Dynamic effects of inertial particles on the wake recovery of a model wind turbine

Abstract

Impacting particles such as rain, dust, and other debris can have devastating structural effects on wind turbines, but little is known about the interaction of such debris within turbine wakes. This study aims to characterize behavior of inertial particles within the turbulent wake of a wind turbine and relative effects on wake recovery. Here a model wind turbine is subjected to varied two-phase inflow conditions, with wind as the carrier fluid (Re λ = 49 − 88) and polydisperse water droplets (26 to 45 µm in diameter) at varied concentrations (Φ v = 0.24×10 −5-1.3×10 −5), comparing with sub-inertial particles that follow the inflow streamlines. Phase doppler interferometry (PDI) and particle image velocimetry (PIV) were employed at multiple downstream locations, centered with respect to turbine hub height. Analysis considers momentum and particle size distribution within the wake focusing on turbulence statistics and preferential concentration. PDI data show droplet size varied with wake location and volume fraction, and the inflow velocity of Re λ = 66.58 demonstrated Φ v-dependent increases in streamwise velocity deficits of 59.5% to 62.6% and 15.8% to 19.8% for near and far wake, respectively. PIV data indicated correlation of particle concentration to wake expansion and amplified downward trajectory over the entire interrogation field. Contributions to kinetic energy and momentum are diminished overall for inertial particle cases compared to single-phase, except turbulent momentum flux u v , where shearing effects are visible at the rotor top edge in near wake and concentrated magnitudes increase in far wake correlating with increased Φ v. Application of Voronoi analysis identified clustering behavior in far wake and was validated as motivation for future studies.

Wind turbine wake influence on the mixing of relative humidity quantified through wind tunnel experiments

“…4(f)]. The measurements of the mean and rms velocity for the non-stratified case are consistent with those reported by Smith et al 23 fortracerparticles.…”

“…The setup is similar to a previous experiment performed on the same facility. 23 The rotor is based on the design of Odemark and Fransson, employing a Blade Element Momentum scheme with Glauert optimization. 24,25 Rotor blade pitch is set at 6.5 to agree with Odemark and Fransson and the rotor diameter was D ¼ 12 cm.…”

Characterization of coupling between inertial particles and turbulent wakes from porous disk generators

“…Particle trapping may be occurring in the wake at as this was also seen at in the wake of a model turbine by Smith et al. (2021). Particle trapping could be confirmed in future experiments with particle tracking velocimetry.…”

“…2021; Smith et al. 2021). Cloud formation, industrial spray applications, combustion and air pollution are also of interest (Chandrakar et al.…”

Scale-dependent particle clustering in transitional wake flow

“…Nevertheless, particle-laden wake flows have been subjected to comparatively few investigations despite their obvious practical relevance. An in-depth understanding of inertial particle dispersion and mixing in a variety of industrial scenarios is paramount to mitigate any adverse impacts, such as scouring around offshore wind turbine foundations caused by suspended sediments (Roulund et al 2005) or airfoil turbine blades exposed to rain droplets (Cohan & Arastoopour 2016;Smith et al 2021). The unsteady flow past a uniform circular cylinder may serve as a prototype flow which includes the essential features of general bluff-body wakes (Zdravkovich 1997).…”