Aircraft Propulsion Nacelle Cooling Layout With Low Aerodynamic Drag
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Solution Overview
Problem
The existing electric propulsion systems for aircraft face challenges in efficiently cooling fuel cells while maintaining optimal aerodynamic performance, especially during high-thrust phases like takeoff, due to the complexity of heat dissipation and potential aerodynamic drag caused by conventional cooling configurations.
Innovation Solution
The propulsion system incorporates an air circulation channel within the nacelle that extends from a longitudinal end, featuring a cylindrical exterior surface to minimize aerodynamic blocking effects, and includes a heat exchanger and fan to promote high air flow and efficient cooling, optimizing pressure losses and maintaining aerodynamic drag characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conventional fuel cell cooling circuit is used with air inlets on the nacelle side face, then the fuel cells can be cooled during operation, but the aerodynamic performance of the nacelle and aircraft is degraded
Solution Approach 1:
The air circulation channel is repositioned to extend from the longitudinal end of the nacelle rather than from the side face, utilizing a different spatial dimension for air intake. This dimensional change allows the cooling function to be achieved without interfering with the aerodynamic flow over the nacelle surface, thereby resolving the contradiction between cooling effectiveness and aerodynamic performance
Solution Approach 2:
The air circulation channel is designed with a cylindrical outer surface that is symmetric with respect to the longitudinal axis of the nacelle. This curved, symmetric geometry minimizes aerodynamic blocking effects and pressure losses, allowing high air flow rates for cooling while maintaining satisfactory aerodynamic drag characteristics
2Temperature
If high air flow rate is circulated for cooling the electricity production system, then the cooling needs are met, but the aerodynamic drag and pressure losses increase
Solution Approach 1:
The cylindrical outer surface of the air circulation channel creates a streamlined geometry that reduces aerodynamic drag and pressure losses. The curved surface allows air to flow smoothly around the channel, minimizing turbulence and energy loss, thereby enabling high air flow rates for effective cooling without excessive pressure losses
Solution Approach 2:
The air circulation channel is positioned asymmetrically within the nacelle, extending from the longitudinal end rather than from the side. This asymmetric positioning, combined with the cylindrical symmetry, optimizes the flow path to reduce pressure losses while maintaining effective cooling of the electricity production system
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 effectively meets the cooling needs of the electricity production system while maintaining satisfactory aerodynamic drag characteristics, ensuring efficient operation and reduced drag.
Implementation Method 1
The air circulation channel receives a heat exchanger provided to allow cooling of the electricity production system
Implementation Method 2
the at least part of the airflow channel contiguous to the first end of the airflow channel is delimited by a cylindrically shaped outer surface surrounding the longitudinal axis of the nacelle allows axial symmetry of the propulsion system. This makes it possible to minimize the aerodynamic blocking effects and therefore the aerodynamic drag of the nacelle
Data Source
Figure 1
Figure 2A~2B
Figure 2C~2D
AI summary
The propulsion system includes a power generation system (10) supplying electricity to at least one electric motor (16) mechanically coupled to a propulsion propeller (18) located near the first longitudinal end (24) of a nacelle (20) that houses at least the power generation system (10) and at least one electric motor (16). An air circulation duct (22), incorporating a heat exchanger (30) for cooling the power generation system (10), extends inside the nacelle from a first end (25) of said air circulation duct located at the first longitudinal end (24) of the nacelle. A portion of the air circulation duct adjacent to its first end (25) is delimited by a cylindrical outer surface (28) surrounding the longitudinal axis (X) of the nacelle.