Verification of the Numerical Algorithm for Parameter Analysis of the Tube Heat Receiver of the Solar Parabolic Trough System

Abstract

This paper presents the results of the first stage of verification of the generalized computational algorithm for determining the geometrical, dynamical, and energy parameters of the “parabolic trough concentrator – tube heat receiver” solar receiver system. This algorithm is based on the dimensionless coupled mathematical model of heat and mass exchange in the “Sun – parabolic trough concentrator – tube receiver” system. The Monte Carlo ray tracing method was used to calculate irregular heat flux from the concentrator to the tube receiver surface. The 3D mathematical model of heat exchange in the tube receiver was solved using the finite volume method. The mathematical model took local climatic and geographical features into account, as well as micro- and macroscopic imperfections of the concentrator surface. The dimensional problem of heat exchange in the tube receiver of the solar parabolic trough system was solved at the first stage of verification. A simplified physical model was described. It was assumed that the glass envelope around the tube receiver was removed. The dimensional mathematical model of heat exchange in the tube receiver is based on the system of Navier–Stokes equations for viscous incompressible liquid with constant physical properties. The mathematical model with real boundary conditions was solved numerically. An analytical solution for the test problem with trivial boundary conditions was obtained. The results of the test numerical problem were compared with analytical solution results and were found to be in close agreement. Numerical experiments with real boundary conditions were conducted using the computational algorithm. The numerical data were compared with the results of field experimental studies and showed nearly total agreement, which proved the adequacy of the basic mathematical model and the resulting numerical algorithm.