Assembly including acoustic baffles
An assembly includes an enclosure including first and second regions spaced apart along a first direction, and a plurality of spaced apart acoustic baffles arranged along a second direction different from the first direction and disposed in the enclosure between the first and second regions. The plurality of spaced apart acoustic baffles includes adjacent first and second acoustic baffles. Each of the first and second acoustic baffles include an acoustically absorptive layer disposed on a sheet having a specific airflow resistance greater than 200 MKS Rayl. The first and second acoustic baffles define a channel therebetween. At least a portion of the channel extends along a longitudinal direction making an oblique angle with the first direction.
1. An assembly comprising:
an enclosure comprising first and second regions spaced apart along a first direction; and
a plurality of spaced apart acoustic baffles arranged along a second direction different from the first direction and disposed in the enclosure between the first and second regions, the plurality of spaced apart acoustic baffles comprising adjacent first and second acoustic baffles, each of the first and second acoustic baffles comprising a first acoustically absorptive layer disposed on a first sheet having a specific airflow resistance greater than 200 MKS Rayl, the first and second acoustic baffles defining a channel therebetween, at least a portion of the channel extending along a longitudinal direction making an oblique angle with the first direction,
wherein for a frequency range extending at least from 1 kHz to 6 kHz, the first acoustically absorptive layer has an average acoustic absorption coefficient of greater than 0.2 as determined according to ASTM E1050-12, and the first sheet has an average acoustic reflectance of greater than 0.3 as determined from an acoustic transfer matrix determined according to ASTM E2611-17 and an average acoustic absorption coefficient of less than 0.05 as determined according to ASTM E1050-12.
2. The assembly of claim 1 , wherein each of the first and second acoustic baffles further comprises a second acoustically absorptive layer disposed on the first sheet opposite the first acoustically absorptive layer.
3. The assembly of claim 1 , wherein the first sheet comprises a microperforated panel.
4. The assembly of claim 1 , wherein the first acoustically absorptive layer comprises a nonwoven layer or a foam layer.
5. The assembly of claim 1 , wherein the first acoustically absorptive layer comprises a nonwoven layer, the nonwoven layer comprising a plurality of melt- blown fibers comprising a thermoplastic polymer blended with at least one of a phosphinate or a polymeric phosphonate.
6. An assembly comprising:
an enclosure comprising first and second regions spaced apart along a first direction; and
a plurality of spaced apart acoustic baffles arranged along a second direction different from the first direction and disposed in the enclosure between the first and second regions, the plurality of spaced apart acoustic baffles comprising adjacent first and second acoustic baffles, each of the first and second acoustic baffles comprising an acoustically absorptive layer disposed on an acoustically reflective layer, the acoustically reflective layer of the first acoustic baffle facing the acoustically absorptive layer of the second acoustic baffle such that at least a portion of sound propagating from the first region toward the second region reflects from the acoustically reflective layer of the first acoustic baffle and is absorbed by the acoustically absorptive layer of the second acoustic baffle,
wherein for a frequency range extending at least from 1 kHz to 6 kHz, the acoustically absorptive layer has an average acoustic absorption coefficient α1 as determined according to ASTM E1050-12, and the acoustically reflective layer has an average acoustic absorption coefficient α2 as determined according to ASTM E1050-12 and an average acoustic reflectance of greater than 0.3 as determined from an acoustic transfer matrix determined according to ASTM E2611-17, α1>0.2, α2<0.05.
7. The assembly of claim 6 , wherein each of the first and second acoustic baffles has a chevron shape.
8. The assembly of claim 6 , wherein at least one of the first and second acoustic baffles comprises at least one region where first and second portions of the acoustic baffle having different locations along a length of the acoustic baffle are attached to one another by one or more of stitching, melt bonding, or ultrasonic bonding.
9. An assembly comprising:
an enclosure comprising first and second regions spaced apart along a first direction;
a plurality of spaced apart acoustic baffles arranged along a second direction different from the first direction and disposed in the enclosure between the first and second regions, the plurality of spaced apart acoustic baffles comprising at least one acoustic baffle comprising first and second acoustically absorptive layers and a microperforated panel disposed therebetween;
one or more fans disposed in, or proximate to, the first region for providing airflow toward the second region; and
one or more hard disk drives disposed in the second region, wherein during operation of the one or more fans:
a pressure drop across the plurality of spaced apart acoustic baffles along the first direction is less than 20 Pa;
a pressure drop between the one or more fans and the one or more hard drives is greater than 200 Pa; and
the plurality of spaced apart acoustic baffles increases a transmission loss between the first and second regions by at least 10 dB for at least one frequency in a range of 1 kHz to 6 kHz.
10. The assembly of claim 9 , wherein the at least one acoustic baffle comprises adjacent first and second acoustic baffles, the first and second acoustic baffles defining a channel therebetween, at least a portion of the channel extending along a longitudinal direction making an oblique angle with the first direction.
11. The assembly of claim 9 , wherein the microperforated panel comprises first and second microperforated layers spaced apart by a spacer layer, the spacer layer comprising a plurality of open cells defined by sidewalls extending along a thickness direction of the spacer layer.
12. The assembly of claim 9 , wherein at least one of first and second acoustically absorptive layers comprises a nonwoven layer or a foam layer.
13. The assembly of claim 6 , further comprising:
one or more fans disposed in, or proximate to, the first region for providing airflow toward the second region; and
one or more hard disk drives disposed in the second region.
14. The assembly of claim 1 , further comprising:
one or more fans disposed in, or proximate to, the first region for providing airflow toward the second region; and
one or more hard disk drives disposed in the second region.
15. The assembly of claim 1 , wherein each of the first and second acoustic baffles has a chevron shape.
16. The assembly of claim 1 , wherein at least one of the first and second acoustic baffles comprises at least one region where first and second portions of the acoustic baffle having different locations along a length of the acoustic baffle are attached to one another by one or more of stitching, melt bonding, or ultrasonic bonding.
17. The assembly of claim 13 , wherein during operation of the one or more fans:
a pressure drop across the plurality of spaced apart acoustic baffles along the first direction is less than 20 Pa;
a pressure drop between the one or more fans and the one or more hard drives is greater than 200 Pa; and
the plurality of spaced apart acoustic baffles increases a transmission loss between the first and second regions by at least 10 dB for at least one frequency in a range of 1 kHz to 6 kHz.
18. The assembly of claim 14 , wherein during operation of the one or more fans:
a pressure drop across the plurality of spaced apart acoustic baffles along the first direction is less than 20 Pa;
a pressure drop between the one or more fans and the one or more hard drives is greater than 200 Pa; and
the plurality of spaced apart acoustic baffles increases a transmission loss between the first and second regions by at least 10 dB for at least one frequency in a range of 1 kHz to 6 kHz.