- "Politecnico di Bari" University
Dept. of Mechanical and Management Engineering
Faculty of Engineering
via Re David 200
70125 Bari
ITALY - +39-080-5963627
Sergio Camporeale
Politecnico di Bari, D.I.Me.G., Faculty Member
- Energy Engineering, Internal Combustion Engines, GAS TURBINE, Wave Energy, Tidal Stream Energy, Classical Thermodynamics, and 19 moreTidal Stream Turbine Modelling, Oscillating Waterv Column, Renewable Energy, Solar Energy, Matlab & Simulink programming, Real Time Computing, Marine Energy, Ocean Energy, Steam Turbine Thermodynamics, Wells Turbine, Oscillating Water Column(OWC), Combustion Instability Modelling and Control, Marine currents, Cross Flow Turbine, Combustion instability, Vertical Axis Turbine, Marine Turbine, Finite Element Methods, and Acousticsedit
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The focus of this paper is on the part load performance of a small scale (100 kWe) combined heat and power (CHP) plant fired by natural gas (NG) and solid biomass to serve a residential energy demand. The plant is based on a modified... more
The focus of this paper is on the part load performance of a small scale (100 kWe) combined heat and power (CHP) plant fired by natural gas (NG) and solid biomass to serve a residential energy demand. The plant is based on a modified regenerative microgas turbine (MGT), where compressed air exiting from recuperator is externally heated by the hot gases produced in a biomass furnace; then the air is conveyed to combustion chamber where a conventional internal combustion with NG takes place, reaching the maximum cycle temperature allowed by the turbine blades. The hot gas expands in the turbine and then feeds the recuperator, while the biomass combustion flue gases are used for preheating the combustion air that feeds the furnace. The part load efficiency is examined considering a single shaft layout of the gas turbine and variable speed regulation. In this layout, the turbine shaft is connected to a high speed electric generator and a frequency converter is used to adjust the frequency of the produced electric power. The results show that the variable rotational speed operation allows high the part load efficiency, mainly due to maximum cycle temperature that can be kept about constant. Different biomass/NG energy input ratios are also modeled, in order to assess the trade-offs between: (i) lower energy conversion efficiency and higher investment cost when increasing the biomass input rate and (ii) higher primary energy savings (PESs) and revenues from feed-in tariff available for biomass electricity fed into the grid. The strategies of baseload (BL), heat driven (HD), and electricity driven (ED) plant operation are compared, for an aggregate of residential end-users in cold, average, and mild climate conditions.
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Particles' mixing and segregation have a strong influence on the performance of fluidized bed reactors for gasification and pyrolysis. The interaction forces between phases are crucial for modeling mixing and segregation. The nature... more
Particles' mixing and segregation have a strong influence on the performance of fluidized bed reactors for gasification and pyrolysis. The interaction forces between phases are crucial for modeling mixing and segregation. The nature of particle characteristics such as shape are also very important to consider for accurate modeling. In this work, the hydrodynamic study of binary mixture of biomass and sand is conducted in a 2-D fluidized bed using Computational Fluid Dynamics (CFD) based on the concept of Euler–Euler two-fluid combined with Kinetic Theory of Granular Flow (KTGF). Modified drag models of Gidaspow and Syamlal–O'Brien are used to determine the drag force between the two phases and the results are compared with the experimental data in literature. The default Gidaspow and Syamlal–O'Brien drag models failed to predict the experimental fluidization behavior. In comparison, the modified models show very good agreement with experiments in terms of pressure drop estimation and particle distribution in the bed. Syamlal–O'Brien model predicted the pressure drop very well, but failed to capture accurate mixing and segregation phenomenon. The Gidaspow model was found to provide better agreement with the experimental results of time-averaged biomass mass fraction along the bed height.
