Research on Mesh Generation Effecting Resistance Calculation

2011 ◽  
Vol 138-139 ◽  
pp. 886-893 ◽  
Author(s):  
Rui Deng ◽  
De Bo Huang ◽  
Guang Li Zhou ◽  
Hua Wei Sun ◽  
Liang Chang ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Mesh Generation ◽  
Engineering Application ◽  
Model Tests ◽  
Influential Factors ◽  
Hydrodynamic Performance ◽  
Calculation Results ◽  
Alternative Set

In order to give consistent and agreeable results in resistance and other hydrodynamic performance with some of the viscous Computational Fluid Dynamics methods which appear to have difficulties when applied to hulls, the investigation of the influential factors like mesh generation which affect the calculation results are taken by the simulation of different cases in the present paper. Through calculation and analysis, specifically with the CFD code FLUENT, an alternative set of computation parameters of mesh generation for engineering application is suggested. The application of the suggestion to the hull researched in this paper result in better agreements with corresponding model tests.

scholarly journals Computational fluid dynamics simulation as a tool for optimizing the hydrodynamic performance of membrane bioreactors

RSC Advances ◽  
2019 ◽  
Vol 9 (55) ◽  
pp. 32034-32046 ◽  
Author(s):  
Yan Jin ◽  
Cheng-Lin Liu ◽  
Xing-Fu Song ◽  
Jian-Guo Yu
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Membrane Fouling ◽  
Membrane Bioreactor ◽  
Membrane Bioreactors ◽  
Dynamics Simulation ◽  
Hydrodynamic Performance ◽  
Shear Stresses ◽  
Computational Fluid Dynamics Simulation ◽  
Hydrodynamic Properties

The hydrodynamic properties and shear stresses experienced by a membrane bioreactor (MBR) are directly related to its rate of membrane fouling.

CFD Comparison of Clearance Flow in a Rotor-Casing Assembly Using Asymmetric vs. Symmetric Lobe Rotors

2003 ◽  
Author(s):  
Bassam Abu-Hijleh ◽  
Jiyuan Tu ◽  
Aleksander Subic ◽  
Huafeng Li ◽  
Katherine Ilie
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Analysis ◽  
Mesh Generation ◽  
Cfd Analysis ◽  
Air Leakage ◽  
Flow Conditions ◽  
Leakage Path ◽  
Clearance Flow ◽  
Computational Fluid Dynamics Cfd

The performance of a Rotor-Casing Assembly is influenced more by the internal air leakages than by any other thermo-fluid aspect of its behaviour. The pressure difference driving the air along a leakage path varies periodically and does so in a manner that may not be the same for every leakage path. So the distribution of leakage through the various leakage paths within the machine is important for the improvement of its performance. The total volume of air leakage and the distribution of the leakage among the different paths depend on the rotor-rotor and rotor-casing clearances as well as the geometry of the rotors’ lobes. Computational Fluid Dynamics (CFD) analysis was carried out using the FLUENT. Geometry definition, mesh generation, boundary and flow conditions, and solver parameters have all been investigated as the part of the numerical analysis. This analysis was conducted for static rotors at different positions. The results indicate that the size of the clearances as well as the geometry of the rotors’ lobes can have a significant effect on the total volume of the air leakage as well as the distribution of the leakage among the three main leakage paths. The results can be used to ascertain the proper levels of clearances to be used and the best rotor lobes geometry to be used for the practical reduction of air leakage.

scholarly journals Numerical study of the effect of penstock slope on the increase in electric power of micro-hydro system using Computational Fluid Dynamics

2021 ◽  
Vol 927 (1) ◽  
pp. 012029
Author(s):  
Yoga Satria Putra ◽  
Evi Noviani ◽  
Muhardi ◽  
Azrul Azwar
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Electric Power ◽  
Numerical Study ◽  
Electrical Power ◽  
Maximum Slope ◽  
The Public ◽  
Hydropower Plants ◽  
Calculation Results ◽  
Alternative Solutions

Abstract Micro-hydropower plants have become one of the alternative solutions to meet the electricity needs of people in remote villages that the public electricity company has not reached. However, the performance of a micro-hydro system has to be continuously developed. This research aims to improve the performance of a micro-hydro system by examining the effect of the slope of the penstock on the increase in electrical power. The penstock slope is varied with diverse angles, namely θ = 50 °, 60 °, 70 °, 80 °, and 90 °. Five simulations of water flow in the penstock for five slope angles were constructed using the open-source CFD software, i.e., OpenFOAM. We calculate the electric power for the five simulations aforementioned. The calculation results show that the variation of the penstock slope can affect the increase of the electric power of a micro-hydro system. The highest electric power occurs at a maximum slope, θ = 90 °.

