Mixer

Patent metadata

Field	Value
Publication number	US-2021172606-A1
Application number	US-202117174939-A
Country	US
Kind code	A1
Filing date	Feb 12, 2021
Priority date	Mar 2, 2017
Publication date	Jun 10, 2021
Grant date	—

Abstract

A mixer having a housing, a duct within the housing, a first and a second injector arranged to inject a fluid at a centre zone of the duct, a third and a fourth injector arranged to inject the fluid at a wall zone of the duct. The first/third injectors are at a distance D1=v/2f1 or odd integer multiples of it from the second/fourth injectors in the absence of an acoustic node between them, or at a distance D1=λconv=v/f1 or full wave length integer multiples of it in the presence of an acoustic node between them. Advantageously f1 is greater than f2.

First claim

1 . A method of dampening oscillating frequencies in a gas turbine mixer, the mixer comprising a housing, a duct within the housing, a first injector and a second injector, each arranged to inject a fluid at a center zone of the duct, a third injector and a fourth injector, each arranged to inject the fluid at a wall zone of the duct,
the method comprising: injecting the fluid through the first injector at a distance D 1 =v/2f 1 or odd integer multiples of it from the second injector in the absence of an acoustic node between the second injector and the first injector, injecting the fluid through the first injector at a distance D 1 =v/f 1 or full wave length integer multiples of it in the presence of an acoustic node between the second injector and the first injector, injecting the fluid through the third injector at a distance D 2 =v/2f 2 or odd integer multiples of it from the fourth injector in the absence of an acoustic node between the third injector and the fourth injector, and injecting the fluid through the third injector at a distance D 2 =v/f 2 from the first injector in the presence of an acoustic node between the third injector and the fourth injector, wherein f 1 is the oscillating frequency to be damped at the wall zone of the duct, f 2 is the oscillating frequency to be damped at the center zone of the duct, v is the fluid flow speed through the duct, wherein f 1 is greater than f 2 .

2 . The method of claim 1 , wherein both f1 and f2 are lower than 150 Hz.

3 . The method of claim 1 , wherein the first injector and/or the second injector and/or the third injector and/or the fourth injector comprise a plurality of rows of nozzles close to one another.

4 . The method of claim 2 , wherein nozzles of different rows of nozzles of a same injector have different penetration.

5 . The method of claim 2 , wherein the nozzles of a same row of nozzles have different penetration.

6 . A method of operating a gas turbine, wherein the gas turbine comprises a compressor, a first combustion chamber, a second combustion chamber fed with a fluid coming from the first combustion chamber, a turbine and a mixer between the first combustion chamber and the second combustion chamber, wherein the mixer comprises a housing, a duct within the housing, a first injector and a second injector, each arranged to inject a fluid at a center zone of the duct, a third injector and a fourth injector, each arranged to inject the fluid at a wall zone of the duct, the method comprising:
injecting the fluid through the first injector at a distance D 1 =v/2f 1 or odd integer multiples of it from the second injector in the absence of an acoustic node between the second injector and the first injector, injecting the fluid through the first injector at a distance D 1 =v/f 1 or full wave length integer multiples of it in the presence of an acoustic node between the second injector and the first injector, injecting the fluid through the third injector at a distance D 2 =v/2f 2 or odd integer multiples of it from the fourth injector in the absence of an acoustic node between the third injector and the fourth injector, injecting the fluid through the third injector at a distance D 2 =v/f 2 from the fourth injector in the presence of an acoustic node between the third injector and the fourth injector, wherein f 1 is the oscillating frequency to be damped at the wall zone of the duct, f 2 is the oscillating frequency to be damped at the center zone of the duct, v is the fluid flow speed through the duct, wherein f 1 is greater than f 2 .

7 . The method of claim 6 , wherein both f1 and f2 are lower than 150 Hz.

8 . The method of claim 6 , wherein at least one of the first injector, or the second injector, the third injector and the fourth injector comprises a plurality of rows of nozzles close to one another.

9 . The method of claim 7 , wherein nozzles of different rows of nozzles of a same injector have different penetration.

10 . The method of claim 7 , wherein the nozzles of a same row of nozzles have different penetration.

11 . A method of operating a gas turbine, comprising:
combusting a fuel in a first combustion chamber, thereby producing a hot gas; flowing the hot gas through a mixer; injecting a fluid in the mixer at a first injection location at a distance D 1 =v/2f 1 or odd integer multiples of it from a second injection location if there are no acoustic nodes between the second injection location and the first injection location, injecting the fluid at the first injection location at a distance D 1 =v/f 1 or full wave length integer multiples of it if there is at least an acoustic node between the second injection location and the first injection location, injecting the fluid at a third injection location at a distance D 2 =v/2f 2 or odd integer multiples of it from a fourth injection location if there are no acoustic nodes between the third injection location and the fourth injection location, and injecting the fluid at the third injection location at a distance D 2 =v/f 2 from the fourth injection location if there is at least an acoustic node between the third injection location and the fourth injection location, wherein f 1 is the oscillating frequency to be damped at the wall zone of the duct, f 2 is the oscillating frequency to be damped at the center zone of the duct, v is the fluid flow speed through the duct, wherein f 1 is greater than f 2 .

12 . The method of claim 11 , wherein injecting a fluid in the mixer at a first injection location includes injecting the fluid at a center zone of the duct.

13 . The method of claim 11 , wherein injecting the fluid at a third injection location includes injecting the fluid at a wall zone of the duct.

14 . The method of claim 11 , comprising directing a mixture of the hot gas and the injected fluid to a second combustion chamber of the gas turbine.

15 . The method of claim 11 , wherein both f1 and f2 are lower than 150 Hz.

16 . The method of claim 11 , wherein the mixer comprises at least a first injector, a second injector, a third injector and the fourth injector and wherein at least one of the first injector, or the second injector, the third injector and the fourth injector comprises a plurality of rows of nozzles close to one another.

17 . The method of claim 16 , wherein nozzles of different rows of nozzles of a same injector have different penetration.

18 . The method of claim 16 , wherein the nozzles of a same row of nozzles have different penetration.

Assignees

• Ansaldo Energia Switzerland AG

Inventors

• Bothien Mirko Ruben
• Scarpato Alessandro

Classifications

• F23R3/00 Primary

  Continuous combustion chambers using liquid or gaseous fuel · CPC title

• F23R3/06

  Arrangement of apertures along the flame tube · CPC title

• F23R3/045

  using pipes · CPC title

• F23R3/002

  Wall structures (F23R3/02 and F23R3/007 take precedence) · CPC title

• F23D14/02

  Premix gas burners, i.e. in which gaseous fuel is mixed with combustion air upstream of the combustion zone · CPC title