Comparison Of Near-infrared Single Point And Area Array Probe Measurement Characteristics And Measurement Model

Gas-liquid two-phase flow is widely used in the oil and gas industry,chemical processes,and nuclear technology.Due to the complex and changeable structure of gas-liquid two-phase flow and the diversity of two-phase flow parameters,the discipline of gas-liquid two-phase flow has become an important theoretical research field and an important engineering application problem.In the process of using optical methods to study the characteristics of gas-liquid two-phase flow and to measure various parameters of two-phase flow,the energy loss of optical signals during the transmission of gas-liquid two-phase flow and the refraction and reflection of light,It is a key issue that must be considered and resolved.In order to reduce the energy loss of the transmission signal of near-infrared rays in the two-phase flow and reduce the refraction and reflection of light,two research methods have been proposed in the early stage of the laboratory,Reduce the energy loss by reducing the optical path and increasing the light emitting area of the light source.Based on the research of the two previous methods in the laboratory,this thesis further analyzes and compares the two methods of point light sources and surface light sources in detail,and explores the differences between point light sources and surface light sources in the measurement process.The specific data during the measurement show what the two-phase flow is.The two light source devices are better,more suitable for the measurement environment,and the data analysis is simpler.Then,the phase content ratio and flow rate measurement are further analyzed.In order not to affect each other,the single-phase flow experiments of the two experimental devices are performed separately.In the near-infrared experiments of single-phase flow,the purpose is to prove that the infrared signal size and absorption rate are only related to the water content of the pipeline,and have nothing to do with the velocity of the single medium.The impact of the near-infrared measurement system is not great,and the results are consistent with expectations.The infrared signal is only related to the water content of the pipeline,and has nothing to do with the flow rate of a single medium.In the two-phase flow experiment,this paper analyzes the near-infrared data of the two devices under three flow patterns of bullet flow,bubble flow and annular flow.By analyzing near-infrared data of single-phase flow and two-phase flow,it is concluded that the measurement effect of the long throat neck venturi device is better than that of the rectangular window device,and the direction of establishing a mathematical model is determined.A better long throat neck venturi tube is selected.Perform further experimental research.During the study of two-phase flow Phase Volume,under the Bobble Flow pattern,by analyzing the infrared signal ratio and the liquid phase volume data distribution chart,it can be seen that when the liquid flow rate is constant,the data distribution curve is arranged Certain rules apply a separate model fit to each curve.A fitting model was established.In the process of fitting,the method used was to fix the liquid flow rate and fit the relationship between the ratio of the near-infrared signal value and the liquid content ratio.The change of the fitting parameters was due to the liquid flow The change of the two-phase flow was found,and the relationship between the two-phase flow and the fitting parameters was found.Finally,the Bobble Flow fitting model was obtained.Annular Flow phase volume research method is the same.For Phase Volume measurement of Slug Flow,in order to simplify the Slug Flow model,the Taylor bubble part is treated like a circular flow,and the Taylor bubble tail bubble part is treated like Bobble Flow.Weighted processing was performed on the Taylor bubble and the tail bubble to finally fit the Phase Volume measurement model of Slug Flow.Through the verification experiments,based on the new model,the relative error of the liquid volumetric volume fraction measurement of the Bobble Flow,Annular Flow,and Slug Flow phase fraction measurement models is within ± 4.96%.In terms of flow research,the classic flow measurement formula was modified to obtain a new model,and the experimental data was used to verify that the relative error distribution of Bobble Flow flow measurement was between-1.39% to 1.86%.Slug Flow two-phase flow volume flow measurement The relative error value is within-3.500344 ~ 3.62727%,and the relative error of Annular Flow two-phase flow volume flow measurement is within-2.117464 ~ 2.05335%.