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Multi-point temperature measurements in packed beds using phosphor thermometry and ray tracing simulations

Particuology 2024年第2期85卷 77-88页

作者： Guangtao Xuan Mirko Ebert Simson Julian Rodrigues Nicole Vorhauer-Huget Christian Lessig Benoit Fond Institute of Fluid Dynamics and Thermodynamics OVGU MagdeburgUniversitaetsplatz 2Magdeburg39106Saxony-AnhaltGermany Institute of Simulations and Graphics OVGU MagdeburgUniversitaetsplatz 2Magdeburg39106Saxony-AnhaltGermany Institute of Process Engineering OVGU MagdeburgUniversitaetsplatz 2Magdeburg39106Saxony-AnhaltGermany ONERA The French Aerospace LabDepartment of AerodynamicsAeroelasticity and Aeroacoustics(DAAA)Paris-Saclay University8rue des VertugadinsMeudon92190France

Packed bed reactors are commonly found in the process industry,for example in flame-assisted calci-nation for cement production.Understanding the heat transfer inside the bed is essential for process control,product quality and energy efficiency.Here we propose a technique to determine the internal temperature distribution of packed beds based on a combination of lifetime-based phosphor ther-mometry,ray tracing simulations,and assimilation of temperature data using finite element heat transfer simulations.To establish and validate the technique,we considered a reproducible regular packing of 6 mm diameter aluminum spheres,with one of the spheres in the top layer being electrically heated.If a sphere inside the packing is coated with thermographic phosphors and excitation light is directed to-wards the packing,luminescence from the coated sphere exits the packed bed after multiple reflection and the sphere's temperature can be determined.Isothermal measurements showed that the temper-ature obtained by phosphor thermometry is independent of the luminescent sphere location.When imaging the luminescence on a camera,the luminescence distribution in recorded image depended,however,on the position of the sphere.Therefore,in setups with multiple phosphor-coated spheres,their signals can be separated using a least squares fit.We demonstrate the approach using a setup with three luminescent spheres and validated the temperature readings against thermocouple measurements.To obtain the spatial signatures for individual sphere positions required for the least squares fit,ray tracing simulations were used.These provide an efficient alternative to single sphere measurements that are only practical for regular spherical packed beds.Multi-point measurements were used as input to a finite element heat transfer simulations to determine parameters such as particle-to-particle air gap distance.With these,the full temperature distribution inside the bed could be assimilated from the measured values.

关键词： Packed beds Phosphor thermometry ray tracing Heat transfer simulation Data assimilation

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The Implementation of ray tracing Algorithm with OpenMP Parallelization

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Journal of Computer and Communications 2024年第1期12卷 120-130页

作者： Noor Alnasser Raghad Alabssi Batool Faran Latifah Alessa Naya Nagy College of Computer Science and IT Imam Abdulrahman Bin Faisal University Dammam Kingdom of Saudi Arabia

ray tracing is a computer graphics method that renders images realistically. As the name suggests, this technique primarily traces the path of light rays interacting with objects in a scene [1], permitting the calculation of lighting and reflecting impact [2]. As ray tracing is a time-consuming process, the need for parallelization to solve this problem arises. One downside of this solution is the existence of race conditions. In this work, we explore and experiment with a different, well-known solution for this race condition. Starting with the introduction and the background section, a brief overview of the topic is followed by a detailed part of how the race conditions may occur in the case of the ray tracing algorithm. Continuing with the methods and results section, we have used OpenMP to parallelize the ray tracing algorithm with the different compiler directives critical, atomic, and first-private. Hence, it concluded that both critical and atomic are not efficient solutions to produce a good-quality picture, but first-private succeeded in producing a high-quality picture.

