Dual Fuel Lance Cooling Microchannels
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Solution Overview
Problem
Conventional lance cooling methods in gas turbines require high-pressure, low-temperature air, which reduces operational efficiency due to the need for compressors and heat exchangers, and there is a need for a dual-fuel capable lance that can operate effectively with lower pressure and higher temperature air for improved turbine efficiency.
Innovation Solution
A dual-fuel lance with a unique geometry featuring concentric conduits for fuel injection and microchannel cooling, where compressed cooling air is used to convectively cool the lance, and strategically placed microchannels reduce the volume of cooling air needed, allowing for efficient cooling at lower pressures and higher temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional convective cooling methods are used with high-pressure, low-temperature air, then the lance is effectively cooled, but the operational efficiency of the gas turbine is reduced due to parasitic loads from compressors and heat exchangers
Solution Approach 1:
The invention changes the parameters of cooling air from high-pressure/low-temperature to lower-pressure/higher-temperature by using microchannel cooling geometry that increases heat transfer efficiency, allowing the use of hotter air that would otherwise be insufficient for cooling
Solution Approach 2:
The invention applies local quality by creating high-density cooling channels specifically at locations of highest thermal load (e.g., fuel injection holes, tip region) rather than uniform cooling throughout, maximizing cooling effectiveness where most needed
2Temperature
If the volume of cooling air is increased to improve cooling effectiveness, then the lance temperature is reduced, but the parasitic loads and operational efficiency issues are exacerbated
Solution Approach 1:
The microchannel geometry fundamentally changes the heat transfer parameters by reducing channel dimensions to micrometer scale, which dramatically increases surface area to volume ratio and heat transfer coefficients, allowing effective cooling with minimal air volume
Solution Approach 2:
The invention transitions from conventional macro-scale cooling channels to micro-scale channels, exploiting the dimensional reduction to achieve superior heat transfer efficiency and reduced cooling media requirements
3Reliability
If high-pressure cooling air is used to achieve sufficient cooling, then the cooling effectiveness is maintained, but the complexity of the cooling system increases due to compressor requirements
Solution Approach 1:
The microchannel geometry changes the pressure parameter requirements by leveraging enhanced heat transfer at micro-scales, allowing effective cooling at lower pressures that eliminate or reduce the need for dedicated cooling compressors
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 lance maintains dual-fuel capability while improving turbine efficiency by effectively cooling the lance using air at lower pressures and higher temperatures, reducing the need for parasitic loads and enhancing operational efficiency.
Implementation Method 1
compressed cooling air is used to convectively cool the lance
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A lance (100) for a burner includes an innermost conduit (150), an intermediate conduct (160), and an outermost conduit (170) in a concentric array. The conduits (150, 160, 170) define respective fluid passages (154, 164, and 174) and respective fuel injection channels (156, 166, 176). Cooling microchannels (200) extend between inlets in the third fluid passage (174) and outlets on the outer surface of the outermost conduit (170).