Low-emission low-swirl direct-injection combustor for gas turbine

Abstract

The invention discloses a low-emission low-swirl direct-injection combustor for a gas turbine. The low-emission low-swirl direct-injection combustor comprises a buffer cavity, a premixing air inlet pipe and a flame tube which are connected and communicated from bottom to top; air enters the buffer cavity through the bottom of the combustor, a main fuel spray pipe and a low-swirl combustor are arranged in the premixing air inlet pipe; the main fuel spray pipe is connected with main fuel through a central air delivery pipe; the low-swirl combustor is located above the main fuel spray pipe; a lean-burn direct spray pipe is arranged in the premixing air inlet pipe and the buffer cavity in the axial direction, the bottom end of the lean-burn direct spray pipe is connected with on-duty fuel, andthe top end of the lean-burn direct spray pipe is higher than the low-swirl combustor and faces the flame tube; and premixed gas is mixed with the on-duty fuel sprayed out from the downstream of thelean-burn direct spray pipe through a swirl channel and a straight-flow channel of the low-swirl combustor to be combusted. According to the low-emission low-swirl direct-injection combustor for the gas turbine provided by the invention, a weak swirl fluid field is guaranteed while an geometric angle of a blade and the blockage ratio of a pore plate are increased, the premixing uniformity of fuel / air is improved, formation of NOx is reduced, risks of spontaneous combustion, tempering, lean-burn flameout and combustion oscillation are reduced, the combustion efficiency is improved, and the combustor is suitable for various combustion modes.

Description

technical field [0001] The invention belongs to the technical field of gas turbine structure design, in particular to a low-swirl direct-injection burner used for low emission of gas turbines. Background technique [0002] As the most advanced heat-to-power conversion device, gas turbines have played an indispensable and important role in energy power and power systems worldwide. In order to make the gas turbine work stably, the combustion chamber, one of the three core components of the gas turbine, widely adopts strong swirling flow to achieve flame stability, and forms a central recirculation zone in the main combustion area to provide a continuous ignition source for the combustion of fresh mixed gas, ensuring that the combustion chamber The stable working range, but the large-scale turbulent flow structure also reduces the volumetric heat release rate. Moreover, under the action of strong swirling flow, lean fuel premixed flames are prone to oscillating combustion. Whe...

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Problems solved by technology

However, it should be noted that since the weak swirl combustion relies on the divergent flow field attenuated by the central velocity, rather than the recirculation zone to stabilize the flame, if the central direct current flux is insufficient, the weak swirl flow field may gradually move towards the traditional strong swirl The flow structure changes, beyond the critical condition, the exit of the nozzle no longer forms a stable detached flame, thus losing the relative advantages of weak swirl combustion

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