scholarly journals Influences of Optical Factors on the Performance of the Solar Furnace

Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3933
Author(s):  
Zhiying Cui ◽  
Fengwu Bai ◽  
Zhifeng Wang ◽  
Fuqiang Wang
Keyword(s):  
Structure Design ◽  
Solar Furnace ◽  
The Finite Element Method ◽  
Tilt Error ◽  
Allowable Error ◽  
Slope Error ◽  
Shape Adjustment ◽  
Solar Heat Flux ◽  
Optical Behavior ◽  
Optical Structure

In this paper, an optical structure design for a solar furnace is described. Based on this configuration, Monte Carlo ray tracing simulations are carried out to analyze the influences of four optical factors on the concentrated solar heat flux distribution. According to the practical mirror shape adjustment approach, the curved surface of concentrator facet is obtained by using the finite element method. Due to the faceted reflector structure, the gaps between the adjacent mirror arrays and the orientations of facets are also considered in the simulation model. It gives the allowable error ranges or restrictions corresponding to the optical factors which individually effect the system in Beijing: The tilt error of heliostat should be less than 4 mrad; the tilt error of the concentrator in the orthogonal directions should be both less than 2 mrad; the concentrator facets with the shape most approaching paraboloid would greatly resolve slope error and layout errors arising in the concentrator. Besides, by comparing the experimentally measured irradiance with the simulated results, the optical performance of the facility is evaluated to investigate their comprehensive influence. The results are useful to help constructors have a better understanding of the solar furnace’s optical behavior under conditions of multiple manufacture restrictions.

scholarly journals Perception on aggregation induced multicolor emission and emission centers in carbon nanodots using successive dilution, anion exchange chromatography, and multi-way statistics

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mohsen Kompany-Zareh ◽  
Saeed Bagheri
Keyword(s):  
Anion Exchange ◽  
Quantum Confinement Effect ◽  
Anion Exchange Chromatography ◽  
Exchange Chromatography ◽  
Carbon Nanodots ◽  
Surface Charges ◽  
Negative Surface ◽  
Amine Groups ◽  
Optical Behavior ◽  
Optical Structure

AbstractExploration in the way of understanding the optical behavior and structure of carbon nanodots has been increased due to their vast application. Their emission dependency on excitation wavelengths is the more prevalent and controversial subject. In this report we considered the optical structure of hydrothermally synthesized carbon nanodots using citric acid and 2,3-diaminopyridine as precursors. The presence of different emission centers experimented through anion exchange chromatography which resulted in fractions with more unique optical structures. The quantum confinement effect and energy exchange between different types of carbon nanodots, due to aggregation in higher concentration levels, was studied applying a stepwise dilution experiment. Analysis of the experimental data was done through the parallel factor analysis and the trajectory pattern recognition which resolved more about optical interactions and the presence of different emission centers in different particles. Results from infrared spectroscopy confirmed the dominating density of carboxyl functional groups on the nanodots with negative surface charges and higher influence of amine groups on dots with positive surface charges.

Energy absorption structures design of civil aircraft to improve crashworthiness

2014 ◽  
Vol 118 (1202) ◽  
pp. 383-398 ◽  
Author(s):  
Y. Ren ◽  
J. Xiang
Keyword(s):  
Finite Element Method ◽  
Energy Absorption ◽  
High Efficiency ◽  
Wave Beam ◽  
Sine Wave ◽  
Structure Design ◽  
Failure Model ◽  
The Finite Element Method ◽  
Civil Aircraft ◽  
Aircraft Crashworthiness

AbstractTo improve the crashworthiness of civil aircraft, the design concept of energy absorption structure for civil aircraft is investigated. Two typical different design principles could be identified. The first category includes Helicopter and Light fixed-wing Aircraft (HLA), and Transport, Mid-size and Commuter type Aircraft (TMCA) are classified into the second group. Frame, strut and bottom structure are the three kinds of energy absorption structure for TMCA. The strut layout of conventional civil aircraft is studied and some energy absorption devices are adopted. High efficiency energy absorption structures such as the foam and sine-wave beam are employed as the bottom structure for both of HLA and LMCA. The finite element method is used to analyse and design energy absorption structure in aircraft crashworthiness problem. Results show that the crashworthiness of civil aircraft could be largely improved by using proper strut layout and excellent energy absorption device. The stiffness combination of frame and strut should be considered to get better global aircraft deformation. Supporting platform and failure model are the two core problems of bottom energy absorption structure design. Foam and sine-wave beam under the lifted frame could improve the crashworthiness of civil aircraft.

