Method and device for estimating a dead zone of a turbomachine discharge valve

A device for estimating a closing dead zone of a first gate of a first discharge valve mounted on a first casing of a turbomachine to be investigated which can operate in flight to propel an aircraft, the first casing delimiting in its inside a first primary gas flow of the turbomachine, the first gate being designed to be able to be moved angularly by a first actuator depending on a first control signal of the first actuator between one and the other of:

• a first opening position of a first orifice of the first casing configured to discharge through this first orifice a portion of the first primary gas flow into a first secondary gas flow located outside the first casing,
• and a first closing position of the first orifice configured to prevent the first primary gas flow from passing through the first orifice,
• the first gate being provided with a first gas seal gasket, able to be compressed against a first edge of the first orifice in the first closing position to seal closing of the first orifice,
• wherein device comprises
• a first position sensor for measuring, for the turbomachine to be investigated operating in flight, a first actual position of the first actuator when the first control signal is equal to a first set point closing signal of the first gate,
• a calculator configured to at least:
• determine, based on the first actual position, a measured droop angle of the first gate with respect to the first casing, and
• determine, for the turbomachine to be investigated operating in flight, a measured closing dead zone of the first gate, in which the first gas seal gasket remains compressed and thus seals closing of the first orifice, by the fact that the measured closing dead zone is equal to a reference dead zone, which was predetermined during operation on the ground on a reference turbomachine which can operate in flight and on the ground, to which has been added the measured droop angle and from which has been subtracted a reference droop angle which was predetermined on the reference turbomachine operating in flight for propelling an aircraft.