Christ University

About: Christ University is a education organization based out in Bengaluru, India. It is known for research contribution in the topics: Computer science & Convection. The organization has 2267 authors who have published 2715 publications receiving 14575 citations. The organization is also known as: Christ College & Christ University.

Control of NOx from a DI diesel engine with hot EGR and ethanol fumigation: An experimental investigation

Abstract: Oxides of nitrogen (NOx) are one of the major hazardous pollutants from diesel engine emission. Various control technologies exist for its control but each technique has advantages and disadvantages. At present, there is no single optimal technique that can control NOx without other side effects. Technologies available for NOx reductions either cause fuel penalty or increase other polluting emissions. Exhaust Gas Recirculation is an effective technique in controlling oxides of nitrogen in diesel engines but do not become attractive at higher loads and higher percentage of recirculated gas as combustion tends to deteriorate at higher loads leading to reduced engine thermal efficiency and increased hydrocarbon and smoke emission. Ethanol is an established alternate fuel used in diesel engine either as a blend or fumigated using a separate injector. Experiments were conducted on a single cylinder diesel engine to examine the effect of EGR temperature on NOx and other emission constituents. Hot EGR gave better results up to 30% EGR rate but EGR cooling was found better in terms of NOx reductions and efficiency. It was found that NOx reductions up to 88% was possible but at the cost of about 18% loss in thermal efficiency. This inconvenience of fuel penalty caused by Exhaust Gas Recirculation can be overcome by applying ethanol fumigation. The findings of experimental results for this combined technique are presented in this paper. With this combined technique, apart from reducing the oxides of nitrogen, engine power and efficiency approaches to that of only diesel combustion condition with improvements in smoke, hydrocarbon and carbon monoxide emissions.

Sensitivity analysis of Marangoni convection in TiO 2 –EG nanoliquid with nanoparticle aggregation and temperature-dependent surface tension

Abstract: The sensitivity analysis of the magnetohydrodynamic thermal Marangoni convection of ethylene glycol (EG)-based titania (TiO2) nanoliquid is carried out by considering the effect of nanoparticle aggregation. The rate of heat transfer is explored by utilizing response surface methodology and estimating the sensitivity of the heat transfer rate toward the effective parameters: radiation parameter (1 ≤ R ≤ 3), magnetic parameter (1 ≤ M ≤ 3) and nanoparticle volume fraction $$(1\% \le \phi \le 5\%$$ ). The heat transfer phenomenon is scrutinized with thermal radiation and variable temperature at the surface. The effective thermal conductivity and viscosity with aggregation are modeled by using the Maxwell–Bruggeman and Krieger–Dougherty models. The governing equations are solved by using the apposite similarity transformations. It is found that when the effect of aggregation is considered, the velocity profile is lower. A positive sensitivity of the Nusselt number toward thermal radiation is observed. Further, a negative sensitivity of the heat transfer rate is observed toward the magnetic field and nanoparticle volume fraction.