| 摘要 |
The present invention relates to a speed measurement system allowing the relative speed V of a moving body in relation to an ambient air mass to be measured independently of the atmospheric conditions, the moving body being designed to move at least at subsonic and transonic speeds. The speed measurement system comprises:
a fin of elongate shape positioned in the ambient air mass and the profile of which comprises a portion A and a portion B, at least one heating means, at least one dynamic-pressure tap PB situated in the portion B, an angle BETA defined between the axis OX and intrados or extrados of the portion A of the fin;at least one static-pressure tap PSat least one means of measuring and/or calculating the angle of attack and possibly at least one means of measuring and/or calculating the sideslip angle,at least one calculation means configured to determine the speed V of the moving body with respect to the ambient air mass (7) from the static pressure PS and dynamic pressure PB values and possibly from the value of the angle of attack ALPHA of the fin and/or the sideslip angle GAMMA, and do so in an injective, univocal manner throughout the subsonic and transonic domain. |
| 主权项 |
1. A speed measurement system measuring the relative velocity V of a mobile body relative to an ambient air mass regardless of weather conditions, the mobile body being adapted to move at least at subsonic and transonic speeds, the said speed measurement system comprising:
an elongated fin disposed in the ambient air mass, having a profile defined by a spanwise axis ZZ′ and a set of points having the coordinates X and Y forming the fin profile for each point of spanwise axis ZZ′, one axis OX of X values defined sensibly pursuant to the longitudinal axis of the fin profile and an axis OY of Y values being perpendicular to the axis OX of X values comprising:
a portion A and a portion B, said portion A having a thickness increasing in the direction of B and forming the leading edge of the fin, said portion B having a decreasing thickness and being located at the rear of portion A relative to the fin moving direction in the mass of air and forming the back of the fin,at least one heating means defined to avoid any risk of icing,at least one dynamic pressure tap PB located in the B portion, comprising at least one orifice having its opening facing in the opposite direction of the displacement direction of the fin in the mass of air.an angle BETA defined between the axis OX and the intrados or the extrados of the A portion of the fin, at least one static pressure tap PS placed on the fuselage or on the base of the fin, at least one means for measuring and/or calculating the angle of attack ALPHA of the fin and optionally at least one means for measuring and/or calculating the sideslip angle GAMMA of the aircraft, at least a calculating means configured to determine the speed V of the mobile body relative to the mass of ambient air from the values of static pressure PS and dynamic pressure PB and possibly the angle of attack ALPHA of the fin and/or the sideslip angle GAMMA. wherein,
The fin is relatively thin and has a wedge shape at least in its front part (portion A), the leading edge of the wedge is a sharp angle of radius less than or equal to 2 mm;The fin has at least partially a tapered and truncated shape comprising at least one sharp edge of radius less than at least 2 mm between the portion A of the portion B so that in transonic speed the wave shock created at the said sharp angle is stabilized and/or the path of field lines is modified at the aft of the fin;The portion B, forming the aft part of the fin, comprises at least a zone having a circular shape convex or concave B1 and/or B2 to filter particles so that the particles of greater density than the density of the air, trapped in the fluid flow to the aft of the fin, are ejected and/or spread out under the effect of centrifugal forces to the area near the pressure tap PB said B1 and/or B2 zone allowing to channel and/or to stabilize the path of the airflow to the aft of the fin, said fluid flow having a roll-shaped and/or a vortex axis substantially parallel to the axis ZZ′;The fin comprises at least one rib disposed substantially perpendicular to the span axis ZZ′ of the fin and extending at least in the portion B of the fin, said rib being adapted to the channel airflow in a region close to the dynamic pressure tap PB located at the aft of the fin;The function F (V)=(PS−PB)/PS enabling to deduct the relative speed V of a mobile structure with respect to a mass of ambient air regardless of weather conditions, is a univocal function in the direction of (PS−PB)/PS to V, strictly increasing as a function of the speed V, preferably as a function of the Mach number, this in the entire subsonic and transonic domain for each value of the angle of attack ALPHA and/or optionally the sideslip angle GAMMA. |
