TECHNICAL FIELD

The present disclosure relates to the field of turbomachines, and in particular to dual-flow turbomachines in which air flows from upstream to downstream. It relates more precisely, but not exclusively, to a turbomachine stator element comprising stator vanes.

BACKGROUND

It is known from the double flow turbomachines comprising a mobile fan arranged upstream of a gas generator according to the flow of gases in the turbomachine. The gas generator is housed in an annular inner casing while the fan is housed in an annular outer casing. These inner and outer casings are separated by an annular inter-duct casing, so as to delimit a primary duct and a secondary duct. The fan comprises fan vanes with the free end facing the outer casing, so as to compress an incident air stream at least in the secondary duct, and preferably also in the primary duct. The turbomachine is called as a ducted fan turbomachine. The air flow circulating in the primary duct is conventionally compressed by compressor stages of the turbomachine before entering the combustion chamber. The combustion energy is recovered by turbine stages which participate in driving the compressor stages and the fan. The air flow circulating in the secondary duct contributes to the thrust of the turbomachine.

Classically, the secondary duct comprises stator vanes downstream of the fan, known as rectifiers or outlet guide vanes (OGV). These stator vanes are arranged radially from the outer surface of the inter-duct casing, downstream of the fan vanes, and help to straighten the flow generated and deflected by the fan as it rotates. Flow straightening allows the static pressure to increase by reducing the flow velocity in the fixed mark, but is accompanied by a total pressure loss. The stator vanes are designed to minimize these losses, which degrade their behaviour. However, there are also friction losses and losses caused by flow vortex. The flow vortex is generated due to the presence of a wall at the root of each vane. These flow vortices take on a roughly horseshoe shape and are distributed on the pressure side and suction side of the vanes. At its entry into a passage formed between two adjacent vanes, the flow vortex migrates from the pressure side of one vane to the suction side of the adjacent vane. When the vortex hits the suction side of the vane, it can give rise to an aerodynamic separation.

A solution to reduce the presence of this vortex between two adjacent vanes is to place several fins between the vanes. An example of fins is described in document WO 2015/092306 where they are arranged between compressor vanes. However, this is a simple modeling using aerodynamic calculations and does not integrate the constraints of manufacturing and location of the fins between the vanes.

The disclosed subject matter is intended to remedy these drawbacks, by proposing a stator element of a turbomachine in which secondary flows (corner vortex, flow vortex) are reduced, so as to guarantee the aerodynamic performance of the turbomachine.

SUMMARY

The present disclosure thus has as its subject a turbomachine stator element extending around a longitudinal axis, the element comprising at least one first stator vane and at least and one second stator vane circumferentially adjacent to the first stator vane, each first and second stator vanes comprising a platform and a blade extending radially from the platform, the stator element also comprising at least one inter-platform seal arranged between the platform of the first stator vane and the platform of the second stator vane.

In the assembly according to the disclosure, the inter-platform seal comprises a flat support provided with an upper surface on which a fin extends.

Thus, by integrating the fin into the inter-platform seal, a single part is formed, which makes it possible to overcome the problems of interface and mechanical strength between the fin and the inter-platform seal. The fin is used to guide the flows and prevent the current lines from going up on the suction side of the stator vanes.

The platform and the blade are monobloc.

The first and second stator vanes are preferably identical.

The fin is advantageously elongated in a direction roughly parallel to the longitudinal axis.

The fin can have the same curvature as the stator vane, whose suction side is located on the side of the fin.

The support of the inter-platform seal may comprise two adjacent longitudinal parts, each part conforming to the contour of one half of a platform of an adjacent vane.

The leading edge of the fin may be located longitudinally at a position between 0% and 25% of the chord connecting the leading edge of a stator vane to the trailing edge of the vane.

The length of the chord of the fin can be between 75% and 100% of the length of the chord of a stator vane.

The maximum thickness of the fin can be between 0.5 and 0.7 times the maximum thickness of a stator vane.

The distance between the fin and a vane adjacent to the fin can be between 30% and 70% of the distance between the two adjacent vanes.

The fin may comprise in cross section a top with a rounded shape.

The connecting zone between the trailing edge and/or the leading edge of the fin and the top can be of curved longitudinal section.

The connecting zone between the lower part of the fin and the upper surface of the flat support of the seal may have a curved cross section.

The radial height of the fin may be between 3% and 5% of the maximum radial height of a secondary annular duct in a turbomachine in which the stator vanes are arranged.

The stator element of the turbomachine according to the present disclosure may comprise one or more of the following characteristics, taken in isolation or in comparison with each other:the flat support has a length greater than that of the platform of the stator vane;each longitudinal part of the support comprises a longitudinal portion and two transverse portions;the fin is carried by at least part of a longitudinal portion of each longitudinal part of the support;each longitudinal portion of the support wraps around one longitudinal edge of the platform and each transverse portion wraps around one half of a transverse edge of said platform;the leading edge of the fin is disposed on a first longitudinal part of the support which is arranged on the suction side of the vane, the trailing edge of the fin is disposed on a second longitudinal part of the support and remote from said first longitudinal part;the connecting zone between the leading edge and its top has a smaller radius of curvature than the connecting zone between the trailing edge and its top;the inter-platform seal comprises fasteners arranged on a radial extension of the longitudinal part of the support.

The disclosure also relates to a turbomachine comprising at least one stator element.

