Purdue University Purdue e-Pubs Publications of the Ray W. Herrick Laboratories School of Mechanical Engineering 6-28-2017 e Application of Microperforated Panels in Duct Systems Seungkyu Lee 3M Company, [email protected]omas P. Hanschen 3M Company, [email protected]J Stuart Bolton Purdue University, [email protected]Follow this and additional works at: hp://docs.lib.purdue.edu/herrick is document has been made available through Purdue e-Pubs, a service of the Purdue University Libraries. Please contact [email protected] for additional information. Lee, Seungkyu; Hanschen, omas P.; and Bolton, J Stuart, "e Application of Microperforated Panels in Duct Systems" (2017). Publications of the Ray W. Herrick Laboratories. Paper 153. hp://docs.lib.purdue.edu/herrick/153
Transcript
Purdue UniversityPurdue e-Pubs
Publications of the Ray W. Herrick Laboratories School of Mechanical Engineering
6-28-2017
The Application of Microperforated Panels in DuctSystemsSeungkyu Lee3M Company, [email protected]
Follow this and additional works at: http://docs.lib.purdue.edu/herrick
This document has been made available through Purdue e-Pubs, a service of the Purdue University Libraries. Please contact [email protected] foradditional information.
Lee, Seungkyu; Hanschen, Thomas P.; and Bolton, J Stuart, "The Application of Microperforated Panels in Duct Systems" (2017).Publications of the Ray W. Herrick Laboratories. Paper 153.http://docs.lib.purdue.edu/herrick/153
TL for Double layered MPP linings of Double Expansion Muffler
Double Chamber FEM
Double Chamber EXP
Double w/ MPP454 FEM
Double w/ MPP454 EXP
Double-layered MPP454 Linings FEM
Double-layered MPP454 Linings EXP
Improve the minima using double lining treatment Achieve TL above 10 dB 5000 Hz with limited space and design of
muffler
8 / 15
Differences in sound?Results
9 / 15
ASTM E2611 Measurement preparationMPP under flow condition
1 34 34 412 12 11 12
1 34 34 412 12 21 22
,/
a a
a a a
p A B pA B T T
v C D p ZC D T T
11 12 0 0 21 22
2
/
jkd
a
eT
T T c cT T
10
120log
a
TLT
4 – Microphone and 2 – load Method
Transfer Matrix Calculation*
Transmission Loss0
cos sin
( / )sin cosc c cjMk l
c cz z l
k l jY k lp pe
j Y k l k lv v
0
2
( )
1c
k j Mk
M
0
0 0
( ) ( )1
M MY Y j
k k
* M. L. Munjal, Acoustics of Ducts and Mufflers, WILEY (2014)
Differentiate end terminations
10 / 15
Prediction model considering mean flow effectMPP under flow condition
Square cross-section standing wave tube model
2
0 0
2
0
1 1( ) ( )
1( ) 0
vv v v
n vv n v =
V
S
jp I p p p p p pp dV
c K
jp I p p dS
c
Variational form, Helmholtz Equation
Sound Pressure along the duct
1 1
jkx jkx
M Mp Ae Be
Anechoic Termination
2(1 ) nanechoic
j iM p Mp p
c Z
0anechoicZ c
11 / 15
MPP modelingMPP under flow condition
MPP modeling
Equivalent fluid – JCA model 1,2
▪ Complex Density and Bulk Modulus were modeled using following equations▪ Calculated properties were implemented in the finite element model of the MPP▪ Rigid inclusions to make the MPP locally reacting. *
2
0 0
2 2 2
0
4( ) 1 1cs j j
0
12
0
2
0
/( )
'8( 1) 1 1
' 16
p
p
PK
Cj j
C
1) Champoux Y. and Allard J.-F., Dynamic tortuosity and bulk modulus in air-saturated porous media, J. Appl. Phys. 70, 1991, pp. 1975-1979
2) L. Jaouen and F.-X. Be´cot, “Acoustical characterization of perforated facings”, J. Acoust. Soc. Am. 129 (3), March 2011* S. Lee, J. S. Bolton and P. A. Martinson, “Design of multi-chamber silencers with microperforated elements,” NoiseCon14 Conference Proceedings, Fort Lauderdale, Florida, USA (2014)
Complex Density :
Complex Bulk Modulus :
φ: Perforation rate
α: Dynamic Tortuosity
σ: Flow resistivity
η: Dynamic viscosity of air
Λ: Viscous characteristic length
Λ‘: Thermal characteristic length
Λ = Λ ‘ = r (radius of perforation)
k: Thermal conductivity
γ: Specific heat ratio of air
Po: Atmospheric pressure
Cp: Specific heat of air at const. pressure
MPP Properties
MPP
12 / 15
MPP lining with flow effectMPP design - Modeling
0 500 1000 1500 2000 25000
1
2
3
4
5
6
7
8
9
Frequency [Hz]
(a)
TL [
dB
]
0 500 1000 1500 2000 25000
1
2
3
4
5
6
7
8
9
Frequency [Hz]
(b)
TL [
dB
]
No MPP without mean flow (Measurement)
No MPP with mean flow, 8.5 m/s (Measurement)
No MPP without mean flow (Prediction)
No MPP with mean flow, 8.5 m/s (Prediction)
0 500 1000 1500 2000 25000
1
2
3
4
5
6
7
8
9
Frequency [Hz]
(a)
TL [
dB
]
0 500 1000 1500 2000 25000
1
2
3
4
5
6
7
8
9
Frequency [Hz]
(b)
TL [
dB
]
MPP549 without no flow fem (Prediction)
MPP549 with mean flow, 8.5 m/s (Prediction)
MPP 549 without mean flow (Measurement)
MPP 549 with mean flow, 8.5 m/s (Measurement)
Measurement Prediction
Mean Flow
P1 P2 P3 P4
No Mean Flow
P1 P2 P3 P4
MPP lining attached
Mean Flow
P1 P2 P3P4
No Mean Flow
P1 P2 P3 P4
No MPP lining
8.5 m/s
8.5 m/s
Low speed flows have very little effect on MPP performance. Good prediction results.
13 / 15
Measurements and predictions comparisons.MPP design - Modeling
0 1000 2000 3000 4000 5000 60000
5
10
15
20
25
30
35
40
45
50
Frequency [Hz]
TL [
dB
]
Transmission Coefficient
Single chamber, No lining, EXP, Flow velocity: 20m/s
Single chamber, No lining, FEM, Flow velocity: 20m/s
Mean Flow
0 1000 2000 3000 4000 5000 60000
5
10
15
20
25
30
35
40
45
50Transmition Loss
Frequency
TL
Single, MPP454 lining, FEM, Flow velocity 20 m/s
Single, MPP454 lining, EXP, Flow velocity 20 m/s
mpp454
0 1000 2000 3000 4000 5000 60000
10
20
30
40
50
60
Frequency [Hz]
TL [
dB
]
Transmission loss
C Type, FEM, flow velocity: 20m/s
C Type, EXP, flow velocity: 20m/s
mpp454
Different muffler design is possible. MPP can help to improve TL when there is spatial limitation.
14 / 15
Use of a silencer with Microperforated Panel (MPP) lining in HVAC duct noise control was studied
Reliable modeling techniques to design a silencer with MPP linings were suggested
In-line MPP treatment inside a silencer helps in minimizing the pressure-drop as well as improving noise
attenuation
More practical studies will be made in the future.
