The Investigation On Precise Flow Rate Measurement Using Gamma Ray Cross-Correlation Technique

This paper presents the current methods of various flow rate measurements, isotope tracer techniques and applications in flow rate measurement, the basic principle of cross-correlation, the methods and applications of cross-correlation; In situ solid-liquid flow experiments, the paper set up a series of cross-correlation techniques in flow rate measurement using isotope tracer and sealed source, and investigates the rules of solid slip velocity in the hydro-transport. The paper gives out a new method to process data for flow rate measurement using the combination of frequency spectral analyses and cross-correlation technique, and obtained improved accuracy.Flow meters are very important for industrial processes. In fact, it's very difficult to measure the multiphase flow such as solid-liquid and solid-gas or liquid-gas flows, although there have been many kinds of multiphase flow meters. More and more studies indicate the improvement in accuracy by using the cross-correlation technique combined with traditional meters. Especially gamma ray cross-correlation meters using sealed sources, are the best choice of multi-phase flow meters. The cross-correlation technique contains powerful data process tool for waveform analysis, delay time determination, thanks to the rapid development of computer. Many companies in the world began to study the techniques of cross-correlation flow meter from 1990.This paper mainly presents a method to measure flow rate by using isotope tracers and sealed sources. Gamma ray absorption method can be used to measure the instantaneous density section of the flow in pipeline. For multiphase flow, the signals from the two-neighboring detectors are the functions of time interval between the two signals, which can be calculated by cross-correlation method. The multiphase flow should be analyzed by a combination of radiotracer and y transmission measurements. Such approach gives an opportunity to take the advantages from both methods, and to set up a series ofmethods and devices for flow rate measurement in detail.In the presented hydro-transport experiment, the value of slip velocity from differences of specific gravity of components and solid fraction's concentration in mixture can be accurately obtained, due to application of sealed radioactive sources and tracers. This result gives out a new method and valuable data for hydro-transport, and makes very important effect to save energy and reduce losses and to increase the transport efficiency.This paper gives out a new data processing method for flow meter. It is a combination of frequency spectral analysis and cross-correlation techniques. It's has the advantages of anti-jamming and fast accurately calculating. The experiment proves the error of transportation delay was keep below 0.5%, it's the one of the best method in the world. Last conclusion is gamma ray cross-correlation technique can be used to determine the velocities of the solid and liquid phases, and obtain improved accuracy.The work described in this paper is the first of its kind in China by information searches.