SEGREGATED SOLUTION TECHNIQUE FOR SIMULATING THE TRANSIENT OPERATION OF HEAT PIPES

Abstract

Simulating the transient operation of fully thawed heat pipes involves solving a highly nonlinear homogeneous two-phase flow problem, which necessitates the development of a stable and efficient numerical technique. In this work, various segregated numerical techniques are implemented, and their accuracy and computation time requirement are examined using experimental data of a water heat pipe. Best results are obtained using an iterative SIMPLEC-type segregated solution technique (HPTAM-Revised), which includes two internal iterative steps to resolve the pressure-velocity coupling and reduce the linearization errors of the kinetic theory relationship and equations of state. While all solution techniques examined performed the same in terms of accuracy, the HPTAM-Revised is 90 times faster than the basic noniterative SIMPLE-type approach in terms of CPU time. Also, using the iterative SIS solver, instead of the banded Gauss-elimination solver, for the discretized energy and momentum equations resulted in more than 50% savings in the CPU time for computational grids larger than 20 × 30.