Aircraft Engine Recuperator Bypass for High-Power Pressure Loss
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Solution Overview
Problem
Aircraft engines with recuperators face inefficiencies during high-power conditions, such as when one engine becomes inoperative, leading to increased pressure loss and limited power output due to the recuperator's heat exchange process.
Innovation Solution
Incorporating a closure mechanism in the aircraft engine that automatically bypasses the recuperator when a pressure drop threshold is exceeded, allowing compressed air to flow directly to the combustor, thereby maintaining power output by minimizing pressure loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the recuperator is used to transfer heat from combustion gases to compressed air, then fuel efficiency is improved, but pressure loss increases during high-power conditions
Solution Approach 1:
The closure is designed to be movable between a closed position (normal operation) and an opened position (high-power condition), allowing the system to dynamically adapt its configuration based on operating conditions. The closure moves in response to pressure differential across the recuperator, enabling automatic bypass when pressure loss becomes excessive.
Solution Approach 2:
The system changes the flow path configuration parameter by moving the closure between closed and open states. This parameter change allows the compressed air flow to switch between passing through the recuperator (normal condition) and bypassing it directly (high-power condition), thereby controlling pressure loss while maintaining fuel efficiency.
2Productivity
If the recuperator is used for heat exchange, then engine efficiency is improved, but power output is limited during high-power demands
Solution Approach 1:
The movable closure enables the system to dynamically switch between two operational modes: normal mode with the closure closed for efficient heat exchange, and high-power mode with the closure open to maximize power output. This dynamic adaptation allows the engine to maintain high power output capability while preserving efficiency during normal operation.
Solution Approach 2:
The flow path is segmented into two separate routes: through the recuperator for efficient heat exchange and direct bypass for high-power conditions. The closure acts as a switch between these segmented paths, allowing the system to select the appropriate route based on power demands.
3Stress or pressure
If a closure mechanism is added to bypass the recuperator, then pressure loss is reduced during high-power conditions, but device complexity increases
Solution Approach 1:
The closure mechanism is designed to be self-actuating, using the pressure differential across the recuperator itself as the actuating force. The higher pressure on the compressed air side automatically pushes the closure open when bypassing is needed, eliminating the need for external actuators, sensors, or control systems.
Solution Approach 2:
The closure acts as an intermediary element between the compressed air flow and the exhaust system, providing a simple mechanical switch that directs flow through or around the recuperator based on pressure conditions.
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 ensures efficient power generation during high-power demands by bypassing the recuperator, enhancing engine performance in critical situations.
Implementation Method 1
a recuperator having a heat absorption conduit fluidly connecting the compressor to the combustor and a exhaust conduit fluidly connecting the turbine to ambient air surrounding the aircraft engine, the heat absorption conduit in heat exchange relationship with the exhaust conduit
Implementation Method 2
the closure is structured to move from the closed position to the opened position upon a pressure drop through the recuperator exceeding a pressure drop threshold
Data Source
Figure 1
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AI summary
An aircraft engine (10) has: a compressor (13), a combustor (14) downstream of the compressor (13), and a turbine (15); a recuperator (20) having a heat absorption conduit (21) fluidly connecting the compressor (13) to the combustor (14) and a exhaust conduit (22) fluidly connecting the turbine (15) to ambient air surrounding the aircraft engine (10), the heat absorption conduit (21) in heat exchange relationship with the exhaust conduit (22); a compressor conduit (23) fluidly connecting the compressor (13) to the heat absorption conduit (21) of the recuperator (20), the compressor conduit (23) defining a bypass outlet (27) upstream of the recuperator (20) relative to the flow of the compressed air; and a closure (28) at the bypass outlet (27), the closure (28) having: a closed position in which the closure (28) closes the bypass outlet (27); and an opened position in which the closure (28) opens the bypass outlet (27), wherein the closure (28) is structured to move from the closed position to the opened position upon a pressure drop through the recuperator (20) exceeding a pressure drop threshold.