Temperature-Responsive Rocket Nozzle Throat Adaptation
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Solution Overview
Problem
Rocket nozzles face challenges in maintaining or varying thrust efficiently due to changes in altitude, environmental conditions, and propellant mass flow, with existing solutions adding complexity, weight, and inefficiency, particularly at sea level versus vacuum conditions.
Innovation Solution
Nozzles with temperature-responsive materials that change internal profiles, such as shape memory alloys and refractory materials, adjust throat diameter in response to temperature changes, maintaining high chamber pressure and thrust efficiency during propellant depletion or varying mission phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If mechanical features are added to adjust nozzle contours and area ratios, then thrust can be varied during flight, but device complexity and weight increase
Solution Approach 1:
The patent replaces mechanical adjustment systems with a material that changes its physical properties in response to temperature variations. The nozzle structure incorporates a material that undergoes phase transition or thermal expansion/contraction to automatically adjust the throat area and contour based on combustion chamber temperature, eliminating the need for external mechanical actuators, motors, or control systems.
Solution Approach 2:
The invention utilizes temperature as a control parameter to induce changes in the nozzle's geometric parameters (throat area, contour, expansion ratio). As the combustion chamber temperature varies during flight, the nozzle material's physical dimensions change accordingly, enabling thrust adaptation without mechanical intervention.
2Adaptability or versatility
If mechanical features are added to adjust nozzle contours and area ratios, then thrust can be varied during flight, but weight increases
Solution Approach 1:
The patent replaces mechanical adjustment systems with a material that changes its physical properties in response to temperature variations. The nozzle structure incorporates a material that undergoes phase transition or thermal expansion/contraction to automatically adjust the throat area and contour based on combustion chamber temperature, eliminating the need for external mechanical actuators, motors, or control systems.
Solution Approach 2:
The nozzle structure serves its own adjustment function by utilizing the thermal environment already present in the combustion chamber. The material's inherent response to temperature changes enables self-regulation of the nozzle geometry, eliminating the need for separate weight-bearing adjustment mechanisms.
3Object-affected harmful factors
If nozzle exit area is reduced for launch and then increased during ascent, then reverse pressure differentials are corrected, but device complexity increases
Solution Approach 1:
The invention utilizes temperature as a control parameter to induce changes in the nozzle's geometric parameters (throat area, contour, expansion ratio). As the combustion chamber temperature varies during flight, the nozzle material's physical dimensions change accordingly, enabling thrust adaptation without mechanical intervention.
Solution Approach 2:
The patent replaces mechanical adjustment systems with a material that changes its physical properties in response to temperature variations. The nozzle structure incorporates a material that undergoes phase transition or thermal expansion/contraction to automatically adjust the throat area and contour based on combustion chamber temperature, eliminating the need for external mechanical actuators, motors, or control systems.
4Productivity
If high area ratio nozzles are used to achieve high specific impulse at high altitude, then thrust efficiency improves, but thrust at sea level decreases
Solution Approach 1:
The patent transforms the nozzle from a static component to a dynamic one that automatically adjusts its geometry in response to changing operating conditions. The nozzle throat area and contour vary with temperature, enabling the same nozzle to optimize performance across different flight phases - achieving high specific impulse at altitude when temperature is high and maintaining adequate sea level thrust when temperature is lower.
Solution Approach 2:
The invention utilizes temperature as a control parameter to induce changes in the nozzle's geometric parameters (throat area, contour, expansion ratio). As the combustion chamber temperature varies during flight, the nozzle material's physical dimensions change accordingly, enabling thrust adaptation without mechanical intervention.
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
This solution allows for adaptive thrust management, maintaining high combustion efficiency and thrust during propellant depletion and varying mission phases without adding weight or complexity, by altering the nozzle profile in response to temperature changes, effectively addressing the inefficiencies of traditional nozzle designs.
Implementation Method 1
The temperature responsivity of the nozzle profile is achieved by constructing the nozzle or parts of the nozzle with one or more materials that have properties that vary with temperature... Useful properties for this purpose are... crystallographic phase (as in the shape memory effect of certain metal alloys)
Implementation Method 2
Portions of the nozzle, such as panels mounted to the nozzle wall or structural members supporting the panels, can be fabricated of materials that display this behavior at the desired temperature. In certain embodiments of this invention, these structural components can be shaped such that once the strength and stiffness of the panel or structural member are lowered the pressure of the gas in the nozzle causes the panel to partially flatten.
Implementation Method 3
The change in profile can for example be produced by a change in contour of one or more interior surfaces of the nozzle, due to a change in shape of an insert residing in the nozzle interior or of a lining on the nozzle wall
Data Source
AI summary
Nozzles that offer shape variability to maintain or purposely change the pressure drop across the throat are obtained by constructing the nozzles with components that change their shape, angle, or curvature in response to temperature changes that occur during the flow of combustion products through the nozzle. The temperature change may be the gradual heating of the nozzle wall from hot combustion gases, and the shape change may result in a decrease in the throat diameter or an expansion of the throat diameter. A decrease in throat diameter will be useful when the depletion of propellant as burning proceeds causes a drop in the pressure or flow rate of the combustion gas and there is a need to compensate for this drop to maintain the pressure drop across the throat. An increase in throat diameter will be useful when an initial high thrust is no longer needed and depletion of the fuel by itself is insufficient to lower the thrust to its desired reduced level. An example of a temperature-responsive material is a shape memory alloy; other examples are presented as well.