关键词： Parallelization ray tracing Parallel Computer Architecture OpenMP

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ray-tracing simulations of whistler-mode wave propagation in different rescaled dipole magnetic fields

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Earth and Planetary Physics 2022年第6期6卷 555-562页

作者： YangGuang Ke QuanMing Lu XinLiang Gao HuaYue Chen Rui Chen CAS Key Laboratory of Geoscience Environment School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026China CAS Center for Excellence in Comparative Planetology Hefei 230026China Collaborative Innovation Center of Astronautical Science and Technology Harbin 150001China

Kinetic simulation is a powerful tool to study the excitation and propagation of whistler-mode waves in the Earth’s inner magnetosphere.This method typically applies a scaled-down dipole magnetic field to save computational time.However,it remains unknown whether whistler wave propagation in the scaled-down dipole field is consistent with that in the realistic dipole field.In this work,we develop a ray-tracing code with a scalable dipole magnetic field to address this concern.The simulation results show that parallel whistler waves at different frequencies gradually become oblique after leaving the equator and propagate in different raypaths in a dipole magnetic field.During their propagation,the higher frequency waves tend to have larger wave normal angles at the same latitude.Compared with the wave propagation in a realistic dipole field,the wave raypath and wave normal remain the same,whereas the wave amplification or attenuation is smaller because of the shorter propagation time in a scaled-down dipole field.Our study provides significant guidance for kinetic simulations of whistler-mode waves.

关键词： whistler wave ray tracing propagation dipole magnetic field magnetosphere

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ray tracing/correlation approach to estimation of surface-based duct parameters from radar clutter

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Chinese Physics B 2010年第4期19卷 484-491页

作者：赵小峰黄思训盛峥 Institute of Meteorology PLA University of Science and Technology

This paper describes a technique to estimate surface-based duct parameters by using a simple ray tracing/correlation method. The approach is novel in that it incorporates the Spearman rank-order correlation scheme between the observed surface clutter and the surface ray density for a given propagation path. The simulation results and the real data results both demonstrate the ability of this method to estimate surface-based duct parameters. Compared with the results obtained by a modified genetic algorithm combined with the parabolic wave equation, the results retrieved from the ray tracing/correlation scheme show a minor reduction in accuracy but a great improvement on computation time. Therefore the ray tracing/correlation method might be used as a precursor to more sophisticated and slower techniques, such as genetic algorithm and particle filters, by narrowing the parameter search space and providing a comprehensive and more efficient estimation algorithm.

关键词： ray tracing Spearman rank correlation surface-based duct radar clutter

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ray tracing Study of Electromagnetic Ion Cyclotron Waves Associated with Bi-Ion Frequencies

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Plasma Science and Technology 2014年第6期16卷 577-581页

作者：周庆华杨昶贺艺华刘斯周晓萍唐立军肖伏良 School of Physics and Electronic Sciences Changsha University of Science and Technology

ray tracing study of electromagnetic ion cyclotron （EMIC） waves is conducted based on a realistic plasma density model. The simulation result shows that EMIC waves propagate away from the equatorial source region to higher latitudes basically along geomagnetic field lines, and are reflected at the region where their frequency matches the local bi-ion frequency. H＋ band suffers H＋-He＋ bi-ion frequency reflection at lower latitudes, whereas He＋ band suffers He＋-O＋ bi-ion frequency reflection at higher latitudes. Moreover, the concentration of heavy ions slightly affects the bi-ion frequencies and then slightly determines the reflection location of ray paths of EMIC waves. The current results present the first detailed study on the propagation characteristics of EMIC waves associated with bi-ion frequencies.

关键词： ray tracing electromagnetic ion cyclotron waves bi-ion frequency

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ray tracing for Doppler Backscattering System in the Experimental Advanced Superconducting Tokamak

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Plasma Science and Technology 2015年第9期17卷 728-732页

作者：周楚刘阿娣胡建强王明远张小辉李弘俞昌旋刘万东兰涛谢锦林 CAS Key Laboratory of Geospace Environment Department of Modern PhysicsUniversity of Science and Technology of China

The Doppler backscattering system has been widely used for turbulence measurements,and the microwave beam will be backscattered near the cut-off layer when the Brag condition is fulfilled.In tokamak,the ray-tracing code is used to obtain the radial position and perpendicular wave number of the scattering layer for turbulence velocity measurement and the WKB（Wentzel-Kramers-Brillouin） approximation should be satisfied for optical propagation.To calculate the backscattering location and wave number at the cut-off layer only,a single ray tracing in the cross section is enough,while for spatial and wave number resolution calculation,multiple rays reflecting the microwave beam size should be used.Considering the angle between the wave vector and the magnetic field,a three-dimension quasi-optical Gaussian ray tracing is sometimes needed.

