A Sensor of Blackbody Cavity With Transparent Wall for Rapidly Measuring the Liquid Temperature (original) (raw)
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International Journal of Thermophysics, 2009
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Metals
In the case of casting processes with permanent molds, there is still a relatively pronounced lack of knowledge regarding the locally prevailing heat transfer between casts and mold. This in turn results in an insufficient knowledge of the microstructure and the associated material properties in the areas of the casting component close to the surface. Therefore, this work deals with the design and evaluation of a test tool with an integrated sensor system for temperature measurements, which was applied to obtain a time-dependent heat transfer coefficient (HTC) during casting solidification. For this purpose, the setup, design and computational approach are described first. Special attention is paid to the qualification of the multi-depth sensor and the calculation method. For the calculations, an inverse estimation method (nonlinear sequential function) was used to obtain the HTC profiles from the collected data. The developed sensor technology was used in a test mold to verify the ...
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Biomedical Journal of Scientific & Technical Research, 2021
Rapid development in the area of temperature measurement techniques arises from various applications, such as the sessile drop, which is of interest in several fields including coating, combustion, and cooling facilities. Accurate depiction of the physical phenomenon entails improvement in the temperature measurement resolution, where average temperature measurements fail to capture, due to their spatial limitation. In the current paper, various optical techniques are reviewed in contrast to conventional measurement approaches, such as thermocouples and microheater arrays. The optical techniques include Infrared thermography and fluorescing materials, such as quantum dots and Temperature sensitive paint. The advantages and shortcomings of such techniques are examined in depth, with respect to their applications in previous works.
Precision Core Temperature Measurement of Metals for Use in Manufacturing Applications
2020
Core temperature variation in metals during manufacturing processes affects both the dimensional accuracy and the surface integrity of manufactured workpieces. Different types of temperature measurement techniques have been applied for obtaining workpiece temperature. However, their main limitations have been an inability to give the core temperature of the workpiece and the reduction in accuracy due to the harsh environment of some manufacturing processes. The velocity of sound in any medium of propagation is dependent on the temperature of that medium. This relationship can be used to obtain a medium's temperature, provided that the velocity of sound through the medium can be measured. This paper investigates the use of ultrasonic waves sent in the continuous mode to measure the temperature variation in a 100 mm steel sample (type EN24T) using the ultrasonic phase-shift method. Simulations and bench tests were performed to obtain a resolution and accuracy better than 0.5 °C and ±1 °C respectively. The results show that the method gives reliable results well within the target specification. Based on these results, ultrasonic thermometry experiments will be carried out during subtractive machining processes to determine the effects of the harsh environment on the accuracy of the proposed method.
DESIGN OF METAL HEAT CONDUCTIVITY MEASUREMENT USING PROBE METHOD
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This study aims to design a tool that can measure the heat conductivity of metals by the Probe method. The design method used a heat-flowing metal beam and an LM35 temperature sensor to measure temperature changes on the probe. This measurement system design is based on conduction heat transfer; meanwhile, the metal used is aluminum and carbon steel. For each tested metal, an LM35 temperature sensor is placed on the metal to find out that a temperature change has occurred. The conductivity value can be obtained from the temperature difference between the probe and the metal being tested, the temperature change of the probe, the temperature change of the metal being tested, and the heating time. This value is processed and calculated by the microcontroller into the value of heat conductivity. The measurement results show that the average heat conductivity value is 214.93 W/m o C for aluminum and 53.81 W/m o C for carbon steel.
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A New Mercury Gas-Controlled Heat Pipe for Temperature Amplifier and as Calibration Facility
International Journal of Thermophysics, 2008
At the Italian National Research Institute of Metrology, the activities and studies concerning gas-controlled heat pipes are constantly increasing in terms of involved personnel, instrumentation, and devices available. In the last two years, among the other activities, a totally new gas-controlled heat pipe operating with mercury as the working fluid has been designed, manufactured, and completely characterized. This heat pipe is made of stainless steel and provided with three thermometer wells. A dedicated furnace has been constructed and specific software algorithms have been implemented for the temperature and pressure control. This device will be used as a low-temperature reference for the new "Temperature Amplifier" and as a calibration facility for thermometers calibrated by comparison between 220 • C and 450 • C. All details regarding this heat pipe, including the assembly, filling, and testing procedures, and the complete characterization campaign are summarized here. Results in terms of temperature stability, uniformity, and time response are reported, and demonstrate the capabilities of this gas-controlled heat pipe to be a useful device for research and applications in contact thermometry. Another gas-controlled heat pipe operating with mercury and provided with six thermometer wells has been manufactured, and will be characterized for the contact thermometry calibration laboratory at INRiM and for other calibration companies in Italy; this device is also presented.
Casting is a widely used manufacturing process for complex shaped-parts with high stiffness due to the monolithic integrity. An added value to these demands is high dimensional precision which casting cannot achieve in most cases. To ensure defect-free products and dimensional precision like side walls, radii, the cast has to be cooled according to material type, product size, filling rate and mold design. Nowadays, the cooling control is based mostly on empirical knowledge. To avoid product quality deterioration it is necessary to have an intelligent control system, which adjusts the cooling parameters according to varying casting conditions. To play with the casting parameters, their influence on the cast part is needed to be scientifically known in order to predict it. Numerical simulation is the suitable tool for getting different influences of the casting parameters on the final part shape and dimensions. Instead of costs of test and trials, numerical simulations needs computat...
The LED Temperature indicator uses the technology of converting environmental temperature to electronic signal. The operation of the LED temperature Indicator is based around a precision temperature sensing Integrated circuit (IC), the LM35Z and the Dot/Bar Graph Display Driver, a monolithic Integrated circuit (LM3914) and other discrete electronic components. The analysis of the work presented here shows a study of the performance/sensitivity of the most active component (LM35) at changes in a heat controlled flask temperatures. The result obtained in this work which, affirms the linearity of the sensor component, has been set as a guide on how to use this component for heat sensing in similar applications.
Contactless, non-intrusive core temperature measurement of a solid body in steady-state
International Journal of Heat and Mass Transfer, 2016
Accurate measurement of temperature is critical for understanding thermal behavior and monitoring safety and performance of engineering systems involving heating and cooling. While a number of methods are available for measurement of temperature on the outside surface of solid bodies, there is a lack of contactless, non-invasive methods for determining temperature inside solid bodies. Development of such methods is likely to impact a wide range of engineering systems. This paper describes and validates a method for measurement of internal temperature of a solid body based on measurement of the temperature distribution on its outside surface. A theoretical model is developed for determining the core temperature of a cylinder based on surface temperature measurement. This method is validated by determining the core temperature of a thermal test cell using infrared temperature measurement on the surface, and comparing with measurements from an embedded thermocouple. The two measurements are found to agree well with each other in a variety of heat generation and cooling conditions. While this validation is presented for a cylindrical body, the method lends itself easily to bodies of other shapes. This work contributes towards fundamental thermal metrology, with possible applications in a wide variety of engineering systems.