Design and Analyzing Vibration with Acoustic …
257
could be deduced. Previous attempts must assume that each cylinder pressure is
incoherent and equal in magnitude and is thus suspect in the low-frequency range
where the signals are coherent. In Meiling et al. [6], it is constructed on a finite-volume
method of the Navier–Stokes equations and solved with flux-difference splitting
and an explicit formulation. In Gen et al. [7], acoustic performance and existing
problems on muffler are analyzed, and the acoustic performance analysis methods
like one-dimension acoustic transfer matrix, finite element method, and boundary
element method using on muffler design are discussed. Based on the actual working
characteristics of a muffler, point out that the influence of airflow and temperature
on muffler acoustic performance cannot be neglected. In Vijayaraj et al. [8], the
measurements data explains that engine noise is highly associated with engine speed
and that the produced noise variation (nearly 10 dB) was high enough to permit the
evaluation of the potential of both approaches for noise assessment during transients.
3 Boundary Conditions
• The muffler design and dimensions are taken from standard data book from Ashok
Leyland.
• Velocity of air = 20 m/s [1],
• Rockwool and carbon fiber mechanical properties are taken from the matweb.com.
• In 3D modelling software (CREO 2.0), the assembly of a muffler is designed, and
2D drawings are given below (Fig. 1).
4 Results and Discussions
The assembly file is converted into step file in Creo 2.0 and imported to the ANSYS
Fluent (Fig. 2; Table 1).
The observation found in Fig. 3a and b is acoustic power level (dB) for the original
and modified model. In this, the (dB) level is less for the modified model because of
the holes and material is used for the simulation is carbon fiber. In this, for the modified model, the acoustic is reduced compared to original due to holes are arranged
in the area of exhaust gas flow. By conducting the FST technique in ANSYS and
with harmonic analysis, the frequencies (Hz) versus amplitude (mm) and phase angle
versus frequency (Hz) for an original and modified model with both materials are
observed.
Amplitude is always inversely proportional to frequency. Frequency is measured
in Hertz. Small waves have less energy, and large waves have high energy. In Fig. 4,
the frequency response is shown for the original model for the carbon material. In
this, at 560 Hz of frequency obtained, the maximum amplitude (8.68e−6 mm) and
minimum (1.37e−8 mm) at 875 Hz were obtained. In Fig. 5, the maximum amplitude
is obtained at 440 Hz when the rockwool material is assigned to the original model.
257
could be deduced. Previous attempts must assume that each cylinder pressure is
incoherent and equal in magnitude and is thus suspect in the low-frequency range
where the signals are coherent. In Meiling et al. [6], it is constructed on a finite-volume
method of the Navier–Stokes equations and solved with flux-difference splitting
and an explicit formulation. In Gen et al. [7], acoustic performance and existing
problems on muffler are analyzed, and the acoustic performance analysis methods
like one-dimension acoustic transfer matrix, finite element method, and boundary
element method using on muffler design are discussed. Based on the actual working
characteristics of a muffler, point out that the influence of airflow and temperature
on muffler acoustic performance cannot be neglected. In Vijayaraj et al. [8], the
measurements data explains that engine noise is highly associated with engine speed
and that the produced noise variation (nearly 10 dB) was high enough to permit the
evaluation of the potential of both approaches for noise assessment during transients.
3 Boundary Conditions
• The muffler design and dimensions are taken from standard data book from Ashok
Leyland.
• Velocity of air = 20 m/s [1],
• Rockwool and carbon fiber mechanical properties are taken from the matweb.com.
• In 3D modelling software (CREO 2.0), the assembly of a muffler is designed, and
2D drawings are given below (Fig. 1).
4 Results and Discussions
The assembly file is converted into step file in Creo 2.0 and imported to the ANSYS
Fluent (Fig. 2; Table 1).
The observation found in Fig. 3a and b is acoustic power level (dB) for the original
and modified model. In this, the (dB) level is less for the modified model because of
the holes and material is used for the simulation is carbon fiber. In this, for the modified model, the acoustic is reduced compared to original due to holes are arranged
in the area of exhaust gas flow. By conducting the FST technique in ANSYS and
with harmonic analysis, the frequencies (Hz) versus amplitude (mm) and phase angle
versus frequency (Hz) for an original and modified model with both materials are
observed.
Amplitude is always inversely proportional to frequency. Frequency is measured
in Hertz. Small waves have less energy, and large waves have high energy. In Fig. 4,
the frequency response is shown for the original model for the carbon material. In
this, at 560 Hz of frequency obtained, the maximum amplitude (8.68e−6 mm) and
minimum (1.37e−8 mm) at 875 Hz were obtained. In Fig. 5, the maximum amplitude
is obtained at 440 Hz when the rockwool material is assigned to the original model.