scholarly journals Off-Axis Diffractive Optics for Compact Terahertz Detection Setup

2020 ◽  
Vol 10 (23) ◽  
pp. 8594
Author(s):  
Paweł Komorowski ◽  
Mateusz Surma ◽  
Michał Walczakowski ◽  
Przemysław Zagrajek ◽  
Agnieszka Siemion
Keyword(s):  
3D Printing ◽  
Small Volume ◽  
Optical Element ◽  
Structure Design ◽  
Thz Radiation ◽  
Direct Printing ◽  
Terahertz Detection ◽  
3D Printed ◽  
Printing Techniques ◽  
Optical Structure

Medical and many other applications require small-volume setups enabling terahertz imaging. Therefore, we aim to develop a device for the in-reflection examination of the samples. Thus, in this article, we focus on the diffractive elements for efficient redirection and focusing of the THz radiation. A terahertz diffractive optical structure has been designed, optimized, manufactured (using extrusion-based 3D printing) and tested. Two manufacturing methods have been used—direct printing of the structures from PA12, and casting of the paraffin structures out of 3D-printed molds. Also, the limitations of the off-axis focusing have been discussed. To increase the efficiency, an iterative algorithm has been proposed that optimizes off-axis structures to focus the radiation into small focal spots located far from the optical axis, at an angle of more than 30 degrees. Moreover, the application of higher-order kinoform structure design allowed the maintaining of the smallest details of the manufactured optical element, using 3D printing techniques.

Numerical and Experimental Investigation of Hydrodynamic Characteristics of Deformable Hydrofoils

2009 ◽  
Vol 53 (04) ◽  
pp. 214-226
Author(s):  
Antoine Ducoin ◽  
François Deniset ◽  
Jacques André Astolfi ◽  
Jean-François Sigrist
Keyword(s):  
Experimental Investigation ◽  
Structure Design ◽  
Hydrodynamic Characteristics ◽  
The Finite Element Method ◽  
Fluid Structure ◽  
Cavitation Inception ◽  
Marine Structure ◽  
Structure Problem ◽  
Volume Method ◽  
Processing Device

The present paper is concerned with the numerical and experimental investigation of the hydroelastic behavior of a deformable hydrofoil in a uniform flow. The study is developed within the general framework of marine structure design and sizing. An experimental setup is developed in the IRENav hydrodynamic tunnel in which a cambered rectangular hydrofoil is mounted. An image-processing device enables the visualization of the foil displacement. As for the numerical part, the structure problem is solved with the finite element method, while the fluid problem is solved with the finite volume method using two distinct numerical codes that are coupled through an iterative algorithm based on the exchange of the boundary conditions at the fluid-structure interface. Results obtained from the coupled fluid-structure computations including deformation and hydrodynamic coefficients are presented. The influence of the fluid-structure coupling is evaluated through comparisons with "noncoupled" simulations. The numerical simulations are in very good agreement with the experimental results and highlight the importance of the fluid-structure coupling consideration. Particular attention is paid to the pressure distribution modification on the hydrofoil as a result of deformations that can lead to an advance of the cavitation inception, which is of paramount importance for naval applications.

scholarly journals Backbone cup – a structure design competition based on topology optimization and 3D printing

2016 ◽  
Vol 7 ◽  
pp. A1 ◽  
Author(s):  
Ji-Hong Zhu ◽  
Kai-Ke Yang ◽  
Wei-Hong Zhang
Keyword(s):  
Topology Optimization ◽  
3D Printing ◽  
Experimental Approach ◽  
Mechanical Performance ◽  
Turnaround Time ◽  
Structure Design ◽  
The Finite Element Method ◽  
New Approach ◽  
Design Competition ◽  
Testing Approach

This paper addresses a structure design competition based on topology optimization and 3D Printing, and proposes an experimental approach to efficiently and quickly measure the mechanical performance of the structures designed using topology optimization. Since the topology optimized structure designs are prone to be geometrically complex, it is extremely inconvenient to fabricate these designs with traditional machining. In this study, we not only fabricated the topology optimized structure designs using one kind of 3D Printing technology known as stereolithography (SLA), but also tested the mechanical performance of the produced prototype parts. The finite element method is used to analyze the structure responses, and the consistent results of the numerical simulations and structure experiments prove the validity of this new structure testing approach. This new approach will not only provide a rapid access to topology optimized structure designs verifying, but also cut the turnaround time of structure design significantly.