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The hydrodynamics and heat transfer of a binary mixture of sand and biomass in a fluidized bed have been numerically investigated. The Eulerian multi-fluid model MFM incorporating kinetic theory of granular flow was used to numerically... more
The hydrodynamics and heat transfer of a binary mixture of sand and biomass in a fluidized bed have been numerically investigated. The Eulerian multi-fluid model MFM incorporating kinetic theory of granular flow was used to numerically investigate fluidized bed. A commercial code has been used together with user-defined functions to correctly predict the hydrodynamics and the heat transfer. Numerical results were validated against the experiment in terms of pressure drop across the bed and concentration of biomass at different heights of the bed. Influence of additional parameters, such as superficial gas velocity and sand sizes on hydrodynamics were investigated. Additionally, heat transfer in the fluidized bed was also studied highlighting the influence of the temperature dependent properties of air on the results. The present results reveal that better mixing is achieved for smallest sand size, also promoting more uniform temperature of biomass.
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Nowadays hydrogen is gaining more and more attention by Industry, Academia and Politics. Being a carbon free fuel, it is supposed to have a key role in the future energy scenario, especially if produced by renewable sources. The use of... more
Nowadays hydrogen is gaining more and more attention by Industry, Academia and Politics. Being a carbon free fuel, it is supposed to have a key role in the future energy scenario, especially if produced by renewable sources. The use of mixtures of hydrogen and conventional hydrocarbons in gas turbines is one of the most promising technical solutions for obtaining a sustainable combustion during the transition toward a full decarbonization. For this reason, it is fundamental to investigate the behaviour of fuels enriched with hydrogen in combustion processes. In this work, a lab-scale swirled premixed burner has been investigated by means of a fully 3D URANS approach. Firstly, a numerical simulation with cold flow has been performed to validate the model against experimental data. Then, reactive flow simulations have been performed. Initially, a combustion with 100% methane was considered. Then, a 30% by volume hydrogen blending has been investigated. The partially premixed combustio...
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The regulatory restrictions, currently acting, impose a significant reduction of the Greenhouse Gas (GHG) emissions. After the coal-to-gas transition of the last decades, the fossil fuel-to-renewables switching is the current perspective.... more
The regulatory restrictions, currently acting, impose a significant reduction of the Greenhouse Gas (GHG) emissions. After the coal-to-gas transition of the last decades, the fossil fuel-to-renewables switching is the current perspective. However, the variability of energy production related to Renewable Energy Sources requires the fundamental contribution of thermal power plants in order to guaranty the grid stability. Moving toward a low-carbon society, the industry is looking at a reduction of high carbon content fuels, pointing to Natural Gas (NG) and more recently to hydrogen-NG mixtures. In this scenario, a preliminary study of the BERL swirled stabilized burner is carried out in order to understand the impact of blending natural gas with hydrogen on the flame morphology and CO emissions. Preliminary 3D CFD simulations have been run with the purpose to assess the best combination of combustion model (Non Premixed and Partially Premixed Falmelets), turbulence model (Realizable ...
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Research Interests: Engineering, Mechanical Engineering, Environmental Science, Renewable Energy, Biomass, and 15 moreEnergy, Process Engineering, Power, Natural Gas, Parabolic Trough, Heat Recovery, Organic rankine cycle, Science Technology, Design Criteria, Interdisciplinary Engineering, Mediterranean Climate, Concentrating Solar Power, Electrical And Electronic Engineering, Brayton Cycle, and CHP Systems
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Research Interests: Engineering, Environmental Science, Technology, Biomass, Waste Management, and 15 moreProcess Engineering, Optimization, Natural Gas, Turbine, Solar Power Plants, Cogeneration, Energy Storage, Thermal Energy Storage, CHP, Science Technology, Combined cycle, Energy and Fuels, ORC, Concentrating Solar Power Industry, and Fluid Mixtures
In this paper different gas-steam combined-cycles fueled by syngas produced in a local downdraft gasifier, are analyzed. At first, the downdraft gasifier model is briefly described, where waste biomass is transformed into syngas, which... more
In this paper different gas-steam combined-cycles fueled by syngas produced in a local downdraft gasifier, are analyzed. At first, the downdraft gasifier model is briefly described, where waste biomass is transformed into syngas, which can be used more efficiently than the original solid biomass to generate useful power, and can be transported much more easily. The gasifier model is able to estimate, with good approximation, the composition of the produced syngas, taking separately into account the biomass drying and the pyrolysis, oxidation and reduction processes. The gasifier operates at ambient pressure using air as gasification agent and biomass as input. Among others, pomace has been considered, since, in Italy (where the plant is supposed to be located) there are many regions, like Apulia, where this biomass is largely available. Three different plant configurations have been proposed and compared in terms of overall performance. The first two, named REXC (Regenerative cycle ...
