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1、高压水射流切割喷嘴的结构设计和参数优化数值模拟研究于洪 陆庭侃（河南理工大学能源科学与工程学院 焦作 河南 454000）摘要：文章应用FLUENT软件对喷嘴的内外部流场进行数值模拟研究，并对影响喷嘴出口速度和动压的四个主要结构参数进行正交试验，模拟研究结果得出适合用于切割的喷嘴结构和优化的结构参数，研究表明喷嘴的收缩角对喷嘴的性能影响最大，喷嘴出口水平过渡段也是一个重要的影响因素。关键词：FLUENT ； 喷嘴结构 ；正交试验 ；参数优化Numerical Simulation Study on Structure Design and Parameters Optimization of
2、High Pressure Water Jet Cutting NozzleYU Hong ,LU Tingkan (School of Energy Science and Engineering, Henan Polytechnic University, Jiaozuo, 454000, China)Abstracts: Numerical simulation study was carried out on the internal and external flow field of the nozzle with FLUENT software in the paper, and
3、 orthogonal experiment was done, which analysis four main structure parameters of nozzle impacting on jet speed and dynamic pressure. The simulation results shows that a nozzle, which suitable for cutting , and that the contraction angle of nozzle has an important impact on the performance ,and the
4、level transition section is also an important factor.Key words：FLUENT，nozzle structure，orthogonal experiment, parameters optimize1 引言高压水射流技术是近二十年来发展起来的一门新技术，其应用日趋广泛。近年来，高压水射流在煤层钻孔和割缝方面正得到越来越多专家学者的关注。高压水射流基本原理是利用高压水发生设备产生高压水，通过喷嘴将压力能转变为高度聚集的水射流动能，可用这种射流对物料进行切割、破碎和清洗。喷嘴是高压水射流设备形成水射流工况的直接元件，喷嘴的好坏直接影响到切
5、割效果，进而影响到系统的其它各个部分。在整个水射流设备中，由高压软管送过来的水经过喷嘴从高压低速转化为低压高速冲击物料表面，通过水射流的冲击作用、动压力作用、脉冲负荷引起的疲劳破坏作用以及水楔作用破坏物料，达到切割效果。因此对水射流喷嘴的分析研究极其重要1-2。2 喷嘴理论基础泵的流量是固定的，泵排出的水一部分经过溢流阀回到水箱，一部分经过管线进入喷嘴形成高压水射流，为了达到切割的目的，必须使经过喷嘴小孔的流体具备一定的速度，这就要求泵必须具备一定的输入功率。当泵的压力和流量等参数确定以后，与之相匹配的喷嘴孔径就能确定下来3：式中：-喷嘴小孔出口截面直径，mm；-泵的流量，L/min；-为流体
6、的流量系数；-为泵的额定压力，MPa。3 喷嘴结构及几何参数分析喷嘴的主要结构参数有：喷嘴的收缩角、入口和出口过渡形状、锥形直线段L、出口直径d、出口段是否具有圆柱段。如果有圆柱段，圆柱段长度l与出口直径d的比值等。目前，水射流切割或清洗工艺中常用的有两种基本的结构：一是圆形孔口型喷嘴，另一是圆锥收敛型喷嘴。其内流道型线均为直线型，且多以平顶形喷嘴、锥形喷嘴和锥直型喷嘴居多，如图3-1所示。(a) 平顶型喷嘴 (b) 锥形喷嘴 (c) 锥直型喷嘴图3-1 喷嘴类型为了获得最佳喷嘴几何结构，针对以上三种类型的喷嘴进行数值模拟研究。分别给出三种喷嘴模拟的几何参数如表3-1：表3-1 喷嘴模拟几何参
7、数喷嘴类型几何参数平顶型喷嘴锥形喷嘴锥直型喷嘴喷嘴直径d/mm收缩角/锥形直线段长度L/mm喷嘴圆柱段长度l/mm214213142131464 喷嘴结构数值模拟模拟软件采用ANSYS公司开发FLUENT，该软件设计基于CFD软件群的思想，针对各种复杂流动的物理现象，采用不同的离散格式和数值方法，以期在特定的领域内使计算速度、稳定性和精度等方面达到最佳组合，从而高效率地解决各个领域的复杂流动计算问题4。4.1控制方程设单位质量流体的紊动动能为，的粘性耗损率为,为轴向速度，为径向速度，为流体的密度。采用应用较为广泛的-紊流模型在轴对称柱坐标下，不可压缩流体二维流动模型封闭的方程组可写成如下的统一
8、形式5：式中变量、方程的源项方程中各项具体的表达式为：（1）连续性方程：（2）动量方程：（3）动量方程：（4）紊动量方程：（5）耗散率方程：其中式中动力粘性系数 紊流粘性系数， 的紊流Prandtl数， 的紊流Prandtl数，方程组中的各常数取值为：，。4.2数值模拟计算条件计算域网格采用结构网格划分，喷嘴的初始条件相同，湍流模型采用k-模型。入口边界条件：压力入口条件，压力为60MPa；出口边界条件：压力出口条件，压力为1MPa；壁面条件：无滑动壁面条件，设置为默认，材料特性设置：水，密度：998.2kg/m3,粘性：4182j/kg-k.解算器参数设定为非耦合隐式求解，二阶迎风格式,其他
9、参数设置为默认。4.3 模拟结果分析在以上的模拟计算条件下，对三种喷嘴的内外部流场进行了模拟，其速度和动压等值线云图如图3-2、图3-3所示。(a) 平顶型喷嘴 (b) 锥形喷嘴 (c) 锥直型喷嘴图3-2 三种喷嘴的速度等值线云图 (a) 平顶型喷嘴 (b) 锥形喷嘴 (c) 锥直型喷嘴图3-3 三种喷嘴的动压等值线云图从三种喷嘴的动压分布图和速度分布图可以看出各个喷嘴因喷嘴结构的不同，所产生的压力等值线和速度等值线的分布均不相同。射流在进入喷嘴后加速，水射流在收缩段产生收缩现象，在收缩段水射流的原始压力增大，射流进入过渡段后，水平的过渡段对射流产生一定的稳定效果，射流离开喷嘴后，发现射流的
10、动压有相应的减小。由于喷嘴结构的不同，对射流产生了较大差别的动压和速度分布，从平顶型喷嘴和锥形喷嘴可以看出，收缩角对射流流场的影响极大，有收缩角的喷嘴产生的流场在喷嘴出口处较细;喷嘴的水平过渡段对流场的影响也很大，对锥形喷嘴和锥直型喷嘴的比较得出，有水平过渡段的喷嘴流场的射流等核区长度明显，无水平过渡的喷嘴流场等核区分布不明显。对于水射流切割喷嘴而言，锥直型喷嘴射出的射流流场特性更好，射流出口轴向速度大，并且半径方向上的径向速度无波动，有利于切割。综合比较后，认为具有收缩段、水平过渡段锥直型喷嘴更适合于做高压水射流切割喷嘴。5 喷嘴参数优化从以上数值模拟研究中，初步选定锥直型喷嘴为本研究选定切
11、割喷嘴，现对其几何参数进行优化设计，为此进行正交试验设计6。本试验是通过喷嘴的出口速度大小来优选喷嘴的几何参数，影响喷嘴出口速度有如下四个因素：1）喷嘴直径d；2）收缩角；3）锥形直线段长度L；4）喷嘴圆柱段长度l。每个因素有三个水平，列成如下的因素水平表，见表5-1。表5-1 因素水平表因素水平喷嘴直径d/mm收缩角/锥形直线段长度L/mm喷嘴圆柱段长度l/mm123A1 =1A2=2A3=3B1=12B2=13B3=14C1=6C2=12C3=18D1=3D2=6D3=9根据因素的水平数，选用L9(34),然后进行表头设计、水平翻译，列出试验方案表，见表5-2。表5-2 正交表因素试验号喷
