Aircraft Fan Housing Airflow for Motor Cooling and Backup Thrust
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Solution Overview
Problem
eVTOL aircrafts lack the autorotation function due to fixed blade angles, and their electric fans require effective cooling solutions to manage motor heat without increasing complexity or size.
Innovation Solution
A fan device with a rotor and stator core configuration, a housing with cooling and housing flow paths, and a compressor to guide compressed air for cooling and generating thrust, including a nozzle surface for ejector effect airflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fan stops rotating, then thrust is lost, but the motor needs continuous cooling
Solution Approach 1:
The patent divides the airflow path into two independent channels: a cooling flow path that continuously supplies compressed air to the motor accommodation space for cooling, and a housing flow path that supplies compressed air to the nozzle surface for thrust generation. This segmentation allows the thrust function and cooling function to operate independently, so thrust can be maintained even when the fan stops rotating.
Solution Approach 2:
The compressed air system serves multiple functions simultaneously: it cools the motor through the cooling flow path and generates thrust through the housing flow path and nozzle surface. This multi-functionality ensures that the motor remains cooled even when the fan is not operating, while also providing thrust capability independent of fan rotation.
2Temperature
If compressed air is supplied to cool the motor, then motor temperature decreases, but airflow separation occurs at the housing boundary
Solution Approach 1:
The patent introduces compressed air as an intermediary substance that serves dual purposes: it cools the motor by flowing through the accommodation space and simultaneously acts as a flow control mechanism to prevent separation at the cylindrical surface boundary. The compressed air supplied to the housing flow path suppresses adverse pressure gradients that would otherwise cause boundary layer separation.
Solution Approach 2:
The patent changes the pressure parameter of the air flow by using compressed air (higher pressure) to suppress boundary layer separation. The high-pressure compressed air injected into the housing flow path increases the energy of the boundary layer, allowing it to withstand adverse pressure gradients and preventing separation at the cylindrical surface boundary.
3Device complexity
If the blade angle is made unchangeable, then device complexity is reduced, but the autorotation function is lost
Solution Approach 1:
The patent replaces the mechanical autorotation system (which would require variable blade angles and complex linkages) with a compressed air-based thrust system. The housing flow path delivers compressed air to the nozzle surface to generate thrust without requiring fan rotation or blade angle changes, thereby eliminating the need for complex mechanical systems while maintaining reliability.
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
Ensures constant thrust and effective motor cooling, even when the fan stops, by using ejector effect airflow and reducing airflow separation.
Implementation Method 1
a compressor configured to compress air
Implementation Method 2
the housing internally defines a cooling flow path configured to guide compressed air from the compressor to the accommodation space
Implementation Method 3
the boundary air outlet is oriented in a direction to blow compressed air along the nozzle surface in the flow direction
Data Source
Figure 1
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AI summary
An embodiment includes: a fan (10) configured to generate an airflow; a rotor core (20) provided outside in the radial direction of the fan (10); a stator core (40) facing the rotor core (20); a housing (30) that forms an inner circumferential surface (31) surrounding the fan (10) and that internally includes an accommodation space (32) accommodating the rotor core (20) and the stator core (40); and a compressor (70). The inner circumferential surface (31) of the housing has a cylindrical surface (31a) and a nozzle surface (31b), the housing (30) internally defines a cooling flow path (Pc) configured to guide compressed air to the accommodation space (32) and a housing flow path (Ph) configured to guide compressed air to a boundary air outlet (33) formed near the boundary between the cylindrical surface (31a) and the nozzle surface (31b), and the boundary air outlet (33) is oriented in a direction to blow compressed air along the nozzle surface (31b) in a flow direction.