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Supercritical CO2 (sCO2) cycles can achieve higher efficiencies than steam Rankine cycles at a higher temperature with a compact plant footprint. Concentrated solar power plants are capital intensive, as there is no fuel-related operating... more
Supercritical CO2 (sCO2) cycles can achieve higher efficiencies than steam Rankine cycles at a higher temperature with a compact plant footprint. Concentrated solar power plants are capital intensive, as there is no fuel-related operating cost, the capital cost must be reduced to realise a reduction in the levelised cost of electricity. Power cycle efficiency and the temperature difference between the hot and cold storage tanks are the critical thermodynamic parameters to reduce the size and the cost of solar field and two-tank storage system whilst the power cycle specific power has also to be maximised to lower the power block cost. With these objectives, three potential cycle configurations were selected for detail assessment; a recompression cycle, partial cooling cycle and a partial heating cycle. A set of performance maps are presented using multi-objective optimisation, which maximises the efficiency and the specific power is explored for five different compressor inlet tempe...
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District heating networks are commonly addressed in the literature as one of the most effective solutions for decreasing the greenhouse gas emissions from the building sector. These systems require high investments which are returned... more
District heating networks are commonly addressed in the literature as one of the most effective solutions for decreasing the greenhouse gas emissions from the building sector. These systems require high investments which are returned through the heat sales. Due to the changed climate conditions and building renovation policies, heat demand in the future could decrease, prolonging the investment return period. The main scope of this paper is to assess the feasibility of using the heat demand – outdoor temperature function for heat demand forecast. The district of Alvalade, located in Lisbon (Portugal), was used as a case study. The district is consisted of 665 buildings that vary in both construction period and typology. Three weather scenarios (low, medium, high) and three district renovation scenarios were developed (shallow, intermediate, deep). To estimate the error, obtained heat demand values were compared with results from a dynamic heat demand model, previously developed and ...
Nowadays, mobility represents a key sector to achieve the goal of carbon neutrality. Indeed, the development of hybrid powertrains is contributing to a reduction in the environmental impact of vehicles. One of the most promising... more
Nowadays, mobility represents a key sector to achieve the goal of carbon neutrality. Indeed, the development of hybrid powertrains is contributing to a reduction in the environmental impact of vehicles. One of the most promising energy-saving solutions is regenerative braking, which enables deceleration while recovering energy, otherwise wasted. Even though much scientific community effort has been addressed to the optimization of this technology in the automotive field, the increase of energy storage systems efficiencies enables the overcoming of the constraints related to the reuse of electric energy in railway vehicles. This solution could be extremely useful for those railway vehicles which operate on non-electrified lines, where traction is usually provided by diesel engines. For this reason, the present work focuses on how regenerative braking technology could be exploited in diesel-powered rail applications. In further detail, a diagnostic train working on real railway lines ...
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This paper describes the design and the assembly of a new type of a ducted wind turbine with an electric power generator adopting permanent high coercive magnets embedded in the peripheral ring of the rotor. The nominal power is 20 kW,... more
This paper describes the design and the assembly of a new type of a ducted wind turbine with an electric power generator adopting permanent high coercive magnets embedded in the peripheral ring of the rotor. The nominal power is 20 kW, and the maximum diameter of the external duct is 9 meters. The project has been carried out within the Marine Energy Laboratory (MEL) funded by the Italian Ministry for Education, University and Research (MIUR) and collects the most advanced technologies of naval maritime engineering and combines them with energy and turbomachinery technologies. The presence of a divergent duct enables the interception of a greater air mass flow rate, allowing the reduction of the rotor diameter and the deflections of the blades; hence, at constant tip speed ratio, a higher rotational speed compared to conventional turbines and a better efficiency of the permanent magnet power generator.
