Дослідження граничнодопустимих режимів роботи теплових чутливих елементів для газоаналітичних пристроїв

Abstract

Досліджуються режими роботи теплового чутливого елемента за постійних значень теплофізичних параметрів газової суміші. За цих самих режимів забезпечується висока відтворюваність результатів вимірювання, висока чутливість і не перевищується допустима температура чутливого елемента. Combined methods of analysis based on the measurement of thermal and mechanical parameters of the gaseous mixture could be applicable in the development of gas analyzers for energy-saving technologies and new technologies of the enhanced raw materials and waste processing. Gas analyzers developed with the application of such methods of measurement have more advanced metrological and operational characteristics under complex measuring conditions and are not susceptible of the effect of corrosive contaminants and acidic gases.Thermal sensors, acting as transducers of thermal-physical and mechanical parameters of the gaseous mixture into an electrical signal, produce the output, the change of electrical resistance, which depends upon the thermal conductivity, heat capacity, energy consumption, density and viscosity of the gaseous mixture. The detection of the optimum operational modes of a heat sensing element, which could be heated up by the current, is essential for the pilot research of new circuit solutions in gas analyzing technologies. With certain restrictions, preconditioned by the small ratio of the length of the sensing element to its diameter, it would be reasonable to investigate the change of the measuring element sensitivity under the conditions of the current change, the change in the gaseous mixture expenditure and the temperature of the sensing element. The mathematical model of the measuring element with the heat sensing element is studied in this paper, obtained as a result of experimental calculations for the purpose of detecting the parameter values.