Numerical Characterization of a High Flux Solar Simulator Using Forward and Inverse Methods

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Mostafa Abuseada ◽  
Nesrin Ozalp
Keyword(s):  
Heat Flux ◽  
Ray Tracing ◽  
Focal Plane ◽  
High Flux ◽  
Solar Simulator ◽  
New Approach ◽  
First Order ◽  
Numerical Characterization ◽  
Tracing Method

Abstract The numerical characterization of a 10 kWe xenon arc high flux solar simulator is thoroughly presented and performed using two approaches: a forward Monte Carlo ray tracing (MCRT) method and an inverse ray tracing method. Experimental characterization was previously performed for the solar simulator using an indirect flux mapping technique, where the experimental heat flux distribution was obtained at the focal plane and additional 12 planes away from the simulator. For the first numerical characterization method, an in-house MCRT code was used to determine the shape of the xenon arc to best model the simulator. It was determined that an isotropic volumetric source consisting of a hemisphere of 1 mm radius that is attached to a cylinder of 1 mm in radius and 10 mm in length well described the experimental results obtained. The in-house code was then used to generate heat flux maps similar to that obtained experimentally and determine the intensity at the focal plane to be used by the inverse ray tracing method presented for its validation. For the inverse method, intensity interpolation schemes of zeroth and first-order were examined in addition to different solution strategies. It is shown that a first-order interpolation scheme unnecessary complicates the inverse problem, leading to larger errors. In addition, a new approach of constraining the formulated system of equations with an equality constraint that works by eliminating intensity values not tracing back to the ellipsoidal reflector is proposed. This new approach provided intensity values with reduced percentage errors.

Operational Performance of the University of Minnesota 45kWe High-Flux Solar Simulator

2012 ◽  
Author(s):  
Katherine R. Krueger ◽  
Wojciech Lipiński ◽  
Jane H. Davidson
Keyword(s):  
Heat Flux ◽  
Focal Plane ◽  
Flux Distribution ◽  
Spectral Characteristics ◽  
Ccd Camera ◽  
Optical Filters ◽  
High Flux ◽  
University Of Minnesota ◽  
Solar Simulator ◽  
The University

This paper presents measured performance of the University of Minnesota’s 45 kWe indoor high-flux solar simulator. The simulator consists of seven radiation units, each comprised of a 6.5 kWe xenon short arc lamp coupled to a reflector in the shape of a truncated ellipsoid of revolution. Data include flux distribution at the focal plane for all seven radiation units operating in tandem and for individual radiation units. The flux distribution is measured optically by acquiring the image of radiation reflected from a Lambertian target with a CCD camera equipped with neutral density optical filters. The CCD camera output is calibrated to irradiation using a circular foil heat flux gage. It is shown that accurate calibration of the heat flux gage must account for its response to the spectral characteristics of the radiation source. The simulator delivers radiative power of approximately 9.2 kW over a 60-mm diameter circular area located in the focal plane, corresponding to an average flux of 3.2 MW m−2, with a peak flux of 7.3 MW m−2.

Design of Ellipsoidal Specular Reflectors of 70 kW High-Flux Solar Simulator

2013 ◽  
Vol 827 ◽  
pp. 163-168
Author(s):  
Zi Jin Li ◽  
Jin Liang Xu
Keyword(s):  
Monte Carlo ◽  
Mathematical Models ◽  
Ray Tracing ◽  
High Flux ◽  
Solar Simulator ◽  
Ray Tracing Method ◽  
Maximum Light ◽  
Major Parameter ◽  
Tracing Method

With the constraint of maximum light-concentrating efficiency, we designed a condenser for a 70 kW high-flux solar simulator. The mathematical models of the optical condenser unit and system were established to determine the condenser shape parameters.The Monte Carlo ray-tracing method was applied to compute the the light-concentrating efficiency for the condenser. It is shown that the truncation angle is the major parameter to influence the light-concentrating efficiency.When the truncation angle is 60 degrees, the condenser aberration is balanced by the truncation loss to reach the maximum light-concentrating efficiency.

scholarly journals Characterization of a New 10 kWe High Flux Solar Simulator Via Indirect Radiation Mapping Technique

