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EP-4741714-A1 - INJECTOR DEVICE FOR AN ENGINE

EP4741714A1EP 4741714 A1EP4741714 A1EP 4741714A1EP-4741714-A1

Abstract

An injector device (10) comprises a plurality of fluid channel assemblies (11), each fluid channel assembly (11) exhibiting an assembly eigenfrequency f a , wherein at least two different types of fluid channel assemblies (11) occur among the plurality of fluid channel assemblies (11). The at least two different types of fluid channel assemblies (11) differ from each other with respect to their assembly eigenfrequency f a . Each fluid channel assembly (11) comprises a fluid channel (111) for guiding a mixture comprising an oxidizing agent and a fuel towards a combustion chamber of an engine device, the fluid channel (111) exhibiting a channel eigenfrequency f c . At least one of the fluid channel assemblies (11) comprises at least one detuning cavity (112) being fluidically connected to its fluid channel (111), the at least one detuning cavity exhibiting a detuning cavity eigenfrequency f d that differs from the channel eigenfrequency f c of the fluid channel (111).

Inventors

  • NOIRAY, NICOLAS
  • MARTIN, RICHARD

Assignees

  • ETH Zurich

Dates

Publication Date
20260513
Application Date
20241106

Claims (15)

  1. An injector device (10) for an engine device (1), the injector device (10) comprising: a plurality of fluid channel assemblies (11), each fluid channel assembly (11) forming an assembly resonator exhibiting an assembly eigenfrequency f a , wherein at least two different types of fluid channel assemblies (11) occur among the plurality of fluid channel assemblies (11), the at least two different types of fluid channel assemblies (11) differing from each other with respect to their assembly eigenfrequency f a , wherein each fluid channel assembly (11) comprises: a fluid channel (111) for guiding an oxidizing agent (O), a fuel (F), or a mixture comprising an oxidizing agent (O) and a fuel (F), towards a combustion chamber (40) of the engine device (1), the fluid channel (111) forming a channel resonator exhibiting a channel eigenfrequency f c , and wherein at least one of the fluid channel assemblies (11) comprises: at least one detuning cavity (112) being fluidically connected to its fluid channel (111), the at least one detuning cavity forming a cavity resonator exhibiting a detuning cavity eigenfrequency f d , wherein the detuning cavity eigenfrequency f d differs from the channel eigenfrequency f c of the fluid channel (111) to which it is connected.
  2. The injector device (10) of claim 1, wherein the fluid channels (111) have a uniform cross-section and a uniform channel length.
  3. The injector device (10) of claim 1 or 2, wherein the difference in assembly eigenfrequency (f a ) between the different types of fluid channel assemblies (11) is at least partially caused by the detuning cavities (112) of the different types having different detuning cavity volumes.
  4. The injector device (10) of any one of the preceding claims, wherein the difference in assembly eigenfrequency f a between the different types of fluid channel assemblies (11) is at least partially caused by the different types having a different number of detuning cavities (112) being fluidically connected to the respective fluid channel (111).
  5. The injector device (10) of any one of the preceding claims, wherein each fluid channel (111) comprises a mixing region (1113) for mixing the oxidizing agent (O) with the fuel (F), and wherein the at least one detuning cavity is arranged downstream of the mixing region (1113).
  6. The injector device (10) of claim 5, wherein each fluid channel is delimited by a channel wall, the channel wall comprising a fuel injection hole (1112) for allowing the fuel (F) to enter the mixing region (1113), and wherein the fuel injection hole (1112) is arranged upstream of the at least one detuning cavity (112).
  7. The injector device (10) of any one of the preceding claims, wherein the fluid channels (111) extend in parallel to each other, thereby defining a common flow direction (Z).
  8. The injector device (10) of claim 7, wherein each fluid channel (111) is spaced apart from the other fluid channels (111) in a plane perpendicular to the flow direction (Z) by a gap which is at least as large as a cross section of the respective fluid channel (111).
  9. The injector device (10) of claim 7 or 8, wherein at least one detuning cavity (112) is arranged in-between two fluid channels (111).
  10. The injector device (10) of any one of the preceding claims, wherein at least one of the detuning cavities (112) is a quarter-wave resonator with a circular cross section that is preferably smaller than a cross section of the fluid channel (111) to which it is fluidically connected.
  11. The injector device (10) of claims 1-9, wherein at least one of the detuning cavities (112) is a Helmholtz-resonator with a main cavity (1121) and a neck (1122) through which the detuning cavity (112) is fluidically connected to the fluid channel (111).
  12. The injector device (10) of any one of the preceding claims, wherein the injector device (10) comprises a number N of fluid channel assemblies (11) and wherein a number M of different types of fluid channel assemblies (11) differing from each other with respect to their assembly eigenfrequency (f a ) occur among the N fluid channel assemblies (11), the ratio M/N being in the range of 0.5-1.
  13. A method of manufacturing an injector device (10) according to any one of the preceding claims, wherein the injector device (10) is manufactured using a 3D-printing process.
  14. The method of claim 13, wherein the 3D-printing process comprises selective laser melting of a powder material.
  15. An engine device (1) comprising: an oxidizer collection space (20) for collecting an oxidizing agent (O); a fuel reservoir (30) for containing a fuel (F), a combustion chamber (40), and an injector device (10) according to any one of the preceding claims, wherein the injector device (10) is arranged to fluidically connect the oxidizer collection space (20) and the fuel reservoir (30) to the combustion chamber (40).

