A CFD Analysis Method for Prediction of Vehicle Exterior Wind Noise

2017 ◽  
Vol 10 (1) ◽  
pp. 286-298 ◽  
Author(s):  
Vinh Long Phan ◽  
Hiroshi Tanaka ◽  
Takaaki Nagatani ◽  
Mikio Wakamatsu ◽  
Tsuyoshi Yasuki
Keyword(s):  
Cfd Analysis ◽  
Analysis Method ◽  
Wind Noise

The Wind Flow Characteristics Measuring Simulations of Soundproof Tunnels on Expressways

2018 ◽  
Vol 878 ◽  
pp. 70-75 ◽  
Author(s):  
Jang Youl You ◽  
Sun Young Paek ◽  
Doo Kie Kim ◽  
Ki Pyo You
Keyword(s):  
Wind Velocity ◽  
Flow Characteristics ◽  
Wind Flow ◽  
Cfd Analysis ◽  
Analysis Method ◽  
Residential Areas ◽  
Heat Islands ◽  
Computational Fluid Dynamics Cfd ◽  
Weather Stations ◽  
Using Data

Soundproof tunnels and soundproof walls constructed on expressways are designed to prevent noise for the nearby surrounding residential areas. These soundproof walls and tunnels feature excellent noise prevention for residential areas nearby, but they hamper the dispersion of air pollutants generated, thus promoting the creation of heat islands during summer and cold islands during winter.The computational fluid dynamics (CFD) analysis method was used to investigate the wind flow around soundproof tunnels. The wind angle and the size of the wind velocity were determined using data from weather stations near soundproof tunnels. The CFD analysis results of the soundproof tunnels on expressways revealed that the wind velocity decreased by 30–60% following the installation of soundproof tunnels.

scholarly journals Shape Optimization with Computer Fluid Dynamic (CFD) Analysis of Micro Electric Vehicle

2019 ◽  
Vol 8 (3) ◽  
pp. 19-22
Keyword(s):  
Energy Consumption ◽  
Electric Vehicle ◽  
Fluid Dynamic ◽  
Human Mobility ◽  
Maximum Speed ◽  
Cfd Analysis ◽  
Wind Noise ◽  
Vehicle Owner ◽  
3D Data ◽  
Model Computer

Car drag reduction activities are parts of exterior body improvement which related to energy consumption, wind noise and stability of overall vehicle. Micro Electric Vehicle (MEV) has emerged as one of human mobility that aligned with the concept of low energy consumption. The concept has gained popularity due to its simplicity in design and manufacturing capability which in overall, leads to less energy consumption for both vehicle owner and manufacturer. The aim of this work is to design an MEV where the passenger’s anthropometry of 95th percentile male and 5th percentile female have been considered as a main factor. 3D data of MEV has been developed based on scaled down conceptual design from clay model. Computer Fluid Dynamic (CFD) analysis were used on actual size of MEV to determine the effect of the vehicle height. Maximum speed of 30m/s has been introduced in the analysis. The speed is a simulation from real world condition of mobility which will be the limit speed of the vehicle. As a result the 128mm increase in streamline height has significant impact on the drag force where the drag coefficient increase approximately 31% to the initial height. As a conclusion CFD approach can be used to successfully determine an optimal height of MEV based on streamline design. The finding significantly assist in future improvement of streamline design of the MEV.

