Thermal Compensator Coating for Rocket Engine Combustion Chamber
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Solution Overview
Problem
In rocket engine combustion chambers, the condensation of combustion gases on the internal face of the divergent wall causes flow disturbances and reduces the chamber's lifespan due to temperature variations, which existing cooling methods using circulating propellants fail to adequately address.
Innovation Solution
A thermal compensator coating is applied to the internal face of the divergent wall, ensuring its temperature remains above the condensation temperature of the combustion gases, preventing condensation and maintaining a stable temperature gradient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If propellant circulation cooling is used to cool the divergent wall, then the wall temperature is reduced to prevent overheating, but the internal face temperature drops below the condensation temperature of combustion gases causing condensation and flow disturbances
Solution Approach 1:
A thermal compensator coating is introduced as an intermediary layer between the cooled wall and the combustion gases. This coating acts as a thermal barrier that prevents direct contact between the cold wall surface and the hot combustion gases, thereby eliminating condensation while maintaining the cooling effect on the wall structure.
Solution Approach 2:
The invention changes the thermal parameters of the internal face by applying a coating with specific thermal conductivity properties. The coating thickness and material composition are designed to maintain the internal face temperature above the condensation temperature of combustion gases, preventing condensation while allowing effective wall cooling.
2Use of energy by moving object
If the internal face roughness is increased to enhance heat exchange surface area, then heat transfer efficiency improves, but manufacturing complexity and modeling difficulty increase significantly
Solution Approach 1:
Instead of creating complex rough surfaces that are difficult to manufacture and model, the invention uses a simple thermal compensator coating that can be applied relatively easily. The coating provides sufficient thermal compensation without requiring complex surface geometries, thereby reducing manufacturing and modeling complexity while maintaining effective heat exchange.
3Object-affected harmful factors
If the internal face temperature is increased to prevent condensation, then condensation is eliminated, but the cooling effectiveness of the propellant circulation system is reduced
Solution Approach 1:
The thermal compensator coating serves as a mediator that allows the wall to be cooled effectively by propellant circulation while preventing the internal face temperature from dropping below the condensation temperature. The coating thickness and thermal properties are optimized to provide this thermal compensation without requiring excessive temperature increases.
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 coating effectively prevents condensation on the internal face of the divergent portion, reducing flow disturbances and extending the chamber's lifespan by maintaining a stable temperature, and is easier to manufacture and adjust than existing solutions.
Implementation Method 1
a coating (40) acting as a thermal compensator so that the temperature of the internal face (42) of this coating is higher than the condensation temperature of the combustion gases on this internal face under operating conditions
Implementation Method 2
the most common method for carrying out this cooling consists in circulating one of the propellants in or in contact with the wall (30) of the divergent (20)
Data Source
Figure 1~2
AI summary
The invention relates to a combustion chamber (10) comprising a neck (15) that is downstream from the gas injection (11) and, downstream from said neck, a divergent tube (20), the outer surface of the wall (30) of which, during operation, is cooled by a cooling system surrounding said outer surface. Said divergent tube (20) comprises, on the inner surface (32) of the wall (30) thereof, a coating (40) playing the role of a heat compensator so that the temperature of the inner surface (42) of the coating (40) is greater than the combustion gas condensation temperature on said inner surface (42) under operating conditions such that no condensation is formed on said inner surface (42).