关键词： Doppler backscattering system ray tracing wave number resolution pitch angle

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ray tracing of turning wave in elliptically anisotropic media with an irregular surface

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Earthquake Science 2017年第5期30卷 219-228页

作者： Minghui Zhang Tao Xu Zhiming Bai Youshan Liu Jue Hou Guiping Yu Key Laboratory of Earthquake Geodesy Institute of SeismologyChina Earthquake AdministrationWuhan 430071China State Key Laboratory of Lithospheric Evolution Institute ofGeology and GeophysicsChinese Academy of ScienceBeijing 100029China CAS Center for Excellence in Tibetan Plateau Earth Sciences Beijing 100101China Institute of Geophysics China Earthquake AdministrationBeijing 100081China University of Chinese Academy of Science Beijing 100049China

Seismic ray tracing in anisotropic media with irregular surface is crucial for the exploration of the fine crustal structure. Elliptically anisotropic medium is the type of anisotropic media with only four independent elastic parameters. Usually, this medium can be described by only the vertical phase velocity and the horizontal phase velocity for seismic wave propagation. Model parameteri- zation in this study is described by flexible triangular grids, which is beneficial for the description of irregular surface with high degree of approximation. Both the vertical and horizontal phase velocities are defined in the triangular grids, respectively, which are used for the description of phase velocity distribution everywhere in the model by linear interpolation. We develop a shooting ray tracing method of turning wave in the elliptically anisotropic media with irregular surface. Runge-Kutta method is applied to solve the partial differential equation of seismic ray in elliptically anisotropic media. Linearly modified method is used for adjusting emergent phase angles in the shooting scheme. Numerical tests demonstrate that ray paths coincide well with analytical trajectories in trans- versely homogeneous elliptically anisotropic media. Seis- mic ray tracing results in transversely inhomogeneous elliptically anisotropic media demonstrate that our method is effective for further first-arrival tomography in ellipti- cally anisotropic media with an irregular surface.

关键词： ray tracing Elliptically anisotropic media Vertical and horizontal phase velocity Irregular surface Triangular grids

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Influence of Cy berKnife Prescription Isodose Line on the Discrepancy of Dose Results Calculated by the ray tracing and Monte Carlo Algorithms for Head and Lung Plans: A Phantom Study

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Current Medical Science 2020年第2期40卷 301-306页

作者： Jing YANG Gang LIU Hong-yuan LIU Xin NIE Zhi-yong YANG Jun HAN Sheng ZHANG Zhi-wen LIANG Cancer Center Union HospitalTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430023China

Incorporation of the Monte Carlo(MC)algorithm in optimizing CyberKnife(CK)plans is cumbersome,and early models unconfigured MC calculations,therefore,this study investigated algorithm-based dose calculation discrepancies by selecting different prescription isodose lines(PIDLs)in head and lung CK plans.CK plans were based on anthropomorphic phantoms.Four shells were set at 2-60 mm from the target,and the constraint doses were adjusted according to the design stratcgy.After optimization,30%-90%PIDL plans were generated by ray tracing(RT).In the evaluation module,CK plans were recalculated using the MC algorithm.Therefore,the dosimetric parameters of different PIDL plans based on the RT and MC algorithms were obtained and analyzed.The discrepancies(mean+SD)were 3.72%+0.31%,3.40%+0.11%,3.47%+0.32%,0.17%+0.11%,0.64%+3.60%,7.73%+1.60%,14.62%+3.21%and 10.10%+1.57%for Djs,Dmeam),Dys,and coverage of the PTV,DGI,V,,V;and V,in the head plans and-6.32%+1.15%,-13.46%+0.98%,-20.63%+2.25%,-34.78%+25.03%,12248%+175.60%,-12.92%+5.41%,3.19%+4.67%and 7.13%+1.56%in the lung plans,respectively.The following parameters were significantly correlated with PIDL:dp98%at the 0.05 level and dpal,dys and dv3 at the 0.01 level for the head plans;dp98e%at the 0.05 level and do1e%,dpmeam,Ccoweange,dool,dvs and dv;at the 0.01 level for the lung plans.RT may be used to calculate the dose in CK head plans,but when the dose of organs at risk is close to the limit,it is necessary to refer to the MC results or to further optimize the CK plan to reduce the dose.For lung plans,the MC algorithm is recommended.For early models without the MC algorithm,a lower PIDL plan is recommended;otherwise,a large PIDL plan risks serious underdosage in the target area.

