In a centrifugal fluid machine, the secondary flow loss inside an impeller is reduced and the occurrence, when the flow rate decreases, of a flow separation/stall on the shroud-side suction surface near the leading edge of each impeller blade is suppressed, thereby making it possible to maintain the
In a centrifugal fluid machine, the secondary flow loss inside an impeller is reduced and the occurrence, when the flow rate decreases, of a flow separation/stall on the shroud-side suction surface near the leading edge of each impeller blade is suppressed, thereby making it possible to maintain the operating range of the impeller. For this, at the trailing edge of each impeller blade, the trailing edge of each impeller blade is inclined so that the shroud side of the impeller blade is positioned more backward in the rotation direction than the hub side thereof as the impeller is seen from the suction direction upstream of the rotary shaft of the impeller. Also, out of two adjacent impeller blades, the shroud side of one impeller blade trailing the other impeller blade in the impeller rotation direction overlaps with the other impeller blade at around the leading edge of the one impeller blade.
대표청구항▼
1. A centrifugal fluid machine having a centrifugal impeller which includes a plurality of impeller blades each having a leading edge, a trailing edge, a shroud side, and a hub side, wherein, when the impeller is seen from a suction direction upstream of a rotary shaft of the impeller which rotates
1. A centrifugal fluid machine having a centrifugal impeller which includes a plurality of impeller blades each having a leading edge, a trailing edge, a shroud side, and a hub side, wherein, when the impeller is seen from a suction direction upstream of a rotary shaft of the impeller which rotates in a rotation direction to produce flow downstream from the leading edge to the trailing edge of each impeller blade, the trailing edge of each impeller blade is inclined so that the shroud side of the impeller blade is positioned more backward in the rotation direction than the hub side thereof and wherein, out of two adjacent impeller blades, the shroud side of one impeller blade trailing the other impeller blade in the impeller rotation direction overlaps with the other impeller blade at a region of the one impeller blade adjacent to the leading edge of the one impeller blade, wherein the impeller is seen from the suction direction upstream in a direction along an axis of the rotary shaft of the impeller; and having the centrifugal impeller in which a shroud diameter at leading edges of impeller blades is larger than a hub diameter at the leading edges of the impeller blades and in which, when the impeller is seen from the suction direction upstream in the direction along the axis of the rotary shaft of the impeller, the shroud side at the leading edge of each impeller blade is, with respect to a line radially extending from a rotation center of the impeller, aligned with or ahead of the hub side at the leading edge of the each impeller blade in the rotation direction. 2. The centrifugal fluid machine according to claim 1, having the impeller in which a rake angle defined to be positive in a direction of impeller rotation reaches a maximum value between the leading edge of each impeller blade and a middle point of the impeller blade in a flow direction and, after reaching the maximum value, decreases on a downstream side to be in a range of −5° to −35° at an impeller outlet, the rake angle being an angle formed between a meridian plane which crosses the rotation center of the impeller to be parallel to the rotary shaft of the impeller and a line which connects a point between a leading edge and a trailing edge of the hub on the meridian plane and a point between a leading edge and a trailing edge of the shroud on the meridian plane, the two points accounting for a same ratio in terms of their positions between the leading edge and the trailing edge of the hub and between the leading edge and the trailing edge of the shroud, respectively. 3. The centrifugal fluid machine according to claim 1, wherein the shroud side of the one impeller blade overlaps with the other impeller blade at the region of the one impeller blade adjacent to the leading edge of the one impeller blade, the region including a shroud side of the leading edge of the one impeller blade. 4. The centrifugal fluid machine according to claim 1, wherein the shroud side of the one impeller blade overlaps with the other impeller blade at the region of the one impeller blade adjacent to the leading edge of the one impeller blade, the region including a portion of the leading edge adjacent to a shroud side of the leading edge of the one impeller blade. 5. The centrifugal fluid machine according to claim 1, wherein the shroud side of the one impeller blade overlaps with the other impeller blade at the region of the one impeller blade adjacent to the leading edge of the one impeller blade, the region including a portion of the shroud side of the one impeller blade adjacent to the leading edge of the one impeller blade. 