Trailing Edge Bluntness Noise Characterization for Horizontal Axis Wind Turbines [HAWT] Blades

Wind turbine noise is becoming a critical issue for many offshore and land-based wind projects. In this work, we analyzed trailing edge bluntness vortex shedding noise source for a land-based turbine of size 2 MW and blade span of 38 m using original Brooks Pope and Marcolini (BPM)and modified BPM noise model. A regression-based curve fitting approach has been implemented to predict the shape function in terms of thickness to chord ratio of aerofoils used for blade. For trailing edge height of 0.1% chord, computations for sound power level were done at wind speed of 8 m/s, 17 RPM. The results showed that present approach for thickness correction predicts the noise peak of ∼78dBA at f ∼ 10 kHz which is ∼15dBA lower than that predicted from original BPM. The results were also validated using experiment data from GE 1.5sle, Siemens 2.3 MW turbines with blade lengths between 78 m and 101 m which agreed within 2% at high frequencies, f > 5 kHz. In addition, results from present approach for trailing edge bluntness noise agreed well with modified BPM by Wei et al. at high frequencies, f ∼ 10 kHz where it becomes dominant. The slope of noise curves from present approach, and modified BPM methods are lower when compared with original BPM

Concise review: aerodynamic noise prediction methods and mechanisms for wind turbines

Wind power plants are increasingly being installed across the world to combat energy deficits and climate change. One of the policy constraints for installing wind turbine plants is acoustic emissions from blades during operation. In this work, a concise review of the quasi-empirical methods important for predicting noise from rotating wind turbine blades is presented. For wind turbines, self-noise mechanisms from blades and random turbulent inflow noise sources influenced by atmospheric turbulence are two major classes which contribute to overall noise signature. It has been found that these sources exhibit narrowband and broadband frequency characteristics. Trailing edge noise from the blade is an important source at mid-band to high frequencies in overall noise spectra while at infrasonic and low frequencies, inflow and impulsive noise sources are dominant which produce high annoyance and harmful effects on inhabitants. Previous research findings related to self-noise mechanisms are discussed thoroughly to provide an insight of aerodynamically produced noise generation

Anatomy of a Fused Filament Fabrication (FFF) 3D Printing System for High-Grade Polymers (HGPs)—An Overview

Fused filament fabrication (FFF) or fused deposition modeling (FDM) is one of the most common extrusion-based technology used for additive manufacturing (AM). It differs from the subtractive manufacturing technique in its material utilization and ability to fabricate complex parts. FFF is found to be convenient and easy in many ways, e.g., associated manufacturing setup and process are non-toxic, cost-energy effective, latest technology driven, less time engineering, virtual inventory control, etc. In the past, many researchers worked on the improvement of process parameters on the functionality of FFF machines to enhance mechanical, thermal, and electrical properties of AM objects. On the other hand, few research groups have worked on the exploration of finding new materials used in medical industry, tissue engineering, dental parts, etc. The core part of the FFF machines are extruder system, and nozzle has been focused by few researchers. FFF led the expansion of many desktop 3D printers based on their material use. However, the design aspects of FFF machine components and their assembly were not much discussed by many in the past. The main focus of the current study is on discussing the design of different prime elements (anatomy) along with their functionality to handle high-grade (performance) polymers (HGPs). This paper confers the shortcomings of filament-based extruder system and also paves future scopes of FFF technology over the existing filament-based extrusion system (filament extruder). © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd

A case study of wind turbine loads and performance using steady-state analysis of BEM

Wind power plants produce energy by utilising the kinetic energy available from wind. Turbine blades undergo millions of revolution during lifetime and subjected to wear and tear due to unsteady aerodynamic forces. In this work, steady-state blade element momentum computations were performed for horizontal axis 2.1 MW wind turbine to evaluate aerodynamic loads and performance. Axial and tangential loads along the blade span were found to increase near the outboard stations of blade but reduced towards tip. Turbine performance parameters viz. thrust and torque coefficients for tip speed ratio range of 5.1–9.5 showed that maximum values are found as 0.95, 0.98 and 0.12, 0.18 for 00 and 100 yaw angles and agreed well with SCADA data used for validation