Математическое моделирование конденсации рабочего тела в системе отдачи тепла холодному источнику энергоустановки малой мощности

Abstract

The purpose of the paper is to offer a method for reducing the temperature and condensation of the working fluid circulating in the power plant due to the fact that the Russian Federation is characterized by uneven provision of electricity and heat (the problem of energy shortage is most acute in the Far East and the Far North regions). The major shortcomings of the current centralized energy supply are great losses during energy delivery and transformation, as well as the possibility of de-energizing a large number of consumers in case of an accident at the сentral power plant. In this regard, the idea of decentralized energy production free from the named shortcomings due to its autonomy and proximity to the places of consumption is becoming increasingly relevant. One of the methods of decentralized generation of heat and electricity is the use of Rankine cycle-based low-capacity power plants with an organic working fluid. Their design includes a boiler heating the working fluid, a turbine driving the electric generator, condenser and a pump. To condense the coolant the organic Rankine cycle must be provided with heat dissipation to the environment. This paper deals with the method of lowering the temperature and condensation of the working fluid circulating in the power plant (by means of a horizontal pipeline plunged to a certain depth in the ground). It is assumed that available temperature potential of the soil provides complete condensation of the working fluid without excessive overcooling. The study of intensity of working fluid cooling and condensation in the pipeline is carried out using a homogeneous and ring flow model. The temperature fields and steam dryness degree are determined by two approaches: in the software package of finite element modeling ANSYS CFX and by the finite difference method (engineering calculation methods). The paper also presents the analysis of the results obtained in the course of solving the problem by means of the finite element analysis and engineering calculation by the finite difference method.