Bellows Wax Thermal Actuator for Uniform Heat Distribution
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Solution Overview
Problem
Current thermal actuators for aircraft engines are inadequate for efficiently regulating engine fluid temperatures, as they lack effective solutions for uniform heat distribution and long cycle life.
Innovation Solution
A thermal actuator comprising a metal bellows filled with wax and an oil film outside, with a piston movable due to thermal expansion, and a heat-transfer fluid for uniform temperature distribution and reduced stress on the metal bellows.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a thermal actuator is used to regulate engine fluid temperatures, then temperature control function is provided, but uniform heat distribution is insufficient
Solution Approach 1:
The patent introduces a bellows as an intermediary component filled with thermal expansion material (wax). This bellows acts as a mediator between the heat transfer fluid and the piston, converting thermal energy into mechanical movement through the expansion and contraction of the wax material, thereby achieving uniform heat distribution and reliable temperature control.
Solution Approach 2:
The patent utilizes the phase transition properties of wax material inside the bellows. The wax undergoes phase change from solid to liquid and back, expanding and contracting in response to temperature changes. This phase transition mechanism enables the bellows to effectively distribute heat uniformly and drive the piston for precise temperature regulation.
2Reliability
If a thermal actuator operates in aircraft engine applications, then temperature control is achieved, but cycle life is insufficient
Solution Approach 1:
The patent changes the physical parameters of the thermal expansion material by selecting wax with specific melting and expansion characteristics. This parameter optimization allows the material to undergo smooth phase transitions with minimal stress, thereby extending the cycle life of the actuator while maintaining reliable operation in aircraft engine environments.
Solution Approach 2:
The bellows structure provides beforehand cushioning by absorbing thermal expansion stresses through its flexible geometry. The convoluted design of the bellows allows it to expand and contract smoothly, cushioning the mechanical stresses that would otherwise limit the cycle life of the actuator during repeated temperature cycling.
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 solution provides efficient temperature regulation and extended cycle life by utilizing the wax's phase change to drive mechanical movement, ensuring reliable operation in aircraft engine applications.
Implementation Method 1
When the temperature rises above the wax melting point, the wax changes phase from solid to liquid, expanding in volume significantly
Implementation Method 2
the wax changes phase from solid to liquid, expanding in volume significantly
Implementation Method 3
a heat-transfer fluid between the housing and the metal bellows, the heat-transfer fluid in heat exchange relationship with the thermal expansion material inside the metal bellows
Data Source
AI summary
A thermal actuator has a bellows construction with a heat-transfer fluid (e.g. oil) located outside the bellows and a thermal expansion material (e.g. wax) located inside the interior volume of the bellows.