9762 papers found
This paper describes the practical application of humidity instrumentation for water management in fuel cells and inlet air monitoring of gas turbines. A description of the instrumentation is provided. Measurement challenges in each application are identified and successful solutions are described in detail.
A dedicated calibration system for contact surface thermometers was designed and constructed and a thermal fluid dynamic model of the system for simulating the impact of the different influence parameters on the measurement was developed. The paper describes the new results of the comparison between the numerical predictions of the calibration system theoretical model and the experimental values, as obtained from its calibration.
Knowledge of temperature course during a certain time is needed in scientific, medical and industrial applications. In some applications, however, the recorded temperature course should be read wirelessly. This paper describes main principles applied in a set of mobile temperature data logger and portable interrogator with wireless transfer of digitized temperature values.
Measurement of a self-heating effect (SHE) of a platinum resistance thermometer (PRT), which is to be performed under real experimental conditions, is the trickiest part in the calibration procedure of PRTs for precise temperature measurements of material artifacts. New double-channel synchronous detection technique has been developed for precise measurement of the SHE of a resistance thermometer, located on the surface of a material artifact. With new technique, we demonstrate that a PRT modifies the temperature distribution in the artifact, and the SHE of a PRT measuring a selected point...
Thermally excited luminescence from rare-earth element doped SiO 2 fibers were studied for the fiber-optic thermometer application in high temperature. Thermal radiation similar to the black body radiation was observed in visible light region from the SiO 2 fibers doped with Y, La, Ce, Pr, Eu, Tb and Lu. Visible light radiation peaks due to f-f transitions of rare-earth ions were clearly observed in the Nd, Dy, Er, Ho, Tm and Yb doped SiO 2 fibers. Intensity ratio of thermal radiation at different wavelength is suitable for the highly sensitive temperature measurement. The hybridization of...
Long afterglow phosphorescent SrAl 2 O 4 and CaAl 2 O 4 based phosphors are found to be a useful sensor head material in the fluorescence thermometer because of extremely long fluorescence lifetime. Highly sensitive temperature sensor can be developed based on temperature dependence of afterglow intensity of long afterglow phosphor. Sensitivity of long afterglow phosphorescent SrAl 2 O 4 :Eu, Ln and CaAl 2 O 4 :Eu, Ln based phosphors are considered to be dominated by depth of the hole traps generated by doped rare-earth elements.
This paper presents a preliminary methodology for the calculation of measurement uncertainty of temperature sensors in dynamic regime. The experimental results show that the proposed methodology is suitable for the determination of the measurement uncertainty in the transient state of the calibration process.
Heat-meters as a kind of revenue meters are metrologically certified and this certification is executed with some measurement uncertainty. Since these certifications are performed by means of temperatures and flow amounts simulations, it obviously results in some measurement uncertainty. The value of the measurement uncertainty can be seen in the following calculation.
It is good calibration practice to test thermocouples for homogeneity of the Seeback’s coefficient during calibration process. If change in homogeneity the coefficient, commonly known as inhomogeneity is not detected, thermometer although calibrated might not be able to measure temperature correctly. Several different testing techniques are developed, depending on type of the thermocouple and the equipment available. In order to automate process of thermocouple inhomogeneity testing for all applicable testing methods a Thermocouple Inhomogeneity Testing Device was developed in Laboratory for...
The gold versus platinum (Au/Pt) thermocouples are very stable under long term repeated usage at higher temperature. Still there are some unsolved problems that the stress-relieving coil at the top of measuring junction is deformed after thermal cycling. In this study twist pair of thermocouple-element and U shape thin Pt wire at the measuring junction instead of the coil are tested in addition to the ordinary measuring junction. It was found that good stability and immersion characteristic is realized by a thermocouple having ordinary junction with appropriate anchoring of the thermocouple...