部分物料沿叶片滑移了一段后就离开了叶片,在惯性及抛送叶轮内气流的作用下,沿圆形外壳出料口向出料直管运动,其中部分物料运动到出料口之前与下一叶片相遇,又被此叶片撞击、带动,直至运动到出料口。
     (4)为了降低抛送功耗,提高抛送效率,采用试验研究、理论分析与虚拟样机技术相结合的方法对所消耗功率进行了研究,对抛送叶轮的结构及运动参数进行了优化分析。建立了叶片式抛送装置所消耗功率、比功耗以及抛送效率表达式,并利用所修正的ADAMS模型对抛送叶轮结构及运动参数进行了优化。通过与试验结果进行比较分析,说明所修正的ADAMS模型及利用虚拟样机技术所进行的优化分析是可信的。结果表明:当叶轮外径为700mm,转速从650r/min增加到1050r/min(叶片末端线速度从25 m/s增加到40m/s),功耗及比功耗增加2~3倍;叶片前倾角从前倾5°增大到25°,比功耗增加5.5%~63.5%;叶片后倾角从后倾5°增大到25°,比功耗增加3.5%~12.7%,增加幅度较小;叶片为径向叶片且转速为650r/min时比功耗最小;径向叶片各转速的抛送效率范围为65%~69.5%,其中转速为950r/min时抛送效率最高。
     (5)为了获得物料流经出料直管及偏转弯管的运动规律,结合试验研究建立了物料流经出料直管的动力学模型,并在引用物料流经偏转弯管动力模型的基础上,利用MATLAB对其进行数值求解。为进一步优化出料直管及偏转弯管的结构参数奠定了基础。
     (6)对物料运动速度和相应位置的气流速度进行比较,发现从离开叶片到进入出料直管阶段,物料向上速度大于相应气流速度,物料主要靠叶片抛扔获得的能量来运动;进入出料直管后,物料向上速度小于相应气流速度,主要靠惯性和气流协助来输送物料。总之,物料主要靠叶片抛扔和气流辅助输送来抛送。
     (7)叶片后倾角为10°时比径向叶片的功耗增加了6.12%,而抛送距离增加了16.16%。实际生产中当不要求远距离抛送时,宜选径向叶片;当需远距离抛送时宜选后倾角为10°的叶片。
     (8)成功研制了叶片式抛送装置试验台,为研究抛送机理提供了试验设备。
Impeller blowers are used widely to convey materials because of their simplicity, reliability, ease of maintenance and adjustment, high capacity and low manufacturing cost. However, they also have some negative problems such as excessive power consumption, inefficiency and even clogging in the process of blowing the materials. Given the existing deficiency of the throwing/blowing theory, the throwing/blowing mechanism of an impeller blower was studied through experiments, theory analysis and computer numerical simulation, and the parameter optimization of the impeller blower was finished in this paper.
     (1) The 3-D air flow in an impeller blower with different parameters was simulated and analyzed using CFD (computational fluid dynamics) software FLUENT, and the basic characteristics about the air field were gained. Comparing simulation results with experimental ones showed that the mathematical model was able to accurately simulate the actual air velocities. Moreover, Study results showed that the air flow pattern would affect the blowing efficiency and power consumption, and the higher the rotational speed of the impeller was, the higher the air flow velocity at a plane of the vertical pipe was, and the farther the straw-threw distance was. Furthermore, some main geometrical parameters, such as the numbers of the paddles, the mounting angle of the paddle, the shape of housing and the arc radius of its outlet etc, were optimized.
     (2) The movement laws of the chopped straws along paddles have been studied by means of theory analysis, virtual prototype and high speed photograph technology. The straw-threw angle at its optimal range was from 80 degree to 130 degree, and the velocity-changing laws that the straws left the paddles were obtained. The ADAMS simulation model of the chopped straws along paddles was established by the virtual prototype technology. Meanwhile, the movement trajectory of the chopped straws was photographed. Then the regression analysis on the data was carried out to determine the value of friction coefficient, and the ADAMS model was modified based on the value of friction coefficient.