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Underlying data for the paper "Thermo-economic Analysis, Optimisation and Systematic Integration of Supercritical Carbon Dioxide Cycle with Sensible Heat Thermal Energy Storage for CSP Application"
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Underlying data for the journal paper "Off-design and Annual Performance Analysis of Supercritical Carbon Dioxide Cycle with Thermal Storage for CSP application "<br>
Supercritical carbon dioxide (sCO2) cycles are considered to provide a faster response to load change owing to their compact footprint. sCO2 cycles are generally highly recuperative, therefore the response time is mainly dictated by the... more
Supercritical carbon dioxide (sCO2) cycles are considered to provide a faster response to load change owing to their compact footprint. sCO2 cycles are generally highly recuperative, therefore the response time is mainly dictated by the heat exchanger characteristics. This study model the transient behaviour of a recuperator in 10 MWe simple recuperative Brayton cycle. The response for the variation of inlet temperature and mass flow boundary conditions were investigated using two approaches based on temperature and enthalpy. The performance of these two approaches are compared and the numerical schemes were discussed along with the challenges encountered. The simulation results were validated against the experimental data available in the literature with a fair agreement. The characteristic time of the heat exchanger for a step change of the boundary conditions is reported that supports the recuperator design process. Compact recuperator responded in less than 20 seconds for the ch...
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Supercritical carbon dioxide (sCO2) cycles are studied as the next-generation power cycles in order to reduce the cost of Concentrating Solar Power (CSP) plants. The design performance of numerous cycles has been investigated,... more
Supercritical carbon dioxide (sCO2) cycles are studied as the next-generation power cycles in order to reduce the cost of Concentrating Solar Power (CSP) plants. The design performance of numerous cycles has been investigated, nevertheless, the off-design and annual performance of these cycles are seldom studied. This plays a critical role in selecting an optimal cycle for CSP application, as an efficient power cycle influences the solar field size, consequently affecting the Levelised cost of electricity (LCOE). In this study, the design, off-design and annual performance of three sCO2 cycles; simple recuperative, recompression and partial-cooling cycles are studied. Multi-objective optimisation was performed and the off-design Pareto fronts were compared for the changes in the power cycle boundary conditions. Annual performance simulation was carried out, and the performance of the three cycles was compared when the power cycle is operated in maximum efficiency mode, which facilit...
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Oscillating water column (OWC) devices, either fixed or floating, are the most common wave energy converter (WEC) devices. In this work, the fluid dynamic interaction between waves and a U-shaped OWC breakwater embedding a Wells turbine... more
Oscillating water column (OWC) devices, either fixed or floating, are the most common wave energy converter (WEC) devices. In this work, the fluid dynamic interaction between waves and a U-shaped OWC breakwater embedding a Wells turbine has been investigated through unsteady Computational Fluid Dynamic (CFD) simulations. The full-scale plant installed in the harbor of Civitavecchia (Italy) was numerically modeled. A two-dimensional domain was adopted to simulate the unsteady flow, both outside and inside the U-OWC device, including the air chamber and the oscillating flow inside the conduit hosting the Wells turbine. For the numerical simulation of the damping effect induced by the Wells turbine connected to the air chamber, a porous medium was placed in the computational domain, representing the conduit hosting the turbine. Several simulations were carried out considering periodic waves with different periods and amplitudes, getting a deep insight into the energy conversion process...
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Sustainable development can no longer neglect the growth of those technologies that look at the recovery of any energy waste in industrial processes. For example, in almost every industrial plant it happens that pressure energy is wasted... more
Sustainable development can no longer neglect the growth of those technologies that look at the recovery of any energy waste in industrial processes. For example, in almost every industrial plant it happens that pressure energy is wasted in throttling devices for pressure and flow control needs. Clearly, the recovery of this wasted energy can be considered as an opportunity to reach not only a higher plant energy efficiency, but also the reduction of the plant Operating Expenditures (OpEx). In recent years, it is getting common to replace throttling valves with turbine-based systems (tuboexpander) thus getting both the pressure control and the energy recovery, for instance, producing electricity. However, the wide range of possible operating conditions, technical requirements and design constrains determine highly customized constructions of these turboexpanders. Furthermore, manufacturers are interested in tools enabling them to rapidly get the design of their products. For these r...
