Heat Resistant Piezo Bimorph Synthetic Jet Thermal Barrier
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Solution Overview
Problem
Existing piezo bimorph synthetic jets are not suitable for pulsing high temperature working fluids due to the risk of damage to ceramic elements from high temperature fluids, such as jet exhaust gases.
Innovation Solution
A heat-resistant piezo bimorph synthetic jet apparatus is designed with thermal insulating layers made of low thermal conductivity materials or cooling fluid chambers to protect the ceramic layers, allowing the apparatus to operate effectively in high temperature environments by alternately expanding and contracting to pulse fluids, and incorporating cooling fluid chambers to manage temperature without additional pumping devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If piezo bimorph synthetic jets are used to pulse working fluid, then fluid pulsing capability is achieved, but ceramic elements are damaged by high temperature fluids
Solution Approach 1:
A thermal barrier layer is introduced as an intermediary between the hot working fluid and the ceramic piezoelectric elements. This layer mediates the thermal interaction by blocking heat transfer from the fluid to the ceramic, allowing the jet to pulse hot fluids without damaging the ceramic components.
Solution Approach 2:
The jet structure is segmented into distinct functional zones: a hot fluid chamber for working fluid pulsing, a thermal barrier layer for thermal protection, and a piezoelectric actuator section for generating pulsing motion. This segmentation allows each component to operate within its optimal temperature range.
2Reliability
If thermal insulating layers are added to protect ceramic elements, then temperature protection is improved, but device complexity increases
Solution Approach 1:
The thermal barrier is implemented as a thin film or coating applied directly to the piezoelectric element surface, rather than a thick rigid insulating layer. This thin-film approach provides effective thermal protection while minimizing added complexity and maintaining the compact structure of the original jet device.
3Temperature
If cooling fluid chambers are added to manage temperature, then thermal management capability is improved, but device complexity and additional pumping requirements increase
Solution Approach 1:
The jet device is configured to use its own pulsing action to drive cooling fluid through the thermal barrier layer. During the pulsing cycle, the pressure differential created by the jet's expansion and contraction naturally circulates cooling fluid, eliminating the need for separate pumping systems and reducing overall device 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 enables the safe and efficient pulsing of high temperature working fluids by protecting ceramic elements from thermal damage and enhancing cooling effects, making the apparatus suitable for use in environments like jet engine exhaust nozzles.
Implementation Method 1
A bimorph piezoelectric structure disposed within the working fluid chamber and configured to alternately increase and decrease chamber volume by alternately expanding and contracting in response to the application of voltage
Implementation Method 2
A thermal insulating layer disposed between the working fluid chamber and the bimorph piezoelectric structure to protect a ceramic structure within the bimorph piezoelectric structure from high temperature fluids
Data Source
AI summary
A heat resistant piezo bimorph synthetic jet apparatus comprises a working fluid chamber partially defined by a plate, a working fluid port that provides fluid flow communication between the working fluid chamber and a working fluid mass, and a bimorph piezoelectric structure included in the plate. The bimorph piezoelectric structure alternately increases and decreases chamber volume by alternately expanding convexly and concavely in response to application of voltage of alternating polarity to alternately draw working fluid into and expel working fluid from the working fluid chamber through the working fluid port. A thermal insulating layer is disposed between the working fluid chamber and the bimorph piezoelectric structure to protect a ceramic layer within the first bimorph piezoelectric structure from high temperature working fluid.