FAST, GH Bladed 및 CFD기법을 이용한 5MW 해상풍력터빈시스템 설계하중조건 해석 및 비교

Abstract

Design lifetime of a wind turbine is required to be at least 20 years. The most important step to ensure the deign is toevaluate the loads on the wind turbine as accurately as possible. In this study, extreme design load of a offshore wind turbineusing Garrad Hassan (GH) Bladed and National Renewable Energy Laboratory (NREL) FAST codes are calculated consideringstructural dynamic loads. These wind turbine aeroelastic analysis codes are high efficiency for the rapid numerical analysisscheme. But, these codes are mainly based on the mathematical and semi-empirical theories such as unsteady blade elementmomentum (UBEM) theory, generalized dynamic wake (GDW), dynamic inflow model, dynamic stall model, and towerinfluence model. Thus, advanced CFD-dynamic coupling method is also applied to conduct cross verification with FAST andGH Bladed codes. If the unsteady characteristics of wind condition are strong, such as extreme design wind condition, it ispossible to occur the error in analysis results. The NREL 5MW offshore wind turbine model as a benchmark case is practicallyconsidered for the comparison of calculated designed loads. Computational analyses for typical design load conditions such asnormal turbulence model (NTM), normal wind profile (NWP), extreme operation gust (EOG), and extreme direction change(EDC) have been conducted and those results are quantitatively compared with each other. It is importantly shown that thereare somewhat differences as maximum amount of 18% among numerical tools depending on the design load cases.