Ram Air Fan Rotor Compound Contoured Surface

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

At lower flight speeds or when an aircraft is on the ground, the ram air pressure is insufficient to provide enough airflow across the heat exchangers in an environmental control system, requiring a fan to enhance airflow for heat removal.

Innovation Solution

A fan rotor with an outer hub portion featuring a compound contoured surface on its upstream arm, which directs air flow around the surface and along the roots of the blades, improving airflow efficiency and reducing disturbances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If ram air pressure is used for airflow across heat exchangers, then the system operates without additional power consumption at high flight speeds, but airflow is insufficient at lower flight speeds or when the aircraft is on the ground

Engineering Contradiction:

Improveairflow across heat exchangersVSAvoidoperational range across different flight speeds

Core Design Contradiction:

ProductivityVSAdaptability or versatility

Solution Approach 1:

The fan rotor design incorporates adjustable pitch blades that can be optimized for different operating conditions. The blade pitch angle can be changed to match the specific airflow requirements at different flight speeds, allowing the fan to maintain high efficiency across both high-speed flight (where ram air is sufficient) and low-speed/ground operations (where enhanced airflow is needed).

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The compound contoured surface on the upstream arm of the hub modifies the airflow parameters by creating specific flow patterns that reduce turbulence and improve air direction. This geometric parameter change allows the system to optimize airflow characteristics across varying operating conditions, bridging the performance gap between high-speed and low-speed operations.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If a fan is added to enhance airflow at low speeds, then airflow performance improves across all operating conditions, but the device complexity and weight increase

Engineering Contradiction:

Improveairflow across heat exchangersVSAvoidfan assembly structure

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The fan rotor is integrated directly into the existing heat exchanger assembly, merging the airflow generation function with the thermal management component. This combination eliminates the need for separate fan housings and mounting structures, reducing overall device complexity while maintaining enhanced airflow performance across all operating conditions.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The fan rotor serves multiple functions: it generates airflow at low speeds, maintains optimal airflow patterns at high speeds, and its compound contoured surface design simultaneously directs air flow and reduces disturbances. This multi-functionality reduces the need for additional components, thereby lowering device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Productivity

If the fan rotor uses traditional blade design, then manufacturing is simpler, but airflow disturbances increase and work output decreases

Engineering Contradiction:

Improvefan work outputVSAvoidblade geometry fabrication

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The compound contoured surface on the upstream arm of the hub uses curved, aerodynamic profiles instead of flat or angular surfaces. This curvature optimizes airflow direction and reduces turbulence, increasing fan work output. While more complex to manufacture than simple geometric shapes, modern manufacturing techniques can produce these contoured surfaces efficiently.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The compound contoured surface is specifically positioned on the upstream arm where airflow first contacts the hub structure. This localized optimization of surface geometry targets the critical airflow entry point, maximizing the benefit to work output while limiting the manufacturing complexity to a specific region rather than the entire component.

Inventive Principle:

Principle #3Local quality

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 compound contoured surface design enhances airflow performance by minimizing disturbances and increasing the fan's work output, thereby improving the operational efficiency of the ram air fan.

Implementation Method 1

The compound contoured surface is configured to direct air flow around the compound contoured surface and along roots of the blades

Methodology Applied

Scientific EffectAir flow direction:

Data Source

PatentUS11434923B2Fan rotor for ram air fan

Publication Date: 2022.09.06 HAMILTON SUNDSTRAND CORP

AI summary

A fan rotor for a ram air fan includes a hub and blades extending radially outwards from the hub. The hub includes an inner hub portion, a disk portion connected to a radially outer surface of the inner hub portion, and an outer hub portion connected to a radially outer surface of the disk portion. The outer hub portion has an upstream arm with a compound contoured surface. The compound contoured surface is configured to direct air flow around the compound contoured surface and along roots of the blades.