Combustor, gas turbine, and method of suppressing oscillating combustion

Abstract

The present invention relates to a combustion chamber of a gas turbine, the combustion chamber includes a flame tube head, and the head includes a main combustion stage and a pre-combustion stage, with the pre-combustion stage as the center, a plurality of the main combustion stages along Circumferentially distributed around the pre-combustion stage, the pre-combustion stage has a pre-combustion stage fuel nozzle and a pre-combustion stage outer wall located outside its circumference, the main combustion stage has a main combustion stage inner wall, and the pre-combustion stage outer wall The radial space inside provides a pre-combustion stage passage for mixing the air entering the pre-combustion stage through the pre-combustion stage intake portion and the fuel injected by the pre-combustion stage fuel nozzle; the pre-combustion stage intake portion includes The first air intake portion of the pre-combustion stage and the second air intake portion of the pre-combustion stage; the first air intake portion of the pre-combustion stage includes a second hole with an acoustic throttling effect penetrating through the radial thickness of the outer wall of the pre-combustion stage .

Description

technical field [0001] In particular, the invention relates to a combustor, a gas turbine and a method of suppressing oscillating combustion. Background technique [0002] In order to meet airworthiness requirements, aeroengines use lean fuel combustion technology to reduce NO x Emissions, but lean combustion is easy to cause oscillating combustion, which will lead to ablation of the hot end components of the combustion chamber in severe cases. In addition, in order to reduce NO x For emission, more air needs to be distributed to the head of the combustion chamber to reduce the equivalent ratio of the combustion zone. At this time, the cooling air of the flame tube decreases, and the acoustic impedance of the wall of the flame tube increases, which also intensifies the degree of oscillating combustion. [0003] In order to suppress oscillating combustion, there are currently two implementations of active control and passive control. For active control, it is necessary to ...

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Problems solved by technology

[0005] For the central staged combustion mode, through optical diagnosis technology, one of the main driving mechanisms of oscillating combustion that has been known so far is the flow instability of the pre-combustion stage. This mechanism is mainly related to the swirl number of the pre-combustion stage. A central recirculation zone is formed to stabilize the flame, but it is easy to form an unstable spiral vortex and vortex shedding. The flame structure changes periodically (that is, the interaction between the flame and the vortex), and the corresponding type of heat release fluctuation occurs in the time and space dimensions of the combustion zone, thereby driving the circumferential modal pressure oscillation of the full-ring combustion chamber (inclining to spiral vortex) and axial mode pressure oscillations (prone to vortex shedding)

[0006] Most of the design results of conventional combustor aerothermal schemes only consider the steady-state working state or stable combustion state, but cannot satisfy the transition state or unsteady combustion state, such as the influence of oscillating combustion on aerodynamic heat

In order to suppress oscillating combustion and ensure safety, performance such as emission and outlet temperature distribution have to be sacrificed. Therefore, it is difficult for the conventional aerothermal design scheme of the combustor to ensure that all indicators are satisfied at the same time.

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