ДОСЛІДЖЕННЯ ПРОЦЕСІВ УТИЛІЗАЦІЇ ТЕПЛА ПАРОПОВІТРЯНИХ СУМІШЕЙ: ІМІТАЦІЙНЕ МОДЕЛЮВАННЯ

The article considers basic approaches to the development of simulation models, their advantages and disadvantages. The article outlines the simulation model for deep heat recovery process of steam-air mixtures with steam-compressor heat pump, including simulation models of the compressor, condenser, electronic expansion valve, evaporator, supercooler and contact heat exchanger recovering heat from steam-air mixtures. The simulation models of these components wereprepared using experimental data obtained by the authors as a result of performing physical field experiments at a laboratory test facility. The function of calculating the "ballast" and "effective" refrigerant flow is implemented in the simulation model of the heat pump evaporator.“Ballast” flow occurs due to the refrigerant supercooling to boiling point and is accompanied by partial evaporation of its share, which does not take part in the heat extraction by the evaporator. To do this, the evaporator simulation model was supplemented with a subsystem calculating the difference in boiling points (pressure) along the length of the evaporator based on the refrigerant flow rate and the evaporator temperature and taking into account the length of the evaporator segment where the liquid phase boils. Dependence of the pressure drop along the length of the evaporator on the refrigerant flow passing through it, is not a monotonically increasing function but is that having an extremum and decreasing at the refrigerant overheating levels ranging from 15 to 0 °C. Evaporator outlet pressure is calculated in the model using a nonlinear function of two variables - the position of EEV and the compressor’s rotational speed. The dynamic properties of the channels are modelledbased the links which transfer functions were obtained as a result of physical experiments. The adequacy of the simulation model was tested and a series of computer experiments were performed under conditions similar to those of the full-scale physical experiments at the laboratory facility. Comparison of simulation results and physical experiment showed a high degree of similarity. [ABSTRACT FROM AUTHOR]