scholarly journals Numerical simulation of a new type of cross flow tidal turbine using OpenFOAM – Part II: Investigation of turbine-to-turbine interaction

2013 ◽  
Vol 50 ◽  
pp. 1005-1013 ◽  
Author(s):  
Mulualem G. Gebreslassie ◽  
Gavin R. Tabor ◽  
Michael R. Belmont
Keyword(s):  
Numerical Simulation ◽  
Cross Flow ◽  
Tidal Turbine ◽  
New Type

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.

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.

scholarly journals Cross-Flow Tidal Turbines with Highly Flexible Blades—Experimental Flow Field Investigations at Strong Fluid–Structure Interactions

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 797
Author(s):  
Stefan Hoerner ◽  
Iring Kösters ◽  
Laure Vignal ◽  
Olivier Cleynen ◽  
Shokoofeh Abbaszadeh ◽  
...  
Keyword(s):  
Flow Field ◽  
High Speed ◽  
Cross Flow ◽  
Speed Ratio ◽  
Fluid Structure Interactions ◽  
Dimensional Parameter ◽  
Fluid Structure ◽  
Passive Flow Control ◽  
Tidal Turbines ◽  
Tidal Turbine

Oscillating hydrofoils were installed in a water tunnel as a surrogate model for a hydrokinetic cross-flow tidal turbine, enabling the study of the effect of flexible blades on the performance of those devices with high ecological potential. The study focuses on a single tip-speed ratio (equal to 2), the key non-dimensional parameter describing the operating point, and solidity (equal to 1.5), quantifying the robustness of the turbine shape. Both parameters are standard values for cross-flow tidal turbines. Those lead to highly dynamic characteristics in the flow field dominated by dynamic stall. The flow field is investigated at the blade level using high-speed particle image velocimetry measurements. Strong fluid–structure interactions lead to significant structural deformations and highly modified flow fields. The flexibility of the blades is shown to significantly reduce the duration of the periodic stall regime; this observation is achieved through systematic comparison of the flow field, with a quantitative evaluation of the degree of chaotic changes in the wake. In this manner, the study provides insights into the mechanisms of the passive flow control achieved through blade flexibility in cross-flow turbines.

Numerical Simulation Study on Cooling Characteristics of a New Type of Film Hole

2020 ◽  
Author(s):  
Chunhai Guo ◽  
Bin Wang ◽  
Zhenya Kang ◽  
Wenwu Zhang ◽  
Huilong Zheng
Keyword(s):  
Numerical Simulation ◽  
Simulation Study ◽  
New Type

Study on the Integrated Design of Underground Construction Lighting and Ventilation System

2011 ◽  
Vol 374-377 ◽  
pp. 702-705
Author(s):  
Wei Feng ◽  
Hui Min Li
Keyword(s):  
Numerical Simulation ◽  
Thermal Environment ◽  
Ventilation System ◽  
Integrated Design ◽  
Structure Design ◽  
Light Environment ◽  
System Model ◽  
Underground Construction ◽  
New Type

In the underground building, Light environment and thermal environment is poorer, in order to improve the problem, this paper brings forward a new type of lighting and ventilation system model; discusses the principle and characteristics of transmission; and analyses the question that influences lighting and ventilated effect in the application. Structure design and numerical simulation is the focus of the next step.

Numerical Simulation of Cross-Flow Vacuum Membrane Distillation and Characteristics Analysis

2011 ◽  
Vol 396-398 ◽  
pp. 1846-1850
Author(s):  
Chang Li ◽  
Bao An Li ◽  
Shi Chang Wang
Keyword(s):  
Numerical Simulation ◽  
Cross Flow ◽  
Membrane Distillation ◽  
Inlet Temperature ◽  
Coefficient Distribution ◽  
Vacuum Degree ◽  
Membrane Flux ◽  
Characteristics Analysis ◽  
Vacuum Membrane Distillation ◽  
Feed Inlet

The mechanism of cross-flow vacuum membrane distillation (VMD) was discussed in this paper, and the coupled process of heat and mass transfer in numerical simulation was realized by writing user defined function (UDF). The numerical simulation results of membrane flux were well agree with experimental data. The membrane flux in various conditions of feed velocity, feed inlet temperature and vacuum degree was obtained in numerical simulation. Around the cross-section of a single hollow fiber, velocity distribution was approximately symmetrical; TPC and heat transfer coefficient distribution are consistent.

The Research of Calculation Method on Vertical Natural Frequency of the New Full-Prefabricated Floor

2016 ◽  
Vol 846 ◽  
pp. 506-511
Author(s):  
Chong Fang Sun ◽  
Shu Ting Liang ◽  
Xiao Jun Zhu
Keyword(s):  
Numerical Simulation ◽  
Natural Frequency ◽  
Calculation Method ◽  
Variable Stiffness ◽  
Series Method ◽  
Numerical Simulation Result ◽  
Stiffness Method ◽  
Calculation Results ◽  
New Type ◽  
Test Result

New-type floor is composed of three kinds of slabs joined together through fittings. It is a kind of anisotropic two-way slab. In order to study the calculation method of natural frequency, series method, variable thickness method and variable stiffness method are adopted to calculate the natural frequency. The calculation results of three methods are compared with test result and numerical simulation result. The conclusion is that the calculation result of the variable stiffness method is the closest to the real natural frequency of new-type floor.

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