CFD Prediction for an Overpressure Buildup Phenomenon of SRI Hydrogen Test in an Open Space

2011 ◽  
Author(s):  
Hyung Seok Kang ◽  
Sang Baik Kim ◽  
Min-Hwan Kim ◽  
Hee Cheon No
Keyword(s):  
Flame Front ◽  
Flame Propagation ◽  
Spark Ignition ◽  
Cell Length ◽  
Cfd Analysis ◽  
Analysis Method ◽  
Step Size ◽  
Time Step ◽  
Time Step Size ◽  
Comparison Results

A computational fluid dynamics (CFD) calculation for a hydrogen explosion test with a complicated obstacle tube geometry of pitch 21.3mm and diameter 99.1mm at a stoichiometric condition was performed to establish a CFD analysis method for a hypothetical hydrogen explosion accident between a very high temperature reactor (VHTR) and a hydrogen production facility. We developed a spark ignition model to simulate high ignition energy of 40J induced by an electric device for 2 ms in the hydrogen explosion based on an energy conservation law. We performed a sensitivity calculation by varying a constant value of the eddy dissipation model (EDM), a time step size, and a cell length size around the obstacle tube to evaluate an effect of each factor on the flame propagation and overpressure buildup phenomenon. The CFD results of the flame front time of arrival (TOA) and overpressure were compared with those of the test data. The comparison results showed that the spark ignition model with a radius of 6 cm, a pressure of 105.7 kPa, a temperature of 1000 K, a turbulent mixing time of 2 ms, and an assumption of the 10% product mass fraction can reasonably initiate the hydrogen flame propagation in the CFD calculation. As for the CFD analysis method, the EDM constants of A = 10 and B = 0.8, the time step size of 0.01 ms, the cell length of 1 cm around the obstacle tube predicted the measured flame front TOA and peak overpressure with an error range of about 27.8% and 53.3%, respectively. Therefore, it is known that the CFD analysis with the EDM may be used as an accurate evaluation tool to provide the 3-dimesnional information of the flame front TOA and overpressure buildup phenomenon if the CFD analysis method is properly chosen.

Tactile Temperature Analysis of Home Theater System

2005 ◽  
Author(s):  
Ho Chul Ryu ◽  
Byung Ju Dan ◽  
In Ho Choi ◽  
Jin Yong Kim
Keyword(s):  
Heat Source ◽  
High Heat ◽  
Heat Sources ◽  
Cfd Analysis ◽  
Analysis Method ◽  
Temperature Analysis ◽  
Temperature Changes ◽  
System A ◽  
Numerical Approaches ◽  
Home Theater

In this work, the tactile temperature of home theater systems under natural convection conditions has been investigated through numerical approaches and experiment. The CFD analysis method was used to observe temperature changes of both the case top and the heat source. Based on numerical simulation results, four types of steel sheet mock-up having different vent sizes and locations were tested. As a consequence of the experiments, relationships in temperature variation between the case top and the heat source were investigated and verified. In addition, by using the validated and improved vent system, a fanless home theater system was proposed under high heat dissipating heat sources.

Research on the Subchannel Analysis Method via CFD Analysis for PWR

2017 ◽  
Vol 188 (3) ◽  
pp. 270-281 ◽  
Author(s):  
Guangliang Chen ◽  
Zhijian Zhang ◽  
Zhaofei Tian ◽  
Thompson Appah ◽  
Lei Li ◽  
...  
Keyword(s):  
Cfd Analysis ◽  
Analysis Method ◽  
Subchannel Analysis

Research on Flow Characteristics of Top and Vertical Containment Surface With Different Structures

2017 ◽  
Author(s):  
Pan Xinxin ◽  
Liu Jie
Keyword(s):  
Water Flow ◽  
Film Flow ◽  
Vertical Wall ◽  
Flow Characteristics ◽  
Water Film ◽  
Low Flow ◽  
Water Evaporation ◽  
Cfd Analysis ◽  
Analysis Method ◽  
Circumferential Welds

