A cooled acoustic liner useful in a
fluid handling duct includes a
resonator chamber 52 with a neck 56, a
face sheet 86, and a
coolant plenum 80 residing between the
face sheet and the chamber.
Coolant bypasses the
resonator chamber, rather than flowing through it, resulting in better acoustic
admittance than in liners in which
coolant flows through the
resonator chamber and neck. In one embodiment, the liner also includes a graze shield 88. Openings 40, 38 penetrate both the
face sheet and the shield to establish a relatively low face sheet
porosity and a relatively high shield
porosity. The shielded embodiment of the invention helps prevent a loss of acoustic
admittance due to fluid
grazing past the liner. Another embodiment that is not necessarily cooled, includes the resonator chamber, low
porosity face sheet and high porosity shield, but no
coolant plenum for bypassing coolant around the resonator chamber. An associated method of
retrofitting an acoustic treatment into a
fluid handling module includes installing openings in the module and mounting a resonator box 44 on the module so that the inlets to the resonator necks register with the installed openings.