Furcating Pilot Pre-Mixer for Gas Turbine Combustion
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Solution Overview
Problem
Conventional pilot pre-mixers in gas turbine engines produce centralized flames that do not efficiently mix with main pre-mixer mixtures, leading to higher NOx emissions and instability in the main pre-mixer flames due to the lack of efficient dispersion of the pilot fuel-air mixture.
Innovation Solution
A furcating pilot pre-mixer design with a conical fuel injector and strategically arranged oxidizer inlet ports that impinge on the fuel to prevent low velocity and promote outward flow, distributing the fuel-air mixture radially towards the main pre-mixers, eliminating the need for internal swirlers and enhancing mixing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a conventional pilot pre-mixer with centralized flame design is used, then the structure is simple, but the dispersion of pilot fuel-air mixture is poor leading to higher NOx emissions
Solution Approach 1:
The pilot pre-mixer outlet is divided into multiple outlet ports arranged in a circular pattern, segmenting the centralized flame into multiple dispersed flames. This segmentation improves the dispersion of pilot fuel-air mixture towards the main pre-mixers, reducing NOx emissions without requiring complex internal swirlers
Solution Approach 2:
The outlet ports are arranged in a circular pattern at an angle relative to the axial direction, transitioning from a one-dimensional centralized outlet to a two-dimensional distributed pattern. This dimensional change enables better radial dispersion of the pilot mixture toward the main pre-mixers
2Productivity
If oxidizer inlet ports are strategically arranged to impinge on fuel, then mixing efficiency is improved, but the device complexity increases
Solution Approach 1:
The oxidizer inlet ports are positioned at specific locations upstream of the mixing chamber to create localized high-velocity oxidizer jets that impinge on the fuel stream. This local quality enhancement promotes turbulent mixing and prevents low-velocity regions without requiring complex internal structures
Solution Approach 2:
The design utilizes fluid dynamic principles where oxidizer inlet ports create high-velocity jets that entrain and mix with the fuel stream through turbulent interaction. The strategic positioning of ports leverages pneumatic principles to achieve efficient mixing without mechanical components
3Reliability
If pilot fuel-air mixture is not efficiently dispersed, then the structure remains simple, but main pre-mixer flame stability deteriorates
Solution Approach 1:
Multiple outlet ports segment the pilot fuel-air mixture into several streams that are distributed toward different main pre-mixers. This segmentation ensures efficient dispersion and improves flame stability in main pre-mixers by providing consistent pilot mixture delivery
Solution Approach 2:
The pilot fuel-air mixture is pre-dispersed through multiple outlet ports before reaching the main pre-mixers, ensuring that the mixture is already distributed and ready to stabilize main pre-mixer flames upon contact, rather than requiring complex post-mixing mechanisms
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design achieves a more stable and efficient dispersion of the pilot fuel-air mixture, reducing NOx emissions and improving the stability of the main pre-mixer flames by ensuring better mixing with the main pre-mixer fuel-air mixture, resulting in lower emissions and improved combustion efficiency.
Implementation Method 1
a plurality of first oxidizer inlet ports arranged to provide an oxidizer agent from outside of the pilot body to the internal mixing chamber
Implementation Method 2
a fuel injector at the first end and communicable with the internal mixing chamber
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A pilot pre-mixer (100) for a gas turbine engine (10) has a pilot body (110) that includes an internal mixing chamber (112), a first end (114) on an upstream side of the internal mixing chamber, a second end (116) on a downstream side of the internal mixing chamber, a fuel injector (118) at the first end and communicable with the internal mixing chamber, a plurality of first oxidizer inlet ports (122) arranged to provide an oxidizer agent from outside of the pilot body to the internal mixing chamber, and a plurality of pilot outlet ports (128) at the second end and communicable with the internal mixing chamber, each of the plurality of pilot outlet ports having an outlet (130) on the second end for dispensing a pilot pre-mixer fluid mixture into a combustion chamber (62) of a combustor (50).