12、嘴直径d/mm收缩角/锥形直线段长度L/mm喷嘴圆柱段长度l/mm喷嘴出口速度/ m/s1234567891(1)1(1)1(1)2(2)2(2)2(2)3(3)3(3)3(3)1(12)2(13)3(14)1(12)2(13)3(14)1(12)2(13)3(14)1(3)2(6)3(9)2(6)3(9)1(3)3(9)1(3)2(6)1(6)2(12)3(18)3(18)1(6)2(12)2(12)3(18)1(6)344.257348.5433346.5619344.1671354.3533342.0943347.1017352.3314349.2469R1039.3621040.615
13、1048.689.3181035.5261055.2281037.90319.7021038.68271041.9571048.0179.33431035.5981037.7391043.067.462T=3128.657试验安排好后，按各号试验的条件进行模拟试验，记录九个喷嘴的模拟试验结果。试验考察的指标为喷嘴出口速度，把九组试验结果列入表5-2的右侧指标栏内，计算因素的极差：RA=9.318, RB=19.702, RC=9.3343, RD=7.462,按极差大小，因素的主次顺序排列如下： 主 次B C A D直接比较9个试验结果的喷嘴出口速度，可以看出：第5号试验的喷嘴出口速度最大，因
14、此喷嘴的较优几何参数如表5-3所示：表5-3 较优喷嘴几何参数喷嘴几何参数参数值喷嘴直径d/mm收缩角/锥形直线段长度L/mm喷嘴圆柱段长度l/mm213966 结论通过对喷嘴结构和几何参数的数值模拟研究，可以得出以下结论:(1) 具有收缩段、水平过渡段喷嘴射流流场特性更好，射流出口轴向速度大，并且半径方向上的径向速度无波动，适合于做高压水射流切割喷嘴。(2) 在喷嘴的四个主要的几何参数中喷嘴的收缩角对喷嘴的流场影响最大，喷嘴是否具有水平过渡段也是影响喷嘴性能的重要的因素，数值模拟研究结论和相关实验研究结果相符。参考文献：1 孙家俊.水射流切割技术M.北京：中国矿业大学出版社，1992.2 崔
15、谟慎,孙家俊.高压水射流技术M.北京：煤炭工业出版社，1993.3 刘俊,秦臻.高压水射流清洗作业中喷嘴的设计原理和选型依据J.管道技术与设备，2007(5),43-444 韩占忠，王敬，兰小平.FLUENT流体工程仿真计算实例与应用M.北京：北京理工大学出版社，2004.5 沈忠厚水射流理论与技术M东营：石油大学出版社，1998.6 赵选民，徐伟，师义民等.数理统计（第二版）M. 北京: 科学出版社, 2002.作者简介：于洪(1983-)，男，硕士研究生，主要从事高压水射流技术和瓦斯抽采技术的研究,通讯地址:河南理工大学能源科学与工程学院，E-mail:iayuhong，联系电话：1372
16、3155439。（英文版 ） Two regulations promulgated for implementation is in the party in power for a long time and the rule of law conditions, the implementation of comprehensive strictly strategic plan, implementation in accordance with the rules and discipline to manage the party, strengthen inner-party s
17、upervision of major initiatives. The two regulations supporting each other, the adhere to a positive advocate, focusing on morality is of Party members and Party leading cadres can see, enough to get a high standard; around the party discipline, disciplinary ruler requirements, listed as negative li
18、st, focusing on vertical gauge, draw the party organizations and Party members do not touch the bottom line . Here, the main from four square face two party rules of interpretation: the first part introduces two party Revised regulations the necessity and the revision process; the second part is the
19、 interpretation of the two fundamental principles of the revision of laws and regulations in the party; the third part introduces two party regulations modified the main changes and needs to grasp several key problems; the fourth part on how to grasp the implementation of the two regulations of the
20、party. and revised the necessity and revised history of the CPC Central Committee the amendment to the Chinese Communist Party members and leading cadres honest politics several guidelines and column 1 by 2015 to strengthen party laws and regulations focus. Two party regulations revision work lasted
21、 a Years, pooling the wisdom of the whole party, ideological consensus, draw historical experience, respect for the wisdom of our predecessors, which reflects the unity of inheritance and innovation; follow the correct direction, grasp the limited goals, adhere to the partys leadership, to solve the
22、 masses of the people reflect a focus on the problem. The new revision of the and , reflects the partys 18 and the eighth session of the third, the spirit of the fourth plenary session, reflecting the experience of studying and implementing the General Secretary Xi Jinping series of important speech
23、, reflects the partys eighteen years comprehensive strictly practice. (a) revised two regulations of the party need of in based on revised, the promulgation and implementation of January 2010, to strengthen the construction of the contingent of leading cadres play an important role. But with the par
