scholarly journals Research on Performance Evaluation of Tidal Energy Turbine under Variable Velocity

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6313
Author(s):  
Chuhua Jiang ◽  
Xuedao Shu ◽  
Junhua Chen ◽  
Lingjie Bao ◽  
Hao Li
Keyword(s):  
Performance Evaluation ◽  
Flow Velocity ◽  
Flow Rate ◽  
Tidal Current ◽  
Evaluation System ◽  
Average Power ◽  
Tidal Energy ◽  
Time Varying ◽  
Practical Applications ◽  
Sea Area

Aiming at the performance evaluation problem of tidal energy turbines in the application of periodic time-varying flow velocity, with the goal of maximizing the efficiency of energy harvesting in practical applications, an evaluation system combining the characteristics of flow velocity changes in practical applications is proposed. After long-term monitoring of tidal current flow velocity in the applied sea area, the actual measured tidal current periodic flow velocity is divided into several flow velocity segments by using statistical segmentation, and the evaluation flow velocity of each flow velocity segment and its time proportion in the tidal current cycle are obtained. A test device with constant torque regulation is built, and capture power tests of different torque loads are carried out under each evaluation flow rate. After comparison, the maximum captured power at each evaluation flow rate is determined. We calculate the weight based on the time proportion of each evaluation flow velocity and obtain the turbine average power of the tidal cycle, thereby evaluating the overall energy capture performance of the turbine under the periodic time-varying flow velocity. Finally, the application test of the turbine in the actual sea area shows that the thin-walled airfoil turbine is more suitable for the sea area, which is the same as the pool evaluation result. The result shows that the evaluation system is reliable and effective and has significance for guiding practical engineering.

scholarly journals Research on Blade Design of Lift–Drag-Composite Tidal-Energy Turbine at Low Flow Velocity

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4258
Author(s):  
Chuhua Jiang ◽  
Xuedao Shu ◽  
Junhua Chen ◽  
Lingjie Bao ◽  
Yawen Xu
Keyword(s):  
Flow Velocity ◽  
Design Method ◽  
Impact Resistance ◽  
Tidal Energy ◽  
Differential Pressure ◽  
Low Flow ◽  
Small Radius ◽  
Tidal Current Energy ◽  
Sea Area ◽  
Current Energy

The research on tidal-current energy-capture technology mainly focuses on the conditions of high flow velocity, focusing on the use of differential pressure lift, while the average flow velocity in most sea areas of China is less than 1.5 m/s, especially in the marine aquaculture area, where tidal-current energy is needed to provide green energy locally. Due to the low flow velocity of this type of sea area, it seriously affects the effect of differential pressure lift, which is conducive to exerting the effect of impact resistance. In this regard, the coupling effect of the differential pressure lift and the impact resistance on the blade torque is comprehensively considered, this research puts forward the design method of the lift-–drag-composite thin-plate arc turbine blade. Based on the blade element momentum (BEM) theory and Bernoulli’s principle, the turbine dynamic model was established, and the nonlinear optimization method was used to solve the shape parameters of the turbine blades, and the thin-plate arc and NACA airfoil blade turbines were trial-produced under the same conditions. A model experiment was carried out in the experimental pool, and the Xiangshan sea area in Ningbo, East China Sea was taken as the experimental sea area. The results of the two experiments showed the same trend, indicating that the energy-harvesting performance of the lift–drag-composite blade was significantly better than that of the lift blade under the conditions of low flow velocity and small radius, which verified the correctness of the blade design method, and can promote the research and development of tidal energy under the conditions of low flow velocity and small radius.

scholarly journals On the Performance Evaluation of Commercial SAW Resonators by Means of a Direct and Reliable Equivalent-Circuit Extraction

Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 303
Author(s):  
Giovanni Gugliandolo ◽  
Zlatica Marinković ◽  
Giuseppe Campobello ◽  
Giovanni Crupi ◽  
Nicola Donato
Keyword(s):  
Performance Evaluation ◽  
Acoustic Wave ◽  
Equivalent Circuit ◽  
Surface Acoustic Wave ◽  
Equivalent Circuit Model ◽  
Practical Applications ◽  
Saw Devices ◽  
S Parameter ◽  
Commercial Device ◽  
Saw Resonators