2019 ◽  
Vol 141 (2) ◽  
Author(s):  
Mostafa Abuseada ◽  
Cédric Ophoff ◽  
Nesrin Ozalp
Keyword(s):  
Heat Flux ◽  
Complementary Metal Oxide Semiconductor ◽  
Threshold Value ◽  
Oxide Semiconductor ◽  
Total Power ◽  
Mapping Technique ◽  
High Flux ◽  
Solar Simulator ◽  
A New Technique

This paper presents characterization of a new high flux solar simulator consisting of a 10 kW Xenon arc via indirect heat flux mapping technique for solar thermochemical applications. The method incorporates the use of a heat flux gauge (HFG), single Lambertian target, complementary metal oxide semiconductor (CMOS) camera, and three-axis optical alignment assembly. The grayscale values are correlated to heat flux values for faster optimization and characterization of the radiation source. Unlike previous work in heat flux characterization that rely on two Lambertian targets, this study implements the use of a single target to eliminate possible errors due to interchanging the targets. The current supplied to the simulator was varied within the range of 120–200 A to change the total power and to mimic the fluctuation in sun's irradiance. Several characteristic parameters of the simulator were studied, including the temporal instability and radial nonuniformity (RNU). In addition, a sensitivity analysis was performed on the number of images captured, which showed a threshold value of at least 30 images for essentially accurate results. The results showed that the flux distribution obtained on a 10 × 10 cm2 target had a peak flux of 6990 kWm−2, total power of 3.49 kW, and half width of 6.25 mm. The study concludes with the illustration and use of a new technique, the merging method, that allows characterization of heat flux distributions on larger areas, which is a promising addition to the present heat flux characterization techniques.

scholarly journals Experimental and numerical characterization of a new 45 kW_el multisource high-flux solar simulator

2016 ◽  
Vol 24 (22) ◽  
pp. A1360 ◽  
Author(s):  
Gaël Levêque ◽  
Roman Bader ◽  
Wojciech Lipiński ◽  
Sophia Haussener
Keyword(s):  
High Flux ◽  
Solar Simulator ◽  
Numerical Characterization

Intensity Distribution From a Single-Bulb Solar Simulator Identification Through Inverse Ray Tracing

2019 ◽  
Author(s):  
Mostafa Abuseada ◽  
Nesrin Ozalp
Keyword(s):  
Inverse Problem ◽  
Intensity Distribution ◽  
Focal Plane ◽  
Percentage Error ◽  
Interpolation Scheme ◽  
Zeroth Order ◽  
Solar Simulator ◽  
Directional Information ◽  
New Approach ◽  
First Order

Abstract Through the flux characterization of a high flux solar simulator, all directional information of the flux distribution is lost. Therefore, an experimental approach is necessary to restore the directional information. In this study, 13 heat flux maps were experimentally obtained from a 10 kWe Xenon arc solar simulator through an indirect flux mapping technique, implementing the use of one Lambertian target. The formulation of the inverse problem of experimentally determining the intensity distribution at the focal plane is presented. In addition, a Monte Carlo ray tracing in-house code modeling the Xenon arc is developed and used to generate the experimentally obtained flux maps and intensity at the focal plane to be used as a reference. Two intensity interpolation schemes were examined; a zeroth and first-order schemes. It is shown that a first order interpolation unnecessary complicates the inverse problem. The percentage error reduced from 90.9% to 82.6% when changing the interpolation scheme from a first to zeroth-order, in addition to a five times reduction in computational time. Furthermore, a new approach of constraining the formulated system of equations with an equality constraint that works by eliminating some of the intensity values that cannot be traced back to the ellipsoidal reflector is proposed. Therefore, it can be used as a technique to change the ill-conditioned problem to a well-conditioned one, without depending heavily on Tikhonov regularization methods. This new approach provided intensity values at the focal plane with a reduced percentage error from 52.2% to 30.4% for the zeroth-order interpolation scheme.

scholarly journals Numerical Characterization of Cohesive and Non-Cohesive ‘Sediments’ under Different Consolidation States Using 3D DEM Triaxial Experiments

Processes ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 1252
Author(s):  
Hadar Elyashiv ◽  
Revital Bookman ◽  
Lennart Siemann ◽  
Uri ten Brink ◽  
Katrin Huhn
Keyword(s):  
Mechanical Response ◽  
Burial Depth ◽  
Cohesive Sediments ◽  
Third Order ◽  
First Order ◽  
Numerical Characterization ◽  
Response To Stress ◽  
Bond Strengths ◽  
Individual Bond