24、ty to manage the party strictly administering the deepening, has not been able to fully meet the actual needs. Content is too complicated, eight prohibition, 52 are not allowed to hard to remember, and also difficult to put into practice; the second is concisely positive advocated by the lack of pro
25、hibited provisions excessive, no autonomy requirements; the third is banned terms and discipline law, both with the party discipline, disciplinary regulations repeat and Criminal law and other laws and regulations repeat; the fourth is to clean the theme is not prominent, not for the existing proble
26、ms, and is narrow, only needle of county-level leading cadres above. is in 1997 based on revision, in December 2003 the promulgation and implementation, to strengthen the construction of the party play very important role. Along with the development of the situation, which many provisions have been
27、unable to fully meet the comprehensive strictly administering the practice needs. One is Ji law, more than half of the provisions and criminal law and other countries laws and regulations Repetition; two is the political discipline regulations is not prominent, not specific, for violation of the par
28、ty constitution, damage the authority of Party Constitution of misconduct lack necessary and serious responsibility to pursue; third is the main discipline for the leading cadres, does not cover all Party members. Based on the above situation, need to and the two is likely to be more relevant regula
29、tions first amendment. By revising, really put the authority of Party discipline, the seriousness in the party tree and call up the majority of Party members and cadres of the party constitution of party compasses party consciousness. (II) two party regulations revision process the Central Committee
30、 of the Communist Party of China attaches great importance to two regulations revision . Xi Jinping, general books recorded in the Fifth Plenary Session of the eighth session of the Central Commission for Discipline Inspection, on the revised regulations made clear instructions. According to the cen
31、tral deployment, the Central Commission for Discipline Inspection from 2014 under six months begin study two regulations revision. The Standing Committee of the Central Commission for Discipline Inspection 4 review revised. Comrade Wang Qishan 14 times held a special meeting to study two regulations
32、 revision, amendment clarifies the direction, major issues of principle, path and target, respectively held a forum will listen to part of the province (area) secretary of the Party committee, Secretary of the Discipline Inspection Commission, part of the central ministries and state organs Departme
33、nt The first party committee is mainly responsible for people, views of experts and scholars and grassroots party organizations and Party members. Approved by the Central Committee of the Communist Party of China, on 7 September 2015, the general office of the Central Committee of the Party issued a
34、 notice to solicit the provinces (autonomous regions, municipalities) Party, the central ministries and commissions, state ministries and commissions of the Party (party), the General Political Department of the military, every 3 people organization of Party of two regulations revision opinion. Cent
35、ral Commission for Discipline Inspection of extensive solicitation of opinions, careful study, attracting, formed a revised sent reviewers. In October 8 and October 12, Central Committee Political Bureau Standing Committee and the Political Bureau of the Central Committee After consideration of the