关键词： CyberKnife prescription isodose line Monte Carlo ray tracing phantom

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A ray-tracing Analysis of ICRH in Tokamaks

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Plasma Science and Technology 2006年第4期8卷 394-396页

作者：张新军赵燕平秦成明 T.WlATARI R.KUMAZAWA T.SEKI Institute of Plasma Physics Chinese Academy of SciencesHefei 230031China National Institute for Fusion Science Furo-choChikusa-kuNagoya 464-01Japan

Power deposition profiles generated by Ion Cyclotron Resonance Heating （ICRH） in non-circular tokamaks are studied using a ray-tracing technique. The simulation results for the Experimental Advanced Superconductor Tokamak （EAST） D-shaped plasma are presented. It is indicated that the spatial distributions of plasma parameters （plasma density, species temperature, minority ion concentration, etc.） have an significant influence on the power deposition profiles. The findings may be highly useful to the planned plasma heating and experiments in EAST.

关键词： ray tracing power deposition ICRH

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A ray tracing and Joint Spectrum Based Clustering and Tracking Algorithm for Internet of Intelligent Vehicles

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Journal of Communications and Information Networks 2020年第3期5卷 265-281页

作者： Luoyan Zhu Danping He Bo Ai Ke Guan Shuping Dang Junhyeong Kim Heesang Chung Zhangdui Zhong State Key Laboratory of Rail Traffic Control and Safety Beijing Jiaotong UniversityBeijing 100044China Beijing Engineering Research Center of High-speed Railway Broadband Mobile Communications Beijing 100044China CEMSE Division King Abdullah University of Science and Technology(KAUST)Thuwal 23955-6900Saudi Arabia Moving Wireless Network Research Section Electronics and Telecommunications Research Institute(ETRI)Daejeon 34129Republic of Korea

Driven by the rapid growth in information services provided by the Internet and the appearance of new multimedia applications,millimeter wave is foreseen as a key enabler towards the Internet of intelligent vehicles(IoIV)for urban traffic safety enhancement.In this regard,cluster-based channel modeling has become an important research topic in the realm of emergency communications.To fully understand the cluster-based channel model,a series of vehicle-to-infrastructure(V2I)channel simulations at 22.6 GHz are conducted by a three-dimensional ray tracing(RT)simulator.The clustering and tracking algorithm is proposed and analyzed from three aspects by the obtained simulation results.The multiple signal classification estimation spectrum is applied to restrain the influence of antenna sidelobes and identify targets at first.Based on the fundamentals,the clusters can be identified and subsequently tracked using the proposed approach.The impacts of antenna sidelobes,angle resolution of beam rotation,and non-line-of-sight propagation path on the performance of clustering and tracking are evaluated.The multi-component-level RT results are adopted as comparison benchmarks,which reflect the ground truth.This work aims to provide a full picture of the clustering characteristics for designing and analyzing emergency communication systems.

关键词： clustering and tracking algorithm Internet of intelligent vehicles(IoIV) millimeter-wave channel modeling ray tracing vehicle-to-infrastructure(V2I)communications

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