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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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Guardone, Alberto (author), Colonna, Piero (author), Pini, M. (author), Spinelli, Andrea (author)The gas dynamics of single-phase nonreacting fluids whose thermodynamic states are close to vapor-liquid saturation, close to the vapor-liquid critical point, or in supercritical conditions differs quantitatively and qualitatively from the textbook gas dynamics of dilute, ideal gases. Due to nonideal fluid thermodynamic properties,...journal article 2024
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Lecardonnel, A. (author), de Servi, C.M. (author), Colonna, Piero (author), Laboureur, D. (author)In evaporators, the distribution of the liquid and vapor phases among the channels is a convoluted problem, depending on a wide range of parameters. However, maldistribution causes important losses of performance. Due to their complexity, the accurate modeling of such two-phase flows is difficult to handle. Hence, experimental studies are...journal article 2024
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Giuffré, A. (author), Colonna, Piero (author), de Servi, C.M. (author)The Environmental Control System (ECS) of passenger aircraft is the main consumer of non-propulsive power aboard. A computationally efficient and accurate thermal model of the fuselage is needed for future sustainable aircraft to address ECS preliminary sizing and control design, as the ECS should be re-designed to exploit possible synergies...journal article 2024
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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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Krempus, D. (author), Beltrame, F. (author), Majer, M. (author), Colonna, Piero (author), de Servi, C.M. (author), Vos, Roelof (author)This paper presents a preliminary study about a combined-cycle engine based on a turboshaft engine and an organic-Rankine-cycle (ORC) bottoming unit to be used onboard an aircraft with a turboelectric propulsion system. The aim is to analyse whether benefits with respect to mission fuel consumption can be derived by employing such a combined...report 2024
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Gradl, P.R. (author), Cervone, A. (author), Colonna, Piero (author)This research evaluates Laser Powder Directed Energy Deposition (LP-DED) for producing fine feature internal microchannels. This study is focused on enhancing and characterising the surfaces of microchannels produced using techniques such as abrasive flow machining, chemical milling, chemical mechanical polishing, electrochemical machining,...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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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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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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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)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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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 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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Colonna, Kyle J. (author), Nane, G.F. (author), Choma, Ernani F. (author), Cooke, R.M. (author), Evans, John S. (author)Coronavirus disease 2019 (COVID-19) forecasts from over 100 models are readily available. However, little published information exists regarding the performance of their uncertainty estimates (i.e. probabilistic performance). To evaluate their probabilistic performance, we employ the classical model (CM), an established method typically used...journal article 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 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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Colonna, Kyle J. (author), Koutrakis, Petros (author), Kinney, Patrick L. (author), Cooke, R.M. (author), Evans, John S. (author)Epidemiologic cohort studies have consistently demonstrated that long-term exposure to ambient fine particles (PM<sub>2.5</sub>) is associated with mortality. Nevertheless, extrapolating results to understudied locations may involve considerable uncertainty. To explore this issue, this review discusses the evidence for (i) the associated risk...review 2022
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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