NUMERICAL-SIMULATION OF THE THERMAL-BEHAVIOR OF HEAT-EXCHANGERS AND STORAGE DEVICES USING MULTILEVEL AND ADI TECHNIQUES

A numerical simulation has been developed to evaluate the thermal behaviour of heat exchangers and storage devices in which the fluid flow is confined in ducts. The simulation takes into account the multi-dimensional and transient aspects that characterize the phenomenon of heat transfer in such units. The simulation carried out allows the analysis of the influence of such aspects as non-uniform inlet flow distribution, variable physical properties, different arrangements of the ducts and flow configurations, etc. The main purpose of this paper is to show the performance of the different numerical techniques employed and to present illustrative examples of the characteristics of the software developed. In steady-state situations the line-by-line, multilevel and ADI techniques have been used. In unsteady-state situations the implicit (with line-by-line and multilevel techniques) and ADI schemes have been employed. The numerical results and CPU times obtained have been compared.