Motor Cooling Circuit With Upstream Particle Separator
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Solution Overview
Problem
At lower flight speeds or when an aircraft is on the ground, the ram air fan assembly experiences inadequate airflow for effective heat removal due to low ram pressure, and existing particle separators are ineffective in removing particulates, leading to motor overheating and reduced cooling flow rates.
Innovation Solution
A ram circuit design incorporating a particle separator that captures dynamic energy from the airflow by facing upstream, reducing particulate ingestion and increasing cooling airflow without significant pressure drop, using a centrifugal separation mechanism to clean the air before it reaches the motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If existing particle separators are used to remove particulate from cooling air, then FOD removal is improved, but pressure drop increases significantly reducing cooling air mass flow rate
Solution Approach 1:
The particle separator is inverted to face upstream into the high velocity airflow, allowing it to capture dynamic energy from the flow rather than resisting it. This inversion enables the separator to remove particulates effectively while maintaining cooling air mass flow rate, as the airflow direction and pressure gradient are optimized to prevent clogging and reduce pressure drop.
2Object-affected harmful factors
If particle separator is placed in high velocity airflow, then particulate removal efficiency is improved, but device complexity and clogging risk increase
Solution Approach 1:
The particle separator is designed with a universal structure that serves multiple functions: it removes particulates, manages airflow direction, and prevents clogging through its geometric design. The separator integrates these functions into a single component, reducing overall device complexity while maintaining high particulate removal efficiency in high velocity airflow conditions.
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 design enhances motor cooling flow rates by up to 26% and reduces motor winding temperatures by 28°C, effectively preventing overheating and motor failures while maintaining airflow efficiency.
Implementation Method 1
using a centrifugal separation mechanism to clean the air before it reaches the motor
Data Source
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AI summary
A ram circuit for an aircraft includes a ram inlet housing (24), a ram outlet housing (36), a heat exchanger (34), a ram air fan (26), and a particle separator (44). The ram inlet housing includes a chamber and an inlet configured to receive air. The ram outlet housing is fluidly connected to the ram inlet housing. The heat exchanger is disposed between and fluidly connected to the inlet housing and the outlet housing. The ram air fan is disposed in the outlet housing and includes a motor (30) with a cooling inlet. The particle separator includes an outer inlet (58) and a clean air outlet (64). The outer inlet is configured to receive ram air from the chamber of the ram inlet housing and faces into a flow of air passing through the chamber. Clean air is discharged through the clean air outlet which is fluidly connected to the cooling inlet of the motor.