가압경수로 2상유동 해석 코드 CUPID 병렬화 및 병렬 특성 평가

다국어 초록 (Multilingual Abstract)

Two-phase thermal hydraulics code, CUPID for multi-dimensional, multi-physics and multi-scale analysis in PWR was parallelized to fulfil the demand for long transient or high-resolved thermal hydraulics calculation. the CUPID code was parallelized based on the domain decomposition method with MPI (Message Passing Interface). For domain decomposition, the CUPID code provides both manual and automatic method with METIS library. For the effective memory management, the CSR (Compressed Sparse Row) format is adopted, which is one of the methods to represent the sparse asymmetric matrix. By performing the verification for the fundamental problem set, the parallelization of the CUPID has been successfully confirmed. In this paper, the characteristics of the parallelized CUPID code were investigated. Since the scalability of a parallel simulation is generally known to be better for fine mesh system, three types of mesh system are considered: 40,000 meshes for coarse system, 320,000 meshes for fine system. In the given geometry, both single- and two-phase calculations are conducted. In addition, two types of preconditioning for matrix solver were compared: diagonal and incomplete LU preconditioning.