Piezofan Heat Sink with Channel Constriction for Vortex Compression
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Solution Overview
Problem
Existing piezoelectric fans lack effective methods to direct air flow when ducts or channels are present, leading to reduced air flow outward and increased recirculation, which is undesirable for cooling applications like electronic devices.
Innovation Solution
An assembly comprising a heat sink, a channel, a piezoelectric fan blade, and a constrictive member, where the blade oscillates to generate air vortices that are compressed and expelled through a constriction in the channel, enhancing heat dissipation by increasing air velocity and preventing recirculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If ducts or channels are added to direct air flow from piezoelectric fan, then heat dissipation capability is improved, but air flow outward is reduced and recirculation increases
Solution Approach 1:
The channel is divided into multiple sections including a vortex generation section, a compression section with constriction, and an expulsion section. This segmentation allows different functions to be performed in different zones: vortex formation at the fan interface, flow acceleration and direction control at the constriction, and enhanced outward expulsion downstream, thereby resolving the contradiction between directing heat away and maintaining outward flow
Solution Approach 2:
A constrictive member is introduced that can be dynamically adjusted to modify the channel cross-section. This dynamic adjustment allows optimization of air flow characteristics - the constriction creates a venturi effect that accelerates flow and prevents recirculation, while proper positioning maintains outward flow direction, thus resolving the contradiction between heat dissipation direction and flow productivity
2Speed
If constrictive member is added to compress vortex, then air velocity is improved, but device complexity increases
Solution Approach 1:
Instead of modifying the entire channel, a localized constrictive member is introduced only in the critical compression zone. This local modification creates the necessary velocity increase through the venturi effect without requiring complex modifications throughout the entire system, thus resolving the contradiction between achieving high air velocity and maintaining simple device structure
Solution Approach 2:
The constrictive member acts as an intermediary element that mediates between the vortex generation region and the expulsion region. It transforms the rotational vortex flow into a more directional, high-velocity flow without requiring complex mechanical components, thereby achieving increased air velocity with minimal added complexity
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 solution effectively directs air flow and enhances heat dissipation from electronic devices by increasing air velocity and preventing recirculation, improving cooling efficiency.
Implementation Method 1
Piezoelectric fans operate as a vortex shedding device. U.S. Pat. No. 4,498,851 nicely describes vortex shedding as a process where air is prevented from being sucked around a piezoelectric fan blade tip when its motion reverses.
Implementation Method 2
The piezoelectric element is activated to cause the blade to oscillate
Implementation Method 3
The constriction in the channel and the blade cooperate with one another such that a vortex that is generated as the blade moves toward a first side of the channel is compressed against the first side of the channel and expelled towards the outlet of the channel
Implementation Method 4
The heat sink is in thermal communication with the electronic device. The heat sink defines a base surface. The base surface of the heat sink at least partially defines the channel.
Data Source
AI summary
An electronic device having enhanced heat dissipation capabilities includes an electronic device, a heat sink, a channel, a piezoelectric element, and a blade. The heat sink is in thermal communication with the electronic device. The channel includes an inlet, an outlet and a constriction disposed along the channel between the inlet and the outlet. The heat sink defines at least a portion of the channel. The blade includes a free end and an attached end. The blade is disposed in the channel and connected to the piezoelectric element. The piezoelectric element is activated to move the blade side to side in the channel to create air vortices. The constriction in the channel and the blade cooperate with one another such that a vortex that is generated as the blade moves toward a first side of the channel is compressed against the first side of the channel and expelled towards the outlet of the channel.