Patent Application
20220049717
The disclosure herein relates generally to an example mixed-flow compressor, and more particularly, to a diffuser structure for use in a mixed-flow compressor of a refrigeration system.
Existing mixed-flow compressors typically include a power driven impeller through which an inflow of refrigerant is induced that is turned radially outward and then back to axial flow into a diffuser. A diffuser of the compressor commonly includes an annular passage defined by a wall surface of a fixed plate radially spaced from a shaped wall surface of a shroud, and a set of vanes. The diffuser has an inlet end receiving the impeller outflow and an outlet end from which refrigerant is provided to a compressor volute that is circumferentially divergent for example. Kinetic energy is converted by the diffuser of the compressor into a static pressure rise within the diffuser.
In one exemplary embodiment, a compressor includes a housing. An impeller is located within the housing and rotatable about an impeller axis in a first rotational direction. A rotor section is rotatable about the impeller axis in a second rotational direction opposite the first rotational direction.
In a further embodiment of the above, the rotor section includes a rotor that has at least one row of rotor blades.
In a further embodiment of any of the above, the impeller includes a hub and a plurality of impeller blades that extend outward from the hub toward a portion of the housing.
In a further embodiment of any of the above, the rotor section includes a cylindrical rotor with a plurality of rotor blades that extend from a surface of the cylindrical rotor.
In a further embodiment of any of the above, the plurality of impeller blades each include an upstream end and downstream end with the upstream end being circumferentially spaced in the first rotational direction from the downstream end. The plurality of rotor blades each include an upstream end and a downstream end with the upstream end being circumferentially spaced in the second rotational direction from the downstream end.
In a further embodiment of any of the above, each of the plurality of rotor blades and each of the plurality of impeller blades include a curvature in the first circumferential direction.
In a further embodiment of any of the above, the impeller is driven by an impeller motor and the rotor is driven by a separate rotor motor.
In a further embodiment of any of the above, the impeller is driven by an impeller motor and the rotor section is driven by the impeller motor through a transmission to reverse a rotational output of the impeller motor.
In a further embodiment of any of the above, the transmission is a variable ratio transmission.
In a further embodiment of any of the above, an outlet of the impeller is immediately upstream of an inlet to the rotor section.
In a further embodiment of any of the above, the compressor is a mixed flow compressor.
In a further embodiment of any of the above, the compressor is operable with a low pressure refrigerant or a medium pressure refrigerant.
In another exemplary embodiment, a method of operating a compressor includes the steps of rotating an impeller in a first rotational direction with an impeller motor to draw refrigerant into an inlet of the compressor. A rotor section is rotated downstream of the impeller in a second rotational direction opposite the first rotational direction. The refrigerant is directed from the rotor section to a compressor outlet.
In a further embodiment of any of the above, the method includes turning a direction of the refrigerant in an axial direction with the rotor section.
In a further embodiment of any of the above, the method includes driving the impeller with an impeller motor and driving the rotor section with a rotor section motor.
In a further embodiment of any of the above, the method includes driving the impeller with an impeller motor and driving the rotor section with the impeller motor through a transmission.
In a further embodiment of any of the above, the method includes varying a magnitude or rotation from an output of the impeller motor with the transmission.
In a further embodiment of any of the above, the method includes reversing a direction of rotation of an output of the impeller motor with the transmission.
In a further embodiment of any of the above, the compressor is a mixed flow compressor.
In a further embodiment of any of the above, the compressor is operable with a low pressure refrigerant or a medium pressure refrigerant.
Mixed-flow compressors are used in a number of applications, such as in a refrigeration system to move a refrigerant through a refrigeration circuit.
In the illustrated example shown in
The compressor 20 also includes a motor section 40 for driving the impeller 26 and/or the rotor 32 in the rotor section 30. In the illustrated example, the motor section 40 includes a stator 42 attached to a portion of the housing 22 that surrounds a rotor 44 attached to an impeller drive shaft 46. The impeller drive shaft 46 is configured to rotate about an axis X. The axis X of rotation is common with the impeller 26, the rotor section 30, the rotor 44, and the impeller drive shaft 46 and is common with a central longitudinal axis extending through the housing 22. In this disclosure, axial or axially and radial or radially is in relation to the axis X unless stated otherwise.
