Francesco Mariani

Protection Ratio and Antenna Separation for DVB—T/LTE Coexistence Issues

This paper concerns the analysis of adjacent channel interference of the 3GPP Long Term Evolution (LTE) E-UTRA (Evolved Universal Terrestrial Radio Access) mobile systems into Digital Video Broadcasting - Terrestrial (DVB-T) systems. The simulated performance of both systems allows us to define recommendations for minimizing the interference effects. The subjective quality of the received TV signal has been evaluated experimentally in terms of picture failure (PF). We also investigated the importance of the selection of suitable Spectral Emission Masks (SEMs) of the LTE downlink transmission. Results show that, by using the ECC 148 SEM, both the protection ratio and the minimum distance between LTE towers and DVB-T receivers can be significantly decreased.

Energy saving strategies in an actual confectionery plant

The achievement of a more rational use of energy can be difficult when large and complex industrial plants are considered. In the present work, an example is given of how a well-focused energy analysis, based on experimental data, can help to point out possible relevant energy savings. In particular, two different refrigeration systems have been examined for a confectionery plant in different seasons, atmospheric and production conditions, allowing us to understand the actual operation. Based on the analysis of the results, energy saving strategies have been proposed and discussed. Copyright

Experimental Validation of Spray Breakup and Fuel Evaporation Models in High Pressure Ambient Conditions

Experimental and numerical computations of transient sprays are performed under ambient Diesel like conditions, in order to investigate on the complex phenomena that occur in the evolution of an evaporating fuel spray (like break up, fuel multicomponent evaporation, liquid gas interaction). An experimental analysis has been carried out using a single hole high pressure electronic control injection system. The investigation procedure exploits a light sheet technique based on a Nd-Yag pulsed laser and a synchronized CCD camera. The measured characteristics are the spray penetration and the spray cone angles, as the fuel jet evolves in a pressurized chamber. Furthermore, a numerical analysis of the spray development has been carried out. The numerical tool used is a modified version of the well known KIVA code in which a new break up model, developed and validated in previous works [1, 2], and a fuel multicomponent evaporation model have been included. The predictive capability of the evaporation model has been evaluated by comparison with single droplet experimental data [3].

Numerical Study Of The Separation Efficiency And Heat Exchange Performance In A Complex Gas–solid Separator

This work presents a study on a gas–solid cyclone separator used in a complex cement production plant. The main objective of the study is based on the performance evaluation and optimization of the cyclone separator in terms of particle separation and heat transfer efficiencies, while keeping pressure losses under control. The thermal interaction is between two gas–solid mixtures, one at 850°C and the other at 600°C, respectively. The solid phase consists mostly of calcium carbonate subsequently intended to the so-called baking process for the production of clinker and ultimately cement. A first model has been setup using experimental data as boundary conditions to assess the physical model behavior and the CFD solver parameters. After that, five additional models with different geometries have been analyzed to evaluate the influence of the vortex finder (vf) length on the separation efficiency and on the heat exchange performance. By increasing the length of the vf, the results show a global improvement in the separation efficiency of up to 5% if compared to the geometry without the vf. Further, the increase in the vf length determines a monotonic decrease of temperature at the exit but a monotonic increase of pressure losses. In the second part of this work, using one of the previous models with vf, a study of the influence of the particle diameter on the separation efficiency has been performed. The increase of particle diameter causes an increase of the separation and thermal exchange performance, decreasing at the same time the pressure drop. The numerical approach for all the cases is based on implicit unsteady simulations using the Eulerian Multiphase model.

Experimental analysis of the actual behaviour of a natural gas fueled engine Caterpillar (CAT)-3516

Abstract In this work, first results are presented of the analysis of the behaviour, in actual, non-new operational conditions, of a lean burning, natural gas (NG) fueled, 1 MWe Caterpillar (CAT)-3516 engine, installed at the Engineering Faculty of Perugia University for the cogeneration of electrical and thermal energy. Data collected daily by the plant manager operators along 24 months of engine operation, which refer to power, electrical efficiency, NG flowrate, availability, and charge temperature, were analysed in connection with the recorded events of breakdown/defects and of maintenance/repair. An acquisition system for the continuous monitoring of several engine and plant quantities is described in detail.

Numerical Study of SI Engine Part Load Operating Conditions Using Different VVA Strategies

In SI engines, VVA (Variable Valve Actuation) technology is mainly used for the reduction of pumping losses at part load. This paper presents the results of fluid dynamic analyses on a 4V engine about the effects of different VVA strategies, by comparing and discussing the results in terms of organized charge motions, turbulence levels, flame developments, NO and CO emissions. CFD simulations cover five load control cases: comparison is among conventional throttling, EIVC (Early Intake Valve Closure) with symmetric and asymmetric intake lifts, LIVC (Late Intake Valve Closure) and symmetrical Multi-Lift strategies. 3D U-RANS simulations are performed, adopting the Extended Coherent Flamelet Model (ECFM) for the description of premixed SI combustion. The 3D model is also coupled to a 1D engine model which provides inlet/outlet boundary conditions. Simulation results highlight the potential of asymmetric Early Intake Valve Closure (EIVC) strategy which allows reducing pumping losses and, at the same time, achieving good turbulence intensity and combustion speed, if compared to other load control strategies. Multi-Lift strategy resulted excellent in terms of burn duration, but pumping losses are practically the same as in the throttled engine.Copyright

Simulation of hydraulic power plant transients using neural networks

Abstract In this work the efficiency of the artificial neural network technology for evaluating the turbine speed and drain synchronous valve during the turn-off transient phase of an actual hydraulic power plant has been evaluated. These results have been achieved avoiding a detailed time consuming analysis of the power plant. Several net architectures have been set up and verified with regard to their response to this strongly non-linear problem.