Aircraft Engine Heat Exchange With Bypass and Recirculation
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Solution Overview
Problem
Existing aircraft engine heat exchangers fail to effectively manage temperature variations of fluids, which can affect the efficiency of components downstream, particularly during changes in power levels such as takeoff and landing.
Innovation Solution
A heat exchange system with bypass and recirculation conduits, controlled by valves and a controller, adjusts fluid flow to maintain temperature within a threshold by diverting fluid through a bypass or recirculation path based on sensor feedback, using a flow inducer to manage pressure differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conventional heat exchanger is used, then heat exchange between fluids occurs, but temperature variations of the fluid cannot be effectively controlled
Solution Approach 1:
The system dynamically switches between bypass mode and recirculation mode based on real-time temperature conditions. The bypass conduit allows cold fluid to skip the heat exchanger when overheating occurs, while the recirculation conduit returns warm fluid to the heat exchanger inlet when underheating occurs, making the temperature control adaptive and dynamic
Solution Approach 2:
The control unit continuously monitors fluid temperature and uses this feedback to automatically adjust the valve positions. When temperature exceeds the threshold, the system activates bypass mode; when temperature is below the threshold, it activates recirculation mode, creating a closed-loop feedback control system
2Use of energy by moving object
If the heat exchanger processes all fluid, then maximum heat exchange occurs, but temperature fluctuations affect downstream components
Solution Approach 1:
The fluid flow is segmented into two separate paths: a bypass path that avoids the heat exchanger and a recirculation path that returns to the heat exchanger inlet. The control unit segments the flow based on temperature needs, allowing precise control over how much fluid undergoes heat exchange versus how much bypasses or recirculates
Solution Approach 2:
The system changes the flow distribution parameter dynamically by adjusting valve positions. The bypass valve and recirculation valve modify the flow split ratio between different paths, changing the effective heat exchange parameter to maintain stable outlet temperature
3Adaptability or versatility
If bypass conduit is added, then temperature control flexibility improves, but system complexity increases
Solution Approach 1:
The control unit serves multiple functions: it monitors temperature, determines the appropriate control mode (bypass or recirculation), and actuates the appropriate valve. This multi-functional control approach manages the complexity of multiple conduits and valves through a single intelligent control element
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 system stabilizes fluid temperature, ensuring optimal operation of downstream components by mitigating temperature fluctuations and maintaining efficiency across varying engine conditions.
Implementation Method 1
a heat exchanger having a first conduit fluidly connected to a source of a fluid being at a lower temperature than the exhaust gases, and a second conduit fluidly connected to the outlet of the thermal engine and in heat exchange relationship with the first conduit
Implementation Method 2
a flow inducer in fluid communication with the recirculation conduit for inducing a flow from the outlet conduit to the inlet conduit via the recirculation conduit
Data Source
Figure 1
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AI summary
An aircraft engine, comprising: a thermal engine having an outlet; a heat exchanger (31) having a first conduit (31A) connected to a source of a fluid, and a second conduit (31B) connected to the outlet; an inlet conduit (32) connecting the source to the first conduit (31A); an outlet conduit (33) connected to an outlet of the first conduit (31A); a component (22) connected to the outlet conduit (33); a bypass conduit (34) and a recirculation conduit (35) both connecting the inlet conduit (32) to the outlet conduit (33) while bypassing the heat exchanger (31); a valve (36, 37) communicating with the recirculation conduit (35) and the bypass conduit (34), the valve (36, 37) operable to selectively allow the fluid to flow in one of the recirculation conduit (35) and the bypass conduit (34) while limiting the fluid from flowing in the other of the recirculation conduit (35) and the bypass conduit (34); and a flow inducer (38) communicating with the recirculation conduit (35) for inducing a flow from the outlet conduit (33) to the inlet conduit (32).