36、two regulations revised draft. On October 18, the Central Committee of the Communist Party of China formally issued two regulations. Can say, two laws amendment concentrated the wisdom of the whole party, embodies the party. Second, and revision of the basic principles of two party regulations revis
37、ion work and implement the partys eighteen, ten eight plenary, the spirit of the Fourth Plenary Session of the Eleventh Central Committee and General Secretary Xi Jinping important instructions on the revised and , highlighting the ruling party characteristics, serious discipline, the discipline qui
38、te in front of the law, based on the current, a long-term, advance as a whole, with Bu Xiuding independent and . Main principle is: first, adhere to the party constitution to follow. The constitution about discipline and self-discipline required specific, awaken the party constitution of party compa
39、sses party consciousness, maintaining the authority of the constitution. General Secretary Xi Jinping pointed out that no rules, no side round. Party constitution is the fundamental law, the party must follow the general rules. In early 2015 held the eighth session of the Central Commission for Disc
40、ipline Inspection Fifth Plenary Session of the 16th Central Committee, Xi Jinping again pointed out that constitution is the party must follow the general rules, but also the general rules. the revision of the and is Method in adhere to the regulations established for the purpose of combining rule o
41、f virtue is to adhere to the party constitution as a fundamental to follow, the constitution authority set up, wake up the party constitution and party rules the sense of discipline, the party constitution about discipline and self-discipline specific requirements. 4 second is to adhere to in accord
42、ance with the regulations governing the party and the party. The Party of rule of virtue de, mainly refers to the partys ideals and beliefs, excellent traditional style. The revised the closely linked to the self-discipline, insisting on the positive initiative, for all members, highlight the vital
43、few, emphasized self-discipline, focusing on the morality, and the majority of Party members and the ideological and moral standards. The revised Ji method separately, Ji, Ji Yan to Method, as a negative list, emphasizing the heteronomy, focusing on vertical gauge. Is this one high and one low, a po
44、sitive reaction, the strict party discipline and practice results transformation for the integration of the whole party to observe moral and discipline requirements, for the majority of Party members and cadres provides benchmarking and ruler. Third, insist on to. In view of the problems existing in
45、 the party at the present stage, the main problems of Party members and cadres in the aspect of self-discipline and abide by the discipline to make clearly defined, especially the partys eighteen years strict political discipline and political rules, organization and discipline and to implement the
46、central eight provisions of the spirit against the four winds and other requirements into Disciplinary provisions. Not one pace reachs the designated position, focusing on in line with reality, pragmatic and effective. After the revision of major changes, major changes in the and modified and needs to grasp several key problems (a)
