Heat engineering aspects of automatic control of the heat-moisture state of the heat carrier in shaft-type grain dryers, Теплотехнічні аспекти автоматичного регулювання тепловологісного стану теплоносія у зерносушарках шахтного типу

<jats:p>The article considers the heat engineering aspects of automatic regulation of the heat-moisture state of the heat carrier in shaft-type grain dryers. The purpose of the study is to substantiate the features of formation and stabilization of the temperature and humidity parameters of the heat carrier under conditions of automated control of the grain drying process. The study is based on methods of analysis and generalization of scientific and technical literature, system analysis, heat engineering analysis of heat and mass transfer processes, as well as mathematical modeling of dynamic control processes in grain drying systems. The physical model of the grain drying process in shaft-type grain dryers was analyzed, and the main factors affecting the formation of the heat-moisture state of the heat carrier were identified. It was established that the efficiency of the drying process largely depends on the stability of the temperature and humidity parameters of the heat carrier, the initial grain moisture content, the airflow rate, and the thermal inertia of the drying system. Based on the heat balance equation and mathematical models of moisture removal from grain material, the relationship between the heat carrier parameters and the intensity of heat and mass transfer in the grain layer was substantiated. A dynamic model of the drying system was proposed, taking into account the inertia of thermal processes and the delay between the control action and the response of the drying chamber. The study substantiates the expediency of using a closed-loop automatic control system based on PID regulation for simultaneous stabilization of the temperature and humidity parameters of the heat carrier. The proposed approach provides continuous monitoring of the heat carrier parameters and adjustment of the operating modes of the heat generator and ventilation system according to changes in the thermal state of the grain mass. The constructed graphical dependences in Cartesian coordinate systems showed that automatic regulation makes it possible to reduce fluctuations in the heat carrier temperature, improve the stability of drying modes, decrease unnecessary heat losses, and increase the energy efficiency of the drying process. It was established that multiparameter control of the heat-moisture state of the heat carrier contributes to more uniform moisture removal from grain material and reduces the risk of local overheating of grain. The practical significance of the obtained results lies in the possibility of using the proposed approaches in the design and improvement of automated control systems for shaft-type grain dryers in order to increase the stability and energy efficiency of grain drying technologies.</jats:p>