Study On The Influence Of Multicomponent Gas Flow And Heat Transfer In The Measurement Section On Optical Detection

With the reduction of conventional oil reserves,the contradiction between the growing market demand and the shortage of conventional oil supply is becoming increasingly prominent.As an important strategic replacement resource,heavy oil has attracted more and more attention.Multiple thermal fluids huff and puff as a new generation of heavy oil thermal recovery technology,based on the thermal viscosity reduction,relies on the synergistic effect of multicomponent gas,and improves the thermal development effect of heavy oil reservoirs by reducing viscosity,boosting drainage and reducing heat loss.The detection of multiple thermal fluids component content has important engineering practical significance for the optimal injection parameters of heavy oil production,the construction and verification of wellbore flow and heat transfer model,and the optimization and regulation strategy of on-site generator combustion.Therefore,it is very important to monitor the multicomponent gas content in the process of multiple thermal fluids thermal recovery in real time and feed it back to the generation system in time.Based on the basic principles of gas-solid two-phase flow,particle dynamics,Mie scattering theory and thermal radiation transmission,taking the mixed particle multicomponent gas as the research object,the flow characteristics of mixed particle multicomponent gas in the optical measurement section were numerically simulated by Euler Lagrange method combined with DPM model.Aiming at the problem of non-absorption loss caused by particles,the influence of particle agglomeration on laser transmission and laser detection was studied,and the influence of gradient refractive index and optical window deformation caused by high temperature and high pressure environment on laser transmission were explored.The influences of the above adverse factors on the laser detection accuracy were weakened by nitrogen purging,the optimization effects of laser transmission after nitrogen purging were summarized,and the thermal radiation level of the detection system before and after purging was evaluated.The main research contents are as follows:(1)The geometric physical model of the optical measurement section and the mathematical model of mixed particles multicomponent gas flow and heat transfer are established to verify the independence of the grid and check the grid quality.The accuracy of the model is verified by comparing the experimental results in the literature.The flow process of mixed particle multicomponent gas in the optical measurement section is numerically simulated and analyzed.(2)The construction method of particle spatial distribution based on random mapping of sample probability density is proposed,the single particle scattering model is established,the process of particle interference with laser transmission is analyzed,and the effects of particle agglomeration on the light intensity distribution and power loss of the receiving surface are obtained.(3)The finite element model of thermal analysis and structural analysis of optical window is established and verified,the refractive index change curve of optical window is fitted,and the influence of refractive index change and deformation of optical window on laser transmission under hot pressing load are analyzed.(4)Based on tdlas-das technology,an experimental platform was built to study the influence of quartz sand particles on laser detection under laboratory conditions.The particle dispel effects and the refractive index change and deformation improvement effect of the optical window under the condition of nitrogen purging are analyzed.The multi factor joint laser transmission before and after nitrogen purging is compared and analyzed,and the internal thermal radiation level of the laser detection system before and after nitrogen purging is evaluated.With laser detection of multicomponent gas content in doped particles as the research background,the influence of light intensity loss caused by particle absorption and scattering,refractive index change and deformation of optical window under hot-pressing load on laser transmission and detection is studied.The simulation analysis of laser transmission and experimental research of particle interference laser detection under different operating conditions are carried out.Finally,the optimization effect of laser transmission after nitrogen purging is analyzed and the heat radiation level of detection system before and after purging is evaluated.The research results of this paper provide certain reference and reference for the future development of on-line multicomponent gas content detection technology in industrial process.