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水力石家庄风机厂风机的数值模拟和设计研究(1)

作者:石家庄风机     日期:2014-10-30     浏览:900     

石家庄风机厂 石家庄风机 石家庄市风机厂 石家庄风机维修 石家庄风机销售

摘要
随着我国船舶事业的不断发展,对船上一些辅助设备的要求越来越高。目前船用水力石家庄风机厂风机不仅要求防火、排烟,而且要求防爆、轻量化。国内对水力石家庄风机厂风机的设计大多采用常规设计方法,本文针对国内某一款高转速、大排烟量的船用便携式水力石家庄风机厂风机采用数值模拟和模型试验相结合的方法进行了研究,填补了国内便携式水力石家庄风机厂风机数值模拟研究方面的空白。本文主要进行了以下工作:
(1)水力石家庄风机厂风机的CFD模型研究
通过分析水力石家庄风机厂风机的结构和工作原理,对流体域进行了合理简化,并在CFD软件Fluent的前处理软件Gambk中完成了水流场和空气流场三维建模和网格划分的研究;基于Fluent的标准1^模型对水轮机和石家庄风机厂风机的内部流动进行了数值模拟,将数值计算结果与试验数据对比,水轮机模拟流量和试验流量的相对误差范围为0.9%?7.6%,石家庄风机厂风机试验全压和模拟全压的相对误差范围为4.7%~15.5%,基本能够满足计算要求,计算模型基本合理。
(2)基于多流场耦合的水力石家庄风机厂风机的性能预测
基于动网格技术,提出了一种多流场弱耦合计算方法:利用Fluent的UDF接口编程,使水力石家庄风机厂风机水流场和空气流场的同步计算,并在每一个时间步长计算结束后,通过数据文件的读写交换两个流场之间的相关数据,直至两个流场达到完全匹配的稳定状态。该方法不但可以完成水力石家庄风机厂风机整体性能预测,而且可以很方便的描述不同流场之间的相互关系,可以为水力石家庄风机厂风机的瞬态计算提供借鉴。
(3)水轮机的流场数值研究和结构改进
对水轮机核心部件一喷嘴和水涡轮的主要结构参数的变化引起水轮机的主要性能参数的变化情况作了分析,讨论的结构参数包括水涡轮叶片型线、叶片数量、叶片高度、喷嘴数量、喷嘴内表面形状、喷嘴斜射角和直径比。模拟结果表明:修改后的叶片型线与常规型线相比水动性能略差,但加工性能大幅提高,可取代常规型线;叶片数量可在较大范围内选择,原模型水轮机叶片数的选择合理;靠单纯的增加叶片高度不能提升水轮机的性能;喷嘴数量的增多可有效增大出力;锥形喷嘴可有效减少压力损失,增大水轮机的功率和效率;喷嘴斜射角越小,水轮机性能越好,但考虑到结构问题和加工难度,斜射角有一定的选择范围;通过增大喷嘴出口段直径和叶片高度减小直径比可明显提高水轮机的过流能力和功率。根据这些研究对水轮机的结构进行了改进,改进后的水轮机功率在进口水压为0.2MPa时增加了 39.4W,增长幅度达24.7%,进口水压为0.7MPa时增加了 330.2W,增长幅度髙达31.7%。
(4)便携式水力石家庄风机厂风机的设计研究
研究了便携式水力石家庄风机厂风机的水动设计、结构设计和气动设计。当缩放系数k为0.9~1.2时,不同水轮机的功率范围为1000W?2200W,为水力石家庄风机厂风机的设计提供了更宽的功率选择范围;在保证结构强度满足的条件下,完成了水轮机和石家庄风机厂风机最大尺寸的选择;结合水轮机的性能曲线,给出了预测石家庄风机厂风机的设计风量和风压范围的方法。根据以上的研究成果,最终提出了一种水力石家庄风机厂风机设计方案,并通过设计案例进行了验证.
关键词:水力石家庄风机厂风机;数值计算;多流场耦合;水涡轮;喷嘴;设计方案

