Two Tandem Cylinders With Turbulence Stimulation in FIV Power Conversion: CFD With Experimental Verification of Interaction

2017 ◽  
Author(s):  
Wenjun Ding ◽  
Hai Sun ◽  
Wanhai Xu ◽  
Michael M. Bernitsas
Keyword(s):  
Frequency Response ◽  
Conversion Efficiency ◽  
Stokes Equations ◽  
Damping Ratio ◽  
Power Conversion ◽  
Clean Energy ◽  
Amplitude Response ◽  
Response Frequency ◽  
Tandem Cylinders ◽  
Spacing Ratio

Flow induced vibrations of two rough, rigid, tandem-cylinders on springs are investigated for power conversion for Reynolds number 30,000 ≤ Re ≤ 120,000. Passive turbulence control (PTC) in the form of roughness strips is employed to enhance FIV and increase the power harness efficiency of the VIVACE (Vortex Induced Vibration for Aquatic Clean Energy) converter. Numerical simulations are performed using two-dimensional, Unsteady Reynolds-Averaged Navier-Stokes equations with the Spalart-Allmaras turbulence model. The center-to-center spacing ratio d / D of the two cylinders is set as 2.0 or 2.57 with mass ratio m* = 1.343 , damping ratio ζ = 0.26, and stiffness K = 1,200 N/m. Amplitude response, frequency response, interaction, energy harvesting, and conversion efficiency are presented and discussed. The main conclusions are: (1) In the VIV region at Re = 60,000, the amplitude response, frequency response, harnessed power, and power conversion efficiency of the upstream cylinder is the same for the two spacing ratios. Due to the shedding effect, the motion of the downstream cylinder for spacing ratio d/D = 2.0 is more severely suppressed than spacing ratio d/D = 2.57, which reduces the harnessed power and conversion efficiency for the downstream cylinder. (2) In the galloping region at Re = 110,000, due to the different impingement of the shed vortices on the downstream cylinder, the upstream cylinder harnesses more power and has higher energy conversion efficiency for spacing ratio d/D = 2.0 than d/D = 2.57.

scholarly journals Modelling of a Flow-Induced Oscillation, Two-Cylinder, Hydrokinetic Energy Converter Based on Experimental Data

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 827
Author(s):  
Yanfang Lv ◽  
Liping Sun ◽  
Michael M. Bernitsas ◽  
Mengjie Jiang ◽  
Hai Sun
Keyword(s):  
Experimental Data ◽  
Prediction Model ◽  
Flow Velocity ◽  
Surrogate Model ◽  
Damping Ratio ◽  
Predictive Tool ◽  
Power Harvesting ◽  
Hydrokinetic Energy ◽  
Tandem Cylinders ◽  
Spacing Ratio

The VIVACE Converter consists of cylindrical oscillators in tandem subjected to transverse flow-induced oscillations (FIOs) that can be improved by varying the system parameters for a given in-flow velocity: damping, stiffness, and in-flow center-to-center spacing. Compared to a single isolated cylinder, tandem cylinders can harness more hydrokinetic energy due to synergy in FIO. Experimental and numerical methods have been utilized to analyze the FIO and energy harnessing of VIVACE. A surrogate-based model of two tandem cylinders is developed to predict the power harvesting and corresponding efficiency by introducing a backpropagation neural network. It is then utilized to reduce excessive experimental or computational testing. The effects of spacing, damping, and stiffness on harvested power and efficiency of the established prediction-model are analyzed. At each selected flow velocity, optimization results of power harvesting using the prediction-model are calculated under different combinations of damping and stiffness. The main conclusions are: (1) The surrogate model, built on extensive experimental data for tandem cylinders, can predict the cylinder oscillatory response accurately. (2) Increasing the damping ratio range from 0–0.24 to 0–0.30 is beneficial for improving power efficiency, but has no significant effect on power harvesting. (3) In galloping, a spacing ratio of 1.57 has the highest optimal harnessed power and efficiency compared with other spacing values. (4) Two tandem cylinders can harness 2.01–4.67 times the optimal power of an isolated cylinder. In addition, the former can achieve 1.46–4.01 times the efficiency of the latter. (5) The surrogate model is an efficient predictive tool defining parameters of the Converter for improved energy acquisition.

A thiourea additive-based quadruple cation lead halide perovskite with an ultra-large grain size for efficient perovskite solar cells

Nanoscale ◽  
2019 ◽  
Vol 11 (45) ◽  
pp. 21824-21833 ◽  
Author(s):  
Jyoti V. Patil ◽  
Sawanta S. Mali ◽  
Chang Kook Hong
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Solar Cells ◽  
Power Conversion Efficiency ◽  
Conversion Efficiency ◽  
Power Conversion ◽  
Perovskite Solar Cells ◽  
Inorganic Perovskite ◽  
Halide Perovskite ◽  
Lead Halide

Controlling the grain size of the organic–inorganic perovskite thin films using thiourea additives now crossing 2 μm size with >20% power conversion efficiency.

The Effect of Donor Molecular Structure on Power Conversion Efficiency of Small-Molecule-Based Organic Solar Cells

2019 ◽  
Vol 16 (3) ◽  
pp. 236-243 ◽  
Author(s):  
Hui Zhang ◽  
Yibing Ma ◽  
Youyi Sun ◽  
Jialei Liu ◽  
Yaqing Liu ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Solar Cells ◽  
Power Conversion Efficiency ◽  
Conversion Efficiency ◽  
Small Molecule ◽  
Organic Solar Cells ◽  
Molecular Design ◽  
Power Conversion ◽  
The Relationship

In this review, small-molecule donors for application in organic solar cells reported in the last three years are highlighted. Especially, the effect of donor molecular structure on power conversion efficiency of organic solar cells is reported in detail. Furthermore, the mechanism is proposed and discussed for explaining the relationship between structure and power conversion efficiency. These results and discussions draw some rules for rational donor molecular design, which is very important for further improving the power conversion efficiency of organic solar cells based on the small-molecule donor.

