P. Colonna di Paliano
139 records found
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Designing high-performance and aerospace-grade heat exchangers requires detailed characterization of the as-manufactured geometry, including cross-sectional area and surface texture, to reduce uncertainties in performance prediction and issues regarding subsequent system integrat
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Waste heat recovery (WHR) from aero engines via compact organic Rankine cycle (ORC) units may increase the fuel efficiency of air transportation. Heat exchangers are arguably the key components of ORC systems for aeronautical applications and their design must be optimized to gua
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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 g
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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 missi
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A novel test setup called the asymmetric shock tube for experiments on nonideal rarefaction waves (ASTER) has been commissioned at Delft University of Technology. The ASTER, which works according to the principle of Ludwieg tubes, is designed to generate and measure the speed of
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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 a
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Images of compressible flows can be post-processed with digital imaging techniques to obtain accurate quantitative information about variables characterizing the flow. For example, the local flow Mach number can be obtained from the angle of Mach lines visualized with the schlier
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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:
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Compressible flows of fluids whose thermophysical properties are related by complex equations are quantitatively and can be qualitatively different from high-speed flows of ideal gases. Nonideal compressible fluid dynamics (NICFD) is concerned with these fluid flows, which are re
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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 increa
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The blade solidity, namely the blade chord-to-pitch ratio, largely affects the fluid-dynamic performance of turbomachinery and its cost. For turbomachines operating with air or steam, the optimal value of the solidity which maximizes the efficiency is estimated with empirical cor
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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 mill
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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,
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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 f
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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 i
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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
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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
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Estimating the speed of sound for the dense vapor phase of D6 (dodecamethylcyclohexasiloxane, C12H36O6Si6) is particularly relevant to the study of nonideal compressible fluid dynamics (NICFD), the gas dynamics of fluids whos
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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 p
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Efficiency in Geothermal Operations
Mixtures as working fluids for ORC Power Plants
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) durin
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