     (3) From high speed photograph, we found that some straws moved along a paddle till the end of paddle; others left the paddle during their movement and moved towards outlet with the help of the air flow inside the impeller, some of them collided with another paddle which took them to the outlet.
     (4) To reduce the power consumption and improve the throwing/blowing efficiency, the power consumption was studied by experimenting, theoretical analyzing and virtual simulating. The mathematical equations for the power consumption, efficiency and specific power consumption of the impeller blower were set up. Moreover, the geometrical and kinematic parameters of the impeller were optimized based on modified ADAMS model. As was shown from the experiment results, the modified ADMAS model and the optimization results using virtual prototype technology were reliable. The results showed that the power and specific power consumption increased by 2-3 times as the rotation speed was increased from 650 to 1050r/min of the impeller (700mm in diameter). At the same time, the specific power consumption increased by 5.5%-63.5% when the forward angle of the paddle was increased from 5°to 25°; and it increased by 3.5%-12.7% when the backward angle of the paddle was increased from 5°to 25°. When paddles were radial arrangement and rotational speed was 650 rpm the specific power consumption was minimum.The throwing/blowing efficiency range for the radial paddle was 65%~69.5% at different rotational speeds and it reached the maximum at 950 rpm.
     (5) To gain basic kinematic characteristics of the chopped straws inside the vertical pipe and spout, the dynamic model of chopped straws moving upward in the vertical pipe has been established, and the dynamic equations were solved with MATLAB. It provided a reference for further optimizing the geometrical parameters of the vertical pipe and spout.
     (6) By comparing the straws velocity and air velocity at same position, it was shown that the upward velocity was bigger than the air velocity in the process of leaving the paddles and getting into the vertical pipe, and the energy of throwing straws comes from rotating paddles; After it got into the vertical pipe, the air velocity was bigger than the straw velocity, the straws were conveyed by means of inertia and air flow, the straws were conveyed mainly by means of the paddle throwing and the air blowing.
     (7) The study results showed that with paddles slanted 10°backward the impeller blower increased the specific power requirement by 6.12% and the throwing distance by 16.16% respectively compared to the impeller blower with radial paddles. Therefore, when required the long distance throwing, it was suitable to select the paddles with 10°backward, if throwing distance was not required, the radial paddles should be selected in the real production.