Abstract
With the continuous development of our marine industry, there are higher and higherrequirements on the marine auxiliary equipment. The marine water driven fans should be notonly fire prevention and smoke prevention, but also explosion-proof and lightweight. Most ofdomestic research on water driven fan adopt conventional design methods. One kind of marineportable water driven fan with high speed and large amount of smoke exhaust in the market wasresearched by adopting the method of numerical simulation and model test, which filled in theblank of the numerical simulation research on portable water driven fan. This paper carried outthe following work:
(1)CFD Model Research on the Water Driven Fan
After analysising the structure and working principles of the research object, the fluiddomain was simplified reasonably and by using the software Gambit the 3D Modeling andmeshing of the water flow field and air flow field were completed; Based on the standard k-£epsilon model of the Fluent software, the internal flow field of the hydraulic turbine and the fanwere simulated, by comparing the results of numerical simulation date and experimental data,the relative error range between the calculated values for the flow rate of the hydraulic turbineand the measured values was 0.9%?7.6%, and the relative error range between the calculatedvalues for the total pressure of the fan and the measured values was 4.7%~15.5%, hich couldbasically meet the computing requirement. Thus the calculation model was basically reasonable.(2)Performance Prediction of the Water Driven Fan Based on Multi Field CouplingA multi field weak coupling calculation method was put forward: water flow field and airflow field are calculated at the same time by using Fluent UDF to program and control theprocess,and after the completion of calculation of each time step, data exchanges between thetwo flow field by reading and writing data files, until two flow field match and become steady.
This method can not only complete the performance prediction of water driven fan,but alsoeasily describes the relationship between different flow fields and provides reference for thetransient calculation of the water driven fan.
(3)The Flow Field Numerical Study and Structure Improvement of the Hydraulic TurbineThe changes of the main hydraulic turbine performance parameters caused by the changesof the structure parameters of the turbine and nozzle which are the main parts of the hydraulicturbine were analyzed. The structure parameters discussed include the type line, the number andthe height of hydraulic turbine blades,nozzle number, nozzle inner surface shape, oblique angle,as well as the cooperative relationship between the hydraulic turbine and nozzle. Simulation
results show that: the hydrodynamic performance of the modfied blde type line is a little lessthan that of the conventional line, but the processng performance can be improved obviously,so the modified blade type line can replace the conventional line; the blade number is availableto choose in a wide range, and the turbine blade number of the original model is reasonable; Byincreasing height of the turbine blade simply cannot improve the performance; The addition ofnozzle number can ffectively increase the output; Conical nozzle can effectively reduce thepressure loss,increase the power and efficiency of the turbine; The smaller the nozzle obliqueAngle is, the better the performance of the turbine will be, but considering the structure and theprocessing difficulty, oblique Angle should be in a certain range; By increasing the nozzle outletdiameter and blade height at the same time to decrease the diameter ratio, the flow capacity andpower of the turbine can be obviously improved. According to the study, the structure of theturbine was improved. When the inlet pressure was 0.2Mpa, the increasement and the grow rateof the turbine power were 39.4W and 24.7%,and when the inlet pressure was 0.7Mpa,theincreasement and the grow rate were 330.2W and 31.7%.
(4)The Design Researches of the Potable Water Driven FanThe hydraulic design, structure design and aerodynamic design of the portable water drivenfan were tudied. When scaling coefficient k is 0.9-1.2, the power range of different turbine is1000W?2200W,which provides wider power range for the design of the fan; nder thecondition of meeting the structural strength requirement, the selection of the urbine and fanmaximum size were completed; Combined with turbine performance curve, the way topredicting the design flow rate and total pressure of the fan was given. A design scheme of thewater driven fan was proposed at last, and was verified through a design case.Key words: water driven fan; numerical calculation; multi flow field coupling;hydraulic turbine; jet; design scheme