Simulation and analysis of optical imaging systems including real freeform components

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
Johannes Stock ◽  
Matthias Beier ◽  
Johannes Hartung ◽  
Sebastian Merx ◽  
Herbert Gross
Keyword(s):  
Experimental Data ◽  
Spatial Frequency ◽  
Optical System ◽  
System Performance ◽  
Imaging Systems ◽  
Optical Surfaces ◽  
Surface Imperfections ◽  
Performance Predictions ◽  
Alignment Errors ◽  
Holistic Description

Abstract In recent years, the precision of the manufacturing process for optical surfaces has improved tremendously. As a result, freefrom surfaces have become more attractive options for imaging applications with increased accuracy requirements. However, with regards the integration into an optical system, performance is often limited due to surface imperfections, such as mid-spatial frequency errors and alignment errors. This demonstrates the need for a more holistic description of systems, including multiple freeform components, which enable performance predictions based on the system as a whole. In this work, a solution for such a simulation is presented and verified by a comparison with the experimental data. This procedure not only predicts system performance but also supports tolerancing and easier alignment.

scholarly journals Study of Factors Making Space-Contaminated Optical System Unusable

2012 ◽  
Vol 2012 ◽  
pp. 1-4
Author(s):  
Dakun Wu ◽  
Yanping Zhou ◽  
Fangkui Sun
Keyword(s):  
Optical System ◽  
Time Domain ◽  
System Performance ◽  
Finite Difference Time Domain ◽  
High Permittivity ◽  
Optical Surfaces ◽  
Particulate Contamination ◽  
2D Fdtd ◽  
Difference Time ◽  
Experimental Effort

Molecular and particulate contamination of space optical surfaces can be extremely detrimental to optical system performance. In order to determine whether optical system is unusable, we must do a lot of tests. For reducing experimental effort, computational criterion for unusable space optical system is put forward, which is based on experimentation and calculation by 2D-FDTD (finite-difference time domain). And then factors making optical system unusable are studied when distribution of light intensity is consistent with the criterion. Results show that small particulate is more detrimental to optical system than big one for particle with high permittivity is. The distribution of particles making optical system unusable is also obtained.

Navier-Stokes and Comprehensive Analysis Performance Predictions of the NREL Phase VI Experiment

2003 ◽  
Author(s):  
Earl P. N. Duque ◽  
Michael D. Burklund ◽  
Wayne Johnson
Keyword(s):  
Experimental Data ◽  
Wind Turbine ◽  
Turbine Rotor ◽  
Operating Conditions ◽  
Navier Stokes ◽  
Horizontal Axis Wind Turbine ◽  
Performance Predictions ◽  
Nasa Ames Research ◽  
Nrel Phase Vi ◽  
Wind Turbine Rotor

A vortex lattice code, CAMRAD II, and a Reynolds-Averaged Navier-Stoke code, OVERFLOW-D2, were used to predict the aerodynamic performance of a two-bladed horizontal axis wind turbine. All computations were compared with experimental data that was collected at the NASA Ames Research Center 80-by 120-Foot Wind Tunnel. Computations were performed for both axial as well as yawed operating conditions. Various stall delay models and dynamics stall models were used by the CAMRAD II code. Comparisons between the experimental data and computed aerodynamic loads show that the OVERFLOW-D2 code can accurately predict the power and spanwise loading of a wind turbine rotor.

scholarly journals Numerical Modeling of Bifacial PV String Performance: Perimeter Effect and Influence of Uniaxial Solar Trackers

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 869 ◽  
Author(s):  
Fabio Ricco Galluzzo ◽  
Pier Enrico Zani ◽  
Marina Foti ◽  
Andrea Canino ◽  
Cosimo Gerardi ◽  
...  
Keyword(s):  
Experimental Data ◽  
System Performance ◽  
Geographical Location ◽  
Performance Model ◽  
Rear Side ◽  
Energy Yield ◽  
Pv System ◽  
Latitude Range ◽  
Accurate Performance ◽  
Solar Tracker

The bifacial photovoltaic (PV) systems have recently met large interest. The performance of such systems heavily depends on the installation conditions and, in particular, on the albedo radiation collected by the module rear side. Therefore, it is of crucial importance to have an accurate performance model. To date, in the scientific literature, numerous models have been proposed and experimental data collected to study and optimize bifacial PV system performance. Currently, 3D and 2D models of bifacial PV devices exist. Though the former are more mathematically complex, they can lead to more accurate results, since they generally allow to fully consider the main aspects influencing a bifacial PV system performance. Recently, we have proposed and validated through experimental data a 3D model tested as a function of module height, tilt angle, and ground albedo. In this work, through such a model, we studied the role played by the perimeter zones surrounding the PV string, by considering PV strings of 30 or 60 modules. We considered the cases of fixed installation with optimal PV module tilt and of installation with uniaxial horizontal solar tracker. We evaluated the PV energy yield as a function of the size of the perimeter zones for the two cases, i.e., both with and without the solar tracker. In optimal perimeter conditions, we then studied the behavior of bifacial and mono-facial PV strings by varying the geographical location in a large latitude range.

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