Emulsion Injection Nozzle for Gas Turbine Combustion
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Solution Overview
Problem
Existing nozzle designs for injecting emulsions into gas turbine engines suffer from carbon deposition, uneven atomization, and air flow separation, leading to inefficient combustion and increased NOx emissions due to inadequate stabilization of the flame temperature.
Innovation Solution
The nozzle design is enhanced by incorporating a swirl injection of the emulsion at the lip, reducing the injector diameter, and using a combination of inner and outer air flows to create a uniform emulsion film, which breaks down into smaller droplets, thereby stabilizing the flame and reducing NOx emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional nozzle designs are used for injecting emulsion, then the structure is simple, but carbon deposition occurs and atomization is uneven
Solution Approach 1:
The nozzle is divided into multiple functional segments: an inner lip for emulsion injection, an outer lip for air flow control, and a swirler component. This segmentation allows each part to perform its specific function optimally, with the inner lip creating the emulsion film and the outer lip controlling air mixing, thereby achieving uniform atomization without excessive overall complexity.
Solution Approach 2:
Different regions of the nozzle are designed with different properties: the inner lip has a specific geometry optimized for emulsion film formation, while the outer lip is designed for air flow control. The nozzle geometry varies locally to control the thickness and distribution of the emulsion film, ensuring uniform atomization at the injection point while maintaining structural feasibility.
2Manufacturing precision
If the injector diameter is reduced to improve atomization, then droplet size decreases, but air flow separation increases
Solution Approach 1:
The design uses a counterbalancing approach where the reduced injector diameter is compensated by optimizing the surrounding air flow geometry. The outer lip and swirler are designed to create stable air flows that counteract the potential instability from the smaller injector diameter, maintaining both fine droplet size and flow stability simultaneously.
Solution Approach 2:
The nozzle design incorporates dynamic air flow control through the swirler and outer lip geometry, which adapts the air flow characteristics to match the reduced injector diameter. This dynamic optimization ensures that the air flow remains stable and properly mixed with the emulsion, preventing separation while maintaining fine atomization.
3Reliability
If inner air flow is increased to stabilize the flame, then combustion stability improves, but carbon deposition increases
Solution Approach 1:
The design optimizes the parameters of the inner air flow, including its velocity, distribution, and mixing characteristics, to achieve the minimum required for combustion stability. By carefully controlling these parameters, the system maintains reliable combustion while minimizing the conditions that lead to carbon deposition on the inner lip surfaces.
Solution Approach 2:
The design uses the outer air flow as a model for optimizing the inner air flow characteristics. The outer lip geometry, which is optimized to prevent carbon deposition, serves as a template for designing the inner lip and controlling the inner air flow, ensuring that stability is achieved without excessive carbon buildup.
4Object-generated harmful factors
If emulsion injection is used to reduce flame temperature, then NOx emissions decrease, but combustion efficiency may be affected
Solution Approach 1:
The design replaces simple liquid injection with an emulsion injection system that combines liquid fuel and air in a controlled mixture. This substitution allows for better vaporization and mixing characteristics, ensuring that the reduced flame temperature from emulsion use does not significantly compromise combustion efficiency, while still achieving NOx reduction goals.
Solution Approach 2:
The emulsion itself acts as an intermediary between the liquid fuel and the air, providing a pre-mixed state that facilitates more complete and efficient combustion. This intermediary form ensures that even at reduced temperatures, the combustion process remains efficient while achieving the desired NOx emissions reduction.
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
This design improves atomization, reduces carbon deposition, and achieves a more stable combustion process with lower NOx emissions by ensuring a uniform emulsion film and efficient break-up into smaller droplets, effectively managing flame temperature and emissions.
Implementation Method 1
the flow of inner air attacks said emulsion film at a surface of a wall adjacent to said emulsion film, thereby disintegrating said emulsion film into a spray of smaller droplets
Implementation Method 2
The jet of outer air will then disintegrate the liquid/emulsion into droplets and distribute them into the jet
Implementation Method 3
The present invention is directed to a nozzle arrangement and a method of injection of an emulsion of fluids into a main flame in a combustion process
Implementation Method 4
Stable combustion in gas turbine engines requires a cyclic process of combustion producing combustion products that are transported back upstream to initiate the combustion process
Implementation Method 5
The heat and free radicals from the previously reacted fuel and air are required to initiate (pyrolyze fuel and initiate chain branching process) and sustain stable combustion of the fresh un-reacted fuel and air mixture
Implementation Method 6
a burner arranged to be fueled with gas fuel... The pilot combustor supplies heat and supplements a high concentration of free radicals directly to a forward stagnation point and a shear layer of the main swirl induced recirculation zone
Data Source
AI summary
An arrangement for injection of an emulsion of a first fluid and a second fluid into a flame of a burner has a central gas duct, an outer gas channel disposed coaxially with the gas duct, and a fluid channel disposed coaxially between the gas duct and the outer gas channel. The central gas duct and the fluid channel are separated by a first frustoconical wall. The fluid channel and the outer gas channel are separated by a second frustoconical wall. The arrangement is mounted concentrically surrounding a heat source which provides through the gas duct hot gases being directed into the flame of the burner. Further, the arrangement includes a mixing device for forming an emulsion of the first fluid and the second fluid, for supplying the emulsion into the fluid channel and for injecting the emulsion from the fluid channel into the flame.