Application Research Of A LabVIEW-based ECT System For Gas-solid Flow Parameter Measurement

This paper is based on the background of the application of ECT on gas-solid two-phase flow real-time monitoring. The mainboad is designed again and the data collecting module on system mainboard is improved and optimized. The collecting rate of system is increased by employing parallel collecting method. Improvement of image forming speed is achieved by invoking COM components, which already meets the need of dynamic imaging. According to correlation of pixels characterized by double layer polar plate in ECT system, cross section on sensor is divided into 120 pixel points and then incorporate them into 16 pixel points, calculating the rate and density of each. The main content is as following:(1) Due to the multiway and parallel collecting function of PCI-6221, the mainboard of ECT is redesigned; the data collecting system is updated, and the direct control of collecting card on multiple option switch is realized. Hence, time on switch-on and switch off is largely shortened.(2) A double layer 8 polar plate capacitor sensor is designed, which enable the system to switch up and down, to collect desirable data and to implement dynamic imaging and measurement of rate distribution.(3) Because the operating of matlab daemon slows down imaging speed when LabVIEW calls matlab node to form image, this study adopts a method to pack imaging algorithm into COM components. Calling these components by LabVIEW will enhance efficiency of program.(4) As to floating object, ECT experimental device help to rebuild algorithm according to various image and contrast the rebuilding effect in terms of different standard,an optimal rebuilding algorithm in line with certain concrete flow type is concluded.The automatic selected of optimal rebuilding algorithm can be acheved base on a priori message of flow patterns.(5) A study on velocity computing of ECT double layer polar plate with correlation method. Based on the method of correlation of pixels, the plane of whole image is divided into 16 units. Velocity distribution is calculated in each unit, combining with density distribution of each phase, and finally comes out quality flow. (6) According to calculating the concentration distribution and vwlocity distribution,the mass flow distribution can be calculated.and get the mass flow of solid through the sensor finally.