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1	Experiments and Computational Fluid Dynamics on Vapor and Gas Cavitation for Oil Hydraulics Osterland, Sven, Günther, Lennard, Weber, Jürgen 27 February 2024 (has links) A compressible Euler-Euler computational fluid dynamics (CFD) model for vapor, gas, and pseudo-cavitation in oil-hydraulic flows is presented. For vapor, the Zwart-Gerber-Belamri (ZGB) model is used and for gas cavitation, the Lifante model. The aim is to determine the empirical parameters within the cavitation models for hydraulic oil by comparing CFD results to experiments in a realistic valve. The cavitating flow is visualized and measured for numerous operating points. By degassing, states of pure vapor cavitation are generated. The major findings are: (1) large eddy simulation turbulence modeling is essential, (2) vapor cavitation in mineral oil can be simulated very well with the ZGB model using the determined parameter, and (3) gas cavitation model provides useful results although not all details can be reflected and its scope is limited. info:eu-repo/classification/ddc/660 ddc:660
2	Basic Comparison of Three Aircraft Concepts: Classic Jet Propulsion, Turbo-Electric Propulsion and Turbo-Hydraulic Propulsion Rodrigo, Clinton January 2019 (has links) (PDF) Purpose - This thesis presents a comparison of aircraft design concepts to identify the superior propulsion system model among turbo-hydraulic, turbo-electric and classic jet propulsion with respect to Direct Operating Costs (DOC), environmental impact and fuel burn. --- Approach - A simple aircraft model was designed based on the Top-Level Aircraft Requirements of the Airbus A320 passenger aircraft, and novel engine concepts were integrated to establish new models. Numerous types of propulsion system configurations were created by varying the type of gas turbine engine and number of propulsors. --- Findings - After an elaborate comparison of the aforementioned concepts, the all turbo-hydraulic propulsion system is found to be superior to the all turbo-electric propulsion system. A new propulsion system concept was developed by combining the thrust of a turbofan engine and utilizing the power produced by the turbo-hydraulic propulsion system that is delivered via propellers. The new partial turbo-hydraulic propulsion concept in which 20% of the total cruise power is coming from the (hydraulic driven) propellers is even more efficient than an all turbo-hydraulic concept in terms of DOC, environmental impact and fuel burn. --- Research Limitations - The aircraft were modelled with a spreadsheet based on handbook methods and relevant statistics. The investigation was done only for one type of reference aircraft and one route. A detailed analysis with a greater number of reference aircraft and types of routes could lead to other results. --- Practical Implications - With the provided spreadsheet, the DOC and environmental impact can be approximated for any commercial reference aircraft combined with the aforementioned propulsion system concepts. --- Social Implications - Based on the results of this thesis, the public will be able to discuss the demerits of otherwise highly lauded electric propulsion concepts. --- Value - To evaluate the viability of the hydraulic propulsion systems for passenger aircraft using simple mass models and aircraft design concept. ddc:620 info:eu-repo/classification/ddc/629.13 Luftfahrt Luftfahrzeug Flugmechanik Betriebskosten Aeronautics Airplanes Airplanes--Performance Cost accounting Ölhydraulik Flugtriebwerk Elektroantrieb Kraftstoffverbrauch Flugzeug Entwurf Dimensionierung Aeroplanes Design Airplanes--Jet propulsion Airplanes--Turbofan engines Electric propulsion Hydraulics Airplanes--Fuel consumption Environmental protection Airbus A320 aircraft aircraft design flight mechanics engines hybrid propulsion hydraulics certification DOC Direct Operating Costs Airbus A320

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Experiments and Computational Fluid Dynamics on Vapor and Gas Cavitation for Oil Hydraulics

Basic Comparison of Three Aircraft Concepts: Classic Jet Propulsion, Turbo-Electric Propulsion and Turbo-Hydraulic Propulsion