Turbomachine blade having a maximum thickness law with high flutter margin
A turbomachine rotor blade is formed of plural blade sections stacked along an axis extending from a blade root to a blade tip. Each blade section located at various heights along the blade is designed to have a given ratio between a maximum thickness, which is measured between a suction side and pressure side of the blade, and a chord, which is defined by a line connecting a leading edge and a trailing edge of the blade. Each blade section is further designed to have a ratio of the maximum thickness to the chord at a given height of the blade relative to a ratio of the maximum thickness to the chord of another blade section located at a different height of the blade.
1. A turbomachine rotor blade comprising
a plurality of sections stacked along an axis Z between a blade root and a blade tip, each section including:
a leading edge,
a trailing edge,
a pressure side, and
a suction side,
each section having:
a height extending from 0% corresponding to the blade root and 100% corresponding to the blade tip,
a chord defined by a length of a portion of a line connecting the leading edge and the trailing edge,
a maximum thickness defined by a maximum distance between the suction side and the pressure side, and
a ratio of the maximum thickness to the chord for each of the plurality of sections,
wherein:
the ratio of a section at 30% of the height of the blade is between 20% and 42% of the ratio of a section at the blade root,
the ratio of a section at 70% of the height of the blade is between 10% and 30% of the ratio of the section at the blade root,
the ratio of a section at 90% of the height of the blade is between 10% and 30% of the ratio of the section at the blade root, and
the ratio of a section at the blade tip is comprised between 3% and 21% of the ratio of the section at the blade root,
wherein the ratio of each section depending on the height of the section is defined by a curve comprising a plurality of linear segments, the ratio defined by the plurality of linear segments decreasing as the height of a given section increases or remaining constant as the height of a given section increases, and
wherein the plurality of line segments of the curve comprises a first line segment extending from the blade to root of 30% of the height of the blade, a second line segment extending from 30% to 70% of the height of the blade, a third line segment extending from 70% to 90% of the height of the blade, and a fourth line segment extending from 90% of the height of the blade to the blade tip.
2. The turbomachine rotor blade according to claim 1 , wherein
the ratio of each section depending on the height of the section is further defined by:
a first curve comprising a plurality of line segments, wherein:
a first line segment defined by a minimum ratio of the section at the blade root equal to 12% and a minimum ratio of the section at 30% of the height of the blade equal to 3%,
a second line segment defined by the minimum ratio of the section at 30% of the height of the blade and a minimum ratio of the section at 70% of the height of the blade equal to 1.5%,
a third line segment defined by the minimum ratio of the section at 70% of the height of the blade and a minimum ratio of the section at 90% of the height of the blade equal to 1.5%, and
a fourth line segment defined by the minimum ratio of the section at 90% of the height of the blade, and a minimum ratio of the section at the blade tip equal to 0.5%, and
a second curve comprising a plurality of line segments, wherein:
a fifth line segment defined by a maximum ratio of the section at the blade root equal to 14%, and a maximum ratio of the section at 30% of the height of the blade equal to 5%,
a sixth line segment defined by the maximum ratio of the section at 30% of the height of the blade, and a maximum ratio of the section at 70% of the height of the blade equal to 3.5%,
a seventh line segment defined by the maximum ratio of the section at 70% of the height of the blade, and a maximum ratio of the section at 90% of the height of the blade equal to 3.5%, and
an eighth line segment defined by the maximum ratio of the section at 90% of the height of the blade, and a maximum ratio of the section at the blade tip equal to 2.5%.
3. The turbomachine rotor blade according to claim 1 , wherein the ratio of the section at 30% of the height of the blade is between 26% and 36% of the ratio of the section at the blade root.
4. The turbomachine rotor blade according to claim 1 , wherein the ratio of the section at 70% of the height of the blade is between 14% and 24% of the ratio of the section at the blade root.
5. The turbomachine rotor blade according to claim 1 , wherein the ratio of the section at 90% of the height of the blade is between 14% and 24% of the ratio of the section at the blade root.
6. The turbomachine rotor blade according to claim 1 , wherein the ratio of the section at the blade tip is between 6.5% and 16.5% of the ratio of the section at the blade root.
7. The turbomachine rotor blade according to claim 1 , wherein the ratio of the section at the blade root is between 8% and 18%.
8. A turbomachine fan including a plurality of turbomachine rotor blades according to claim 1 radially extending from a rotor and arranged about an axis of rotation of the rotor.
9. A turbomachine comprising the turbomachine fan according to claim 8 .