6. A centrifugal fluid machine having a centrifugal impeller in which a shroud diameter at leading edges of impeller blades is larger than a hub diameter at the leading edges of the impeller blades, in which, when the impeller is seen from a suction direction upstream of a rotary shaft of the impeller which rotates in a rotation direction to produce flow downstream from a leading edge to a trailing edge of each impeller blade, the trailing edge of each impeller blade is inclined so that a shroud side of the impeller blade is positioned more backward in the rotation direction than a hub side thereof, and in which the shroud side at the leading edge of the each impeller blade is, with respect to a line radially extending from a rotation center of the impeller, aligned with or ahead of the hub side at the leading edge of the each impeller blade in the rotation direction, wherein the impeller is seen from the suction direction upstream in a direction along an axis of the rotary shaft of the impeller. 7. The centrifugal fluid machine according to claim 6, having the impeller in which a rake angle defined to be positive in a direction of impeller rotation reaches a maximum value between the leading edge of each impeller blade and a middle point of the impeller blade in a flow direction and, after reaching the maximum value, decreases on a downstream side to be in a range of −5° to −35° at an impeller outlet, the rake angle being an angle formed between a meridian plane which crosses the rotation center of the impeller to be parallel to the rotary shaft of the impeller and a line which connects a point between a leading edge and a trailing edge of the hub on the meridian plane and a point between a leading edge and a trailing edge of the shroud on the meridian plane, the two points accounting for a same ratio in terms of their positions between the leading edge and the trailing edge of the hub and between the leading edge and the trailing edge of the shroud, respectively. 8. The centrifugal fluid machine according to claim 6, wherein, out of two adjacent impeller blades, the shroud side of one impeller blade trailing the other impeller blade in the impeller rotation direction overlaps with the other impeller blade at a region of the one impeller blade adjacent to the leading edge of the one impeller blade, wherein the impeller is seen from the suction direction upstream in the direction along the axis of the rotary shaft of the impeller. 9. A centrifugal fluid machine having an impeller in which, when the impeller is seen from a suction direction upstream of a rotary shaft of the impeller which rotates in a rotation direction to produce flow downstream from the leading edge to the trailing edge of each impeller blade, a trailing edge of each impeller blade is inclined so that a shroud side of the impeller blade is positioned more backward in the rotation direction than a hub side thereof and in which an incidence angle to the impeller is 0° or less, wherein the incidence angle is a blade inlet angle of the impeller blade minus an inlet relative flow angle at a specified point, wherein the impeller is seen from the suction direction upstream in a direction along an axis of the rotary shaft of the impeller; and wherein, out of two adjacent impeller blades, the shroud side of one impeller blade trailing the other impeller blade in the impeller rotation direction overlaps with the other impeller blade at a region of the one impeller blade adjacent to the leading edge of the one impeller blade, wherein the impeller is seen from the suction direction upstream in the direction along the axis of the rotary shaft of the impeller. 10. The centrifugal fluid machine according to claim 9, having the impeller in which a shroud diameter at leading edges of impeller blades is larger than a hub diameter at the leading edges of the impeller blades and in which, when the impeller is seen from the suction direction upstream in a direction along the axis of the rotary shaft of the impeller, the shroud side at the leading edge of each impeller blade is, with respect to a line radially extending from a rotation center of the impeller, aligned with or ahead of the hub side at the leading edge of the each impeller blade in the rotation direction. 11. The centrifugal fluid machine according to claim 10, having the impeller in which a rake angle defined to be positive in a direction of impeller rotation reaches a maximum value between the leading edge of each impeller blade and a middle point of the impeller blade in a flow direction and, after reaching the maximum value, decreases on a downstream side to be in a range of −5° to −35° at an impeller outlet, the rake angle being an angle formed between a meridian plane which crosses the rotation center of the impeller to be parallel to the rotary shaft of the impeller and a line which connects a point between a leading edge and a trailing edge of the hub on the meridian plane and a point between a leading edge and a trailing edge of the shroud on the meridian plane, the two points accounting for a same ratio in terms of their positions between the leading edge and the trailing edge of the hub and between the leading edge and the trailing edge of the shroud, respectively.
※ AI-Helper는 부적절한 답변을 할 수 있습니다.