Active Vortex Generator for Heat Exchanger Mixing
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Solution Overview
Problem
Passive rigid mixers in heat exchangers are ineffective at adapting to changing fluid flow rates, particularly in laminar flow conditions, and two-phase heat exchangers face reduced heat transfer due to bubble insulation without proper bubble management.
Innovation Solution
An active vortex generator is integrated into the heat exchanger, featuring a flexible sheet or plate with a rigid portion, affixed to an anchor that oscillates within the fluid channel, creating vortices to enhance mixing and heat transfer by adapting to flow rates and managing bubbles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a passive rigid mixer is used in a heat exchanger, then the structure is simple and manufacturing is easy, but the mixing effectiveness is reduced when flow rates change particularly in laminar flow
Solution Approach 1:
The vortex generator is designed with a flexible portion that allows it to dynamically adapt its configuration based on flow conditions. The flexible sheet or plate can bend and deform in response to changing flow rates, enabling the device to maintain effective vortex generation across a range of operating conditions rather than being fixed in a single rigid configuration
Solution Approach 2:
The vortex generator utilizes changes in physical parameters (flexibility, oscillation frequency, amplitude) to adapt to different flow conditions. By allowing the structure to flex and oscillate, the device changes its effective geometry and motion characteristics based on the flow rate, thereby maintaining mixing effectiveness across varying operational parameters
2Productivity
If bubbles are present in two-phase heat exchangers, then latent heat of vaporization is leveraged for high heat transfer rates, but bubble insulation limits maximum heat transfer rate
Solution Approach 1:
The oscillating vortex generator creates mechanical vibrations and disturbances in the fluid flow that actively manage bubble behavior. The oscillation breaks up bubble clusters, prevents bubble coalescence, and promotes bubble departure from the heat transfer surface, thereby reducing the insulating effect of bubbles while maintaining the beneficial latent heat transfer
Solution Approach 2:
The invention converts the harmful insulating effect of bubbles into a beneficial process by using the vortex generation and oscillation to actively manage bubble dynamics. The same flow disturbances that create vortices for mixing also serve to break up and manage bubbles, transforming the bubble insulation problem into an opportunity for enhanced two-phase heat transfer through improved bubble distribution and departure
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 active vortex generator increases heat transfer rates by promoting fluid mixing and preventing temperature stratification, effectively managing bubbles to maintain high heat transfer even during two-phase processes.
Implementation Method 1
an active vortex generator affixed to the anchor and configured to extend in a direction parallel to the heat transfer surface
Implementation Method 2
The active vortex generator increases heat transfer rates by promoting fluid mixing and preventing temperature stratification
Implementation Method 3
a cooling fluid channel comprising a heat transfer surface
Implementation Method 4
a cooling fluid channel comprising a heat transfer surface
Implementation Method 5
an active vortex generator comprising a flexible sheet of material selected
Data Source
AI summary
An active vortex generator adapts to a flow rate of fluid through and/or a heat flux applied through a heat exchanger channel to improve the heat transfer rate of the heat exchanger. In some implementations, the movement of the active vortex generator may be induced by the fluid flow through the heat exchanger channel. In some implementations, the movement of the active vortex generator may be induced through an externally applied force on the active vortex generator. An actuated active vortex generator is particularly suited to heat exchangers with high heat flux dissipation requirements. Locating an actuated active vortex generator proximate to such high heat flux dissipation locations provides for improved heat transfer that can be activated when needed, such as upon operation of a high heat flux component.