Three-Stream Gas Turbine Layout for High Thrust Without Larger Fans
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Solution Overview
Problem
Conventional turbofan engine design faces challenges in increasing fan diameter for higher thrust while maintaining efficient propulsive performance, leading to installation, weight, and thermal management issues.
Innovation Solution
A three-stream gas turbine engine design incorporating a primary and secondary fan, with a third stream airflow managed through a ducted fan, utilizing variable geometry components and heat exchangers to optimize thrust-to-power airflow and core bypass ratios, enhancing propulsive efficiency and thermal management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If fan diameter is increased for higher thrust, then thrust is improved, but installation and weight issues worsen
Solution Approach 1:
The engine airflow is segmented into three separate streams: a core stream through the combustor, a bypass stream around the core, and a third stream through the ducted fan. This segmentation allows each stream to be independently optimized and managed, enabling high thrust production without requiring a single oversized fan that would create installation and weight problems.
Solution Approach 2:
The patent introduces a third stream dimension by adding the ducted fan system alongside the traditional two-stream (core and bypass) configuration. This dimensional expansion of the airflow architecture provides additional thrust generation capability without increasing the diameter of individual fan components, thereby avoiding the installation and weight issues associated with larger fans.
2Force
If fan diameter is increased for higher thrust, then thrust is improved, but thermal management issues worsen
Solution Approach 1:
By segmenting the airflow into three separate streams, the patent distributes thermal loads across multiple pathways. The ducted fan's third stream provides an additional channel for heat dissipation and thermal management, preventing concentration of thermal energy in a single location that would occur with a larger, single-fan design.
3Productivity
If third stream airflow is increased, then propulsive efficiency is improved, but device complexity worsens
Solution Approach 1:
The ducted fan and associated third stream components are designed with variable geometry capabilities, allowing the system to dynamically adjust airflow distribution among the three streams based on operating conditions. This dynamic adaptability optimizes propulsive efficiency across different flight regimes while the modular architecture manages the inherent complexity through systematic organization.
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 design maintains or improves propulsive efficiency, addresses packaging and weight concerns, and enhances thermal management, facilitating rapid down-selection of engine configurations that meet mission requirements.
Implementation Method 1
utilizing variable geometry components and heat exchangers to optimize thrust-to-power airflow and core bypass ratios
Data Source
AI summary
A gas turbine engine is provided. The gas turbine engine includes a turbomachine defining an engine inlet to an inlet duct, a fan duct inlet to a fan duct, and a core inlet to a core duct; a primary fan driven by the turbomachine; and a secondary fan located downstream of the primary fan within the inlet duct. The gas turbine engine defines a thrust to power airflow ratio between 3.5 and 100 and a core bypass ratio between 0.1 and 10, wherein the thrust to power airflow ratio is a ratio of an airflow through a bypass passage over the turbomachine plus an airflow through the fan duct to an airflow through the core duct, and wherein the core bypass ratio is a ratio of the airflow through the fan duct to the airflow through the core duct.