Наведено огляд двоканальних методів вимірювання температури об’єктів за випроміненням. На основі комп’ютерного моделювання проаналізовано інструмен- тальну та методичну складові похибки вимірювання температури цими методами. Визначено умови, за яких доцільне їх застосування, та загальні недоліки використання цих методів.
Запропоновано шумову модель вхідного кола шумового термометра на основі інструментального підсилювача, яка описує залежність вихідної напруги підсилювача від шумових параметрів чутливого елемента первинного перетворювача, лінії зв’язку, операційних підсилювачів та резисторів зворотного зв’язку першого каскаду. Отримано математичний вираз еквівалентної сумарної шумової напруги, зведеної до входу шумового термометра.
Розглянуто вплив шумів приймача випромінення на похибку пірометра у процесі його калібрування. Визначено математичну залежність між похибкою вимірювання температури та відношенням сигнал/шум за різної кількості спектральних каналів пірометра, що досліджено за допомогою математичного моделювання.
Eradiation receiver impact on the pyrometer error in the process of calibration has been considered in the proposed article. The mathematical dependence of temperature measurement error on signal/noise ratio at various amount of spectral pyrometer channels is determined by the modeling.
Temperature is one of the main parameters that determine the quantitative and qualitative indicators of products. Therefore, it is difficult to name a field of technology or a branch of industry where it would not be necessary to measure the temperature of solid, liquid, or gaseous substances.
The error of measuring the temperature of gas flows by contact methods consists of two main components: 1) the error that occurs in the process of measuring the physical quantity into which the temperature is converted (the error of the measuring means); 2) errors arising in the process of converting the temperature into a measured physical value using a thermo transducer.
To study the metrological characteristics, there were studied manufactured based on the Ti-Cu-Co-Si alloy, obtained by quenching from the melt, the sensitive element of the resistance thermotransducer. The instability of its metrological characteristics as a function of temperature up to 350 oC and operation time up to 3000 hours was investigated; it does not exceed 0.025% under the worst operating conditions. In addition, the methodological error of measurement caused by heating of the sensitive element by the measuring current was examined.
The paper presents the analysis of scientific and technical sources on the influence of constructive features of pressure differential flowmeters on flow rate measurement error. According to the research results, the significant surface roughness of pipe sections downstream of the orifice plate does not significantly affect the flow measurement result. The influence of the pipe roughness upstream of the orifice plate depends on geometric characteristics of roughness, the pipe diameter, the relative area of the orifice plate throat, and the Reynolds number.
A mathematical model for determining the temperature of an electrically conductive plate element under the action of pulsed electromagnetic radiation of the radio-frequency range is proposed. This model allows us to take into account the influence of the process of thermoelastic energy dissipation on the forecasting of the value of temperature in addition to the joule heat. This process is determined by thermal expansion and the action of poendromotive forces arising in the element. This approach allows us to predict a decrease in the error of temperature determination. On this basis, t
Study of the dependence of the temperature determination error on the emissivity factor of materials is conducted in the paper. The mathematical models, which describe the ratio of thermodynamic temperature and measured imaginary temperatures, taking into account the emissivity factor, are analyzed. The constructions of the full radiation, brightness radiation, and spectral ratio radiation pyrometers are underpinned by the considered models.
The choice of ways of obtaining information about the temperature of the surface layers of a moving object is the crucial in determining the type of temperature transducers. This choice depends on the row of specific factors: the speed of movement of the measured object relative the object, the state of the surface, the presence of related agents in near-surface layers, the presence of disturbing factors - noise, vibration, etc. The major factor seems to be the value of the heat carried out from the diagnosed object with the help of intermediate substance.