Nowadays, surface acoustic wave (SAW) resonators are attracting growing attention, owing to their widespread applications in various engineering fields, such as electronic, telecommunication, automotive, chemical, and biomedical engineering. A thorough assessment of SAW performance is a key task for bridging the gap between commercial SAW devices and practical applications. To contribute to the accomplishment of this crucial task, the present paper reports the findings of a new comparative study that is based on the performance evaluation of different commercial SAW resonators by using scattering (S-) parameter measurements coupled with a Lorentzian fitting and an accurate modelling technique for the straightforward extraction of a lumped-element equivalent-circuit representation. The developed investigation thus provides ease and reliability when choosing the appropriate commercial device, depending on the requirements and constraints of the given sensing application. This paper deals with the performance evaluation of commercial surface acoustic wave (SAW) resonators by means of scattering (S-) parameter measurements and an equivalent-circuit model extracted using a reliable modeling procedure. The studied devices are four TO-39 packaged two-port resonators with different nominal operating frequencies: 418.05, 423.22, 433.92, and 915 MHz. The S-parameter characterization was performed locally around the resonant frequencies of the tested SAW resonators by using an 8753ES Agilent vector network analyzer (VNA) and a home-made calibration kit. The reported measurement-based study has allowed for the development of a comprehensive and detailed comparative analysis of the performance of the investigated SAW devices. The characterization and modelling procedures are fully automated with a user-friendly graphical user interface (GUI) developed in the Python environment, thereby making the experimental analysis faster and more efficient.

On-Line Monitoring System for Monitoring SO2 in Fumes (1) — Monitoring Subsystem for SO2 Mass Concentration

2011 ◽  
Vol 422 ◽  
pp. 296-299
Author(s):  
Shi Long Wang ◽  
Li Na Wang ◽  
Hong Bo Wang ◽  
Yong Hui Cai
Keyword(s):  
Flow Velocity ◽  
Monitoring System ◽  
Flow Rate ◽  
Mass Concentration ◽  
National Monitoring ◽  
Monitoring Result ◽  
Short Period ◽  
On Line ◽  
Working Principle

In order to achieve the target of controlling SO2 emissions in fumes in a short period of time in China, a SO2 on-line monitoring system (CEMS) has been developed by the authorased on the principle of electrochemistry. This system consists of two subsystems: (1) SO2 mass concentration monitoring and (2) SO2 flow velocity and flow rate monitoring. In the paper, the procedure of system and working principle and method of SO2 mass concentration monitoring subsystem are described in detail (SO2 flow velocity and flow rate monitoring subsystem is described by another paper).Two subsystems work synchronously to monitor and calculate the SO2 emissions, then the on-line monitoring of SO2 emissions is achieved. Through experiment and testing, monitoring result of the system is stable and reliable, which has reached the national monitoring standards and passed the appraisal.

Dissipativity analysis of delayed stochastic generalized neural networks with Markovian jump parameters

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Grienggrai Rajchakit ◽  
Ramalingam Sriraman ◽  
Rajendran Samidurai
Keyword(s):  
Linear Matrix ◽  
Time Varying ◽  
Matrix Inequalities ◽  
Markovian Jump ◽  
Stochastic Perturbations ◽  
Practical Applications ◽  
Markovian Jump Parameters ◽  
Generalized Neural Networks ◽  
System Information ◽  
Dissipativity Analysis

Abstract This article discusses the dissipativity analysis of stochastic generalized neural network (NN) models with Markovian jump parameters and time-varying delays. In practical applications, most of the systems are subject to stochastic perturbations. As such, this study takes a class of stochastic NN models into account. To undertake this problem, we first construct an appropriate Lyapunov–Krasovskii functional with more system information. Then, by employing effective integral inequalities, we derive several dissipativity and stability criteria in the form of linear matrix inequalities that can be checked by the MATLAB LMI toolbox. Finally, we also present numerical examples to validate the usefulness of the results.

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