Cabin Air Compressor Motor Cooling via Centrifugal Blower
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Solution Overview
Problem
The performance of aircraft cabin air compressors is limited by the pressure drop from the compressor inlet to the ram air system, which restricts the cooling airflow and reduces the efficiency of the air-cooled electric motors driving the compressors.
Innovation Solution
Incorporating a blower with centrifugal rotor blades in the cabin air compressor assembly to increase the pressure differential and mass flow of the cooling airflow across the motor, enhancing the cooling efficiency of the CAC motor and thus improving the compressor's performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If air-cooled electric motors are used to drive cabin air compressors, then the system structure is simplified, but the cooling performance is limited by pressure drop from compressor inlet to ram air system
Solution Approach 1:
A blower is introduced as an intermediary device between the compressor and the ram air system. The blower actively moves cooling air through the motor, overcoming the pressure drop limitations and enhancing heat removal without requiring a completely different cooling architecture.
Solution Approach 2:
The invention utilizes pneumatic principles by employing a blower to create positive pressure in the cooling air flow. This pneumatic assistance overcomes the natural pressure drop limitations and forces adequate cooling airflow through the motor, resolving the contradiction between simple structure and effective cooling.
2Temperature
If cooling airflow is increased to improve motor cooling, then motor temperature decreases, but pressure drop from compressor inlet to ram air system increases
Solution Approach 1:
The blower acts as a mediator that decouples the relationship between cooling airflow demand and system pressure drop. It provides the necessary pressure boost locally at the motor cooling inlet, allowing high cooling airflow without proportionally increasing the overall system pressure drop from compressor inlet to ram air system.
Solution Approach 2:
The blower performs preliminary action by pre-pressurizing the cooling air before it enters the motor. This preliminary pressurization ensures adequate cooling airflow is delivered to the motor without requiring a large pressure drop across the entire ram air system, thereby improving cooling efficiency while limiting system-wide pressure losses.
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 increased pressure differential and mass flow of the cooling airflow effectively enhance the cooling of the CAC motor, leading to improved performance of the cabin air compressor and the overall environmental control system.
Implementation Method 1
Incorporating a blower with centrifugal rotor blades in the cabin air compressor assembly to increase the pressure differential and mass flow of the cooling airflow across the motor
Implementation Method 2
The CAC motor 28 is cooled by a cooling flow drawn across the CAC motor 28... removing thermal energy from the stator windings 38 and the bearings 40
Data Source
Figure 1
Figure 2
AI summary
A cabin air compressor assembly includes a cabin air compressor (12) disposed at a compressor inlet (16) and a cabin air compressor motor (28) operably connected to the cabin air compressor (12). At least one cooling flow inlet (46) is located at a first end of the cabin air compressor motor (28) substantially opposite a second end whereat the cabin air compressor (12) is located. The cooling flow inlet (46) is configured to direct a cooling flow across the cabin air compressor motor (28). A blower (68) is operably connected to the cabin air compressor (12) and is configured to urge a cooling flow from across the cabin air compressor motor (28) toward a cooling flow outlet, thereby increasing the cooling flow across the cabin air compressor motor (28).