scholarly journals Alignment Strategy Optimization Method for Dish Stirling Faceted Concentrators

2007 ◽  
Author(s):  
Charles E. Andraka
Keyword(s):  
Flux Distribution ◽  
Single Point ◽  
Optimization Method ◽  
Spot Size ◽  
Geometric Constraints ◽  
Novel Approach ◽  
Peak Flux ◽  
Flux Profile ◽  
Receiver Plane ◽  
Alignment Strategy

A Dish Stirling parabolic concentrator typically consists of a number of mirror facets that must be aligned to focus the concentrated sunlight on the engine receiver. An alignment strategy must be developed to deliver the energy uniformly to the receiver while maximizing system performance. Several criteria must be met in order to maximize the performance and lifetime of the system. The peak flux should be minimized at the receiver to extend life. This is accomplished by locally optimizing the mirror aimpoints, minimizing overlap of facet images. The energy delivered to each cylinder of a multi-cylinder engine should be balanced to maximize the power production capability of the engine. This is accomplished through globally optimizing the mirror aimpoints. Depending on dish geometry, both of these constraints will be met by moving the aimpoints of certain facets away from a single point at the center of the aperture. However, this often results in a larger aperture or more flux spillage. The larger aperture results in greater thermal and reflective losses from the receiver cavity. This paper proposes and demonstrates a novel approach to optimizing the alignment strategy while obeying these constraints. The method uses an approach similar to molecular dynamics to globally and locally distribute the power on the receiver, while imposing movement constraints at the aperture to limit the focal plane spot size. The method can also impose additional geometric constraints at the receiver plane to accommodate un-cooled surfaces. The method is explored and demonstrated on the Stirling Energy Systems 25kW dish Stirling system at Sandia National Laboratories. The approach provides a receiver flux distribution and power balance equal to the strategy developed by McDonnell Douglas in the early 1980’s, but with an aperture size equal to that of the single aimpoint strategy. This should result in about a 1kW increase in power generated at rated conditions, with no additional cost, due to reduced thermal losses from the receiver. The method can be extended to other point-focus concentrating solar technologies. On a tower, the heliostat aiming strategy could be dynamically updated to accommodate flux profile needs, sun position, or maintenance in the field.

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.

UNCERTAINTY BASED ROBUST OPTIMIZATION IN AERODYNAMICS

2009 ◽  
Vol 23 (03) ◽  
pp. 477-480 ◽  
Author(s):  
ZHILI TANG
Keyword(s):  
Nash Equilibrium ◽  
Robust Design ◽  
Single Point ◽  
Optimization Method ◽  
Equilibrium Solutions ◽  
Design Problems ◽  
Nash Equilibrium Solutions ◽  
Definition Of ◽  
Taguchi Robust Design ◽  
Statistical Definition

The Taguchi robust design concept is combined with the multi-objective deterministic optimization method to overcome single point design problems in Aerodynamics. Starting from a statistical definition of stability, the method finds, Nash equilibrium solutions for performance and its stability simultaneously.

An Improved Shape Annealing Method for Truss Topology Generation

1994 ◽  
Author(s):  
Giridhar Reddy ◽  
Jonathan Cagan
Keyword(s):  
Simulated Annealing ◽  
Optimization Method ◽  
Geometric Constraints ◽  
Truss Structures ◽  
Model Design ◽  
Topology Generation ◽  
Truss Topology ◽  
Gradient Based ◽  
Annealing Algorithm ◽  
Annealing Method

Abstract A method for the design of truss structures which encourages lateral exploration, pushes away from violated spaces, models design intentions, and produces solutions with a wide variety of characteristics is introduced. An improved shape annealing algorithm for truss topology generation and optimization, based on the techniques of shape grammars and simulated annealing, implements the method. The algorithm features a shape grammar to model design intentions, an ability to incorporate geometric constraints to avoid obstacles, and a shape optimization method using only simulated annealing with more consistent convergence characteristics; no traditional gradient-based techniques are employed. The improved algorithm is illustrated on various structural examples generating a variety of solutions based on a simple grammar.

scholarly journals Optimal Falling Track Design for Twice detonating Fuze of Double event Fuel air Explosive with High Speed

