进气歧管噪声与排气系统噪声

SPL at Outlet
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Aero-Acoustic Noise results
Noise Source
SPL Map
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Outside SPL MAP
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Mazda had to consider many structural modifications in
order to fix this problem
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Computational Process
Intake Vibrations
Study of the Noise radiated by an Intake Manifold
Hiroyuki Abe – MAZDA Work presented at the Actran 2011 User’s Meeting in Japan
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TMM（Transfer Matrix Method)
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Catalysis
Definition of BIOT parameters from measurements
Introduction
Mazda has developed a new engine in order to reduce the fuel consumption as well as the weight (among others)
To achieve this, Mazda decided to use a thin resin
Acoustic
PT Vibration - NASTRAN
Evaluation Point
3 3
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Results
Rigid Parts except Intake Test-CAE 4000rpm Original 4000rpm
Test Test C AE CAE
use the numerical simulation to improve the acoustic performance of its
engines
90 85 80 75 70 65 60 55 50
一目盛り 5dBA
来自百度文库
Point1 SPL 2000rpm
BASE MODIFY
S.P.L. （dBA）
ACTRAN Aero-Acoustics（~3000Hz） Visualization by ACTRAN/VI
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1D simulation
1200 1000 800 600 400 200 0 0 -200 クランク角度 200 400 600 800 全圧 bar 密度 kg/m^3 質量流量 kg/s 流速 m/s ガス温度
Correlations are very good!
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Comparison with Experiment – Waterfall Diagram
Mic1
一目盛り 5dBA
Mic2
一目盛り 5dBA 一目盛り 5dBA
Test
2500
Aero-acoustic Analysis with Actran
Suzuki Motor – Yoshisada Sakamoto
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Exhaust Noise Analysis
Exhaust of Motorcycle
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Process Flow
1D Simulation Pressure Temperature Velocity
Unsteady CFD Analysis
Actran iCFD
(Mohring Noise Source, Mean Velocity, Mean Pressure, Mean Temperature)
315
400
500
630
800
1000
1250
1600
2000
Element Contribution
1/3Oct. Band （Hz）
The weight has been reduced as well as the noise (4dB at the maximum)
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intake manifold Consequence: many modes are present because of the low rigidity of the intake manifold and therefore some significant noise problem occur
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Aero-Acoustic Noise results
Calculation Time = 2.5hours
(10hz Resolution)
One can identify the 0.5 order harmonics of engine revolution
These data are used as the input condition for the unsteady CFD
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CFD Analysis in StarCCM+
Turbulence Model Cell Calculation Time Time Step DES（Detached Eddy Simulation） 11,000,000 1week（64Core） 5.0e-5
CAE
Correlations are very good!
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一目盛り 5dBA
Design Improvement
Thanks to the accuracy and to the performance of Actran, Mazda can