Searched for: author%3A%22Colonna%2C+Piero%22
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Krempus, D. (author), Bahamonde, Sebastian (author), van der Stelt, T.P. (author), Klink, Wolfgang (author), Colonna, Piero (author), de Servi, C.M. (author)
The use of mixtures as working fluids of organic Rankine cycle (ORC) waste heat recovery (WHR) power plants has been proposed in the past to improve the matching between the temperature profile of the hot and the cold streams of condensers and evaporators, thus to possibly increase the energy conversion efficiency of the system. The goal of...
journal article 2024
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Ascione, F. (author), Colonna, Piero (author), de Servi, C.M. (author)
The aircraft Environmental Control System (ECS) is the primary consumer of non-propulsive power at cruise conditions, hence, its performance optimization is crucial for the reduction of specific fuel consumption. A novel integrated system design optimization method is presented: thermodynamic cycle, component sizing and working fluid are...
journal article 2024
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Tosto, F. (author), Pini, M. (author), Colonna, Piero (author)
The blade solidity, namely the blade chordtopitch ratio, largely affects the fluiddynamic performance of turbomachinery. For turbomachines operating with air or steam, the optimal value of the solidity which maximizes the efficiency is estimated with empirical correlations such as the ones proposed by Zweifel (1945) and Traupel (1966). However,...
conference paper 2024
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Mercier, B. (author), Chandrasekaran, N.B. (author), Colonna, Piero (author)
Estimating the speed of sound for the dense vapor phase of D<sub>6</sub> (dodecamethylcyclohexasiloxane, C<sub>12</sub>H<sub>36</sub>O<sub>6</sub>Si<sub>6</sub>) is particularly relevant to the study of nonideal compressible fluid dynamics (NICFD), the gas dynamics of fluids whose properties depart significantly from those related by the...
journal article 2023
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Head, A.J. (author), Michelis, Theodorus (author), Beltrame, F. (author), Fuentes Monjas, B. (author), Casati, Emiliano (author), de Servi, C.M. (author), Colonna, Piero (author)
This paper describes an experiment conducted within the nozzle test section of the Organic Rankine Cycle Hybrid Integrated Device (ORCHID) aimed at providing accurate data for the validation of NICFD flow solvers [5]. A supersonic flow of the dense vapor siloxane MM established in the nozzle of the setup was characterized by means of the...
book chapter 2023
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Chandrasekaran, N.B. (author), Michelis, Theodorus (author), Mercier, Bertrand (author), Colonna, Piero (author)
This paper describes the design, functioning, and preliminary experiments in the Asymmetric Shock Tube for Experiments on Rarefaction Waves (ASTER), a Ludwieg-type shock tube designed and realised to measure waves propagating in dense vapour flows of organic fluids. The setup is designed to operate at pressures and temperatures of up to 15...
book chapter 2023
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Gradl, P.R. (author), Cervone, A. (author), Colonna, Piero (author)
Metal additive manufacturing (AM) is being used for mission-critical applications in both developmental and production components, driven by economic and technical benefits. Laser powder directed energy deposition (LP-DED) allows manufacturing of thin wall geometric features for various components at diameters larger than 2 m. The...
journal article 2023
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Gradl, P.R. (author), Cervone, A. (author), Colonna, Piero (author)
Heat exchangers for use in propulsion applications are very critical components because they must be efficient, compact and light and often operate with working fluids at extreme temperatures or pressures or both. Various components and systems use heat exchangers such as combustion chambers of gas turbines and internal combustion engines, fuel...
conference paper 2022
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Tosto, F. (author), Giuffré, A. (author), Colonna, Piero (author), Pini, M. (author)
In this work we examine the flow deviation and its relationship to critical choking, i.e., choking of the meridional component of velocity, in transonic turbine cascades operating with non-ideal compressible flows. To this purpose, a generalized expression of the corrected flow per unit area as a function of both the thermodynamic state and...
journal article 2022
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Giuffré, A. (author), Colonna, Piero (author), Pini, M. (author)
The impact of size and working fluid on the efficiency, operating range, and axial thrust on bearings is examined for high-speed, oil-free centrifugal compressors. First, the development and validation of a reduced-order model based on scaling principles is documented. Then, the validated compressor model is used to generate design maps for...
