Turbine with mixers and ejectors
View Patent ↗A Mixer/Ejector Wind/Water Turbine (“MEWT”) system is disclosed which routinely exceeds the efficiencies of prior wind/water turbines. Unique ejector concepts are used to fluid-dynamically improve many operational characteristics of conventional wind/water turbines for potential power generation improvements of 50% and above. Applicants' preferred MEWT embodiment comprises: an aerodynamically contoured turbine shroud with an inlet; a ring of stator vanes; a ring of rotating blades (i.e., an impeller) in line with the stator vanes; and a mixer/ejector pump to increase the flow volume through the turbine while rapidly mixing the low energy turbine exit flow with high energy bypass fluid flow. The MEWT can produce three or more time the power of its un-shrouded counterparts for the same frontal area, and can increase the productivity of wind farms by a factor of two or more. The same MEWT is safer and quieter providing improved wind turbine options for populated areas.
1. A method of increasing energy extraction from a fluid stream, comprising:
providing an axial flow fluid turbine comprising:
an aerodynamically contoured turbine shroud with an inlet, an outlet, and a ring of mixer lobes arranged along a trailing edge;
a turbine stage comprising a single stator ring and a single ring of rotor blades downstream of the single stator ring, the turbine stage being positioned within the turbine shroud; and
an ejector shroud having an inlet and an outlet, the ejector shroud being located downstream of the turbine shroud;
wherein the turbine shroud defines a (i) primary fluid stream that passes though the turbine stage and (ii) a secondary fluid stream that bypasses the turbine stage and enters the ejector shroud inlet, and (iii) the mixer lobes are downstream of the turbine stage;
placing the turbine in contact with a fluid stream;
extracting energy from the primary fluid stream to form a reduced-energy fluid stream; and
mixing the reduced-energy fluid stream with the secondary fluid stream to transfer energy from the secondary fluid stream to the reduced-energy fluid stream, thereby enhancing the flow of the primary fluid stream through the turbine and increasing the amount of energy extraction.
2. The method of claim 1 , wherein the fluid turbine is a horizontal axis wind turbine.
3. The method of claim 1 , wherein each mixer lobe has an inner trailing edge angle and an outer trailing edge angle, the inner angle being different from the outer angle.
4. The method of claim 3 , wherein the inner angle is greater than the outer angle.
5. The method of claim 3 , wherein the inner angle is less than the outer angle.
6. The method of claim 3 , wherein the inner angle and the outer angle are independently in the range of 5 to 25 degrees.
7. The method of claim 1 , wherein each mixer lobe has an inner trailing edge angle and an outer trailing edge angle, the inner angle being equal to the outer angle.
8. The method of claim 1 , wherein the ejector shroud further comprises a ring of mixer lobes around the ejector shroud outlet.
9. The method of claim 1 , wherein the mixer lobes direct the reduced-energy fluid stream away from a central axis and direct the secondary fluid stream towards the central axis.
10. The method of claim 1 , wherein the inlet of the turbine shroud has a circular cross-section.
11. The method of claim 1 , wherein the turbine shroud has between 6 and 14 mixer lobes.
12. The method of claim 1 , wherein the ejector shroud inlet has a circular cross-section.
13. The method of claim 1 , wherein the height-to-width ratio of lobe channels of the mixer lobes is between 0.5 and 4.5.
14. The method of claim 1 , wherein the mixer lobes of the turbine shroud penetrate the ejector shroud between 50% and 80%.
15. The method of claim 1 , wherein the length to distance (L/D) of the fluid turbine is between 0.5 and 1.25.
16. A method of increasing the amount of energy extracted by a fluid turbine, comprising:
providing a fluid turbine comprising:
an aerodynamically contoured turbine shroud with an inlet, an outlet, and a ring of mixer lobes arranged along a trailing edge;
a power extraction unit comprising a single stator ring and a single ring of rotor blades downstream of the single stator ring, the turbine stage being positioned within the turbine shroud; and
an ejector shroud having an inlet and an outlet, the ejector shroud being located downstream of the turbine shroud;
wherein the turbine shroud defines a first fluid stream that passes though the turbine stage and (ii) a second fluid stream that bypasses the turbine stage and enters the ejector shroud inlet, and (iii) the mixer lobes are downstream of the turbine stage;
extracting energy from the first fluid stream with the power extraction unit to produce a reduced-energy fluid stream; and
directing the second fluid stream to mix with the reduced-energy fluid stream, thereby transferring energy from the second fluid stream to the reduced-energy fluid stream and enhancing the flow of the primary fluid stream through the power extraction unit.
17. The method of claim 16 , wherein each mixer lobe has an inner trailing edge angle and an outer trailing edge angle, the inner angle being different from the outer angle.
18. The method of claim 17 , wherein the inner angle and the outer angle are independently in the range of 5 to 25 degrees.
19. The method of claim 16 , wherein the ejector shroud further comprises a ring of mixer lobes around the ejector shroud outlet.
20. The method of claim 16 , wherein the turbine shroud directs the reduced-energy fluid stream away from a central axis and directs the second fluid stream towards the central axis.