     (8) The experiment equipment of an impeller-blower were developed by ourselves.
引文
1 Shinners K J, Koegel R G and Pritzl P J. An upward cutting cut-and-throw forage harvester to reduce machine energy requirements [J]. Transactions of the ASAE, 1991, 34(6): 2287-2290
    2 李林,杨明韶,王春光等.9R一40型揉碎机的研制与试验[J].内蒙古农牧学院学报,1997,18(3):69-74
    3 Appell Paul. Traité de Mecanique Rationnelle [J].paris 1921,484-492
    4 Kampf G. Beitrag Zur theoris des Wurfgeblase [J]. Landtechnische Forshung, 1956, (3): 152-158
    5 В.А.Зуев, В. В. Красников. Механизация и злектрификация Социалистического Сельского Хозяйства[J].1962, (5):29-33
    6 Chancellor W J. Influence of particle movement on energy losses in an impeller blower [J]. Agricultural Engineering.1960, 41(2):92-94
    7 Chancellor W J and Laduke G E. Analysis of forage flow in a deflector elbow [J]. Agricultural Engineering, 1960, 41(4):234-236, 240
    8 Chancellor W J. Relations between air and solid particles moving upword in a vertical pipe [J]. Agricultural Engineering, 1960, 41:168-171,176
    9 Totten D S and Millier W F. Energy and particle path analysis[J]: forage blowers and vertical pipe. Transactions of the ASAE, 1966, 9(5):629-636, 640
    10 Shinners K J, Koegel R G, Pritzl P J and Lehman L L. Band lubrication to reduce friction loss in forage blowers [J]. Transactions of the ASAE, 1991, 34(5):1962-1966
    11 Shinners K J, Stelzle M and Koegel R G. Improving the throwing effectiveness of an upward-cutting forage harvester [J]. Transactions of the ASAE, 1994, 37(4):1059-1067
    12 Chattopadhyay P S, Pandey P S. Effect of knife and operational parameters on energy requirement in flail forage harvesting [J]. Agricultural Engineering Research, 1999,73:3-12
    13 Chattopadhyay P S, Pandey P S. Influence of knife configuration and tip speed on conveyance in flail forage harvesting [J]. Agricultural Engineering Research, 2001,78(3):245-252
    14 胡瑞谦.质点在绕水平轴等速旋转平面型叶片上运动的分析[J].农业机械学报,l980(4):62-71
    15 朱松明,吴春江.物料在叶片式抛送器内的运动[J].浙江农业大学报,1994, 20(4):349-353
    16 朱松明,吴春江.叶片式抛送器功耗与效率的研究[J].浙江农业大学学报,1995, 21(2):169-172
    17 尚书旗,孟海波,于文星等.玉米茎秆甩刀式切抛器的设计研究[J].农业工程学报, 1998,14(2):82-85
    18 贾洪雷,马成林.曲面直刃刀切碎与抛送变量的研究[J].农业机械学报,2002, 33(6):41-43
    19 贾洪雷,王增辉,马成林等.玉米秸秆切碎抛送装置的试验研究[J].农业机械学报,2003, 34(6):96-99
    20 张海琨,付敏良,王敦军等.秸秆揉搓机物料抛送过程的理论分析与试验[J].农机化研究,2006,(9):69-70
    21 陆林,李耀明.虚拟样机技术及其在农业机械设计中的应用[J].中国农机化, 2004,(4):59-61
    22 高建民,区颖刚.甘蔗螺旋扶起机构的理论研究及虚拟样机仿真[J].农业工程学报,2004,20(3):1-5
    23 赵冰,陈国晶,袁长胜.单圆盘甘蔗切割器运动仿真[J].农业装备技术,2006,32(1):1-2
    24 蒲明辉,刘先杰,徐锡晨.小型甘蔗收割机喂入机构的设计与仿真分析[J].农机化研究,2006,(4):101-104