2020 ◽  
Vol 70 (4) ◽  
pp. 366-373
Author(s):  
Congliang Ye ◽  
Qi Zhang
Keyword(s):  
High Speed ◽  
High Efficiency ◽  
Single Point ◽  
Design System ◽  
Motion Trajectory ◽  
Novel Approach ◽  
Scale Experiment ◽  
Set Up ◽  
Point Center ◽  
Double Event

To prevent the initiation failure caused by the uncontrolled fuze and improve the weapon reliability in the high-speed double-event fuel-air explosive (DEFAE) application, it is necessary to study the TDF motion trajectory and set up a twice-detonating fuze (TDF) design system. Hence, a novel approach of realising the fixed single-point center initiation by TDF within the fuel air cloud is proposed. Accordingly, a computational model for the TDF motion state with the nonlinear mechanics analysis is built due to the expensive and difficult full-scale experiment. Moreover, the TDF guidance design system is programmed using MATLAB with the equations of mechanical equilibrium. In addition, by this system, influences of various input parameters on the TDF motion trajectory are studied in detail singly. Conclusively, the result of a certain TDF example indicates that this paper provides an economical idea for the TDF design, and the developed graphical user interface of high-efficiency for the weapon designers to facilitate the high-speed DEFAE missile development.

scholarly journals Cloud photogrammetry with dense stereo for fisheye cameras

2016 ◽  
Vol 16 (22) ◽  
pp. 14231-14248 ◽  
Author(s):  
Christoph Beekmans ◽  
Johannes Schneider ◽  
Thomas Läbe ◽  
Martin Lennefer ◽  
Cyrill Stachniss ◽  
...  
Keyword(s):  
Stereo Matching ◽  
Geometric Constraints ◽  
Large Field ◽  
Cloud Base ◽  
Strong Wind ◽  
Real World Data ◽  
First Case ◽  
Novel Approach ◽  
Stereo Reconstruction ◽  
Fisheye Lenses

Abstract. We present a novel approach for dense 3-D cloud reconstruction above an area of 10 × 10 km2 using two hemispheric sky imagers with fisheye lenses in a stereo setup. We examine an epipolar rectification model designed for fisheye cameras, which allows the use of efficient out-of-the-box dense matching algorithms designed for classical pinhole-type cameras to search for correspondence information at every pixel. The resulting dense point cloud allows to recover a detailed and more complete cloud morphology compared to previous approaches that employed sparse feature-based stereo or assumed geometric constraints on the cloud field. Our approach is very efficient and can be fully automated. From the obtained 3-D shapes, cloud dynamics, size, motion, type and spacing can be derived, and used for radiation closure under cloudy conditions, for example. Fisheye lenses follow a different projection function than classical pinhole-type cameras and provide a large field of view with a single image. However, the computation of dense 3-D information is more complicated and standard implementations for dense 3-D stereo reconstruction cannot be easily applied. Together with an appropriate camera calibration, which includes internal camera geometry, global position and orientation of the stereo camera pair, we use the correspondence information from the stereo matching for dense 3-D stereo reconstruction of clouds located around the cameras. We implement and evaluate the proposed approach using real world data and present two case studies. In the first case, we validate the quality and accuracy of the method by comparing the stereo reconstruction of a stratocumulus layer with reflectivity observations measured by a cloud radar and the cloud-base height estimated from a Lidar-ceilometer. The second case analyzes a rapid cumulus evolution in the presence of strong wind shear.

Automated Tool-Orientation Determinations for 4-Axis Non-Gouge, Non-Interference Milling of Axial-Flow Compressors Airfoils

2007 ◽  
Author(s):  
Zezhong C. Chen ◽  
Gang Liu
Keyword(s):  
Manufacturing Industry ◽  
Axial Flow ◽  
Optimization Method ◽  
Free Form ◽  
Software Systems ◽  
Cnc Milling ◽  
Novel Approach ◽  
Cad Cam ◽  
Free Form Surfaces ◽  
Axial Flow Compressors

