Blade with non-axisymmetric platform

A blade for a turbomachine impeller, comprising:

• an airfoil including a pressure surface, a suction surface, a trailing edge, a leading edge;
• and
• a platform extending at one of ends of the airfoil in a direction that is globally perpendicular to a longitudinal direction of the airfoil;
• wherein
• the blade is configured to be arranged with a plurality of substantially identical blades to form a ring around a ring axis and define therealong upstream and downstream directions, with the ring having the airfoils arranged substantially radially therein;
• adjacent portions of platform surfaces of two adjacent blades located between their respective airfoils define an inter-airfoil surface;
• a suction surface profile is projected on the platform surface at a constant distance from the suction surface;
• a pressure surface profile along the pressure surface is projected on the platform surface at a constant distance from the pressure surface;
• the pressure surface profile includes a pressure surface recessed part, at least 90% of said pressure surface recessed part being contained within a downstream half of the airfoil and at most 10% of said pressure surface recessed part lying in an upstream half of the airfoil;
• most of the inter-airfoil surface is a surface with a shape corresponding to a motion from upstream to downstream of a line segment in a direction parallel to the ring axis, the line segment having a first end point on the suction surface profile and a second end point on the pressure surface profile, and presenting an angle relative to the ring axis;
• and
• the angle is between 60 and 120 degrees.