SIMULATION OF LAMINAR STRATIFIED FLOW BOILING OF LIQUID IN A HORIZONTAL TUBE BY THE COUPLED MAP LATTICE MODEL

摘要

A new heat transfer model for stratified flow boiling in a horizontal tube is proposed in this present study. In recent years, the subject of nonlinear dynamics has progressed and various tools of analysis have been proposed for complex systems. Coupled Map Lattice (CML) method is one such tool which makes it possible to simulate complex systems and to capture the qualitative nature of the phenomenon. In this work, steady stratified flow boiling of water is simulated qualitatively by using the CML model for laminar, hydrodynamically and thermally developing flow and heat transfer in a horizontal tube. The liquid enters in a constantwall temperature tube (T_w~*>T_(sat) at P_(entrance)~*) in a subcooled or saturated condition. The present modeling by CML is based on the assumption that the flow boiling is governed by nucleation from cavities on the heated surface, migration of vapor into the core, forced convection and phase change in the bulk. The macroscopic variable chosen is temperature. The influences of mass flow rate, inlet subcooling and wall temperature have been studied. The results of the computations provide information on the effect of aforementioned parameters on the heat transfer coefficient and void fraction. The results show that the CML has been able to model flow boiling in a realistic manner.