Fluid-cooling device for a turbine engine propulsive unit

A fluid cooling device for a propulsion unit of a propfan type aircraft, said propulsion unit comprising a turbomachine that drives in rotation at least one rotor comprising a plurality of fan blades, said turbomachine being supplied with outside air by an air inlet, said turbomachine comprising a compressor, disposed upstream of the rotor and the fan blades, with at least two stages, and generating heating of a lubricant during operation thereof, the fluid cooling device comprising:

• a pressurized air intake;
• a volumetric/surface cooler which cools the lubricant;
• an air vein which conveys pressurized air to the cooler;
• a regulator valve which regulates a flow of pressurized air into the air vein;
• and
• a controller configured to control the regulator valve,
• wherein the cooler includes
• a matrix body provided with a plurality of ducts for a cooling agent, said ducts extending along a first inner surface of the matrix body up to a second outer surface of the matrix body, and
• a set of fins extending from the outer surface of the matrix body towards an outside of the propulsion unit, and oriented mainly parallel to a direction of airflow when the aircraft is in flight,
• wherein the cooler is disposed downstream of the air inlet, and disposed upstream of the fan blades such that the set of fins is disposed upstream of the fan blades, and
• wherein the controller is configured to set the regulator valve in an open position when a speed of the aircraft is below a first predetermined value such that the pressurized air flowing into the air vein passes through the ducts of the matrix body, and the controller is configured to set the regulator valve in a closed position when the speed of the aircraft is above a second predetermined value and an outside temperature is below a predetermined temperature.