Performance of a Shore Fixed Oscillating Water Column Device for Different Bottom Slopes and Front Wall Drafts: A Study Based on Computational Fluid Dynamics and BIEM

2020 ◽  
Vol 143 (3) ◽  
Author(s):  
Piyush Mohapatra ◽  
K. G. Vijay ◽  
Anirban Bhattacharyya ◽  
Trilochan Sahoo
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Water Column ◽  
Wave Energy ◽  
High Efficiency ◽  
Boundary Integral ◽  
Hydrodynamic Performance ◽  
Chamber Pressure ◽  
Front Wall ◽  
Oscillating Water Column

Abstract Oscillating water column (OWC) wave energy converters are one of the most widely researched devices for ocean wave energy harvesting. This study investigates the hydrodynamic performance of a shore-fixed OWC device for different bottom slopes using two numerical approaches, namely, computational fluid dynamics (CFD) and boundary integral equation method (BIEM). In the BIEM method, the boundary value problem is solved in two-dimensional Cartesian coordinates using the linear water wave theory. The CFD model uses a numerical wave tank (NWT) built using the volume of fluid (VOF) method. Numerical computations are carried out for different sloped bottom geometries and front wall drafts to analyze the hydrodynamic efficiency. There is a general agreement between CFD and BIEM results in terms of resonating behavior of the device. It is observed that the front wall draft has a more significant effect, a lower draft leading to a wider frequency band for optimum conversion at high efficiency. While the BIEM-based analysis resulted in improved performance curve for few of the steeper slopes, the CFD study predicted a lower peak efficiency for the same slopes due to the consideration of real fluid characteristics. Detailed performance comparisons are presented using the time histories of free surface elevation, chamber pressure, and streamlines at different time instants within the OWC chamber.

scholarly journals Numerical investigations on effect of wear-ring clearance on performance of a submersible well pump

2017 ◽  
Vol 9 (7) ◽  
pp. 168781401770415 ◽  
Author(s):  
Weidong Shi ◽  
Xiongfa Gao ◽  
Qihua Zhang ◽  
Desheng Zhang ◽  
Daoxing Ye
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Computational Fluid Dynamics ◽  
Flow Field ◽  
Reverse Flow ◽  
Internal Flow ◽  
Experimental Results ◽  
Ring Size ◽  
Numerical Investigations ◽  
Calculation Results

A typical submersible well pump was investigated in this article. The whole flow field of submersible well pump was numerically simulated by computational fluid dynamics software. The influence of clearance of wear-rings on the external characteristic and internal flow field was analyzed through comparing the calculation results with experimental results. The result of the numerical simulation shows that changing clearance of front wear-ring has a greater impact on pump performances than changing clearance of back wear-ring, and the head and efficiency of pump decrease with the increase in the size of clearance. Especially when the size of clearance is larger than 0.5 mm, decreasing becomes more obvious. When the front and back wear-ring size of the clearance comes to 1.0 mm, the efficiency decreases from the highest point of 75.31% to 65.44% at rated flow, and the head of pump decreases about 3.5 m. When the size of clearance is 0.2 mm, reverse-flow will appear in the front shroud cavity of the impeller, and leakage from back wear-ring through the balance hole into the impeller, which has a little influence on the flow field of the impeller inlet.

Computational Fluid Dynamics Simulation of Ventilation Effect of a Large Cross-Section Cable Tunnel

2013 ◽  
Vol 353-356 ◽  
pp. 1404-1410
Author(s):  
Jun Sheng Chen ◽  
Shu Zhuo Liu ◽  
Ying Guang Fang ◽  
Hai Hong Mo
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Temperature Distribution ◽  
Cross Section ◽  
Air Temperature ◽  
Influential Factors ◽  
Dynamics Simulation ◽  
Airflow Rate ◽  
Large Cross Section ◽  
Finite Element Software

The finite element software ADINA was employed in this paper to study the ventilation effect of a large cross-section cable tunnel by using a computational fluid dynamics method. The temperature and ventilation zoning inside a cable tunnel were determined according to the characteristics of the large cross-section cable tunnel. With the ambient tunnel characteristics and tunnel cross-section layout being taken into consideration, a three-dimensional model for large cross-section cable tunnels was established; the computations indicate that the main influential factors of ventilation effect of large cross-section cable tunnels are intake airflow rate, intake air temperature, exhaust airflow rate, ventilation duration, tunnel length, fire door layout, and so on. The average air velocity in the tunnel was about 60 % of the intake airflow rate. The intake air temperature has much impact on tunnel temperature distribution within a range of 30 m away from the tunnel origin, as shown by a significant cooling effect when intake air temperature falls; whereas the intake air temperature has less impact on tunnel temperature distribution beyond 30 m from the tunnel origin.

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