Air turbine starter with shaped vanes
An air turbine starter comprising a housing defining an inlet, an outlet, and a flow path, a turbine having a rotor with circumferentially spaced blades extending into the flow path, a drive shaft operably coupled to and rotating with the rotor, and at least one vane located within the flow path, upstream of the blades. The at least one blade being defined by an acute axial angle and an acute tangential angle.
1. An air turbine starter, comprising:
a housing defining an inlet, an outlet, and a flow path extending between the inlet and the outlet;
a turbine having a rotor with circumferentially spaced blades located within the housing, at least a portion of the circumferentially spaced blades extend into the flow path and rotate in a rotational direction in response to a fluid flowing along the flow path from the inlet to the outlet;
a drive shaft operably coupled to and rotating with the rotor to define a rotational axis; and
set of vanes located within the flow path, upstream of the circumferentially spaced blades, the set of vanes being circumferentially spaced about the rotational axis, with each vane of the set of vanes having an outer wall defining a pressure side and a suction side extending between a leading edge and a trailing edge to define a chord-wise direction, and between a root and a tip to define a span-wise direction;
wherein each vane of the set of vanes is shaped such that a line, extending between the root and the tip at the same percent of the vane in the chord-wise direction, forms an acute axial angle relative to a ray extending perpendicularly from the rotational axis and intersecting the line when viewed in a plane including the line and the rotational axis, and
an acute tangential angle is formed between the line and the ray extending perpendicularly from the rotational axis when viewed in a plane that is normal to the rotational axis; and
wherein the set of vanes includes a first vane and a second vane, with the acute tangential angle of the first vane being non-zero and the acute tangential angle of the second vane being zero.
2. The air turbine starter of claim 1 , wherein the acute axial angle is between 3 and 5 degrees.
3. The air turbine starter of claim 1 , wherein the acute tangential angle is between −1.5 and −5.0 degrees or 1.5 and 5.0 degrees.
4. The air turbine starter of claim 1 , wherein the acute axial angle where the root intersects the trailing edge is 3 degrees.
5. The air turbine starter of claim 4 , wherein the acute axial angle where the root intersects the leading edge is non-equal to the acute axial angle where the root intersects the trailing edge.
6. The air turbine starter of claim 1 , wherein the acute axial angle is non-constant in the span-wise direction or chord-wise direction.
7. The air turbine starter of claim 1 , wherein the acute tangential angle is non-constant in the span-wise direction or chord-wise direction.
8. The air turbine starter of claim 1 , wherein an upstream point along the tip at the leading edge defines a farthest upstream portion of each vane of the set of vanes, and a downstream point along the root at the trailing edge defines a farthest downstream portion of each vane of the set of vanes.
9. The air turbine starter of claim 8 , wherein the flow path comprises:
an inner periphery; and
an outer periphery located radially outwardly from the inner periphery with respect to the rotational axis;
wherein at least a portion of the flow path that is axially between the upstream point and the downstream point of each vane of the set of vanes defines a curved flow path such that the inner periphery or the outer periphery extends at an acute angle with respect to the rotational axis.
10. The air turbine starter of claim 9 , wherein the inner periphery within the curved flow path is defined by a first local tangent line along any portion of the inner periphery, and the outer periphery within the curved flow path is defined by a second local tangent line along any portion of the outer periphery.
11. The air turbine starter of claim 10 , wherein a first angle is formed between the first local tangent line and the rotational axis, and a second angle is formed between the second local tangent line and the rotational axis, wherein the first angle is between 0 and 25 degrees, and the second angle is between 0 and 15 degrees.
12. The air turbine starter of claim 10 , wherein at least one of the first local tangent line or the second local tangent line is non-constant between the upstream point and the downstream point of each vane of the set of vanes.
13. The air turbine starter of claim 1 , wherein the set of vanes includes a first group of vanes including the first vane and a second group of vanes including the second vane, with the acute tangential angle of each vane of the first group of vanes being non-zero, and the acute tangential angle of each vane of the second group of vanes being zero.
14. The air turbine starter of claim 13 , wherein the first group of vanes and the second group of vanes are non-alternately spaced about the rotational axis.
15. The air turbine starter of claim 14 , wherein the first group of vanes is located within a first half of the set of vanes, and the second group of vanes is located within second half of the set of vanes, with the first half being opposite the second half.
16. The air turbine starter of claim 1 , wherein the set of vanes includes a first group of vanes and a second group of vanes, wherein the first group of vanes includes at least two vanes adjacent to and spaced a first distance from each other, and the second group of vanes includes at least two vanes adjacent to and spaced a second distance from each other, with the first group of vanes and the second group of vanes being spaced a third distance from each other.
17. The air turbine starter of claim 16 , wherein the first distance and the second distance are each smaller than the third distance.
18. At least two vanes including a first vane and a second vane located within a flow path of an air turbine starter that includes a drive shaft defining a rotational axis, each vane of the at least two vanes comprising:
an outer wall defining a pressure side and a suction side extending between a leading edge and a trailing edge to define a chord-wise direction, and between a root and a tip to define a span-wise direction;
wherein the first vane and the second vane shaped such that a line, intersecting the root and the tip at the same percent of each vane in the chord-wise direction, forms an acute axial angle relative to a ray extending perpendicularly from the rotational axis and intersecting the line when viewed in a plane including the line and the rotational axis, and
an acute tangential angle is formed between the line and the ray extending perpendicularly from the rotational axis when viewed in a plane that is normal to the rotational axis; and
wherein the acute tangential angle of the first vane is non-zero and the acute tangential angle of the second vane is zero.
19. The at least two vanes of claim 18 , wherein the acute axial angle is between 3 and 5 degrees.
20. The at least two vanes of claim 18 , wherein the acute tangential angle is between −1.5 and −5.0 degrees or 1.5 and 5.0 degrees.