Description

TECHNICAL FIELD The present invention relates to an injector device for an engine device, an engine device comprising said injector device, and a method of manufacturing said injector device. PRIOR ART In combustors of turbines, rocket engines, and furnaces, fuel and oxidizer are typically mixed in an injector device, often called a burner, and then led to a combustion chamber arranged downstream of the injector device. The stability of the combustion process is affected by multiple factors, among others the acoustics of the injector device and the combustion chamber. Instabilities arising from a thermoacoustic feedback loop can impinge on a safe and clean operation of the combustor and the engine. These thermoacoustic instabilities may be mitigated using active or passive control strategies. US 2022106928 A1 discloses an injector device for an engine device for introducing a fuel and an oxidizing agent into a combustion chamber of an engine device. The injector device defines a longitudinal axis and comprises a first injection element, which is configured in the form of a first fluid channel for fluidically connecting a first collection space for the fluidic oxidizing agent and the combustion chamber, and a second injection element, which is configured in the form of a second fluid channel for fluidically connecting a second collection space for the fluidic fuel and the combustion chamber. At least one first resonator element is associated with the first injection element and/or at least one second resonator element is associated with the second injection element. The first resonator element is adapted to an eigenfrequency of the associated first injection element and/or the second resonator element is adapted to an eigenfrequency of the associated second injection element. The first resonator element and the second resonator element form damping elements in order to dampen flame oscillations in the combustion chamber with the acoustic eigenfrequencies of the injection elements. However, in order to precisely hit the eigenfrequency, several parameters need to be taken into account. US 2022106928 A1 discloses that to make the geometrical design of the resonator element independent of the sound speed and thus also independent of the respective fluid, flushing channels are needed that connect the resonator element to the respective collection space so that the sound speed in the injection element is the same as in the resonator element. Such flushing channels however lead to a more complex structure of the injector device, which is also more difficult to manufacture. SUMMARY OF THE INVENTION In a first aspect, it is thus an object of the present invention to provide an injector device which enables a suppression of thermoacoustic instabilities while being simple to design and manufacture. This object is solved by an injector device according to claim 1. Further embodiments of the invention are laid down in the dependent claims. An injector device for an engine device is thus provided, the injector device comprising: a plurality of fluid channel assemblies, each fluid channel assembly forming an assembly resonator exhibiting an assembly eigenfrequency,wherein at least two different types of fluid channel assemblies occur among the plurality of fluid channel assemblies, the at least two different types of fluid channel assemblies differing from each other with respect to their assembly eigenfrequency fa,wherein each fluid channel assembly comprises: a fluid channel for guiding an oxidizing agent, a fuel, or a mixture comprising an oxidizing agent and a fuel, towards a combustion chamber of the engine device, the fluid channel forming a channel resonator exhibiting a channel eigenfrequency fc, andwherein at least one of the fluid channel assemblies comprises: at least one detuning cavity being fluidically connected to its fluid channel, the at least one detuning cavity forming a cavity resonator exhibiting a detuning cavity eigenfrequency fd,wherein the detuning cavity eigenfrequency fd differs from the channel eigenfrequency fc of the fluid channel to which it is connected. By having at least two types of fluid channel assemblies that differ from each other with respect to their assembly eigenfrequency fa, resonances are distributed over a larger frequency range and thus acoustic instabilities are mitigated compared to a case in which all fluid channel assemblies have the same assembly eigenfrequency fa. When designing the injector device, making sure that the detuning cavity eigenfrequency fd differs from the channel eigenfrequency fc of the fluid channel to which it is connected represents a significantly simpler task than having to precisely match the channel eigenfrequency fc. Non-matching eigenfrequencies imply that a larger range of parameter values for different design parameters, in particular geometrical dimensions, may be used, which furthermore lowers the demands regarding manufacturing precision. Th