scholarly journals Numerical and Experimental Study of Lightning Stroke to BIPV Modules

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 748
Author(s):  
Xiaoyan Bian ◽  
Yao Zhang ◽  
Qibin Zhou ◽  
Ting Cao ◽  
Bengang Wei
Keyword(s):  
Numerical Simulation ◽  
Experimental Study ◽  
Coupling Model ◽  
Maximum Temperature ◽  
Lightning Stroke ◽  
Study Results ◽  
Pv Modules ◽  
New Type ◽  
Metal Frame ◽  
Current Flows

Building Integrated Photovoltaic (BIPV) modules are a new type of photovoltaic (PV) modules that are widely used in distributed PV stations on the roof of buildings for power generation. Due to the high installation location, BIPV modules suffer from lightning hazard greatly. In order to evaluate the risk of lightning stroke and consequent damage to BIPV modules, the studies on the lightning attachment characteristics and the lightning energy withstand capability are conducted, respectively, based on numerical and experimental methods in this paper. In the study of lightning attachment characteristics, the numerical simulation results show that it is easier for the charges to concentrate on the upper edge of the BIPV metal frame. Therefore, the electric field strength at the upper edge is enhanced to emit upward leaders and attract the lightning downward leaders. The conclusion is verified through the long-gap discharge experiment in a high voltage lab. From the experimental study of multi-discharge in the lab, it is found that the lightning interception efficiency of the BIPV module is improved by 114% compared with the traditional PV modules. In the study of lightning energy withstand capability, a thermoelectric coupling model is established. With this model, the potential, current and temperature can be calculated in the multi-physical field numerical simulation. The results show that the maximum temperature of the metal frame increases by 16.07 °C when 100 kA lightning current flows through it and does not bring any damage to the PV modules. The numerical results have a good consistency with the experimental study results obtained from the 100 kA impulse current experiment in the lab.

Predicting the number of fiber roots in lola drafting based on multi-field coupling

2020 ◽  
Vol 90 (23-24) ◽  
pp. 2769-2781
Author(s):  
Xin rong Li ◽  
LiuBo Wu ◽  
Zhaoning Bu ◽  
Lidong Liu
Keyword(s):  
Change Point ◽  
Production Efficiency ◽  
Slip Rate ◽  
Sharp Decrease ◽  
Coupling Model ◽  
Production Costs ◽  
Weak Effect ◽  
Field Coupling ◽  
Theoretical Support ◽  
New Type

Pullout theory is very important in improving efficiency, quality, and production costs. Because production efficiency is too low for mechanical drafting equipment, a simple multi-field coupling model of fiber mechanics based on conserving momentum is proposed that considers the distribution of the fiber speed point, slip rate, and friction mechanics. When the roller draft multiple is increased, the position near the rear roller clamp mouth in the draft area will show a sharp decrease of fiber, which is caused by the rapid movement of the front fiber to drive the floating fiber movement, and it is also the existence of the fiber change point. When the roller spacing increases, the draft efficiency decreases, although the pressure applied by the roller to the fibrous strip has a weak effect on the draft efficiency. This research increases our understanding of drawing and provides theoretical support for the design of a new type of drawing.

Experimental study and numerical simulation of urea-assisted SAGD in developing exra-heavy oil reservoirs

2021 ◽  
Vol 201 ◽  
pp. 108436
Author(s):  
Daode Hua ◽  
Pengcheng Liu ◽  
Peng Liu ◽  
Changfeng Xi ◽  
Shengfei Zhang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Experimental Study ◽  
Heavy Oil ◽  
Oil Reservoirs ◽  
Heavy Oil Reservoirs

Sublimation of composite ice and its influence on performance of ice shells

2021 ◽  
Vol 36 (1) ◽  
pp. 67-77
Author(s):  
Yue Wu ◽  
Junkai Huang ◽  
Jiafeng Chen
Keyword(s):  
Numerical Simulation ◽  
Shell Structure ◽  
Composite Shell ◽  
Engineering Practice ◽  
Sublimation Rate ◽  
Long Span ◽  
Static Performance ◽  
New Type ◽  
Ice Sublimation ◽  
Composite Shell Structure

The long-span ice composite shell structure is a new type of ice and snow structure developed in recent years. The engineering practice of ice composite shell shows that sublimation is one of the important reasons for its damage and even collapse. In this paper, we firstly supplemented the existing H-K equation and obtained the revised ice sublimation equation through indoor evaporative plate experiment considering the influence of admixtures and wind speed. Afterwards, combining the simulations of solar radiation and CFD, the numerical simulation of sublimation distribution on the surface of were realized by programming in Grasshopper platform. During sublimation, the thickness of the ice composite shell decreases by 0.38 mm every 10 days and the sublimation rate on the sunny side was 1.7 times that on the shady side. Finally, the static performance and stability of the sublimated ice composite spherical shell were analyzed. After 70 days of sublimation, the thickness of the ice composite shell structure becomes thinner and uneven, which leads its sensitivity to external load increases.

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