journal article 2022
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Galieti, L. (author), de Servi, C.M. (author), Colonna, Piero (author), Silva, Paolo (author), Bombarda, Paola (author)
The use of mixtures in place of pure fluids in Organic Rankine Cycle (ORC) power plants is proposed as a possible improvement in terms of efficiency, environmental benefit and safety of the system. In particular, zeotropic mixtures exhibit a temperature variation (or glide) during phase change, because the components have different boiling...
abstract 2022
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Giuffré, A. (author), Colonna, Piero (author), Pini, M. (author)
The environmental control system (ECS) is the largest auxiliary power consumer, i.e, around 75% of non-propulsive power, among the aircraft subsystems. The adoption of a novel ECS architecture, based on an electrically-driven vapor compression cycle system, can enable a twofold increase of coefficient of performance (COP), as compared to the...
conference paper 2022
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Tosto, F. (author), Lettieri, C. (author), Pini, M. (author), Colonna, Piero (author)
Paradigmatic compressible one-dimensional flows provide insights regarding the loss mechanisms of fluid machinery components typical of power and propulsion systems, like turbomachines and heat exchangers. Their performance also depends on the working fluid, thus, on both molecular complexity and thermodynamic state. Four typical flow...
journal article 2021
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Chandrasekaran, N.B. (author), Mercier, B. (author), Colonna, Piero (author)
Flows of fluids made of complex organic molecules exhibit unconventional fluid dynamic behavior in the vapor phase if their thermodynamic state is close to that of the vapor-liquid critical point. If the molecule is sufficiently complex, this thermodynamic domain is characterized by negative values of the fundamental derivative of gasdynamics...
journal article 2021
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Rubino, A. (author), Colonna, Piero (author), Pini, M. (author)
The lack of established optimal design guidelines for turbomachinery operating in the nonideal flow regime (e.g., organic Rankine cycle turbines, CO<sub>2</sub> compressors, compressors for refrigeration systems) demands for effective and efficient automated design methods. Past research work focused on gradient-free methods applied to...
journal article 2021
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Beltrame, F. (author), Head, A.J. (author), de Servi, C.M. (author), Pini, M. (author), Schrijer, F.F.J. (author), Colonna, Piero (author)
This paper reports one of the initial NICFD experiments in the nozzle test section of the ORCHID aimed at providing accurate data for the validation of flow solvers, albeit, at this stage of the research, the focus is limited to inviscid phenomena. Notably, a series of schlieren photographs displaying Mach waves in the supersonic flow of the...
conference paper 2021
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Tosto, F. (author), Giuffré, A. (author), Colonna, Piero (author), Pini, M. (author)
In this work we examine the behavior of non-ideal compressible swirling flows. Based on a first-principle analysis, we derive a generalized expression of the corrected flow per unit area as function of the isentropic exponent, characteristic Mach numbers, and swirl parameter. The calculated trends of the corrected flow with respect to these...
book chapter 2021
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Chandrasekaran, N.B. (author), Mercier, B. (author), Colonna, Piero (author)
The nonlinear propagation of finite amplitude waves in the non-ideal compressible fluid dynamic (NICFD) region of high-molecular weight fluids, and in particular in cases where non-classical gas dynamic phenomena like the formation of rarefaction shock waves may be expected, is of great scientific interest. Almost all the theoretical...
book chapter 2021
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Mercier, B. (author), Chandrasekaran, N.B. (author), Colonna, Piero (author)
Speed of sound measurements are currently of the utmost importance for the development of thermodynamic models of fluids. A need for accurate thermodynamic models was identified for siloxanes, because of their use as working fluid in organic Rankine cycle power systems and because of the scientific interest in non ideal and non classical gas...
book chapter 2021
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Rubino, A. (author), Vitale, S. (author), Colonna, Piero (author), Pini, M. (author)
The possibility of taking into account unsteady flow effects if performing turbomachinery shape optimization is attractive to accurately address inherently time dependent design problems. The harmonic balance method is an efficient solution for computational fluid dynamics problems of turbomachinery characterized by quasi-periodic flows. If...
journal article 2020
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