Dual Counter-Rotating Impeller Fan for Portable Chassis Cooling
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Solution Overview
Problem
Portable information handling systems face challenges in efficiently cooling components due to limited airflow and heat dissipation, especially in rectangular fan areas where the ratio of width to length is disproportionate, and increasing fan speed is not feasible without compromising noise levels.
Innovation Solution
A cooling system with a fan housing containing two counterrotating impellers, where the axes of rotation are aligned non-parallel to the rear surface of the portable chassis, and the fan housing is shaped to direct airflow effectively, allowing for increased volumetric flow and distribution of airflow, accommodating heat pipes and other components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If fan speed is increased to improve cooling performance, then heat dissipation is improved, but noise level increases
Solution Approach 1:
The fan assembly is segmented into two separate impellers (first and second impellers) that rotate in opposite directions. This segmentation allows each impeller to operate at lower speeds while collectively generating sufficient airflow, thereby reducing noise levels while maintaining effective heat dissipation from the processor and other components.
Solution Approach 2:
Two impellers are merged into a single fan housing structure, working in opposition to each other. The combined airflow generation capability of both impellers replaces what would require a single high-speed impeller, achieving the same cooling effect at lower rotational speeds and thus lower noise.
2Productivity
If impeller diameter is increased to improve airflow, then volumetric flow is improved, but the fan housing size increases
Solution Approach 1:
The solution transitions from a single large-diameter impeller to two smaller-diameter impellers arranged in a dual-rotation configuration. This dimensional reorganization allows the fan housing to maintain a compact form factor while achieving equivalent or superior volumetric flow through the combined effect of both impellers rotating in opposite directions.
3Device complexity
If single impeller configuration is used to simplify structure, then device complexity is reduced, but airflow distribution is insufficient
Solution Approach 1:
The single impeller is segmented into two counter-rotating impellers, each contributing to different aspects of airflow generation. This segmentation improves airflow distribution across the heat sinks and processor surfaces while maintaining relatively simple fan housing and mounting structures.
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 configuration enhances airflow velocity and volumetric flow, effectively cooling components while maintaining a quiet operation by allowing larger impeller diameters and adjusting rotational speeds to optimize airflow distribution and direction, thus improving heat transfer efficiency.
Implementation Method 1
a first impeller positioned in the fan housing and configured to rotate in a first direction about a first axis of rotation, a second impeller positioned in the fan housing and configured to rotate in a second direction opposite the first direction about a second axis of rotation
Implementation Method 2
the fan housing is configured to direct at least a portion of the airflow out the fan outlet... the fan housing is configured to direct a portion of the airflow through a fin stack
Implementation Method 3
the fan housing has a curved side proximate a heat pipe
Data Source
AI summary
A cooling system for an information handling system in a portable chassis comprises a fan housing containing two counterrotating impellers, wherein the axes of rotation of the two impellers are aligned with an axis of orientation relative to a rear surface of the portable chassis. By changing the angle of the axis of orientation, impellers with larger diameters may be positioned in the same fan area for increased volumetric airflow. The shape of the fan housing, the diameter of each impeller and the angle of the axis of orientation may be selected to direct and distribute a greater volumetric airflow for improved cooling of components in the portable chassis.