US Patent 11920500 Passive flow modulation device

A passive flow modulation device for a machine defining an axial direction and a radial direction, the passive flow modulation device including: a first ring with a first coefficient of thermal expansion; a second ring disposed coaxially with the first ring and positioned at least partially inward of the first ring along the radial direction, spaced from the first ring along the axial direction, or both, the first ring, the second ring, or both defining at least in part one or more passages, the second ring with a second coefficient of thermal expansion that is less than the first coefficient of thermal expansion to passively modulate a size of the one or more passages during operation.