Multi-pass Heat Exchanger Bypass Valves for Thermal Strain Reduction
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Solution Overview
Problem
Conventional heat exchangers in gas turbine engines provide either full heat transfer or no heat transfer, failing to offer sufficient temperature control across a range of engine operating conditions, leading to thermal strain and transient thermal shock in hydrogen-fuel propulsion systems.
Innovation Solution
A multi-pass heat exchanger with active or passive bypass valves is introduced, allowing for modulation of heat transfer rates between hot and cold fluids based on engine operating conditions, ensuring finer temperature control and reducing thermal strain by fluidly coupling a primary tube outlet with a secondary or intermediate tube outlet.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional heat exchangers provide full heat transfer or no heat transfer, then heat transfer capability is maintained, but temperature control precision deteriorates
Solution Approach 1:
The patent applies the dynamics principle by introducing bypass valves that can dynamically adjust the heat transfer rate between hot and cold fluids. The bypass valves enable the heat exchanger to transition between different heat transfer modes (full heat transfer, partial heat transfer, or no heat transfer) based on engine operating conditions, thereby achieving precise temperature control across a wide range of operating conditions without causing thermal strain or transient thermal shock.
2Reliability
If conventional heat exchangers operate without bypass capability, then device complexity is reduced, but thermal strain and transient thermal shock increase
Solution Approach 1:
The patent applies the intermediary principle by introducing bypass valves as mediator components between the hot fluid channel and cold fluid channel. These bypass valves act as control intermediaries that can selectively allow or block heat transfer paths, enabling precise temperature regulation and preventing thermal strain and transient thermal shock in hydrogen-fuel propulsion systems while maintaining manageable device complexity through standardized valve components.
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 enables precise temperature control and reduces thermal strain by dynamically adjusting heat transfer rates, effectively addressing the limitations of existing heat exchangers in gas turbine engines, particularly in hydrogen-fuel propulsion systems.
Implementation Method 1
Heat exchangers are utilized to transfer waste heat from the turbofan jet engine to various fluids such as jet fuel, hydrogen gas and lubricating oil
Data Source
AI summary
A heat exchanger includes an inlet plenum chamber, an outlet plenum chamber fluidly coupled to the inlet plenum chamber, and a plurality of intermediate plenum chambers disposed downstream from the inlet plenum chamber and upstream from the outlet plenum chamber. The plurality of intermediate plenum chambers includes a first intermediate plenum chamber, at least one tube bundle, and a first bypass valve fluidly coupled to the first intermediate plenum chamber. The first bypass valve is configured to control fluid flow rate from the first intermediate plenum chamber to the outlet plenum chamber.