The Research On The Auto-test System Of Centrifugal Pump Cavitation Performance

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 instrumentsThrough 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.