Air-Cooled Electric Motor Airflow Routing for Stator Cooling
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Solution Overview
Problem
Current electric motor designs for air-conditioning systems in large commercial aircraft suffer from limited cooling airflow, leading to overheating and operational failures of the Cabin Air Compressor (CAC).
Innovation Solution
The design incorporates a separator plate and motor cavity separator wall through-holes to create a secondary airflow stream that enhances stator cooling by utilizing compressor seal leakage and bearing cooling airflow, increasing the overall cooling airflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional motor cooling design is used, then the structure is simple, but the stator cooling airflow is insufficient leading to overheating
Solution Approach 1:
The motor cooling structure is segmented into multiple functional zones using a separator plate that divides the motor cavity into a stator cooling cavity and a rotor cavity. This segmentation allows independent optimization of cooling airflow paths for the stator, enabling effective heat dissipation while maintaining clear functional separation between cooling zones.
Solution Approach 2:
A separator plate is introduced as an intermediary component between the rotor and stator regions. This separator plate with its opening acts as a mediator to guide and regulate the cooling airflow from the rotor back-face cavity to the stator, ensuring proper airflow distribution without direct mechanical connection between the rotating and stationary parts.
2Reliability
If cooling airflow is increased to prevent overheating, then stator cooling improves, but the motor structure becomes more complex
Solution Approach 1:
The separator plate serves multiple functions simultaneously: it acts as a structural support element, a flow guide for cooling air, a separator between rotating and stationary cavities, and a means to regulate airflow distribution. This multi-functionality improves reliability without adding separate dedicated components for each function.
Solution Approach 2:
The motor's own operational characteristics (rotor rotation, back-face cavity airflow generation) are utilized to create the cooling airflow for the stator. The system self-regulates by using the airflow already present in the motor operation to serve the cooling function, eliminating the need for external cooling systems or complex controlled mechanisms.
3Quantity of substance
If separator plate opening area is increased to improve cooling, then stator cooling airflow increases, but airflow leakage may increase
Solution Approach 1:
The separator plate opening area is optimized to specific parameter ranges that balance cooling airflow quantity with airflow containment. By carefully selecting the opening dimensions, the design achieves sufficient cooling air supply to the stator while maintaining proper airflow direction and minimizing unwanted leakage, representing an optimal parameter selection to resolve the contradiction.
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 solution effectively increases stator cooling airflow by approximately 10% while maintaining the performance of the CAC and aircraft Environmental Control System (ECS), without increasing power consumption or weight.
Implementation Method 1
the separator plate is disposed to create high pressure area within the separator plate cavity and a low pressure area proximate the stator outlet cavity
Implementation Method 2
cooling airflow is limited around the stator by current design deficiencies which lead to overheating
Implementation Method 3
One way to reject this generated heat is to direct a cooling airflow over the stator outer diameter to cool the stator
Implementation Method 4
This electric current generates a significant amount of heat that needs to be removed or rejected out of the windings and through the stator housing
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A method (400) for increasing stator cooling airflow in an air cooled electric motor (100) is provided, wherein the air cooled electric motor includes a compressor outlet housing (102) having a motor cavity separator wall (106) and a separator plate (108) defining a separator plate opening (109), wherein the compressor outlet housing defines a separator plate cavity (110) and a compressor rotor back-face cavity (112) configured to receive a back-face cavity airflow. The motor cavity separator wall separates the separator plate cavity from the compressor rotor back-face cavity and defines a motor cavity separator wall through-hole (114) which communicates the separator plate cavity with the compressor rotor back-face cavity and a motor cooling housing (200) including a motor cooling outlet structure (206) which defines a stator outlet cavity (210), wherein the separator plate is disposed to separate the stator outlet cavity from the separator plate cavity.