Fan Case Evaporator Layout for Compact Aircraft Steam Generation
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Solution Overview
Problem
Existing aircraft propulsion systems face challenges in incorporating large heat exchangers for steam generation due to space constraints, which affect the efficiency of thermal communication between exhaust gas flow and recovered water.
Innovation Solution
An evaporator system with heat exchangers mounted to the fan case of the propulsion system, utilizing an exhaust duct to route exhaust gas flow for steam generation, including multiple stages for efficient thermal energy transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If large heat exchangers are used for steam generation, then thermal communication efficiency between exhaust gas flow and recovered water is improved, but space constraints in the propulsion system are exceeded
Solution Approach 1:
The heat exchangers are mounted within the fan case structure, nesting the thermal communication system inside the existing propulsion system envelope. The exhaust duct routes exhaust gas through the fan case to reach the heat exchangers, utilizing the fan case internal volume for steam generation without increasing overall propulsion system volume.
Solution Approach 2:
The exhaust duct system creates a three-dimensional flow path that routes exhaust gas from the core engine through the fan case to reach heat exchangers mounted on the fan case. This spatial arrangement allows thermal communication without requiring large planar heat exchanger surfaces, instead using the depth and volume of the fan case interior.
2Volume of moving object
If heat exchangers are mounted to the fan case, then space utilization is improved, but system complexity increases
Solution Approach 1:
The fan case serves multiple functions: it houses the fan, provides structural support for the propulsion system, and acts as a mounting structure and thermal pathway for the evaporator system. The exhaust duct similarly serves to route exhaust gas and provides the thermal pathway for steam generation.
Solution Approach 2:
The evaporator system components (heat exchangers, exhaust duct, condenser) are integrated into the existing fan case structure rather than being separate additions. The heat exchangers are mounted directly to the fan case, and the exhaust duct is routed through the fan case, merging the steam generation function with the existing propulsion system architecture.
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
Facilitates compact steam generation within the propulsion system, enhancing propulsive efficiency by injecting steam into the combustor, thereby increasing mass flow without additional compressor work.
Implementation Method 1
a condenser assembly where water is condensed from the exhaust gas flow that is generated by the core engine
Implementation Method 2
an evaporator system where heat from the exhaust gas flow is used to transform water from the condenser assembly into a steam flow
Implementation Method 3
The evaporator system includes at least one heat exchanger stage that is mounted to the fan case and is in communication with the exhaust gas flow routed through the exhaust duct
Data Source
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AI summary
An aircraft propulsion system includes an exhaust duct (74) that defines a flow path for the exhaust gas flow to a condenser assembly (86), and an evaporator system (64) where heat from the exhaust gas flow is used to transform water from the condenser assembly (86) into a steam flow for injection into the core engine (24). The evaporator system (64) includes at least one heat exchanger stage (66, 68) that is mounted to the fan case (70) and is in communication with the exhaust gas flow routed through the exhaust duct (74).