Segmented Heat Exchanger for Turbojet Integration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The increasing size of turbojets due to higher bypass ratios and pressure ratios reduces the space allocated to heat exchangers, causing perturbations to the boundary layer and making integration challenging in aircraft propulsion systems.
Innovation Solution
The proposed aircraft propulsion system incorporates a main and sub heat exchanger configuration with separate supply and evacuation pipes, a regulating valve, and a control unit, allowing for reduced size and improved integration by optimizing the placement of heat exchangers within the limited space between the pylon and pylon fairing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the turbojet size is increased to achieve higher bypass ratio and pressure ratio, then the propulsion efficiency is improved, but the space allocated to the heat exchanger is reduced
Solution Approach 1:
The heat exchanger is divided into a main heat exchanger and a sub heat exchanger. The main heat exchanger processes the majority of the hot air flow, while the sub heat exchanger handles a portion of the cold air flow. This segmentation allows the heat exchange function to be distributed across two smaller units rather than one large unit, enabling better integration in the constrained space between the pylon and pylon fairing while maintaining the required heat exchange capacity for the larger turbojet engine.
2Volume of stationary object
If the heat exchanger size is reduced to fit in the limited space, then the integration is improved, but the heat exchange efficiency may deteriorate
Solution Approach 1:
The heat exchanger is configured with a longitudinal extension along the airflow direction. By utilizing the longitudinal dimension rather than only increasing cross-sectional area, the heat exchange surface area is increased without significantly increasing the radial or lateral footprint. This allows the heat exchanger to maintain adequate heat exchange efficiency while fitting within the constrained space between the pylon and pylon fairing.
3Volume of stationary object
If the heat exchanger is placed close to the leading edge of the wing, then the space utilization is improved, but perturbations to the boundary layer are created
Solution Approach 1:
The heat exchanger is strategically positioned within the limited space between the pylon and pylon fairing, away from the wing leading edge. This local placement optimizes space utilization in the available volume without creating harmful boundary layer perturbations. The configuration allows the heat exchanger to be integrated into the propulsion system while maintaining favorable aerodynamic conditions on the wing surface.
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
This configuration reduces the bulkiness of the heat exchanger system, enabling better integration and maintaining efficient air management for both air conditioning and de-icing systems while minimizing space usage and pressure losses.
Implementation Method 1
a main heat exchanger including a main hot supply connection, a main hot transfer connection pneumatically connected to the main hot supply connection through the main heat exchanger, a main cold supply connection and a main cold evacuation connection pneumatically connected to the main cold supply connection through the main heat exchanger
Implementation Method 2
a sub heat exchanger including a sub hot supply connection, a sub hot transfer connection pneumatically connected to the sub supply connection through the sub heat exchanger, a sub cold supply connection and a sub cold evacuation connection pneumatically connected to the sub cold supply connection through the sub heat exchanger
Data Source
AI summary
An aircraft propulsion system, including a turbojet and a heat exchanger system including a main heat exchanger, a hot air supply pipe and regulating valve, a high pressure pipe bleeding high pressure stage hot air through a first valve, an intermediate pressure pipe bleeding intermediate pressure stage hot air through a second valve, a pipe transferring hot air to an air management system, a main supply pipe supplying fan duct cold air including a main regulating valve, an evacuation pipe expelling air to the outside, a sub heat exchanger, wherein the supply pipe from the regulating valve goes through the sub heat exchanger, a sub supply pipe supplying cold air from the main supply pipe, a sub evacuation pipe expelling air to the fan duct, a temperature sensor measuring hot air temperature exiting the main heat exchanger, and a controller controlling the valves according to the measured temperature.