Combustion Chamber Heat Exchanger Ducts for Fuel Preheating
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Solution Overview
Problem
Existing combustion chamber designs for engines using gaseous fuels like hydrogen lack efficient preheating mechanisms and cooling systems, leading to inefficient fuel injection and increased emissions, particularly NOx emissions.
Innovation Solution
A combustion chamber assembly with integrated heat exchanger ducts in the combustion chamber wall for preheating fuel and cooling the chamber, utilizing the high temperatures within the combustion space for efficient heat transfer and reducing the need for additional cooling air flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If fuel is injected directly into the combustion chamber without preheating, then the fuel injection system is simpler, but the fuel temperature remains low leading to inefficient combustion and increased emissions
Solution Approach 1:
The patent combines the fuel preheating function with the combustion chamber wall structure by integrating heat exchanger ducts into the wall. The fuel flows through these ducts, utilizing the high-temperature combustion gases on one side and the cooler fuel on the other side to achieve heat transfer. This merging eliminates the need for separate preheating equipment while effectively raising the fuel temperature before injection.
Solution Approach 2:
The combustion chamber wall with integrated heat exchanger ducts acts as an intermediary between the hot combustion gases and the cold fuel. The wall structure mediates heat transfer from the combustion process to the fuel, allowing the fuel to be preheated indirectly through the duct walls rather than direct contact with combustion gases.
2Temperature
If additional cooling air flow is used to cool the combustion chamber, then the chamber temperature is controlled, but less air is available for combustion and NOx emissions increase
Solution Approach 1:
The fuel serves a dual function: it is both the combustion material and the cooling medium. As the fuel flows through the heat exchanger ducts in the combustion chamber wall, it absorbs heat from the combustion gases, thereby cooling the chamber wall. This self-service approach eliminates the need for separate cooling air flows, keeping more air available for combustion and reducing NOx emissions.
Solution Approach 2:
The patent recovers heat from the hot combustion gases that would otherwise be wasted. By channeling this thermal energy through the heat exchanger ducts to preheat the fuel, the system recovers energy that would otherwise be lost, improving overall efficiency while maintaining chamber temperature control without additional cooling air.
3Duration of action of stationary object
If the combustion chamber wall is cooled by fuel flowing through it, then the chamber wall temperature is reduced extending its lifetime, but the fuel requires additional flow pathways
Solution Approach 1:
The fuel flow system is designed to perform multiple functions simultaneously: it delivers fuel to the combustion chamber, preheats the fuel through heat exchange with combustion gases, and cools the combustion chamber wall. By making the fuel flow pathway multi-functional, the patent avoids adding separate systems for each function, thereby extending chamber lifetime without proportionally increasing complexity.
Solution Approach 2:
The patent utilizes the wall thickness dimension of the combustion chamber to create heat exchanger ducts. By flowing fuel through the wall structure itself rather than adding external cooling systems, the solution uses the existing spatial dimension of the wall to achieve cooling, integrating the function into the existing geometry rather than adding complexity.
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
Enhances fuel preheating efficiency, reduces NOx emissions, and extends the lifetime of the combustion chamber by optimizing fuel injection and cooling, while allowing more air for combustion.
Implementation Method 1
at least one integrated heat exchanger duct via which the fuel is routed within a first duct section of the heat exchanger duct which is connected to the fuel line from the combustion chamber head in the direction of the combustion chamber outlet and, after flowing through a deflection region, in a second duct section of the heat exchanger duct, back in the direction of the combustion chamber head and of the nozzle head
Implementation Method 2
utilizing the high temperatures within the combustion space for efficient heat transfer and reducing the need for additional cooling air flow
Data Source
AI summary
A combustion chamber assembly for an engine includes a combustion chamber defining a combustion space delineated by a combustion chamber wall and extending in a main flow direction from a combustion chamber head to a combustion chamber outlet. A fuel injection system is joined to the wall at the combustion chamber head and has a fuel feed for fuel and a nozzle head for injecting the fuel into the combustion space. The wall also has an integrated heat exchanger duct via which the fuel is routed within a first duct section of the heat exchanger duct which is connected to the fuel line from the combustion chamber head in the direction of the combustion chamber outlet and, after flowing through a deflection region, in a second duct section of the heat exchanger duct, back in the direction of the combustion chamber head and of the nozzle head.