Passive Heat Exchanger Flow Control Using Heat Pipe Actuation
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Solution Overview
Problem
Conventional heat exchanger systems in aircraft turbojet engines require complex installations with valves and control units to manage fluid flow, which complicates thermal regulation and increases system complexity.
Innovation Solution
A passive heat exchanger system utilizing a shape memory element and heat pipe to control fluid flow based on the temperature of a second fluid, eliminating the need for valves and control units by using a shape memory element to move a closure mechanism within the heat exchanger.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional valves and control units are used to control fluid flow, then thermal regulation is achieved, but system complexity increases
Solution Approach 1:
The heat exchanger system uses the thermal energy of the second fluid itself to drive the flow control mechanism. The temperature-dependent viscosity change of the second fluid automatically regulates the flow of the first fluid without external control systems, making the system self-regulating and eliminating complex control units.
Solution Approach 2:
The patent replaces conventional mechanical valves and electronic control units with a passive fluidic resistance control mechanism. The control is achieved through temperature-dependent viscosity changes of the second fluid, substituting complex mechanical/electrical systems with a simpler thermally-driven fluid dynamic system.
2Ease of operation
If valves and control units are installed, then fluid flow control is precise, but installation complexity increases
Solution Approach 1:
The invention extracts and eliminates the need for separate valves and control units by integrating the flow control function directly into the heat exchanger structure. The channel geometry and fluid properties themselves provide the control mechanism, removing unnecessary components and simplifying installation.
Solution Approach 2:
The second fluid serves multiple functions: it is the heat transfer medium and simultaneously the control medium for regulating the first fluid flow. This multi-functionality eliminates the need for separate control systems and reduces installation complexity.
3Device complexity
If passive control based on temperature is implemented, then system complexity is reduced, but control precision may be affected
Solution Approach 1:
The system exploits changes in the temperature-dependent viscosity parameter of the second fluid to achieve flow control. As the temperature of the second fluid changes, its viscosity changes, which passively and precisely regulates the flow rate of the first fluid through the shared channel, providing accurate control without complex instrumentation.
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 simplifies the system by allowing passive control of fluid flow based on temperature, reducing complexity and enhancing thermal regulation efficiency without the need for additional control components.
Implementation Method 1
an actuation system (350) which comprises a heat pipe (402) and a shape memory element (404), the shape memory element (404) being in thermal contact with the heat pipe (402) and being arranged so as to move the closure means (312) according to its temperature
Implementation Method 2
an actuation system (350) which comprises a heat pipe (402) and a shape memory element (404), the shape memory element (404) being in thermal contact with the heat pipe (402)
Data Source
Figure 1~2
Figure 3~4
AI summary
The invention relates to a heat exchanger system (300) comprising a heat exchanger (302) with a first inlet (304) and a first outlet (306) for a first fluid, a second inlet (308) and a second outlet (310) for a second fluid, a closure means (312) that is movable and arranged to partially or fully close the first inlet (304) or the first outlet (306), and an actuation system (350) comprising a closed heat pipe filled with a heat transfer fluid and whose first end is immersed in the second fluid, and a shape memory element that is in thermal contact with the heat pipe and is arranged to move the closure means (312) according to its temperature. Such an architecture thus allows passive control of the flow of one of the fluids based on the temperature of the other fluid.