РАДИОФОТОННАЯ СИСТЕМА ИЗМЕРЕНИЙ РАСПРЕДЕЛЕНИЯ ТЕМПЕРАТУР И ИНТЕНСИВНОСТИ ЭЛЕКТРОМАГНИТНОГО ПОЛЯ В РАБОЧЕЙ КАМЕРЕ ЛАБОРАТОРНОЙ ТЕХНОЛОГИЧЕСКОЙ УСТАНОВКИ СВЧ-ДИАПАЗОНА
Authors: Кувшинов Н.Е. , Мисбахов Р.Ш. , Мисбахов Р.Ш. , Морозов О.Г. , Морозов Г.А. , Насыбуллин А.Р. , Сахабутдинов А.Ж. , Застела М.Ю. , Акишин Б.А. , Чони Ю.И. 
Published: February 2025

В статье предложена модернизация калориметрического метода измерения распределения температур и интенсивности электромагнитного поля (ЭМП) в рабочей камере лабораторной СВЧ технологической установки на базе матрицы дискретных термопреобразователей из поглощающего материала. После измерения поля температур термопреобразователей оно может быть пересчитано в распределение интенсивностей ЭМП, учитывая пропорциональность приращения их температур интенсивностям, которые воздействуют на каждый из них определённый период времени. Для решения вопроса удешевления системы опроса термопреобразователей и улучшения её метрологических характеристик предложено использовать волоконные брэгговские структуры адресного типа, встраиваемые в каждый термопреобразователь, и радиофотонные системы опроса полученной последовательности термопреобразователей-датчиков, соединённых оптическим волокном, которые, кроме высокой чувствительности и высокой скорости отклика на изменение температуры, обеспечивают оператора информацией о номере опрашиваемого элемента матрицы (адресе). Экспериментальные результаты показывают, что точность измерения температур повышается как минимум на порядок. Кроме того, устраняются сложность реализации процедур и методические погрешности измерения температур, присущие модернизируемому калориметрическому методу.
Introduction. A plenty of chemistry applications for the conversion of biomasses, synthesis of polymers and their depolymerization, processing of organic animal waste, separation of water-oil emulsions, etc. exhibit more efficient reactions when using microwave processing, which is typically involves microwave heating. An accurate and reliable system for laboratory temperature measurement in media processed by microwave radiation is urgent not only for the development of monitoring systems and adaptive control of ongoing chemical reactions, but also for comparing the efficiency of various microwave reactor systems and laboratory microwave facilities. Experimental methods and techniques for research. To solve the problem of reducing the cost of the interrogation system and improving its metrological characteristics, there is proposed to use address-type Bragg structures with radio-photon interrogation located on a single fiber as sensors. Sensors are built into each thermal converter, which, in addition to high sensitivity and high response rate to temperature changes, provides the operator an information about the number of the monitored matrix element (field distribution coordinate). Presented new system for measuring the distribution of temperatures and EMF intensity in the working chamber of a laboratory technological facility of the microwave range has a very simple structure formed by a wideband laser diode and an array of thermal converters. Each converter has a built-in temperature sensor based on multicomponent addressable fiber Bragg structures with a unique addressing frequency for a two-component structure or a set of unique addressing frequencies for a three-component structure. The multi-frequency radiation reflected from the matrix, passing through the circulator and the optical filter, enters the photodetector. The mathematical model of the implementation of radio-photon interrogation of the MAVBS array built into thermal converters and the temperature measurement algorithm are described in the paper. Findings. The paper proposes to improve the calorimetric method for measuring the distribution of temperatures and intensity of EMF in the working chamber of a laboratory technological facility of the microwave range by the change of the temperature of the elements of the matrix of discrete thermal converters made of absorbing material with the use of external electronic sensors. Experimental findings showed that the temperature measurement accuracy increased by at least an order of magnitude. In addition to this, the complexity of the implementation of procedures and methodological errors in temperature measurement (an additive error of 1-2 °С) observed in the modernized calorimetric method are eliminated. Moreover, there is shown the possibility of comparing the synthesized distributions of EMF intensities in working chambers with different methods of their excitation. For a working chamber with coherent excitation by five pins, the ratio of the maximum and minimum values of the intensities in the distribution, obtained from the transformed distribution of the temperature field, was (1.8 / 1.2) 1.33 times with a temperature measurement accuracy of ±0.01 °C. The uniformity of distribution in this case increased by 1.7 times in comparison with the single-element excitation of the same working chamber.