Presentation of the first law of thermodynamics for open systems using a graphical user interface

摘要

This paper presents the development of two cases of the first law of thermodynamics in open systems through the use of a registered graphical user interface (GUI) made in Matlab, as a complementary tool in the process of teaching undergraduate students of mechanical engineering from Universidad del Atlántico. Several experimental correlations reported in the literature for solving problems were considered. It was used the thermodynamic equations in the development of the algorithm of the software to perform energy analysis in a practical, interactive and user-friendly way, allowing students to identify the general behavior in nuzzles and heat exchangers when they operate under specific conditions. It was obtained the exit velocity profiles as a function of changes in temperature and pressure in nuzzles. In heat exchanges, the total heat transferred and the difference in temperature for the cold fluid is linearly dependent on the difference in temperature of the hot fluid with a higher efficiency when water is the cold fluid.