毕业论文（设计）基于MATLAB 的风机试验系统模拟仿真.doc

基于MATLAB的风机试验系统模拟仿真Simulation of Fan Test System Based on MATLAB陈建国 聂 波 /华东理工大学机械工程学院 摘要：介绍了用90°弧形进口喷嘴试验装置采集试验数据，再根据国际标准对风机的进出口压力、通风机压力、效率等试验数据进行了计算。利用MATLAB对以上的公式进行程序设计，利用MATLAB中的GUI面板，制作了友好的人机交互式界面，从而使这个复杂的计算过程得到大大的简化，加快整个计算过程和提高整个计算过程的精度。关键词：通风机 性能试验 计算机 模拟中图分类号：TP273 文献标识码：B文章编号：1006-8155（2005）06-0028-03Abstract:Test data collected by 90°are inlet nozzle test unit is instroduced ,according to international standard,Test data such as inlet and outlet pressure,fan pressure,efficiency and etc.are computed. Procedure design of the formulas can be performed using MATLAB. Friendly man-machine interface can be made using GUI panel in MATLAB, thus the so complicated calculation process is greatly simplied, the whole calculation process and the presision is improved.Keywords: Fan Performance test Computer simulation1 引言通风机性能试验是通风机设计、生产、检验中必不可少的项目。随着我国经济与科技的发展，对于引进的通风机技术和产品及我国出口的国际市场的通风机产品，必须对其质量和水平进行严格的考核和认定。对于同一台风机，由于采用不同的试验装置或不同的国家标准，往往会导致通风机性能试验结果的差异。因此，本文在对进、出口通风机产品质量考核中要求执行的公认的权威性试验标准中采用了ISO5801：1997（E）通风机空气动力性能和试验方法。MATLAB是集数值计算、符号运算及图形处理等强大功能于一体的科学计算语言。作为强大的科学计算平台，它几乎能够满足所有的计算需求。在美国及其它发达国家的理工科院、大型公司或企业的工程计算部门，MATLAB也是最为普遍的计算工具之一。鉴于篇幅所限，只介绍“带有进口和出口试验管道的标准方法：D型装置”中的“带有公用段和防涡流装置的出口管道及公用进口管道的C型装置。2 风机试验和计算方法2.1 测量装置采用90°弧形进口喷嘴，见图1。_收稿日期：2004-05-13 上海市 200237图1 90°弧形进口喷嘴2.2 试验期间的测量值转速n或旋转频率N；输入功率Pe；流量计差压p； 流量计上游压力pe7或pe3；进口静压p e3；风机出口压力pe4。在试验空间内测量：通风机所在高度上的大气压力pa；环境温度t a（靠近风管进口）；干球和湿球温度t d和t w；确定环境空气密度a和湿空气的气体常数R w。2.3 流量的计算 式中 qm气体质量流量2.4 通风机进口压力计算设平面5和平面3之间无辅助风机： 而求马赫数Ma3和 时，可有下列公式计算： 和 （1） 即 （2） 则 = 和所以，进口滞止压力psg1可按下式求得式中 常规损失系数马赫系数综上即可得 2.5 通风机出口压力计算通风机出口静压p2等于大气压pa，即 而由式（1）同理可得所以 而综上亦可得；又由；式中Ma2可由式（2）同理可得。由上两式可得所以压力由以上的参数可以计算出容积流量、通风机压力、通风机空气功率和效率，同时，在Ma2ref小于0.15时还因马赫系数等于1和截面上滞止温度和静态温度相等而使上述公式可以得到简化，由于篇幅所限，就不再进行展开。3 MATLAB程序设计MATLAB语言提供了用户界面的设计功能，用户可以自行设计别具风格的人机交互界面，输入各种计算过程中所需的参数，通过建立友好的用户截面而使计算更为方便快捷。很显然，由于在风机试验计算中有很多参数是来回迭代的，手算工作量十分巨大，而MATLAB在数学计算中具有十分强大的功能。因此，笔者利用MATLAB软件进行了程序设计，作出了一个可供处理试验数据的软件。 图2 风机试验数据处理系统程序界面在此软件中，左侧数据输入栏可以输入已知量，点击OK键以后就可以在数据输出栏中得到想要的数据。 4 试验数据图像处理从框图的右侧得到了试验计算数据以后，由于风机试验通常是测多个点的数据，则所得的数据也为多个点的数据，在MATLAB中有强大的绘图功能，用最小二乘法的线性拟和可得到试验数据的数据图。利用MATLAB中plot的命令，可以直接得到试验数据图线。如压力线、效率线等。然后经过最小二乘法线性拟和后，利用polyfit函数进行多项式拟和，然后再利用矩阵除法解决复杂型函数的拟和。则可以得到压力效率图，压力温度图等关系数据图。5 结论从试验数据的读出开始，经过经验公式的计算，使用国际标准，借助MATLAB强大的计算功能，大大地简化风机试验中数据计算的工作强度，并提高了计算准确性，缩短工作时间。编制程序以后，可以避免多次试验的重复计算，将风机试验的数据处理融入现代计算机时代中。同时也借助于MATLAB的强大的图形功能，使最后的数据得以图形显示，使处理结果更加直观化，有助于试验结果的对比、判断试验结果的合理性及试验规律总结。参 考 文 献1 GB/T1236-2000 工业通风机 用标准化风道进行性能试验.国家质量技术监督局.2000.2 王沫然.MATLAB6.0与科学计算.电子工业出版社，2001.3 续魁昌.风机手册.机械工业出版社，1999 .Editor's note: Judson Jones is a meteorologist, journalist and photographer. He has freelanced with CNN for four years, covering severe weather from tornadoes to typhoons. Follow him on Twitter: jnjonesjr (CNN) - I will always wonder what it was like to huddle around a shortwave radio and through the crackling static from space hear the faint beeps of the world's first satellite - Sputnik. I also missed watching Neil Armstrong step foot on the moon and the first space shuttle take off for the stars. Those events were way before my time.As a kid, I was fascinated with what goes on in the sky, and when NASA pulled the plug on the shuttle program I was heartbroken. Yet the privatized space race has renewed my childhood dreams to reach for the stars.As a meteorologist, I've still seen many important weather and space events, but right now, if you were sitting next to me, you'd hear my foot tapping rapidly under my desk. I'm anxious for the next one: a space capsule hanging from a crane in the New Mexico desert.It's like the set for a George Lucas movie floating to the edge of space.You and I will have the chance to watch a man take a leap into an unimaginable free fall from the edge of space - live.The (lack of) air up there Watch man jump from 96,000 feet Tuesday, I sat at work glued to the live stream of the Red Bull Stratos Mission. I watched the balloons positioned at different altitudes in the sky to test the winds, knowing that if they would just line up in a vertical straight line "we" would be go for launch.I feel this mission was created for me because I am also a journalist and a photographer, but above all I live for taking a leap of faith - the feeling of pushing the envelope into uncharted territory.The guy who is going to do this, Felix Baumgartner, must have that same feeling, at a level I will never reach. However, it did not stop me from feeling his pain when a gust of swirling wind kicked up and twisted the partially filled balloon that would take him to the upper end of our atmosphere. As soon as the 40-acre balloon, with skin no thicker than a dry cleaning bag, scraped the ground I knew it was over.How claustrophobia almost grounded supersonic skydiverWith each twist, you could see the wrinkles of disappointment on the face of the current record holder and "capcom" (capsule communications), Col. Joe Kittinger. He hung his head low in mission control as he told Baumgartner the disappointing news: Mission aborted.The supersonic descent could happen as early as Sunday.The weather plays an important role in this mission. Starting at the ground, conditions have to be very calm - winds less than 2 mph, with no precipitation or humidity and limited cloud cover. The balloon, with capsule attached, will move through the lower level of the atmosphere (the troposphere) where our day-to-day weather lives. It will climb higher than the tip of Mount Everest (5.5 miles/8.85 kilometers), drifting even higher than the cruising altitude of commercial airliners (5.6 miles/9.17 kilometers) and into the stratosphere. As he crosses the boundary layer (called the tropopause), he can expect a lot of turbulence.The balloon will slowly drift to the edge of space at 120,000 feet (22.7 miles/36.53 kilometers). Here, "Fearless Felix" will unclip. He will roll back the door.Then, I would assume, he will slowly step out onto something resembling an Olympic diving platform.Below, the Earth becomes the concrete bottom of a swimming pool that he wants to land on, but not too hard. Still, he'll be traveling fast, so despite the distance, it will not be like diving into the deep end of a pool. It will be like he is diving into the shallow end.Skydiver preps for the big jumpWhen he jumps, he is expected to reach the speed of sound - 690 mph (1,110 kph) - in less than 40 seconds. Like hitting the top of the water, he will begin to slow as he approaches the more dense air closer to Earth. But this will not be enough to stop him completely.If he goes too fast or spins out of control, he has a stabilization parachute that can be deployed to slow him down. His team hopes it's not needed. Instead, he plans to deploy his 270-square-foot (25-square-meter) main chute at an altitude of around 5,000 feet (1,524 meters).In order to deploy this chute successfully, he will have to slow to 172 mph (277 kph). He will have a reserve parachute that will open automatically if he loses consciousness at mach speeds.Even if everything goes as planned, it won't. Baumgartner still will free fall at a speed that would cause you and me to pass out, and no parachute is guaranteed to work higher than 25,000 feet (7,620 meters).It might not be the moon, but Kittinger free fell from 102,800 feet in 1960 - at the dawn of an infamous space race that captured the hearts of many. Baumgartner will attempt to break that record, a feat that boggles the mind. This is one of those monumental moments I will always remember, because there is no way I'd miss this.