Damper for combustion oscillation damping in a gas turbine
The invention relating to a A damper for combustion oscillation damping for a gas turbine, includes a resonator cavity with a box or cylinder shape, a neck in flow communication with the resonator cavity and a combustion chamber. The length L neck of the neck is equal or greater than a maximum distance l max that a hot gas ingested from the combustion chamber reaches in the neck. The maximum distance l max is determined according to the following equation: l max = ∫ t 1 t 2 U - p ^ ρ U ζ sin ( ω t ) d t . With the solution of the present invention, the damper used to damping combustion oscillation may prevent hot gas ingestion during normal operations by uniquely determining the dimensions of the neck connecting the resonator cavity and the combustion chamber.
1. A system for combustion oscillation damping for a gas turbine comprising:
a damper, and a combustion chamber, wherein the damper includes:
a resonator cavity having a cross section in a shape of one of a rectangle, a square or a cylinder, a neck in flow communication with the resonator cavity and the combustion chamber, wherein a length L neck of the neck is equal or greater than a maximum distance l max , wherein a hot gas ingested from the combustion chamber will reach the maximum distance l max in the neck, wherein the maximum distance l max is determined according to an equation:
l
max
=
∫
t
1
t
2
U
-
p
^
ρ
U
ζ
sin
(
ω
t
)
d
t
wherein U represents a mean flow velocity in the neck, {circumflex over (p)} represents a pressure amplitude in the combustion chamber, ρ represents a density of flow, and ζ represents a pressure loss coefficient, wherein the neck includes a first neck part and a second neck part, wherein the first neck part is proximate the combustion chamber and is made of a first material that is heat resistant, and the second neck part is distal from the combustion chamber and is made from a second material that is different from the first material, and wherein a length of the first neck part is dimensioned to be equal or larger than the maximum distance l max .
2. The system according to claim 1 , wherein the length L neck of the neck is equal to 1.1˜2.0 times of the maximum distance l max .
3. The system according to claim 1 , wherein the length L neck of the neck is equal to 1.4˜1.8 times of the maximum distance l max .
4. The system according to claim 1 , wherein the length L neck of the neck is equal to 1.5 times of the maximum distance l max .
5. The system according to claim 1 , wherein the damper comprises:
one or more spacers disposed in the resonator cavity to separate the resonator cavity into multiple parts, and an inlet tube disposed on the resonator cavity, wherein an effective diameter d of the inlet tube is determined in accordance with an equation:
d
=
D
U
(
3
ρ
4
Δ
p
c
)
1
/
4
wherein Δp c is a pressure over a cooling air supply, and D represents an effective diameter of the neck.
6. The system according to claim 5 , wherein a cross section of the inlet tube is shaped as circular, square, rectangular or oval.
7. The system according to claim 1 , wherein the length of the first neck part is dimensioned to be equal to 1.1˜2.0 times of the maximum distance l max .
8. The system according to claim 1 , wherein the length of the first neck part is dimensioned to be equal to 1.4˜1.8 times of the maximum distance l max .
9. The system according to claim 1 , wherein the length of the first neck part is dimensioned to be equal to 1.5 times of the maximum distance l max .
10. The system according to claim 1 , wherein a cross section of the neck is shaped as circular, square, rectangular or oval.