Heat Sink Rectifying Portion Airflow Velocity Management
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Solution Overview
Problem
The cooling efficiency of heat sinks mounted in movable bodies, which rely on traveling air streams for cooling, is not consistently sufficient due to variations in airflow velocity along the fins, leading to inadequate heat dissipation of heating elements.
Innovation Solution
The heat sink design incorporates a rectifying portion at the upstream end and a protruding portion at the rear end of the fins to manage airflow velocity, maintaining it across the slit-shaped flow paths, thereby enhancing cooling efficiency by suppressing velocity decreases and increasing airflow near the heating element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a heat sink uses traveling air stream for cooling without additional components, then energy consumption is reduced, but cooling efficiency becomes insufficient due to airflow velocity decrease along the flow path
Solution Approach 1:
A rectifying portion is introduced as an intermediary component between the airflow source and the heating element. This rectifying portion actively manages the airflow velocity profile, preventing the natural decay that occurs in conventional heat sinks. The rectifying portion mediates between the traveling air stream and the heat dissipation fins, ensuring consistent cooling efficiency without requiring increased energy consumption or forced convection systems
2Device complexity
If the heat sink relies on natural traveling air stream, then device complexity is reduced, but airflow velocity decreases along the longitudinal direction leading to inadequate heat dissipation
Solution Approach 1:
The rectifying portion serves as a flow management intermediary that maintains airflow velocity without adding complex forced convection mechanisms. It passively rectifies the airflow using the existing traveling air stream, preventing velocity decay through its geometric configuration rather than active intervention
Solution Approach 2:
The rectifying portion extends in the longitudinal direction (third dimension relative to the fin cross-section) to create a three-dimensional flow management structure. This longitudinal extension allows the rectifying portion to interact with airflow at multiple positions along the flow path, maintaining velocity distribution without requiring complex multi-component systems
3Area of stationary object
If fins are arranged vertically on the base, then heat dissipation surface area is increased, but airflow velocity decreases toward the rear end reducing cooling effectiveness
Solution Approach 1:
The rectifying portion acts as an intermediary flow control element positioned upstream of the fin array. It prepares the airflow before it encounters the fins, ensuring that the increased surface area provided by the vertical fins does not come at the cost of velocity decay. The rectifying portion balances the trade-off between surface area and flow velocity
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 significantly improves the cooling efficiency of the heat sink by maintaining high airflow velocity and reducing temperature gradients across the heat dissipation surface, ensuring effective heat transfer and energy savings.
Implementation Method 1
The heat sink is exposed to a traveling air stream generated while the movable body moves, and therefore heat of the power semiconductor device is dissipated by heat transfer through each of the fins
Implementation Method 2
a rectifying portion which can change conditions for an airflow into the slit-shaped flow path is attached near the upstream end (i.e., the front end) of the fin, and therefore the decrease in airflow velocity as air flows toward the rear end side can be suppressed
Data Source
Figure 1
Figure 2
Figure 3(a)~3(d)
AI summary
A heat sink which is mounted in a movable body and which is to be exposed to a traveling air stream generated while the movable body moves includes a base and a heat dissipating portion having a plurality of fins. At least in a front end portion of the heat dissipating portion, the heat dissipating portion includes a rectifying portion provided so as to extend across a predetermined area in a longitudinal direction in front portions of slit-shaped flow paths at an upstanding end (i.e., an end apart from the base).