J056034 空力弾性解析による小形風車翼の確率論的疲労評価法の検討(〔J056-03〕再生可能エネルギー(風力発電)(3))

Abstract

In this research, we aim to reveal, 1. The difference of fatigue load from aeroelastic model and SLM 2. The reasons of difference between aeroelastic model and SLM 3. The applicability of the idea that operation around Vdesign can represent the lifetime fatigue load which is the background of SLM For fatigue load design of small wind turbines, IEC61400-2 Ed.2[1] provides two fatigue load calculation methods; Simplified load model(SLM) and aeroelastic modeling. Although aeroelastic modeling includes more realistic effect, most of small wind turbines below 1kW in Japan are designed using SLM because of the complicated procedure of aeroelastic modeling. So, we aims to reveal how SLM is applicable for these “micro wind turbines” and how these turbines designed for SLM are safety or danger sided or how much the cost of energy increase or decrease using SLM instead of aeroelastic model. Moreover, we wish to establish more practical and theoretical load design method affordable for micro wind turbine manufacturers. In this research, fatigue load design is focused. Fatigue load estimation by the aeroelastic modeling was carried out for AURA1000 135W small wind turbine with 1m diameter In this research. The results were compared with the simplified load model (SLM). And the reasons of difference between two methods are discussed. An aeroelastic simulation code for 5 bladed wind turbines based on NREL’s FAST[2] is used for aeroelastic modeling. Four annual wind speed distributions are considered; Class I to Class IV defined in IEC61400-2 Ed.2. The result of fatigue load showed that SLM is more sensitive to annual average wind speed than the aeroelastic modeling. And the difference indicated that SLM’s assumption cannot be applied for the researched turbine In addition, the idea of representative operational range around Vdesign which is used in SLM is applied for the result of Aeroelastic model. It is revealed that wider range than the assumption of SLM in most cases. Especially in Class IV, the ranges were unrealistic value.