Motor Cooling via Ejector Pump and Ram Air
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Solution Overview
Problem
Traditional nitrogen generation system motor cooling systems are ineffective at low ram air speeds and high ram air temperatures, as they rely on pressurized compressor outlet flow which is hot and inefficient.
Innovation Solution
A motor cooling system utilizing a passive ejector pump to create a pressure drop and divert bypass flow from the compressor outlet to the motor outlet line, with a valve to control the flow and a heat exchanger to enhance cooling, allowing ram air to be used for cooling, reducing motor temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressurized compressor outlet flow is used for motor cooling, then cooling is provided during flight, but cooling effectiveness deteriorates at low ram air speeds and high ram air temperatures
Solution Approach 1:
The system dynamically switches between two cooling modes: using compressor outlet flow during flight when ram air is insufficient, and using ram air during ground operations when it is cooler and more abundant. This dynamic adaptation resolves the contradiction by selecting the optimal cooling source based on operating conditions.
Solution Approach 2:
The motor cooling system is designed to perform effectively in both flight and ground operations by incorporating dual cooling sources. The system universally handles different operating environments (high altitude/low speed and ground/high temperature) through a unified design that selects the appropriate cooling source.
2Reliability
If two cooling sources with two cooling ports are used, then cooling coverage is improved, but device complexity increases
Solution Approach 1:
The system merges two cooling sources (compressor outlet flow and ram air) into a unified cooling system that serves the motor. By combining these sources with a common outlet and using a single valve to switch between them, the system achieves comprehensive cooling coverage while avoiding the complexity of entirely separate cooling circuits.
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 system effectively reduces motor stator and rotor temperatures by 22 and 50 degrees Celsius respectively, improving thermal performance and reliability, and reduces motor power consumption, making the system more efficient and lighter.
Implementation Method 1
The pump can be a passive pump that has no moving parts. For example, the pump can be an ejector pump configured to create a pressure drop by effusing bypass flow into or downstream of the motor outlet line.
Implementation Method 2
In certain embodiments, the system can include a heat exchanger in fluid communication with the compressor outlet line.
Data Source
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AI summary
A system can include a compressor outlet line (101) configured to receive compressor outlet flow (102) from a compressor (103), a bypass line (105) in fluid communication with the compressor outlet line and a motor outlet line (107) to divert a bypass flow (109) of the compressor outlet flow. The system can include at least one pump (111) in fluid communication between the bypass line and the motor outlet line such that the bypass flow at least partially drives the pump to pull cooling flow through a motor to cool the motor.