Impeller assembly of fluid rotary machine and manufacturing method thereof

1. A method of manufacturing an impeller assembly, the method comprising:

providing an impeller comprising:

a rotary shaft;

a base portion radially extending outward from the rotary shaft; and

a plurality of blades extending radially outward from the rotary shaft and disposed on the base portion, each of the plurality of blades provided apart from one another in a circumferential direction around the rotary shaft;

providing a mold in an area between the plurality of blades; and

forming a shroud covering upper portions of the plurality of blades and an upper portion of the mold, the shroud having a first surface and a second surface opposite to the first surface,

wherein the forming the shroud comprises applying a melted metal on the upper portions of the plurality of blades and the upper portion of the mold to generate an entirety of the shroud extending from the first surface to the second surface, the first surface contacting the upper portions of the plurality of blades and the second surface corresponding to a top surface of the impeller assembly.

2. The method of claim 1 , wherein the forming the shroud comprises:

supplying metal powder to the upper portions of the plurality of blades and the upper portion of the mold; and

irradiating laser onto the metal powder to melt the metal powder.

3. The method of claim 1 , wherein the forming the shroud comprises:

melting a metal;

applying the melted metal onto the upper portions of the plurality of blades and the upper portion of the mold; and

hardening the applied metal.

4. The method of claim 1 further comprising forming the shroud with at least two layers.

5. The method of claim 1 , wherein the providing the impeller comprises performing three-dimensional (3D) printing the plurality of blades.

6. The method of claim 5 , wherein the performing 3D printing comprises repeatedly stacking a plurality of layers on the base portion.

7. The method of claim 1 , wherein widths of the plurality of blades decrease from a contacting portion of the plurality of blades and the base portion toward an end portion of the plurality of blades.

8. The method of claim 7 , wherein the mold is provided between adjacent blades, and

wherein a width of the mold increases from a contacting portion of the mold and the base portion toward an end portion of the mold.

9. The method of claim 1 , wherein the providing the mold between the plurality of blades comprises filling spaces between adjacent blades with a ceramic material paste.

10. The method of claim 9 , wherein the providing the mold between the plurality of blades further comprises hardening the mold after the mold is provided between the plurality of blades.

11. The method of claim 1 , wherein the providing the mold between the plurality of blades comprises inserting a pre-manufactured mold having a shape corresponding to spaces between adjacent blades.

12. The method of claim 1 , further comprising removing the mold.

13. The method of claim 12 , wherein the removing the mold comprises at least one of grinding the mold, delivering ultrasonic vibration to the mold, spraying high-pressure water onto the mold, and irradiating laser beams onto the mold.

14. The method of claim 1 , wherein the forming the shroud comprises spraying the melted metal on the upper portions of the plurality of blades and the upper portion of the mold.