Enhanced efficacy of defect passivation and charge extraction for efficient perovskite photovoltaics with a small open circuit voltage loss

2019 ◽  
Vol 7 (15) ◽  
pp. 9025-9033 ◽  
Author(s):  
Jin-Feng Liao ◽  
Wu-Qiang Wu ◽  
Jun-Xing Zhong ◽  
Yong Jiang ◽  
Lianzhou Wang ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Power Conversion Efficiency ◽  
Conversion Efficiency ◽  
Open Circuit Voltage ◽  
Power Conversion ◽  
Charge Recombination ◽  
Open Circuit ◽  
Polymeric Semiconductor ◽  
Voltage Loss ◽  
Defect Passivation

A multifunctional 2D polymeric semiconductor was incorporated to provide surprisingly robust efficacy in grain boundary functionalization and defect passivation of perovskite, which suppresses charge recombination and thus affording an illustrious photovoltage of 1.16 V and power conversion efficiency of 21.1%.

scholarly journals High performance tandem organic solar cells via a strongly infrared-absorbing narrow bandgap acceptor

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Zhenrong Jia ◽  
Shucheng Qin ◽  
Lei Meng ◽  
Qing Ma ◽  
Indunil Angunawela ◽  
...  
Keyword(s):  
Solar Cells ◽  
Power Conversion Efficiency ◽  
Conversion Efficiency ◽  
Organic Solar Cells ◽  
High Performance ◽  
Short Circuit ◽  
Power Conversion ◽  
High Power Conversion Efficiency ◽  
Device Structure ◽  
Narrow Bandgap

AbstractTandem organic solar cells are based on the device structure monolithically connecting two solar cells to broaden overall absorption spectrum and utilize the photon energy more efficiently. Herein, we demonstrate a simple strategy of inserting a double bond between the central core and end groups of the small molecule acceptor Y6 to extend its conjugation length and absorption range. As a result, a new narrow bandgap acceptor BTPV-4F was synthesized with an optical bandgap of 1.21 eV. The single-junction devices based on BTPV-4F as acceptor achieved a power conversion efficiency of over 13.4% with a high short-circuit current density of 28.9 mA cm−2. With adopting BTPV-4F as the rear cell acceptor material, the resulting tandem devices reached a high power conversion efficiency of over 16.4% with good photostability. The results indicate that BTPV-4F is an efficient infrared-absorbing narrow bandgap acceptor and has great potential to be applied into tandem organic solar cells.

Renovating electrical power-to-TEM00 mode laser power conversion efficiency with four-lamp/four-rod pumping scheme

2021 ◽  
pp. 1-11
Author(s):  
Miguel Catela ◽  
Dawei Liang ◽  
Cláudia R. Vistas ◽  
Dário Garcia ◽  
Bruno D. Tibúrcio ◽  
...  
Keyword(s):  
Power Conversion Efficiency ◽  
Conversion Efficiency ◽  
Laser Power ◽  
Power Conversion ◽  
Electrical Power ◽  
Mode Laser ◽  
Tem00 Mode

scholarly journals Digital printing of a novel electrode for stable flexible organic solar cells with a power conversion efficiency of 8.5%

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
S. Wageh ◽  
Mahfoudh Raïssi ◽  
Thomas Berthelot ◽  
Matthieu Laurent ◽  
Didier Rousseau ◽  
...  
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Power Conversion Efficiency ◽  
Conversion Efficiency ◽  
Organic Solar Cells ◽  
Power Conversion ◽  
Transport Layer ◽  
Electron Transport Layer ◽  
Solution Processed ◽  
Transparent Conducting

AbstractPoly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) mixed with single-wall nanotubes (SWNTs) (10:1) and doped with (0.1 M) perchloric acid (HClO4) in a solution-processed film, working as an excellent thin transparent conducting film (TCF) in organic solar cells, was investigated. This new electrode structure can be an outstanding substitute for conventional indium tin oxide (ITO) for applications in flexible solar cells due to the potential of attaining high transparency with enhanced conductivity, good flexibility, and good durability via a low-cost process over a large area. In addition, solution-processed vanadium oxide (VOx) doped with a small amount of PEDOT-PSS(PH1000) can be applied as a hole transport layer (HTL) for achieving high efficiency and stability. From these viewpoints, we investigate the benefit of using printed SWNTs-PEDOT-PSS doped with HClO4 as a transparent conducting electrode in a flexible organic solar cell. Additionally, we applied a VOx-PEDOT-PSS thin film as a hole transporting layer and a blend of PTB7 (polythieno[3,4-b] thiophene/benzodithiophene): PC71BM (phenyl-C71-butyric acid methyl ester) as an active layer in devices. Zinc oxide (ZnO) nanoparticles were applied as an electron transport layer and Ag was used as the top electrode. The proposed solar cell structure showed an enhancement in short-circuit current, power conversion efficiency, and stability relative to a conventional cell based on ITO. This result suggests a great carrier injection throughout the interfacial layer, high conductivity and transparency, as well as firm adherence for the new electrode.

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