Finite Element Numerical Analysis of the LGV Frame Based on ANSYS

2012 ◽  
Vol 590 ◽  
pp. 487-491
Author(s):  
Qin Man Fan
Keyword(s):  
Finite Element ◽  
Element Model ◽  
Mechanical Analysis ◽  
Structure Design ◽  
Frame Structure ◽  
The Finite Element Method ◽  
Element Analysis ◽  
Static And Dynamic Characteristics ◽  
The Finite Element Analysis ◽  
Optimizing Design

The frame is the main part of the force matrix of truck vehicle and the stress state is complex and difficult to design. The finite element method is more accurate for the analysis of the static and dynamic characteristics of the frame, which provide guidance for the frame structure design. Establish finite element model of the frame with the application of ANSYS. According to the mechanical analysis of the model, impose reasonable constraints and load, the most typical of the four conditions in the frame is calculated with the finite element analysis, and predicted the weak parts of the frame according to the frame stress-strain cloud, which provided a very important theoretical basis for the improvement of the frame structure of the frame and optimizing design of the frame.

Wave-optical structure design with the local plane-interface approximation

2000 ◽  
Vol 47 (13) ◽  
pp. 2335-2350 ◽  
Author(s):  
Albrecht V. Pfeil ◽  
Frank Wyrowski
Keyword(s):  
Structure Design ◽  
Plane Interface ◽  
Local Plane ◽  
Optical Structure

The Modeling of Constant/Variable Solar Heat Flux Into a Porous Coil With Concentrator

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Sayyed Aboozar Fanaee ◽  
Mojtaba Rezapour
Keyword(s):  
Heat Flux ◽  
Heat Fluxes ◽  
The Finite Element Method ◽  
Governing Equations ◽  
Solar Heat ◽  
Clear Sky ◽  
Alumina Nanofluid ◽  
Solar Heat Flux ◽  
The City ◽  
Acceptable Agreement

In this paper, thermal-fluid modeling of nonporous/porous thermal coil filled by alumina nanofluid is discussed considering constant/variable solar heat fluxes. The fluxes are calculated for a parabolic concentrator at the solar paths for the city with a longitude of 59.20 deg and latitude of 32.87 deg in the clear sky at spring season. The governing equations are included as continuity, momentum, and energy conservations with considering variable solar flux by shadow effects of the coil on the parabolic concentrator. The numerical model is based on the finite element method by LU algorithm using the mumps solver. The results show that, in a porous medium, that the normalized temperature of the presented model has an acceptable agreement with experimental data with maximum errors of 3%. The existence of porosity significantly increases heat transfer parameters that improve transferred solar heat from the wall of the coil to nanofluid. The variable solar heat flux increases the temperature in the length of the coil rather than constant heat fluxes because of increasing exchanged heat to nanofluid.

Jacking Technology for a Simply Supported Girder Bridge

2013 ◽  
Vol 477-478 ◽  
pp. 675-680
Author(s):  
Li Ge Xu ◽  
Yi Li Wang ◽  
Chang Jie Xu
Keyword(s):  
Finite Element ◽  
Reference Value ◽  
The Finite Element Method ◽  
Stress Monitoring ◽  
Element Analysis ◽  
Simply Supported ◽  
Allowable Error ◽  
Girder Bridge ◽  
Jack Up ◽  
Engineering Projects

Numerous bridges have to be lifted to meet increased navigation capacity. However, no relevant technical standard for the jack-up technique is yet available. This paper presents a study on the integral lifting of simply supported girder bridge which implements the finite element method. Finite element analysis provides a reliable basis in controlling construction. Research shows that stress concentration is evident near support points in the lifting process. Thus, stress monitoring is necessary. These points should be near to the bridge web. Moreover, beam span and section rigidity should also be considered when jacking up a bridge. The value of allowable error in the jacking-up process decreases with increasing beam span or decreasing section stiffness. Therefore, jacking up a bridge will be safer when section rigidity is large enough and beam span is not extremely long. This paper offers tremendous reference value with regard to engineering projects.

A Material Selection Method Based on Finite Element Method

2014 ◽  
Vol 887-888 ◽  
pp. 1013-1016
Author(s):  
Sheng Bin Wu ◽  
Xiao Bao Liu
Keyword(s):  
Mathematical Model ◽  
Finite Element Method ◽  
Finite Element ◽  
Material Selection ◽  
Selection Method ◽  
Structure Design ◽  
The Finite Element Method ◽  
The Mathematical Model ◽  
Selection Of ◽  
Element Method

A new method for material selection in structure design based on the theory of the finite element method was presented. The method made material selection and structure design working at the same time. The mathematical model was established based on the finite element method. Finally, the material selection of an excavator's boom was verified, the results show that the proposed method is effective and feasible.

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