The Discrete Element Method has been widely used to simulate geo-materials due to time and scale limitations met in the field and laboratories. While cohesionless geo-materials were the focus of many previous studies, the deformation of cohesive geo-materials in 3D remained poorly characterized. Here, we aimed to generate a range of numerical ‘sediments’, assess their mechanical response to stress and compare their response with laboratory tests, focusing on differences between the micro- and macro-material properties. We simulated two endmembers—clay (cohesive) and sand (cohesionless). The materials were tested in a 3D triaxial numerical setup, under different simulated burial stresses and consolidation states. Variations in particle contact or individual bond strengths generate first order influence on the stress–strain response, i.e., a different deformation style of the numerical sand or clay. Increased burial depth generates a second order influence, elevating peak shear strength. Loose and dense consolidation states generate a third order influence of the endmember level. The results replicate a range of sediment compositions, empirical behaviors and conditions. We propose a procedure to characterize sediments numerically. The numerical ‘sediments’ can be applied to simulate processes in sediments exhibiting variations in strength due to post-seismic consolidation, bioturbation or variations in sedimentation rates.

Design of a New 45 kWe High-Flux Solar Simulator for High-Temperature Solar Thermal and Thermo-Chemical Research

2010 ◽  
Author(s):  
Katherine R. Krueger ◽  
Jane H. Davidson ◽  
Wojciech Lipin´ski
Keyword(s):  
High Temperature ◽  
Focal Plane ◽  
Flux Distribution ◽  
Solar Thermal ◽  
Optimized Design ◽  
High Flux ◽  
Chemical Research ◽  
Solar Simulator ◽  
Peak Flux ◽  
The Common

In this paper, we present a systematic procedure to design a solar simulator for high-temperature concentrated solar thermal and thermo-chemical research. The 45 kWe simulator consists of seven identical radiation units of common focus, each comprised of a 6.5 kWe xenon arc lamp close-coupled to a precision reflector in the shape of a truncated ellipsoid. The size and shape of each reflector is optimized by a Monte Carlo ray tracing analysis to achieve multiple design objectives, including high transfer efficiency of radiation from the lamps to the common focal plane and desired flux distribution. Based on the numerical results, the final optimized design will deliver 7.5 kW over a 6-cm diameter circular disc located in the focal plane, with a peak flux approaching 3.7 MW/m2.

Design and characterization of a high-flux non-coaxial concentrating solar simulator

2018 ◽  
Vol 145 ◽  
pp. 201-211 ◽  
Author(s):  
Jun Xiao ◽  
Xiudong Wei ◽  
Raúl Navío Gilaber ◽  
Yan Zhang ◽  
Zengyao Li
Keyword(s):  
High Flux ◽  
Solar Simulator

Design, Construction, and Characterization of an Adjustable 70 kW High-Flux Solar Simulator

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Jinliang Xu ◽  
Cheng Tang ◽  
Yongpan Cheng ◽  
Zijin Li ◽  
Hui Cao ◽  
...  
Keyword(s):  
Focal Plane ◽  
Cooling System ◽  
Air Cooling ◽  
Power Capacity ◽  
Solar Simulator ◽  
Participating Media ◽  
System A ◽  
Full Power ◽  
Design Construction

The design, construction, and characterization of a solar simulator are reported. The solar simulator consists of an optical system, a power source system, an air cooling system, a control system, and a calibration system. Seven xenon short-arc lamps were used, each consuming 10 kW electricity. The lamps were aligned at the reflector ellipsoidal axis. The stochastic Monte Carlo method analyzed the interactions between light rays and reflector surfaces as well as participating media. The seven lamps have a common focal plane. The focal plane diameters can be changed in the range of 60–120 mm with the lamp module traveling the distance in a range of 0–300 mm. The calibration process established a linear relationship between irradiant fluxes and grayscale values. The measures to reduce irradiant flux error and fluctuations were described. The irradiant flux distribution can be changed by varying the power capacities and/or moving the focal plane locations. The peak fluxes are 1.92, 3.16, and 3.91 MW/m2 for 25%, 50%, and 75% of the full power capacity. The peak flux and temperature exceed 4 MW/m2 and 2300 K, respectively, for the full power capacity. A 8 cm thick refractory brick can be melt in 2 min with the melting temperature of about 2300 K when the solar simulator is operating at 70% of the maximum power capacity.

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