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This paper presents the results of the numerical simulations carried out to evaluate the performance of a high solidity Wells turbine designed for an oscillating water column wave energy conversion device. The Wells turbine has several... more
This paper presents the results of the numerical simulations carried out to evaluate the performance of a high solidity Wells turbine designed for an oscillating water column wave energy conversion device. The Wells turbine has several favorable features (e.g., simplicity and high rotational speed) but is characterized by a relatively narrow operating range with high efficiency. The aim of this work is to investigate the flow-field through the turbine blades in order to offer a description of the complex flow mechanism that originates separation and, consequently, low efficiency at high flow-rates. Simulations have been performed by solving the Reynolds-averaged Navier–Stokes equations together with three turbulence models, namely, the Spalart–Allmaras, k-ω, and Reynolds-stress models. The capability of the three models to provide an accurate prediction of the complex flow through the Wells turbine has been assessed in two ways: the comparison of the computed results with the availa...
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Research Interests: Engineering, Materials Science, Economics, Convection, Performance, and 15 moreNumerical Simulation, Graphite, Shell and tube heat exchanger design, System, Phase Change Materials, Thermal Energy Storage, Enclosure, Applied Energy, PCM, Technology and Engineering, Concentrated Solar Power, Cfd, Molten Salts, Shell and Tube, and Charging Process
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In the recent years a great interest has been devoted to the understanding of the nonlinear dynamics characterizing the thermoacoustic combustion instabilities. Although linear techniques are able to predict whether the non-oscillating... more
In the recent years a great interest has been devoted to the understanding of the nonlinear dynamics characterizing the thermoacoustic combustion instabilities. Although linear techniques are able to predict whether the non-oscillating steady state of a thermoacoustic system is “asymptotically” stable (without oscillations) or unstable (increasing oscillations), a thermoacoustic system can reach a permanent oscillating state (the so called “limit cycle”), even when it is linearly stable, if a sufficiently large impulse occurs. A nonlinear analysis is able to predict the existence of this oscillating state and the nature of the bifurcation process.The aim of this work is to investigate the behavior of gas turbine combustion chambers in presence of nonlinear flame models. The bifurcation diagrams, obtained by using a continuation technique in the frequency domain, give the amplitude of the oscillations as a function of a chosen flame parameter. The Helmholtz equation is used to model the combustion chamber and nonlinear terms are introduced in the flame model, starting from the classical k–τ formulation. A three-dimensional finite element method (FEM) is used for discretization of the computational domain and a solver of quadratic eigenvalue problems is combined with Newton technique in order to identify the points of the bifurcation diagram. First, a simple Rijke tube configuration, as can be found in the literature, is examined in order to obtain bifurcation diagrams. Then, the nonlinear analysis is extended to simplified annular configurations. The obtained results show how the nonlinear behavior is influenced by varying some control parameters, such as the time delay, yielding useful indications to designers and experimentalists.Copyright © 2013 by ASME
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A three-dimensional finite element code is used for the eigenvalue analysis of the thermoacoustic combustion instabilities modeled through the Helmholtz equation. A full annular combustion chamber, equipped with several burners, is... more
A three-dimensional finite element code is used for the eigenvalue analysis of the thermoacoustic combustion instabilities modeled through the Helmholtz equation. A full annular combustion chamber, equipped with several burners, is examined. Spatial distributions for the heat release intensity and for the time delay are used for the linear flame model. Burners, connecting the plenum and the chamber, are modeled by means of the transfer matrix method. The influence of the parameters characterizing the burners and the flame on the stability levels of each mode of the system is investigated. The obtained results show the influence of the 3D distribution of the flame on the modes. Additionally, the results show what types of modes are most likely to yield humming in an annular combustion chamber. The proposed methodology is intended to be a practical tool for the interpretation of the thermoacoustic phenomenon (in terms of modes, frequencies, and stability maps) both in the design stage...