Constructing fast and representative analytical models of wind turbine main bearings

Abstract

Abstract. This paper considers the modelling of wind turbine main bearings using analytical models. The validity of simplified analytical representations used in existing work is explored by comparing main-bearing force reactions with those obtained from higher-fidelity 3D finite-element models. Results indicate that there is good agreement between the analytical and 3D models in the case of a non-moment-reacting support (such as for double-row spherical roller bearings), but the same does not hold in the moment-reacting case (such as for double-row tapered roller bearings). Therefore, a new analytical model is developed in which moment reactions at the main bearing are captured through the addition of torsional springs. This latter model is shown to significantly improve the agreement between analytical and 3D models in the moment-reacting case. The new analytical model is then used to investigate load characteristics, in terms of forces and moments, for this type of main bearing across different operating points and wind conditions.

Impacts of wind field characteristics and non-steady deterministic wind events on time varying main-bearing loads

“…These studies all considered only the case of a non-moment reacting support at the main-bearing, a condition that generally holds for a double-row spherical roller bearing (SRB) in a three-point mounting configuration but does not hold for paired tapered roller bearings (TRBs) which, as a unit, provide a combination of force and moment reactions to applied loads. Stirling et al (2021) proposed an extension of the preceding analytical main-bearing representations that accounts for moment reactions via inclusion of rotational springs.…”

Wind Turbine Drivetrain Reliability and Wind Plant Operations and Maintenance Research and Development Opportunities

“…Bearing fatigue life standards are reaching their limit for calculating main bearing rating life due to low operational speeds, high axial loads, and lubrication characteristics, especially as tall land-based and offshore turbines continue to increase in size. These types of failures can be better understood through both accelerated benchtop as well as full-scale investigations supported by modeling (Sethuraman, Guo, and Sheng 2015;Stirling, Hart, and Kazemi Amiri 2021;Guo et al 2021). The aim of this work should be to help identify root causes and make better-informed initial design and maintenance decisions .…”

Wind turbine main-bearing lubrication – Part 2: Simulation based results for a double-row spherical roller main-bearing in a 1.5 MW wind turbine

“…This was done using the statically determinate single main-bearing model previously used in Hart et al (2019); Hart (2020); Stirling et al (2021) and discussed in Section 2. As described earlier, evaluation of main-bearing applied loading involves a static load balance at each timestep.…”

“…Main-bearing research to-date has mainly focused on load modelling (Kock et al, 2019;Hart, 2020;Wang et al, 2020;Zheng et al, 2020a;Stirling et al, 2021), load characteristics (Cardaun et al, 2019;Hart et al, 2019;Hart, 2020;Guo et al, 2021) and implications for fatigue damage (Zheng et al, 2020b;Loriemi et al, 2021). Lubrication conditions within the main-bearing are generally not considered.…”

“…Applied loads at the turbine hub are obtained from simulations (described below) and the radial loads at the main-bearing are resolved independently in horizontal and vertical planes. In Stirling et al (2021) it was shown that, for the single main-bearing configuration, this simplified drivetrain representation is able to accurately recreate the radial response at the main-bearing seen in a higher fidelity, but still relatively simple, 3D finite element model. All thrust is assumed to be reacted by the main-bearing for the single main-bearing configuration (equivalently, "three point suspension") studied here.…”