SMA Flow Control Nozzle for Viscosity-Compensated Constant Flow
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Solution Overview
Problem
Existing jet pipe servo valves and other flow control applications are susceptible to performance degradation due to fluctuations in fluid viscosity caused by temperature changes, leading to variations in flow rate.
Innovation Solution
The use of Shape Memory Alloy (SMA) materials to dynamically adjust the flow area of a flow control nozzle, reducing the flow area as temperature increases to maintain a constant flow rate by compensating for viscosity changes, typically by reducing the nozzle diameter according to a predetermined relationship.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed flow control nozzle is used, then the device structure is simple, but the flow rate varies with temperature due to viscosity changes
Solution Approach 1:
The nozzle structure is transformed from fixed to dynamic by incorporating a deformable element that can change its geometry in response to temperature variations. The deformable element includes shape memory alloy material that automatically adjusts the flow area based on temperature, maintaining consistent flow rate without complex control systems.
Solution Approach 2:
The physical parameters of the nozzle (flow area, diameter) are made changeable through the deformable element. The shape memory alloy material changes its dimensional parameters in response to temperature changes, allowing the nozzle to adapt its flow characteristics dynamically while keeping the overall device structure relatively simple.
2Reliability
If the flow area is reduced to compensate for viscosity decrease at high temperature, then the flow rate can be maintained constant, but the nozzle geometry becomes complex
Solution Approach 1:
The deformable element with shape memory alloy material serves itself by automatically adjusting its geometry in response to temperature changes. The material inherently possesses the ability to change its shape and dimensions based on thermal input, eliminating the need for external actuators, sensors, or control systems, thus maintaining simple device geometry while achieving flow rate consistency.
3Reliability
If a deformable element with SMA material is used to adjust flow area, then flow rate consistency is improved, but the device complexity increases
Solution Approach 1:
Traditional mechanical adjustment mechanisms (actuators, linkages, control systems) are replaced by the inherent thermomechanical properties of the shape memory alloy material. The material directly converts thermal energy into mechanical deformation, substituting complex mechanical control systems with a simple thermal-responsive material that automatically adjusts the flow area.
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 approach effectively maintains a substantially constant flow rate over a range of operating temperatures, ensuring consistent performance despite temperature variations, as demonstrated by the use of Nickel-Titanium alloys like Nitinol, which can be trained to deform in a controlled fashion to adjust the nozzle dimensions accordingly.
Implementation Method 1
a deformable element, particularly one comprising or being connected to Shape Memory Alloy (SMA) material and configured to change its dimensions, particularly to reduce the flow area, as a function of temperature
Implementation Method 2
SMA materials are a class of materials whose properties change with temperature. For example, at low temperatures, the SMA may take a more flexible form, referred to as the 'martensitic' state. At high(er) temperatures, the SMA material changes state to a more rigid form, referred to as the 'austenitic' state.
Implementation Method 3
the viscosity of the fluid is closely dependent on temperature... As the operating temperature increases, the viscosity of the fluid will typically decrease and if this were not compensated for the flow rate would therefore increase
Data Source
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AI summary
There is disclosed a flow control nozzle (40, 40') for controlling the flow of an incompressible fluid, the flow control nozzle (40, 40') having a flow area and comprising a deformable element (50, 60) comprising a shaped memory alloy (SMA) material wherein within a range of operating temperatures the SMA material is configured to reduce the flow area of the flow control nozzle as the operating temperature increases. The flow control nozzle (40, 40') is thus able to dynamically compensate for changes in operating temperature in order to maintain a constant flow.