In one example, the rotor 32 in the rotor section 30 is driven by the motor section 40 through a transmission 50 in engagement with the drive shaft 46. The transmission 50 receives an input driving force from the drive shaft 46 rotating in a first rotational direction and reversed the input from the drive shaft 46 to create an output that rotates the rotor 32 in a second rotational direction opposite from the first rotational direction. Furthermore, the transmission 50 can be a variable ratio transmission such that a magnitude of the rotation in the first rotational direction can be increased or decreased in relation to a magnitude of the rotation in the second rotational direction. Alternatively, the rotor 32 in the rotor section 30 could be driven by a rotor drive motor 52 in engagement with the rotor 32. The engagement of the rotor drive motor 52 with the rotor 32 is schematically illustrated in
As shown in
A plurality of passages 66 is defined between adjacent blades 60 to discharge a fluid passing over the impeller 26 generally parallel to the axis X. As the impeller 26 rotates, fluid approaches the front side 56 of the impeller 26 in a substantially axial direction and flows through the passages 66 defined between adjacent blades 60. Because the passages 66 have both an axial and radial component, the axial flow provided to the front side 56 of the impeller 26 simultaneously moves both parallel to and circumferentially about the axis X of the drive shaft 46. In combination, an inner surface 68 (shown in
The rotor 32 forms fluid passages 90 between adjacent blades in the first and second rows of blades 70, 72 in cooperation with the body portion 74 and an inner surface 88 of the housing 22. The inner surface 88 is located axially downstream from the inner surface 68. The inner surface 88 extends in an axial direction with a generally constant radial dimension such that the fluid passage 90 also extends in an axial direction to the volute 34.
Each of the blades in the first row of blades 70 includes an upstream end 80 that is circumferentially spaced in a second rotational direction R2 from a downstream end 82. The first row of blades 70 can be straight or include a curvature that extends in the first rotational direction. Similarly, each of the blades in the second row of blades 72 includes an upstream end 84 circumferentially spaced in the second rotational direction R2 from a downstream end 86. Also, the second row of blades 72 includes a curvature that extends in the first rotational direction R1. Furthermore, in the illustrated example, the curvature of the second row of blades 72 is a larger curvature than the first row of blades 70.
During operation of the compressor 20, the impeller 26 rotates in the first rotational direction R1 and the rotor 32, 32A rotates in the second rotation direction R2 which is opposite from the first rotational direction R1. The rotor 32, 32A also turns the refrigerant in an axial direction. The rotor 32, 32A can rotate with the same magnitude but in an opposite rotational direction from the impeller 26 through the use of the transmission 50 between the rotor 32, 32A and the drive shaft 46. Alternatively, the transmission 50 can vary the magnitude of rotation of the rotor 32, 32A compared to the impeller 26 based on a desired operating condition of the compressor 20. Furthermore, the rotor 32, 32A can be driven separately from the impeller 26 with the use of the rotor drive motor 52 schematically illustrated in
Although the different non-limiting examples are illustrated as having specific components, the examples of this disclosure are not limited to those particular combinations. It is possible to use some of the components or features from any of the non-limiting examples in combination with features or components from any of the other non-limiting examples.
It should be understood that like reference numerals identify corresponding or similar elements throughout the several drawings. It should also be understood that although a particular component arrangement is disclosed and illustrated in these exemplary examples, other arrangements could also benefit from the teachings of this disclosure.
The foregoing description shall be interpreted as illustrative and not in any limiting sense. A worker of ordinary skill in the art would understand that certain modifications could come within the scope of this disclosure. For these reasons, the following claim should be studied to determine the true scope and content of this disclosure.
This application claims priority to U.S. Provisional Application No. 62/868,480, which was filed on Jun. 28, 2019 and is incorporated herein by reference.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2020/037850 | 6/16/2020 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62868480 | Jun 2019 | US |
