Numerical Simulation of Elongational Flow in Polymer Vane Extruder

2011 ◽  
Vol 421 ◽  
pp. 415-418 ◽  
Author(s):  
Jin Song Wen ◽  
Yao Huan Liang ◽  
Zhi Min Chen

Polymer vane extruder is a new type of extrusion machine, whose plasticating and conveying method is based on elongational rheology. The vane extruder has many advantages over conventional plasticating method, such as shortening thermo-mechanical experience of plasticating and conveying, reducing the energy consumption of plasticating and conveying, and improving adaptability to diverse materials. Currently, research for characteristics of vane extruder is mostly focused on theoretical derivation and experiments. However, these methods lead to high consumption of time and energy, and cannot provide an intuitive view of the flow. In this paper, 3D finite element numerical simulation was performed to investigate the flow in one of the vane units with POLYFLOW. The elongation flow was investigated by analyzing velocity field, pressure field, local-shear-rate distribution and mixing index distribution. The results show that numerical simulation is an efficient method to optimize process parameters and the structure of vane extruder.

Author(s):  
Xiaoming Lou ◽  
Mingwu Sun ◽  
Jin Yu

AbstractThe fissures are ubiquitous in deep rock masses, and they are prone to instability and failure under dynamic loads. In order to study the propagation attenuation of dynamic stress waves in rock mass with different number of fractures under confining pressure, nonlinear theoretical analysis, indoor model test and numerical simulation are used respectively. The theoretical derivation is based on displacement discontinuity method and nonlinear fissure mechanics model named BB model. Using ABAQUS software to establish a numerical model to verify theoretical accuracy, and indoor model tests were carried out too. The research shows that the stress attenuation coefficient decreases with the increase of the number of fissures. The numerical simulation results and experimental results are basically consistent with the theoretical values, which verifies the rationality of the propagation equation.


Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 748
Author(s):  
Xiaoyan Bian ◽  
Yao Zhang ◽  
Qibin Zhou ◽  
Ting Cao ◽  
Bengang Wei

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.


2021 ◽  
Vol 36 (1) ◽  
pp. 67-77
Author(s):  
Yue Wu ◽  
Junkai Huang ◽  
Jiafeng Chen

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.


Author(s):  
Chunhai Guo ◽  
Bin Wang ◽  
Zhenya Kang ◽  
Wenwu Zhang ◽  
Huilong Zheng

2012 ◽  
Vol 229-231 ◽  
pp. 55-58
Author(s):  
Jun Fan

To obtain the know-how of the deficiency for the filling capability, taking Ti75 alloy as the research object, at the same height of reducing, strain rates during forming as the control objective, the finite element numerical simulation method was used to simulate the hot compression with DEFORM-3D, analyzing the effect of the strain rates on the distribution of strain and stress.


2011 ◽  
Vol 374-377 ◽  
pp. 702-705
Author(s):  
Wei Feng ◽  
Hui Min Li

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.


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