Combustion system of a flow engine and method for determining a dimension of a resonator cavity

Abstract

A combustion system of a flow engine has at least one combustion chamber, a shared manifold to feed a flow medium via at least two injectors to the at least one combustion chamber and at least one resonator with at least one resonator cavity, wherein the at least one resonator is arranged functionally in/at the manifold. To obtain good combustion performance with a homogenous fuel flow rate and high combustion stability, the resonator includes at least one perforated section with at least two orifices, wherein the at least two orifices provide access to the at least one resonator cavity of the at least one resonator.

1 .- 17 . (canceled) 
     
     
         18 . A combustion system of a flow engine, comprising
 at least one combustion chamber and at least two injectors,   a shared manifold to feed a flow medium via the at least two injectors to the at least one combustion chamber, and   at least one resonator with at least one resonator cavity,   wherein the at least one resonator is arranged functionally in/at the manifold,   wherein the resonator comprises at least one perforated section with at least two orifices,   wherein the at least two orifices provide access for the flow medium in the manifold directly to the at least one resonator cavity of the at least one resonator to modulate and/or damp perturbations in the flow medium in the manifold,   wherein the at least one resonator has at least one restriction device that is constructed to prevent a flow of flow medium through the at least two orifices from the manifold into the resonator cavity, wherein the at least one restriction device is a membrane or a differential pressure between the resonator cavity and the manifold, wherein a pressure (P) in the resonator cavity is higher than a pressure (p) in the manifold.   
     
     
         19 . The combustion system according to  claim 18 , wherein at least two resonators are provided and each resonator has a different resonator cavity volume. 
     
     
         20 . The combustion system according to  claim 18 , wherein at least one of the resonators has at least two resonator cavities and each resonator cavity has a different resonator cavity volume. 
     
     
         21 . The combustion system according to  claim 18 , wherein the at least one perforated section is formed in a part of the manifold. 
     
     
         22 . The combustion system according to  claim 18 , wherein the at least one perforated section is formed in a wall of the manifold and defines part of the flow path of the fuel through the manifold, the at least one resonator cavity is partly defined by the at least one perforated section. 
     
     
         23 . The combustion system according to  claim 18 , wherein the at least one perforated section has a shape of a hollow cylinder. 
     
     
         24 . The combustion system according to  claim 23 , wherein the at least one perforated section comprises a plurality of orifices, which are distributed along a whole circumference of a jacket of the hollow cylinder. 
     
     
         25 . The combustion system according to  claim 18 , wherein the at least one resonator has a shape of a linear body having an axial extension and wherein the at least one perforated section comprises a plurality of orifices, which is distributed along the whole axial extension of the linear body. 
     
     
         26 . The combustion system according to  claim 25 , wherein the at least one resonator cavity of the at least one resonator comprises at least one wall arranged basically along the axial extension of the linear body of the at least one resonator and wherein the at least one wall of the at least one resonator cavity and a part of the manifold, which is arranged basically along the axial extension of the linear body, are arranged like in a pipe in pipe system. 
     
     
         27 . The combustion system according to  claim 18 , wherein the at least one perforated section comprises a plurality of orifices, which are evenly distributed over the at least one perforated section. 
     
     
         28 . The combustion system according to  claim 18 , further comprising
 a selected number of injectors and a selected number of resonators wherein the number of resonators is equal or less than the number of injectors.   
     
     
         29 . The combustion system according to  claim 18 , further comprising
 at least a second resonator wherein the first resonator and the at least second resonator differ in at least one characteristic.   
     
     
         30 . The combustion system according to  claim 18 , wherein the at least one resonator is placed in a location of a pressure anti-node of a standing wave established in the manifold due to perturbations of a flow rate of a flow medium travelling in the manifold. 
     
     
         31 . The combustion system according to  claim 18 , wherein the at least one resonator cavity has a volume, which is adjustable. 
     
     
         32 . A method for determining a dimension of a resonator cavity of a resonator of a combustion system of a flow engine according to  claim 18 , comprising:
 determining at least one frequency that will be established in the combustion system under defined conditions and that needs modulation to provide optimum damping around a combustion dynamics frequency of the combustion system,   evaluating the dimension of the resonator cavity of the resonator using the Helmholtz equation in dependency of the determined at least one frequency,   adjusting the dimension according to the evaluation, and   preventing a flow of flow medium through the at least two orifices from the manifold into the resonator cavity by using at least one restriction device of the at least one resonator wherein the at least one restriction device is a membrane or a differential pressure between the resonator cavity and the manifold,   wherein a pressure (P) in the resonator cavity is higher than a pressure (p) in the manifold.   
     
     
         33 . The method for determining a dimension of a resonator cavity of a resonator of a combustion system of a flow engine according to  claim 32 , wherein two or more cavities are provided, the method further comprising:
 determining a range of frequencies that will be established in the combustion system under defined conditions and that needs modulation to provide optimum damping around a combustion dynamics frequency of the combustion system,   evaluating the dimension of each resonator cavity of the resonator using the Helmholtz equation in dependency of the determined at least one frequency, and   adjusting the dimension of each resonator cavity according to the evaluation to provide different cavity characteristics and which cover the range of frequencies.