Drained fluid evacuation stub for a propulsion assembly
View Patent ↗Stub for discharging drained fluids for a propulsion unit. The stub includes a cavity for storing the drained fluids and at least one orifice for discharging the fluids contained in the storage cavity, and elements for measuring a difference in pressure outside the stub and a member for draining the storage cavity. The member is able to move between a first position of closing the discharge orifice and a second position of releasing the orifice, and is configured so as to move from the first to the second position when the difference in pressure is greater than, or equal to, a predetermined value.
1. A stub for a propulsion unit, the stub configured for discharging drained fluids, said stub comprising a storage cavity for storing the drained fluids and at least one discharge orifice for discharging the drained fluids contained in the storage cavity, wherein the stub comprises elements for measuring a difference in pressure outside the stub and a member for draining the storage cavity, the member being able to move between a first position for closing the at least one discharge orifice and a second position for opening the at least one discharge orifice, the member being configured so as to move from the first to the second position when said difference in pressure is greater than, or equal to, a predetermined value; wherein the elements for measuring the difference in pressure outside the stub comprises a first orifice and a second orifice provided on an external surface of the stub.
2. The stub according to claim 1 , wherein the first orifice is configured for measuring the total pressure outside the stub and the second orifice is configured for measuring the static or pseudo-static pressure outside the stub.
3. The stub according to claim 2 , wherein the member is able to reciprocate in a recess in the stub and comprises or carries a transverse element separating two chambers inside the recess, a first chamber being fluidly connected to the first orifice and a second chamber being fluidly connected to the second orifice.
4. The stub according to claim 3 , wherein the first orifice is fluidly connected to the first chamber by a duct comprising two parts, one of which is inclined or perpendicular with respect to the other.
5. The stub according to claim 1 , wherein the stub has an aerodynamic profile.
6. The stub according to claim 5 , wherein the first orifice is configured for measuring the total pressure outside the stub and the second orifice is configured for measuring the static or pseudo-static pressure outside the stub, and the first orifice is situated on a leading edge of the profile and the second orifice is situated on a side of the profile.
7. The stub according to claim 6 , wherein the second orifice is situated in a region of the profile where a pressure coefficient Cp has a substantially maximum value.
8. The stub according to claim 1 , wherein the stub has a substantially radial orientation with respect to the longitudinal axis of the propulsion unit and at least partly projects on an external surface of a nacelle of the propulsion unit, the first orifice and the second orifice being situated in the vicinity of the radially external end of the stub.
9. A method for designing the stub according to claim 1 , wherein the method comprises the steps: —determining an aerodynamic profile of the stub, —positioning the first orifice on a leading edge of the profile, —determining by calculation the distribution of the pressure coefficient Cp along the profile and deducing therefrom a region of the profile where said pressure coefficient Cp has a substantially maximum value, and —positioning the second orifice in said region.
10. The stub according to claim 5 , wherein the aerodynamic profile is a NACA profile of the biconvex symmetrical type.
11. The method according to claim 9 , wherein the aerodynamic profile is a NACA profile of the biconvex symmetrical type.