Energy We present a study on the influence of the turbulence generated by a cylinder on the performance of a free horizontal-axis turbine. The analysis focuses on the power coefficient, flow characteristics, and Turbulence Kinetic Energy (TKE) spectral density distribution. The mean velocity, turbulence intensity, and TKE are evaluated in the upstream and downstream planes…

Renewable Energy The bottleneck of urban forest waste (UFW) as biofuel relies on surpassing its logistical management, feedstock quantity and supply, heterogeneity, and property drawbacks. This article proposes a hybrid approach based on multicriteria decision methods (MCDM) and response surface methodology (RSM) to optimize the definition of UFW blends and their torrefaction (temperature and process time). First, proximate, ultimate, and calorific…

Landfill gas (LFG) is related to the biochemical processes generating heat and releasing CH4, CO2, and other gases in lower concentrations, which result in environmental impacts and risk of local explosion. Thermal infrared imagery (TIR) is employed to detect CH4 leakage as a risk control approach. However, the challenge for LFG leakage detection using TIR is…

IJHE This study aims to simulate the steam-enhanced co-gasification of hybrid blends (HB) composed of municipal solid waste (MSW) and urban forest waste (UFW), with torrefaction as pretreatment. Experimental (torrefaction), numerical (gasification thermodynamic equilibrium model), and optimization (response surface methodology) techniques evaluated the gasification process to produce (i) hydrogen-rich gas or (ii) enhanced calorific value gas. The torrefaction (225–275 °C), steam-to-biomass (0.4–1.2 S/B) ratio, and HB…

A common method used to obtain cellulosic fibers is alkalinization with NaOH. Depending on NaOH content, treatments remove significant quantities of lignin and hemicellulose as small molecules. In biorefineries, where the preservation of components is needed, KOH may prevent hemicellulose chain formation. Here, we studied the efficacy of obtaining cellulosic fibers from jute using KOH.…

A 3D numerical investigation on the magnetization of dilute magnetic emulsions subjected to shear flows and external magnetic fields is carried out. The present study is an extension of the previous work of Cunha et al. [“Effects of external magnetic fields on the rheology and magnetization of dilute emulsions of ferrofluid droplets in shear flows,” Phys. Fluids 32,…

A dilute magnetic emulsion under the combined action of a uniform external magnetic field and a small amplitude oscillatory shear is studied using numerical simulations. We consider a three-dimensional domain with a single ferrofluid droplet suspended in a non-magnetizable Newtonian fluid. We present results of droplet shape and orientation, viscoelastic functions and bulk emulsion magnetization…

A systematic review and analysis of the literature of diffuser-augmented horizontal-axis turbines are presented. A collection of 155 articles in the area is analyzed and classified. The work sample is divided into 16 main research branches for discussion. Performance assessment metrics are proposed based on power coefficient and tip-speed-ratio, to quantify and compare all diffuser-augmented turbines in a unified,…

In the present paper, wind tunnel experiments with horizontal axis propellerhydrokineticturbine models are carried out. The turbine performance is assessed for different diffuser configurations and operational ranges. The present experiments evaluate the use of two different geometries of rear diffusers to enhance the power output of the free flow machine. The present paper reports an increase of the power coefficient of…