Angelo Algieri

Experimental and Numerical Investigation on the Effects of the Seeding Properties on LDA Measurements

The characteristics of the seeding particles, which are necessary to implement the laser Doppler anemometry (LDA) technique, may significantly influence measurement accuracy. LDA data were taken on a steady-flow rig, at the entrance of the trumpet of the intake system of a high-performance engine head. Five sets of measurements were carried out using different seeding particles: samples of micro-balloons sieved to give three different size ranges (25-63 μm, 90-200 μm, and standard as received from the manufacturer 1-200 μm), smoke from a home-made sawdust burner (particle size ≤1 μm), and fog from a commercial device (particle size around 1 μm). The LDA data were compared with the results of two-phase computational fluid dynamics simulations.

Simulation and experimental validation of the flow field at the entrance and within the filter housing of a production spark-ignition engine

Abstract The paper aims to analyse the flow field at the entrance and within the filter housing of a production four-cylinder, spark-ignition engine during the intake phase. To this purpose a computational fluid dynamic (CFD) analysis was carried out adopting a finite volume code, while an experimental activity was performed at a steady flow rig to validate the computational model. The comparison between numerical data and experimental measurements showed a good agreement and it demonstrated the capabilities of the proposed CFD model to predict in detail the flow field within a complex production automobile component that largely influences the efficiency and reliability of actual internal combustion engines (ICEs).

Numerical and Experimental Analysis of the Intake Flow in a High Performance Four-Stroke Motorcycle Engine: Influence of the Two-Equation Turbulence Models

An experimental and numerical analysis of the intake system of a production high performance four-stroke motorcycle engine was carried out. The aim of the work was to characterize the fluid dynamic behavior of the engine during the intake phase and to evaluate the capability of the most commonly used two-equation turbulence models to reproduce the in-cylinder flow field for a very complex engine head. Pressure and mass flow rates were measured on a steady-flow rig. Furthermore, velocity measurements were obtained within the combustion chamber using laser Doppler anemometry (LDA). The experimental data were compared to the numerical results using four two-equation turbulence models (standard k-e, realizable k-e, Wilcox k-w, and SST k-ω models). All the investigated turbulence models well predicted the global performances of the intake system and the mean flow structure inside the cylinder. Some differences between measurements and computations were found close to the cylinder head while an improving agreement was evident moving away from the engine head. Furthermore, the Wilcox k-w model permitted the flow field inside the combustion chamber of the engine to be reproduced and the overall angular momentum of the flux with respect to the cylinder axis to be quantified more properly.

Influence of Valve Lift and Throttle Angle on Intake Flow in a High-Performance Four-Stroke Motorcycle Engine

A high-performance four-stroke motorcycle engine was analyzed at a steady flow rig. The aim of the work was to characterize the fluid dynamic behavior of the engine head during the intake phase. To this purpose a twofold approach was adopted: the dimensionless flow coefficient was used to evaluate the global breathability of the intake system, while the laser doppler anemometry (LDA) technique was employed to define the flow structure within the combustion chamber. The analysis gave evidence of two contrarotating vortices with axes parallel to the cylinder axis and showed variations in the flow structure when moving away from the engine head. Furthermore, the study highlighted the great influence of the throttle angle on the head fluid dynamic efficiency and how this influence changes with the valve lift. Experimental data were correlated by a single curve adopting a new dimensionless plot. Moreover, LDA measurements were used to evaluate the angular momentum of the flux and an equivalent swirl coefficient, and to correlate them to a previous global swirl characterization carried out on the same engine head using an impulse swirl meter.

Biomass Exploitation in Efficient ORC Systems

The research intends to investigate the energetic performances of Organic Rankine Cycles (ORCs) for the exploitation of the biomass resulting from agricultural residues. To this purpose, a parametric analysis has been carried out. Saturated and superheated conditions at the turbine inlet have been imposed and the effect of the internal regeneration on plant performances has been studied. The results highlight that ORC plants represent an interesting and sustainable solution for small-scale and decentralised power production. Moreover, the analysis shows the significant impact of the temperature and internal regeneration technique on the performances of the biomass power plants.

Comparative Investigation of the Performances of Subcritical and Transcritical Biomass-Fired ORC Systems for Micro-scale CHP Applications☆

Abstract The paper aims to analyse the energetic performances of Organic Rankine Cycles (ORCs) for biomass micro-scale CHP applications. Subcritical and transcritical cycles have been compared and the influence of internal regeneration on system behaviour has been evaluated. The investigation illustrates the noticeable influence of the operating conditions and ORC configuration on the main CHP performances. Furthermore, results reveal that the proper choice of the organic working fluid is fundamental to assure proper operations and optimise the system behaviour. The analysis shows that the transcritical cycle with internal regeneration offers the maximum electric performances, whereas the saturated cycle in simple configuration guarantees the highest thermal efficiency. Furthermore, all the investigated systems guarantee positive energy saving capabilities.

Energetic Investigation of Organic Rankine Cycles (ORCs) for the Exploitation of Low-Temperature Geothermal Sources – A possible application in Slovakia

Abstract: The paper aims at analysing the energetic performances of Organic Rankine Cycles (ORCs) for the exploitation of low temperature heat sources. Specifically, the attention has been focused on low-enthalpy geothermal energy for small-scale applications. To this purpose a thermodynamic model has been developed and a parametric investigation has been performed considering different organic fluids (isobutane, isopentane, and R245ca). Saturated conditions at the expander inlet have been adopted and the effect of the internal regenerator on the system performances has been evaluated. The investigation highlights the large impact of the evaporation temperature on the ORC behaviour and the positive influence of the internal regenerator at the highest temperatures. Conversely, the effect of the internal heat exchanger reduces when the evaporation temperature decreases. Furthermore, a possible application in the Kosice Basin (Slovakia) has been analysed. The investigation demonstrates that the organic Rankine cycle represents an interesting option for efficient valorisation of low-enthalpy geothermal resources and electricity production in small-scale applications.