Ultrasonic Waveguide Surface Temperature Measurement Without Signal Leakage
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Solution Overview
Problem
Conventional ultrasonic waveguides used for surface temperature measurement are susceptible to leakage and property changes due to heat transfer, leading to inaccurate results and challenging calibration.
Innovation Solution
An apparatus with an elongated waveguide having a predefined cross-section, coupled with a transducer assembly, supplies ultrasonic signals along a segment not in contact with the object, using ultrasonic shear horizontal waves, and employs a data acquisition unit to determine surface temperature based on reflected signals, with features like grooves, bends, and notches to enhance measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the waveguide is made of metal and attached to the object for surface temperature measurement, then the ability to measure temperature at high temperatures and hazardous conditions is improved, but ultrasonic sound wave leakage occurs and calibration becomes challenging
Solution Approach 1:
The waveguide is divided into multiple segments or sections along its length, with each segment having specific functional characteristics. This segmentation allows different portions to serve different purposes - some for temperature sensing, others for signal transmission - thereby reducing overall signal leakage while maintaining measurement capability in harsh environments
Solution Approach 2:
Different portions of the waveguide are assigned different properties or configurations. Specifically, certain sections have modified geometries or material characteristics optimized for minimizing ultrasonic leakage, while other sections maintain properties suitable for temperature sensing. This local differentiation resolves the contradiction by addressing leakage issues only where necessary without compromising overall measurement function
2Reliability
If the waveguide remains in continuous contact with the object for temperature monitoring, then continuous temperature data is obtained, but mechanical properties of the waveguide change due to heat transfer leading to leakage and inaccurate results
Solution Approach 1:
A thermal barrier or intermediate layer is introduced between the waveguide and the object surface. This intermediary layer reduces direct heat transfer from the hot object to the waveguide, thereby maintaining the mechanical stability and material properties of the waveguide while still allowing sufficient thermal coupling for accurate temperature measurement
Solution Approach 2:
The waveguide is constructed using composite material structures that combine materials with different thermal and acoustic properties. This composite construction allows the waveguide to maintain mechanical stability under thermal stress while still functioning as an effective ultrasonic waveguide for temperature sensing
3Measurement precision
If the waveguide is frequently replaced or redeveloped to account for mechanical property changes, then measurement accuracy is maintained, but device complexity and maintenance requirements increase
Solution Approach 1:
The waveguide is pre-conditioned or pre-heated during installation to accelerate thermal equilibrium, and preliminary calibration is performed under simulated operating conditions. This preliminary action reduces the rate of mechanical property changes during actual operation, thereby extending the service life and calibration interval of the waveguide
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 apparatus provides accurate and reliable surface temperature measurement by preventing ultrasonic wave leakage and enabling rapid calibration, suitable for critical components with minimal mechanical property changes.
Implementation Method 1
The transducer is configured to supply the ultrasonic signals along at least one segment of the pre-defined cross-section of the elongated waveguide which is not in contact with the object
Implementation Method 2
reflections (echoes) are captured by a receiver. Any change in temperature of the media (liquid/fluid/gas) in vicinity of the objects, causes change in material property/geometric configuration of the object and it in turn triggers change in velocity of the introduced/reflected sound waves
Implementation Method 3
Any change in temperature of the media (liquid/fluid/gas) in vicinity of the objects, causes change in material property/geometric configuration of the object and it in turn triggers change in velocity of the introduced/reflected sound waves
Data Source
AI summary
The present disclosure relates to an apparatus and a method for determining surface temperature of an object The apparatus includes an elongated waveguide defining a pre-defined cross-section. Further, at least a portion of the waveguide is in contact with a surface of an object whose surface temperature is to be measured. The apparatus further includes a transducer assembly having at least one transducer coupled to the waveguide for supplying ultrasonic signals along at least one segment of the pre-defined cross-section waveguide which is not in contact with the object and for detecting reflected signals from the waveguide. The apparatus also includes a data acquisition unit which is coupled to the transducer to receive the reflected signals and to determine the surface temperature at one or more positions of the object.