离心泵汽蚀性能自动测试系统的研究

发布时间：2020-05-12 10:26

【摘要】： This paper described development process of cavitation performance auto-test system on the centrifugal pump in detailly . Through serious analyzing the current trends of automatic test system and the composed schemes which always used in virtual instruments. finally set the scheme of testing system which composed by the single-chip microcomputer and serial virtual instruments Through making the study of the National Standards of GB/T3216-2005《Rotodynamic pumps-Hydraulic performance acceptance tests-Grade 1 and 2》, ascertained the Grade-2 precision as the design objectives of the auto-test systems. Based on this index,combined with the used situation,computed and chose the physical sensors,contactor, regulating valve and so on. Beside that, designed the system hardware circuitry which cores is the model of AT89C51ac2 single-chip microcomputer including the display interface hardware circuit, serial communications interface circuits, contact driver circuit and so on. A testing system should have testing software as supporting based on the designed hardware, so, the softs of snigle-chip microcomputer and PC were designed in detail in this paper. The testing soft of PC which was programmed with LabVIEW was divided into three modules which included database access module, serial communication module and data analysis module. to realize the acquistion、analysis、display of collected data. Data was storaged in the Access database of the office which was realized by using the LabSQL. In order to analysis data and curve fitting quickly, we used ActiveX technology, to call the MATLAB because of the powerful data processing function of MATLAB. The testing soft of the snigle-chip microcomputer which was divided into three parts that was AD converter module, PID regulator module and the crew of serial communications interface module mainly achieved parameters collection and upload,besided that ensured a constant flow in the acquisition process. This paper also introduced a method to diagnose critical cavitation points of centrifugal pump. Wavelet analysis was used to detect the mutation point of the import pressure pulse signals of centrifugal pump in order to determine the cavitation critical point in the paper. This method was more accurate compared with traditional methods.
【图文】：

程序流程图,中值滤波,程序流程图,采样值

离心泵汽蚀性能自动测试系统的研究所谓“中值滤波”就是对某一个测量连续采样N次(一般N取奇数)，然后把N个采样值从小到大(或从大到小)排队，再取中值作为本次采样值。程序流程图如图2.1所示。 iii=i+lllsss(j)与s(i)互换换 iii===十 lll采采样值=中问值值 iii=111 iii=i+lll图2.1中值滤波程序流程图中值滤波法的效果与N值有关。一般来说，N的值不宜太大，，否则滤波效果反而不好。N值一般取3一5即可。中值滤波法对于去掉脉动性质的干扰比较有效。2.2.2.2算术平均值法算术平均法是寻找这样一个歹作为本次采样的平均值，使该值与本次各采样值间误差的平均和最小，即百=:客?)!.nin=…客住一川Inin(2一13)由一元函数求极值原理得(2一14)N艺间1一N式中:Y一一N次采样值的算术平均值;xi—第i次采样值;N—采样次数。算术平均值适用与对压力、流量一类信号的平滑处理。2.2.3去除采样数据的趋势项等待处理的数据中，一般都包含有两种分量:一是周期大于数据采集周期的频率成

LCD接口电路,单片机

示模块作为存储器或1/0设备直接挂在单片机的总线上。模块的数据线接在单片机的数据总线上，片选及寄存器选择信号由单片机的地址总线提供，读和写操作由单片机的读写信号控制。其具体的接口电路实现如图3.4所示。
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2008
【分类号】：TH311

【引证文献】