Combustor with improved aerodynamics

Abstract

A lean burn combustor includes a plurality of lean burn fuel injectors, each including a fuel feed arm and a lean burn fuel injector head with a lean burn fuel injector head tip, wherein the lean burn fuel injector head tip has a lean burn fuel injector head tip diameter, the lean burn fuel injector head including a pilot fuel injector and a main fuel injector, the main fuel injector being arranged coaxially and radially outwards of the pilot fuel injector; and a combustor chamber extending along an axial direction for a length and including a radially inner annular wall, a radially outer annular wall, and a meter panel defining the size and shape of the combustor chamber, wherein the combustor chamber includes primary and secondary combustion zones. A ratio of the combustor chamber length to the lean burn fuel injector head tip diameter is less than 5.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS[0001]This specification is based upon and claims the benefit of priority from UK Patent Application Number 2019222.5 filed on Dec. 7, 2020, the entire contents of which are incorporated herein by reference.BACKGROUND1. Field of the Disclosure[0002]The present disclosure relates to combustion equipment, and in particular to lean burn combustors for gas turbine engines for aircraft, industrial, and marine applications.2. Description of the Related Art[0003]A gas turbine engine for aircraft applications typically comprises, in axial flow arrangement, a fan, one or more compressors, a combustion system and one or more turbines. The combustion system typically comprises a plurality of fuel injectors having fuel spray nozzles which combine fuel and air flows and generate sprays of atomised liquid fuel into a combustion chamber. The mixture of air and atomised liquid fuel is then combusted in the combustion chamber and the resultant hot combustion pr...

AI Technical Summary

Benefits of technology

The present invention is about a unique pilot fuel nozzle design for a lean burn combustor that optimizes combustion efficiency and reduces nitrogen oxides (NOX) and smoke. The design allows for a so-called S-shaped recirculation zone, which helps the pilot fuel nozzle support the main fuel nozzle combustion. The S-shaped recirculation zone is formed by the burning mixture of pilot fuel and air coming from the pilot fuel injector. The inventors found that this design can be scaled up and down without affecting the combustion efficiency. Other non-dimensional parameters can also be advantageous in improving combustion efficiency when designing a lean burn combustor's combustor chamber.

Problems solved by technology

On the other hand, keeping the combustion temperature relatively low could lead to incomplete or weak combustion, which in turn may lead to producing other pollutants, such as carbon monoxide (CO) and unburned hydrocarbons (UHC), and / or flame instability and rumble, which in turn may cause fatigue failure of components in the engine and / or passenger discomfort, depending on the frequency of the rumbling.

Gas turbine engines for industrial and marine applications face similar challenges as gas turbine engines for aircraft applications.

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