    25 张长水,蒙艳玫,李尚平等.甘蔗剥叶元件工作过程受力的动态仿真分析[J].农机化研究,2005,(1):78-81
    26 付刚,董钢.油菜收获机清选装置虚拟样机的建模与仿真实验[J].农机化研究2006,(7):96-98
    27 贾晶霞,张东兴.马铃薯收获机摆动筛与块茎运动仿真分析[J].中国农业大学学报,2006,11(3):79-82
    28 何波,李成华,张勇.铲式玉米精密播种机的运动仿真[J].农机化研究,2005,(6):78-81
    29 孙秀花,梁式,胡珊珊.基于柔性化的小型甘蔗收获机的仿真技术[J].机械设计与制造,2005,(7):62-64
    30 肖体琼,张文毅.三种计算机辅助工程软件在农业机械虚拟设计中的组合运用[J].中国农机化,2006,(6):94-97
    31 周成,夏吉庆.虚拟样机技术及其在水稻插秧机设计中的应用[J].现代化农业, 2006,(7):29-31
    32 彭建恩.对粉碎料采用气力输送方式的探讨[J].粮食科技与经济,1996,(6):37-38
    33 向卫兵.水稻气力有序抛栽机理[D].博士学位论文.华南农业大学.2003,2-4
    34 姚 征,陈康民.CFD 通用软件综述[J].上海理工大学学报,2002, 24(2): 137-144
    35 Levy A and Mason D J. The effect of a bend on the particle cross-section concentration and segregation in pneumatic conveying systems [J]. Powder Technology, 1998, 98:95-103
    36 Lee L Y, Quek T Y, Deng R, Ray M B and Wang C. Pneumatic transport of granular materials through a 90° bend [J]. Chemical Engineering Science, 2004, 59:4637-4651
    37 Dennis Lammers. Determination of the air and crop flow behaviour in the blowing unit and spout of a pull-type forage harvester [D]. A thesis for the degree of master of science, Saskatchewan: University of Saskatchewan, 2005,52-58
    38 田铖,张欢,由世俊等.利用FLUENT软件模拟地铁专用轴流风机的内部流场[J].流体机械,2003,31(11):13-15
    39 张力,席德科.前向多翼离心通风机性能改进数值模拟[J].风机技术,2005,(6):8-11,30
    40 邹建煌,杜群贵,谢在玉.离心风机的流场分析和参数化设计[J].机床与液压,2005,(2):65-66
    41 李建锋,吕俊复.风机流场的数值模拟[J].流体机械,2006,34(4):10-13,62
    42 袁凤东,由世俊,高立江.基于CFD 的地铁用轴流风机性能模拟[J].流体机械,2006,34(5):26-30
    43 卢池,陈次昌,杨昌明等.低比转速离心泵内部流场的数值模拟[J].排灌机械,2005,23(6):6-9
    44 黄思,王国玉.离心泵内流场非对称性及受力三维数值分析[J].农业机械学报,2006,37(10):66-69
    45 施卫东,叶忠明,刘建瑞等.一种新型射流式自吸泵进口流场的数值模拟[J]. 农业机械学报,2006,37(10):50-52,61
    46 王学农,李从权,史建新等.抛送式秸秆粉碎还田机风场模拟 [J]. 农业机械学报,2007,38(8):67-69
    47 王福军.计算流体动力学分析—CFD软件原理与应用[M].北京:清华大学出版,2004,122-138
    48 段江南.流体机械虚拟实验平台的开发与实践[D].硕士学位论文.华中科技大学.2002,29-39
    49 华南工学院,上海化工学院编.流体力学-风机及泵[M].中国建筑工业出版社,1980,70-71
    50 朱维兵,晏静江.虚拟样机技术在振动筛动力学分析中的应用[J].钻采工艺, 2005,28(3):77-79
    51 熊光楞,李伯虎,柴旭东.虚拟样机技术[J].系统仿真学报,2001,13(1):114-117
    52 包金宇,廖文和,薛善良.虚拟样机技术初探[J].机械制造与自动化, 2003,(6):1-3,6
    53 祖旭,黄洪钟,张旭.虚拟样机技术及其发展[J].农业机械学报,2004,35(2):168-171
    54 周成,王静学,马增奇.虚拟样机技术及其在农机产品开发中的应用[J].现代化农业,2004,(11):30-32
    55 郝云堂,金烨,季辉.虚拟样机技术及其在ADAMS中的实践[J].机械设计与制造, 2003,(3):16-18
    56 姜士湖,闫相桢.虚拟样机技术及其在国内的应用前景[J].机械,2003,30(2): 4-6,9
    57 王成,王效岳.虚拟样机技术及ADAMS[J].机械工程与自动化, 2004,(6):66-68,75
    58 刘小平,郑建荣,朱志国等.虚拟样机技术及其相关研究和实践[J].机械科学与技术,2003,22(增):235-238
    59 续彦芳,崔俊杰,苏铁雄.虚拟样机技术及其在ADAMS中的应用[J].机械管理开发, 2005,(1):70-71,73
    60 苑绍志,胡爱军,谢金法.机电产品虚拟样机的建模和仿真技术及其实践[J].河南科技大学学报(自然科学版),2004,25(6):16-19
    61 马国强等编.虚拟样机技术及其在 ADAMS 上的实践[M].西北工业大学出版社, 2002,51-85
    62 郑建荣.ADAMS虚拟样机技术入门与提高[M].北京:机械工业出版社,2001,101-200
