• Energy Research

Small and micro hydropower systems represent an attractive solution for generating electricity at low cost and with low environmental impact. The pump-as-turbine (PAT) approach has promise in this application due to its low purchase and maintenance costs. In this paper, a new method to predict the inverse characteristic of industrial centrifugal pumps is presented. This method is based on results of simulations performed with commercial three-dimensional Computational Fluid Dynamics (CFD) software. Model results have been first validated in pumping mode using data supplied by pump manufacturers. Then, the results have been compared to experimental data for a pump running in reverse. Experimentation has been performed on a dedicated test bench installed in the Department of Civil Construction and Environmental Engineering of the University of Naples Federico II. Three different pumps, with different specific speeds, have been analyzed. Using the model results, the inverse characteristic and the best efficiency point have been evaluated. Finally, results have been compared to prediction methods available in the literature.

Small and micro hydropower systems represent an attractive solution for generating electricity at low cost and with low environmental impact. The pump-as-turbine (PAT) approach has promise in this application due to its low purchase and maintenance costs. In this paper, a new method to predict the inverse characteristic of industrial centrifugal pumps is presented. This method is based on results of simulations performed with commercial three-dimensional Computational Fluid Dynamics (CFD) software. Model results have been first validated in pumping mode using data supplied by pump manufacturers. Then, the results have been compared to experimental data for a pump running in reverse. Experimentation has been performed on a dedicated test bench installed in the Department of Civil Construction and Environmental Engineering of the University of Naples Federico II. Three different pumps, with different specific speeds, have been analyzed. Using the model results, the inverse characteristic and the best efficiency point have been evaluated. Finally, results have been compared to prediction methods available in the literature.

The objective of this study is to investigate the effect of bioethanol-gasoline blends on the exhaust emissions and engine combustion of a four-stroke motorcycle. Ethanol is known as an alternative fuel for spark-ignition engines and is suitable for making blends with gasoline, increasing the oxygen content and decreasing emission of incomplete combustion products. An experimental investigation was performed on a Euro 3 large-size motorcycle fuelled with commercial gasoline and bioethanol/gasoline blends (range of bioethanol 5% v to 30% v). Regulated and unregulated emissions and fuel consumption were quantified over the execution of chassis-dynamometer tests. The combustion analysis, realized by acquiring the pressure cycle inside the cylinder, highlights the auto adjustment of the engine control unit and guarantees use within the same parameters of several tested fuels, with the except of fuel injection time, which increases with increasing ethanol percentage. A significant reduction in carbon monoxide and particle number is associated with the ethanol content of the fuel. Volatile organic compounds, mainly alkanes and aromatics, are not substantially influenced by the bioethanol content of the fuel. The contribution of carcinogenic benzene ranges between 2 and 5%.

The objective of this study is to investigate the effect of bioethanol-gasoline blends on the exhaust emissions and engine combustion of a four-stroke motorcycle. Ethanol is known as an alternative fuel for spark-ignition engines and is suitable for making blends with gasoline, increasing the oxygen content and decreasing emission of incomplete combustion products. An experimental investigation was performed on a Euro 3 large-size motorcycle fuelled with commercial gasoline and bioethanol/gasoline blends (range of bioethanol 5% v to 30% v). Regulated and unregulated emissions and fuel consumption were quantified over the execution of chassis-dynamometer tests. The combustion analysis, realized by acquiring the pressure cycle inside the cylinder, highlights the auto adjustment of the engine control unit and guarantees use within the same parameters of several tested fuels, with the except of fuel injection time, which increases with increasing ethanol percentage. A significant reduction in carbon monoxide and particle number is associated with the ethanol content of the fuel. Volatile organic compounds, mainly alkanes and aromatics, are not substantially influenced by the bioethanol content of the fuel. The contribution of carcinogenic benzene ranges between 2 and 5%.