As important components of gas turbine engines, axial-flow compressors have been improved with a more complex and accurate airfoil design to meet high aerodynamic requirements; specifically, the pressure and suction surfaces of the airfoils (or blades) are now represented with free-form surfaces in CAD software systems. Since quality of the blades affects efficiency of the engines and safety of the aircrafts, some types of compressors are produced with the blades and the hub as a single piece on 4-axis CNC milling machines. However, it is still quite challenging to automatically determine cutter sizes and orientations without gouging and interference during the 4-axis milling, because the geometric shape of the blades is complex and the blades overlap with each other. As a result, the established method of determining tool size and orientation in industry is by trial and error in a repetitive process of selecting cutters and planning tool-paths with CAM systems. To address this problem, a novel approach is proposed to automatically determine cutter sizes and orientations for 4-axis milling of the axial-flow compressors blades without gouging and interference. The main contribution of this work is that (1) a mathematical model for optimizing cutter sizes in 4-axis milling is established; and (2) by applying a global optimization method — the particle swarm optimization method — to this model, the maximum allowable size of a cutter and its corresponding orientation can be found at each cutter-contact (CC) point on the surface being machined. Therefore, all the maximum allowable sizes of cutters for all the CC points and the corresponding cutter orientations can be computed. A group of standard cutters are then selected; each of which can sweep particular CC points without damaging the compressor. Since it is efficient and reliable, this newly proposed approach can be directly implemented in commercial CAD/CAM software systems to benefit the manufacturing industry.

scholarly journals A Single Point-Based Multilevel Features Fusion and Pyramid Neighborhood Optimization Method for ALS Point Cloud Classification

2019 ◽  
Vol 9 (5) ◽  
pp. 951 ◽  
Author(s):  
Yong Li ◽  
Guofeng Tong ◽  
Xiance Du ◽  
Xiang Yang ◽  
Jianjun Zhang ◽  
...  
Keyword(s):  
Point Cloud ◽  
Single Point ◽  
Point Clouds ◽  
Optimization Method ◽  
Gaussian Kernel ◽  
Support Vector ◽  
Angle Distribution ◽  
Features Fusion ◽  
Cloud Classification ◽  
Point Cloud Classification

3D point cloud classification has wide applications in the field of scene understanding. Point cloud classification based on points can more accurately segment the boundary region between adjacent objects. In this paper, a point cloud classification algorithm based on a single point multilevel features fusion and pyramid neighborhood optimization are proposed for a Airborne Laser Scanning (ALS) point cloud. First, the proposed algorithm determines the neighborhood region of each point, after which the features of each single point are extracted. For the characteristics of the ALS point cloud, two new feature descriptors are proposed, i.e., a normal angle distribution histogram and latitude sampling histogram. Following this, multilevel features of a single point are constructed by multi-resolution of the point cloud and multi-neighborhood spaces. Next, the features are trained by the Support Vector Machine based on a Gaussian kernel function, and the points are classified by the trained model. Finally, a classification results optimization method based on a multi-scale pyramid neighborhood constructed by a multi-resolution point cloud is used. In the experiment, the algorithm is tested by a public dataset. The experimental results show that the proposed algorithm can effectively classify large-scale ALS point clouds. Compared with the existing algorithms, the proposed algorithm has a better classification performance.

scholarly journals Novel Approach to detect Anomalies using Defensive Algorithm in SDN flows

2021 ◽  
Vol 12 (2) ◽  
pp. 536-542
Author(s):  
Sugandhi Midha, Et. al.
Keyword(s):  
Single Point ◽  
Denial Of Service ◽  
Holistic Approach ◽  
Dos Attack ◽  
New Paradigm ◽  
Novel Approach ◽  
Network Flexibility ◽  
Novel Method ◽  
Entire Network ◽  
Poor Management

The exponential growth of network users has to lead to poor management of networks that use the traditional networking approach. Traditional networking approaches have become an overhead in terms of flexibility, innovations, complexity, and programmability among the network. SDN guarantees a holistic approach to network flexibility and programmability. Network visibility in SDN gives scope for rapid innovation. SDN being a new paradigm, less work has been done towards security. Security is one of the biggest concerns in SDN. Separation of control and data plane in SDN has to lead to the emergence of Denial of Service (DoS) attack. The centralized controller in SDN makes it the best target for attackers and acts as a single point of failure. Attacks on the SDN controller can bring the entire network down. This paper presents an approach to monitor traffic and we propose a novel method to mitigate these anomalies and attacks in the network. We believe that the DoS attack can be toned down using this new technique.

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