Bearing damper for cold engine ground starts or in-flight re-starts

A damper for a bearing assembly of a gas turbine engine, comprising:

• a damper housing;
• a lubricant passage defined in the damper housing, the lubricant passage including an inlet and an outlet;
• and
• a valve positioned within the lubricant passage, the valve comprising a stem and a head, the stem having a base end opposite a head end, the head disposed at the head end of the stem, the head having a shape complementary to a shape of the lubricant passage to block a flow of lubricant through the lubricant passage,
• wherein the valve is configured to increase leakage of a lubricant through the outlet when a reference temperature is below a threshold temperature, and
• wherein the base end of the stem is disposed adjacent the outlet such that the stem extends within the lubricant passage downstream of the head.

A damper for a bearing assembly of a gas turbine engine, comprising:

• a damper housing;
• a lubricant passage defined in the damper housing, the lubricant passage including an inlet and an outlet;
• and
• a passively actuated valve positioned within the lubricant passage, the valve comprising a stem and a head that are both disposed in the lubricant passage, the stem having a base end opposite a head end, the head disposed at the head end of the stem, the head having a shape complementary to a shape of the lubricant passage to block a flow of lubricant through the lubricant passage,
• wherein the valve is configured to move within the lubricant passage to control the flow of lubricant from the inlet to the outlet based on a reference temperature, and
• wherein the stem of the valve is formed from a first material and the damper housing is formed from a second material, the first material having a higher coefficient of thermal expansion than the second material.