Temperature measurement

About: Temperature measurement is a research topic. Over the lifetime, 18186 publications have been published within this topic receiving 167735 citations. The topic is also known as: Thermometry.

Fiber-optic temperature sensor based on interference of selective higher-order modes

Abstract: A fiber-optic temperature sensor based on the interference of selective higher-order modes in circular optical fibers is described. The authors demonstrate that by coupling the LP01 mode in a standard single-mode fiber to the LP0m modes in a multimode fiber, and utilizing the interference of the higher-order modes, a fiber-optic temperature sensor which has an extremely simple structure and is suitable for high-temperature measurements can be constructed. The sensing principle, temperature measurement experiments, and results are presented.

A Fabry–Pérot fiber-optic ultrasonic hydrophone for the simultaneous measurement of temperature and acoustic pressure

Abstract: A dual sensing fiber-optic hydrophone that can make simultaneous measurements of acoustic pressure and temperature at the same location has been developed for characterizing ultrasound fields and ultrasound-induced heating. The transduction mechanism is based on the detection of acoustically- and thermally-induced thickness changes in a polymer film Fabry-Perot interferometer deposited at the tip of a single mode optical fiber. The sensor provides a peak noise-equivalent pressure of 15 kPa (at 5 MHz, over a 20 MHz measurement bandwidth), an acoustic bandwidth of 50 MHz, and an optically defined element size of 10 microm. As well as measuring acoustic pressure, temperature changes up to 70 degrees C can be measured, with a resolution of 0.34 degrees C. To evaluate the thermal measurement capability of the sensor, measurements were made at the focus of a high-intensity focused ultrasound (HIFU) field in a tissue mimicking phantom. These showed that the sensor is not susceptible to viscous heating, is able to withstand high intensity fields, and can simultaneously acquire acoustic waveforms while monitoring induced temperature rises. These attributes, along with flexibility, small physical size (OD approximately 150 microm), immunity to Electro-Magnetic Interference (EMI), and low sensor cost, suggest that this type of hydrophone may provide a practical alternative to piezoelectric based hydrophones.

Atmospheric pressure plasma jet in Ar and Ar/H2O mixtures: Optical emission spectroscopy and temperature measurements

Abstract: An atmospheric pressure plasma jet generated in Ar/water vapor mixtures has been investigated and the effect of water content on plasma properties has been studied. Plasma generated in Ar/water (0.05%) mixture shows higher intensity of OH radicals in emission spectra than pure argon alone. Plasma density has been estimated from current measurement and is in order of 1.5×1013 cm−3. Electron temperature has been estimated as 0.97 eV in pure Ar and it decreases with an increase in water content in plasma. The gas temperature has been determined by fitting of the experimental spectra and using the Boltzmann plot method. The gas temperature increases with the addition of water to feed gas from 620 K in pure Ar up to 1130 K for 0.76% H2O.

Measurement of flame temperature and adiabatic burning velocity of methane/air mixtures

Abstract: A simple and accurate method is presented to determine the flame temperature and the adiabatic burning velocity of laminar premixed flat flames, using a specially constructed flat flame burner. The heat loss of the flat flame is determined from measurement of the temperature profile of the burner plate. The adiabatic burning velocity is found when the burner plate temperature profile is uniform, implying that the net heat loss of the flame is zero. Several methods are presented to determine the thermal conductivity of the burner plate. The results for methane/air mixtures are compared with experimental data found in the literature and one-dimensional flame calculations, and close agreement is found. The method is particularly useful in providing an accurate reference for other temperature measurement techniques (e.g. spectroscopic laser diagnostics), and to determine adiabatic burning velocities over the entire range of flamm ability

Fundamentals of Temperature, Pressure, and Flow Measurements

Abstract: TEMPERATURE AND ITS MEASUREMENT. Early Attempts to Measure Degrees of Heat. The Air Thermometer. Thermodynamic Viewpoints of Temperature. The International Practical Temperature Scale. Liquid--in--Glass Thermometers. Resistance Thermometry. Thermoelectric Thermometry. Optical Pyrometry. Calibration of Temperature Sensors. Uncertainties and Statistics. Temperature Measurement in Moving Fluids. Installation Effects on Temperature Sensors. Transient Temperature Measurement. PRESSURE AND ITS MEASUREMENT. The Concepts of Pressure. Pressure Standards. Principles of Conventional Pressure Transducers. Pressure Measurement in Moving Fluids. Transient Pressure Measurement. FLOW AND ITS MEASUREMENT. The Concept of Flow Rate. Open--Channel Flow. Theoretical Rates in Closed--Channel Flow. The Discharge Coefficient. The Expansion Factor. Installations and Uncertainties. Answers to Problems. Solutions to Problems.