    63 李军,邢俊文,覃文洁等编.ADAMS实例教程[M].北京:北京理工大学出版社,2002,10-12
    64 李增刚编.ADAMS入门详解与实例[M].北京:国防工业出版社,2006,82-90
    65 王洪波.羊草可压缩性及其应力松弛特性的虚拟样机分析研究[D].博士学位论文.内蒙古农业大学.2007,69
    66 廖庆喜.免耕播种机防堵与排种装置试验研究[D].博士学位论文.中国农业大学.2003,35-37
    67 刘孝民,桑正中,王建国.潜土旋耕试验研究(3)—潜土逆转旋耕仿真试验研究[J].佳木斯工学院学报,1998,16(3):283-287
    68 Sitkei G. Mechanics of agricultural materials[M]. Elsevier, New York, NY.1986:100-110
    69 赵学家,张魁学,张振京.短茎秆的气动特性及其在气流中的运动[J].农业机械学报,1982(2):55-65
    70 Aarseth K A. Attrition of feed pellets during pneumatic conveying: the influence of velocity and bend radius [J]. Biosytems Engineering, 2004, 89(2):197-213
    71 Baker J D and Klinzing G E. Optimal performance of pneumatic transport systems [J]. Powder Technology, 1999, 104:240-247
    72 Mason D J, Marjanovic P and Levy A. A simulation system for pneumatic conveying systems [J]. Powder Technology, 2000, 95:7-14
    73 Stoess H A. Pneumatic conveying [M], 2nd edition. New York:John Wiley & Sons Inc.1983:120-130
    74 Tremblay D, Savoie P and Q Le Phat. Reducing forage harvester peak power with a flywheel [J]. Applied Engineering in Agriculture, 1991,7(1):41–45
    75 Liljedhal J B; Jackson G L; de Gra4 R P; Schroeder M E Measurement of shearing energy [J]. Agricultural Engineering, 1961, 42(4), 298-301
    76 Chancellor W J. Energy requirement for cutting forage [J]. Agricultural Engineering, 1958, 39(10): 633-636
    77 Berentsen O J. Energy requirements for grass chopping [J]. Norway Institute of Agricultural Engineering Research, 1973, Report 22
    78 Bockhop C W, Barns K K. Power distribution and requirement of a flail-type forage harvester [J]. Agricultural Engineering, 1955, 36(7): 453-457
    79 Chattopadhyay P S. Studies on design parameters of the cutting unit of flail-type forage harvesting machine [D]. Ph.D.thesis. Agricultural and Food Engineering Dept, I I T Kharagpur, India, 1997
    80 李林,杨明韶,王春光等.9R一40型揉碎机的研制与试验[J].内蒙古农牧学院学报,1997,18(3):69-74
    81 史建新,陈发,郭俊先.抛送式棉秆粉碎还田机的设计与试验[J].农业工程学报, 2006,22(3):68-72
    82 张莉.离心叶轮机械内部非定常流动的研究[D].博士学位论文.上海交通大学.2001,5-7;98-99
    83 <<现代综合机械设汁手册>>编委会.现代综合机械设汁手册[M].北京出版社.1999,952-972
    84 权威,王净莹.Pro/ENGINEER Wildfire中文版实例教程[M].北京:清华大学出版社.2005,160-167;417-424
    85 姚兴军.Pro/ENGINEER野火版实用教程[M].人民邮电出版社.2005,227-231
    86 祝凌云,李斌,王寄燕.Pro/ENGINEER野火版入门指南[M].人民邮电出版社. 2003,1-193
    87 张延松.机械脱污及其应用研究[J].重庆环境科学.1995,17(6):28-30
    88 孔珑.两相流体力学[M].北京:高等教育出版社2004,86-110
    89 沈卫强,周松,叶云霞.9RSZ-540型秸杆揉碎机的设计[J].农机化研究, 2004,(2):143-144
    90 陈海霞,董德军,张凤菊.大型秸秆揉搓机的研究设计[J].农机化研究,2005,(1):177-178
    91 孟海波,曲峻岭,刘依.我国秸秆饲料加工机械现状及发展[J].农机化研究, 2002,(4):1-3;29-31
    92 张 越 ,宋 健 .多 体 动 力 学 仿 真 软 件 ADAMS 理 论 及 应 用 研 讨 [J].机 械 科 学 与 技术,1999,16(5):753-758,776

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