Following an accident, the passive nuclear power plant CAP1400 mainly uses cooling water evaporation on the outer containment surface to remove the decay heat inside containment to outside environment to ensure the plant to a stable status. But the outside surface of the containment vessel is attached by a large number of different forms of the disorder structure including circumferential welds and longitudinal welds on the containment surface, and small local bulge, which may affect water film flow and coverage outside containment surface. Once a large amount of water splashes and can’t return to the containment surface, the heat removal capacity of the system during and after an accident will be significantly reduced, and the safety of power plants will be threatened. This paper simulates the water flow characteristics on the containment surface. Firstly, a simplified analysis model of water film flow structure is established considering different forms of structures including the circumferential weld, small local bulge and etc. The circumferential weld is simplified with the horizontal protrusion. Local small uplift is simulated with point-like protrusion. Computational fluid dynamics (CFD) software STAR CCM+ is applied in this simulation with the volume of fluid method and surface tension model, and sets contact angle and other parameters according to the characteristics of the containment surface coating, so as to establish the CFD analysis method. The analysis results and water flow test results agree well. And then, the CFD analysis method is used to analyze the flow patterns of water film on the surface of the wall under different conditions. The results show that the circumferential weld has a certain influence on the initial water film covering only. But the film coverage rate of the water film is stable after the water film is stable, and there is no loss of the water film. For the circumferential weld on the vertical wall, the effect on the water film coverage is little. Water film loss of low-flow is negligible, and water film loss of high-flow is no more than 1%. For the form of local small protrusions, little change of the flow characteristics of water film can be observed. The structure form of the containment outside wall is various. According to the rules of the water film, including the water film covering width and the water film loss, it can be used as the design input of the accident analysis program WGOTHIC to guide the system design.

Effect of Partial Admission and Swirl Brakes on Destabilization Force of Labyrinth Gas Seal

2020 ◽  
Author(s):  
Makoto Iwasaki ◽  
Rimpei Kawashita ◽  
Naoto Omura ◽  
Kazuyuki Matsumoto ◽  
Kenichi Murata ◽  
...  
Keyword(s):  
Steady State ◽  
Steam Turbine ◽  
Large Scale ◽  
Labyrinth Seal ◽  
Cfd Analysis ◽  
Analysis Method ◽  
Labyrinth Seals ◽  
Fluid Force ◽  
Swirl Velocity ◽  
Partial Admission

Abstract Destabilization forces in labyrinth seals can cause subsynchronous vibration and many researchers have investigated the destabilization force under full admission (FA). It is known that partial admission (PA) can increase rotor instability, but there is little knowledge about seal fluid force under PA. In this study the experiment was conducted in order to confirm the effect of PA and swirl brakes (SB) on swirl velocity and destabilization force. For the experiment, a 500mm diameter rotor was used so that size of the labyrinth seal can be close to the large-scale steam turbine. According to the experimental results, it was found that (1) average swirl velocity and destabilization force under PA became larger than FA, (2) relationship between average swirl velocity and destabilization force under PA was almost same with that of FA, (3) seal fluid force under PA had anisotropy by the instant rotor position, (4) SB reduced 70% of swirl velocity and destabilization force under both FA and PA. Also it was found that CFD analysis could predict the effect of PA and SB on swirl velocity and seal fluid force. For predicting the effect of SB under FA, new steady state CFD analysis method applying frozen rotor interface at SB region was proposed.

The Research on Post Rolling of Aerodynamic Characteristics Numerical Simulation of Flow Field

2014 ◽  
Vol 684 ◽  
pp. 30-33
Author(s):  
Qi Wang ◽  
Jing Zhang ◽  
Ming Ming ◽  
Xiao Xu Chen
Keyword(s):  
Flow Field ◽  
Preliminary Analysis ◽  
Aerodynamic Force ◽  
Aerodynamic Characteristics ◽  
Source Model ◽  
Cfd Analysis ◽  
Analysis Method ◽  
Model Flow ◽  
The Difference ◽  
Aerodynamic Torque

In this paper, according on post rolling maneuver and the flow field, we build a CFD analysis method about momentum source model flow field and aerodynamic characteristics. Preliminary analysis of the numerical has be finished to contrast the difference of post rolling maneuver. The changing law of aerodynamic force, aerodynamic torque variation and the focus position have be given.

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