The Effect of Bluff Body Shape on Flame Stability in a Non-Premixed Hydrogen-Methan-Air Mixture Combustion

The goal of this study, which focuses on the effect of the bluff-body form on the flame’s stability, is to contribute to the study of the stability of a CH4-H2-Air diffusion flame. It is, in fact, a numerical simulation of a diffusion flame CH4-H2-Air stabilized by a bluff body in three different shapes: cylindrical, semi-spherical and conical. The equations governing turbulent reactive flow are solved using the Ansys CFX program (Navier Stokes equations averaged in sense of Favre). The k-ε model simulates turbulence. For combustion, a mixed EDM/FRC (Finite Rate Combustion) model is utilized. The results of the analysis of temperature profiles, CO2 concentrations, and velocity in axial sections very close to the injector are satisfactory: they meet the criteria of stability, high temperature at a lower speed, and more stable in the case of a cylindrical shape than in the other two cases.

Influence of DC Electric Field on the Propane-Air Diffusion Flames and NOx Formation

The aim of this research is to investigate the effects of a direct current (DC) electric field on the combustion behavior of a co-flow propane diffusion flame. The flame length and NOx emission were observed and measured. The electric field enhances the combustion process of propane diffusion flame by causing the movement of ions and molecules in the flame, resulting in a change in the shape of the flame. The flame heights decrease with an increase in the applied voltage and polarity, a more dominant effect to be observed with a positive DC electric field. However, for the applied negative polarity, the inner-cone of the propane diffusion flame is shifted by the electric field. Drastic reduction in the NOx emission is observed with an increase in the applied DC voltage and polarity. In the existing system, the reduction percentage of NOx is within the range of 55 to 78%.

Analyzing the Reuse Potentials of Landfilled Solid Wastes for Farm Water Treatment and Reuse

The increasing solid waste management problems in developing countries necessitated landfill mining to determine the reuse potentials of landfilled solid waste materials. In this study, characterization of landfilled solid waste obtained from a closed landfill site in Malaysia was conducted to ascertain its reuse potentials for biodegradation in wastewater treatment. The results revealed adequate neutral pH, Moisture Content of 34 %, Organic Content of 10.4 % and Bacterial Population in terms of Total Coliform of 8.3 × 105 CFU/100 mL, which are ideal conditions for biodegradation while porosity n of 51%, allow free flow of water during treatment. The SEM showed irregular shapes and pore spaces and a BET surface area of 3.376 m 2 g-1 which enables adsorption of pollutants on its surface, air diffusion and re-aeration. Furthermore, the waste material was used as media for biodegradation in a lab-scale bioreactor at a hydraulic loading of 4 L m-3 d-1 and inflow rate of 0.1 L min-1. The results showed maximum removal rates of 95, 97, 86, 70, 70, and 98% for COD, BOD, TSS, TDS, NH3-N, and TP respectively. Utilization of this technology as bioreactor landfills will solve landfill congestion and also provide cheap wastewater treatment option.