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View article: Mechanical design and rotordynamic analysis of the ORCHID turbine
Mechanical design and rotordynamic analysis of the ORCHID turbine Open
The ORCHID turbine is a laboratory single-stage 10 kW high-speed (∼100 krpm) radial-inflow turbine for high-temperature/high-efficiency organic Rankine cycle (ORC) systems, designed at the Aerospace Propulsion and Power laboratory of Delft…
View article: Enhancement of friction factors for microchannels fabricated using laser powder directed energy deposition
Enhancement of friction factors for microchannels fabricated using laser powder directed energy deposition Open
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 is…
View article: The effect of working fluid and compressibility on the optimal solidity of axial turbine cascades
The effect of working fluid and compressibility on the optimal solidity of axial turbine cascades Open
The blade solidity, namely the blade chord-to-pitch ratio, largely affects the fluid-dynamic performance of turbomachinery and its cost. For turbo-machines operating with air or steam, the optimal value of the solidity which maximizes the …
View article: Impact of the working fluid in orc-based waste heat recovery systems for turboshaft engines
Impact of the working fluid in orc-based waste heat recovery systems for turboshaft engines Open
Waste heat recovery in aircraft engines is a promising solution to enhance their performance and reduce the mission fuel consumption. The combined-cycle turboshaft (CC-Turboshaft) is a concept which features a Brayton cycle with a subseque…
View article: Design maps for axial turbines operating with non-ideal organic compounds
Design maps for axial turbines operating with non-ideal organic compounds Open
Axial turbines are arguably the most common configuration of expanders employed in organic Rankine cycle (ORC) power plants of large power capacity. In most of these power plants, the working fluid enters the turbine with a few degrees of …
View article: Optimal design of a ram air cooling duct housing the condenser of an airborne ORC WHR unit
Optimal design of a ram air cooling duct housing the condenser of an airborne ORC WHR unit Open
Thermal energy harvesting from aero engines using compact organic Rankine cycle (ORC) units can reduce aircraft fuel consumption and emissions. Heat exchangers (HX) are key components of such ORC systems: the primary heat exchanger, or eva…
View article: Development and experimental evaluation of surface enhancement methods for laser powder directed energy deposition microchannels
Development and experimental evaluation of surface enhancement methods for laser powder directed energy deposition microchannels Open
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 …
View article: Nonideal Compressible Fluid Dynamics of Dense Vapors and Supercritical Fluids
Nonideal Compressible Fluid Dynamics of Dense Vapors and Supercritical Fluids Open
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…
View article: ON AIR-COOLED CONDENSERS FOR ORC SYSTEMS OPERATING WITH ZEOTROPIC MIXTURES
ON AIR-COOLED CONDENSERS FOR ORC SYSTEMS OPERATING WITH ZEOTROPIC MIXTURES Open
The use of mixtures as working fluids of ORC systems is being intensively investigated because of the better temperature profile matching achievable in the heat exchangers, resulting in lower thermodynamic irreversibilities and increased e…
View article: Mechanical Design and Rotor-dynamic Analysis of the ORCHID Turbine
Mechanical Design and Rotor-dynamic Analysis of the ORCHID Turbine Open
The ORCHID turbine is a 10 kW, high-speed (~100 krpm) radial-inflow organic Rankine cycle (ORC) turbine, under realization in the Propulsion and Power laboratory of Delft University of Technology. The turbine will be installed and tested i…
View article: On mixtures as working fluids of air-cooled ORC bottoming power plants of gas turbines
On mixtures as working fluids of air-cooled ORC bottoming power plants of gas turbines Open
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…
View article: Integrated design optimization method for novel vapour-compression-cycle-based environmental control systems
Integrated design optimization method for novel vapour-compression-cycle-based environmental control systems Open
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 …
View article: Speed of Sound Measurements in Dense Siloxane D<sub>6</sub> Vapor at Temperatures up to 645 K by Means of a New Prismatic Acoustic Resonator
Speed of Sound Measurements in Dense Siloxane D<sub>6</sub> Vapor at Temperatures up to 645 K by Means of a New Prismatic Acoustic Resonator Open
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 whose properties d…
View article: Design Optimization of a High-Speed Twin-Stage Compressor for Next-Gen Aircraft Environmental Control System
Design Optimization of a High-Speed Twin-Stage Compressor for Next-Gen Aircraft Environmental Control System Open
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 compre…
View article: Flow deviation and critical choking in transonic turbine cascades operating with non-ideal compressible flows
Flow deviation and critical choking in transonic turbine cascades operating with non-ideal compressible flows Open
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 gener…
View article: The Effect of Size and Working Fluid on the Multi-Objective Design of High-Speed Centrifugal Compressors
The Effect of Size and Working Fluid on the Multi-Objective Design of High-Speed Centrifugal Compressors Open
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 sca…
View article: Void Fraction Experimental Determination in Gas/Liquid Horizontal Pipe Flow by Mean of a Dual Optical Probe
Void Fraction Experimental Determination in Gas/Liquid Horizontal Pipe Flow by Mean of a Dual Optical Probe Open
Proceedings of the 7th World Congress on Momentum, Heat and Mass Transfer (MHMT'22) Lisbon, Portugal Virtual Conference – April 07 – 09, 2022 Paper No. ICMFHT 151
View article: Nonlinear wave propagation in dense vapor of Bethe–Zel'dovich–Thompson fluids subjected to temperature gradients
Nonlinear wave propagation in dense vapor of Bethe–Zel'dovich–Thompson fluids subjected to temperature gradients Open
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, t…
View article: Dense-vapor effects in compressible internal flows
Dense-vapor effects in compressible internal flows Open
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…