Combustion Chamber Air Split Control for Low-Emission Turbines
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Solution Overview
Problem
Existing combustion chamber arrangements in micro gas turbines face challenges in maintaining optimal air-fuel ratios across varying load ranges, leading to inconsistent emissions due to fixed geometry and limited adjustment capabilities, which affect the efficiency and emissions of gas turbines.
Innovation Solution
A combustion chamber arrangement with an adjusting device that separates the primary and secondary oxidizer flows, allowing for precise adjustment of the split ratio through a movable adjusting element, independent of the fuel line, to optimize emissions over a wide load range and varying conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed geometry combustion chamber arrangement is used, then the structure is simple and reliable, but the air-fuel ratio cannot be optimized across varying load ranges, leading to increased emissions
Solution Approach 1:
The patent applies the dynamics principle by making the primary channel flow cross-section adjustable during operation. An adjusting device with an adjusting element (such as a movable plate or ring) is integrated into the primary channel, allowing the flow cross-section to be dynamically changed based on load conditions. This enables the combustion chamber to adapt its air-fuel ratio to varying load ranges, resolving the contradiction between fixed structure simplicity and adaptability requirements.
2Object-generated harmful factors
If the flow cross-section of the primary channel is adjusted to optimize air-fuel ratio, then emissions are minimized, but the adjusting device complexity increases
Solution Approach 1:
The patent applies segmentation by separating the adjusting function from the fuel supply system. The adjusting device is designed as an independent component with an adjusting element that can be operated separately from the fuel line and injection timing controls. This segmentation allows the air flow adjustment to be optimized for emissions reduction without being constrained by fuel system requirements, while keeping the overall device complexity manageable through functional separation.
3Adaptability or versatility
If an orifice plate is used to control mixing air openings, then the split can be controlled, but high temperatures and thermal expansion affect tolerance and effectiveness
Solution Approach 1:
The patent applies the extraction principle by removing the adjusting element from the high-temperature combustion zone environment. The adjusting device is positioned in the oxidizer plenum or primary channel upstream of the combustion chamber, where temperatures are significantly lower. This extraction of the adjusting mechanism from the thermal environment eliminates thermal expansion issues and tolerance degradation, ensuring reliable long-term operation while maintaining split control capability.
Data Source
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Figure 3A~3B
AI summary
The invention relates to a combustion chamber arrangement (1), particularly for a gas turbine, especially a micro gas turbine, comprising: - a combustion chamber (2) extending along a longitudinal axis (L) and comprising a combustion chamber wall (10), a combustion chamber (4) circumferentially bounded by the combustion chamber wall (10), an inlet-side end wall (12), and at least one secondary opening (36) arranged downstream of the end wall (12) in the combustion chamber wall (10) for adding a secondary flow of oxidizer from the oxidizer plenum (6) into the combustion chamber (2); - an oxidizer plenum (6) arranged upstream of the combustion chamber (2); - at least one feed nozzle (16) arranged on the end wall (12) with a primary channel (22) extending on a nozzle axis (M) and bounded by a nozzle wall (20), with an oxidizer outlet opening (24) downstream for swirl-free supply of a Primary flow to oxidizer from the oxidizer plenum (6) via the inlet-side end wall (12) into the combustion chamber (4),- at least one, possibly one per feed nozzle (16), fuel line (26) with a fuel channel (28) and a fuel outlet opening (30) located downstream within the primary channel (22) and/or at the level of the oxidizer outlet opening (24) for supplying the fuel to the oxidizer and/or to the combustion chamber (4), and - an adjusting device (40) by means of which a split between the primary flow and the secondary flow can be adjusted during operation by adjusting a flow cross-section (224) of the primary channel (22). Minimized emissions over a wide operating range are achieved by the adjusting device (40) having an adjusting element (42) separate from the fuel line (26) and assigned to the at least one feed nozzle (16), which in a first position opens the flow cross-section (224) to the maximum, and/or in a second position closes the flow cross-section (224) to the maximum.