Multi-Cone Premix Burner Varying Cone Angle Flame Stability
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Solution Overview
Problem
Current premix burners for gas turbines face issues with flame stability and axial oscillations due to fixed design parameters, leading to constraints on burner length and envelope, and require a bluff body for stable combustion.
Innovation Solution
A multi-cone premix burner design with a varying cone angle generated by twisting a common cone around the central axis, allowing for a bell-shaped configuration with adjustable swirl strength and eliminating the need for a long lance, achieved by rotating meridians to create shells with inclined premix gas channels for efficient fuel-air mixing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a fixed cone angle is used in the premix burner design, then the burner structure is simple and manufacturing is easier, but the flame stability is reduced and axial oscillations occur
Solution Approach 1:
The burner employs a variable cone angle design where the cone angle changes along the axial direction rather than being fixed. This dynamic geometric variation allows the swirl strength to be optimized at different positions, enhancing flame stability and reducing axial oscillations while maintaining a relatively simple overall structure.
Solution Approach 2:
The invention changes the geometric parameter (cone angle) along the axial direction to optimize performance. By varying the cone angle, the swirl strength distribution is improved, which stabilizes the flame and reduces oscillations without requiring complex additional components.
2Stability of the object's composition
If a long lance is used as a bluff body for stable combustion, then flame stability is improved, but the burner length increases and the envelope is constrained
Solution Approach 1:
Instead of using a long fixed bluff body (lance), the invention employs a variable cone angle design that dynamically optimizes swirl strength along the axial direction. This approach achieves stable combustion without requiring an extended burner length or large envelope.
Solution Approach 2:
The variable cone angle parameter allows the burner to achieve stable combustion through optimized flow dynamics rather than relying on a long physical structure. This parameter variation enables compact burner design while maintaining combustion stability.
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 enhances flame stability by varying swirl strength along the axis, reducing axial oscillations and enabling stable combustion without a bluff body, allowing for a shorter burner layout and improved fuel evaporation time for dry oil injection.
Implementation Method 1
the combustion air required for this purpose is directed through tangential air-inlet ducts into an interior space of the burner. This directing of the flow results in a swirl flow in the interior space
Implementation Method 2
the swirl strength is increasing linearly along the axis until it reaches the critical swirl strength for vortex breakdown near to the burner axis
Data Source
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Figure 5
AI summary
The invention relates to a premix burner (10) of the multi-cone type for a gas turbine, comprising a plurality of shells (16a-d), which are arranged around a central burner axis (11) and are parts of a virtual, axially extending common cone, which opens in a downstream direction, whereby said parts are displaced perpendicular to said burner axis (11) such that a tangential slot (17) is defined between each pair of adjacent shells (16a-d). The flame front of such a burner (10) is stabilized by providing a virtual common cone with a cone angle, which varies in axial direction.