Research Of Unsteady Tiny Flow Characteristics Under Small Scale Channel

With the development of the fluid system in the direction of miniaturization，demands for accurate measurements of small flow rate increase gradually. In medicalapparatus and instruments, fluid components leak detection, irregular parts fittolerance test, small fluid flow characteristics device research, small aperture orcapillary diameter measurement and biochemical protection, usually a small flow ofhigh precision measurement needs to be tested under the condition of steady flow ofsmall flow measurement.At present for the flow rate under the condition of steady flow measurement, themeasurement system must have high precision liquid constant pressure device, whichincreases the complexity of the measurement system. Again, some problems oftenappear for the commonly used flow meter in the measurement of tiny flow, forexample, the error big pressure loss. Therefore, it is difficult to directly apply to smallflow measurement system. The principle of measuring small flow rate under thecondition of steady flow is essentially "stopwatch-measuring cup method".For the problems arising from the small flow measurement, this paper putsforward a kind of small flow measuring principle and realization method, whichregards the unsteady flow as stationary flow. This paper designs the liquid flowmeasurement device, making the structure of device simple, making operation of thedevice convenient, making cost of the device lower, reducing man-made factors inmeasurement process. Author completes the measurement test of micro flow and getsa lot of experimental data, analyzing experimental data in detail. Based on dataanalysis, this paper proposes a rational nonlinear mathematical model. Finally, bymultivariate nonlinear regression, this paper derives a mathematical model. The maincontent of this paper includes the following aspects:Chapter1, expounds the research meaning and purpose, and summarizes theresearch status quo of small flow measurement and development status, the problemsexisting in the existing methods, summarizes the main research content of this article. Chapter2, expounds the principle of small flow measurement methods,advantages and disadvantages and scope of use, and then discusses the tiny flowmeasurement of the test apparatus.Chapter3, detailedly introduces the experiment of experimental principle,experimental device, system structure, the experiment process.Chapter4, analyzes the data, the relationship between the relationship of flowand pressure data analysis, the relationship between traffic data and pipe diametersquare data analysis, data flow and the relationship between the length of dataanalysis, the data analysis is the foundation of the mathematical model.Chapter5, based on the large amounts of data obtained from experiment,through Matlab multivariate nonlinear regression analysis, the mathematical model ofsmall flow rate.Chapter6, finally, summarizes the research work and conclusions of this paper,and prospects the future research work.Summary: this article first analyzes the tiny flow measurement status quo athome and abroad, then analyzes the principle of the experiment of small flowmeasurement and typical experiment device and the advantages and disadvantagesand application scope, on this basis, this paper puts forward a new experiment insmall flow measurement principle and design the system experiment device, finallyhas carried on the microscopic flow measurement experiment, it is concluded that alarge number of experimental measurement data, carried on the analysis ofexperimental data, nonlinear flow model is put forward, and the traffic model isobtained, the significant analysis, results show that the model has a certain practicalsignificance.