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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Porovnání jednotělesové a dvoutělesové parní turbíny / Comparison of single-cylinder and double-cylinder steam turbines

Bunček, Patrik January 2021 (has links)
The master thesis deals with design and comparison of condensing steam turbine for steam-gas cycle for single-cylinder and double-cylinder body with air condenser at its end, one regulated take and ability to use additive steam. Thesis is based on the calculation of thermal scheme which is followed by a preliminary and subsequently a detailed design of steam turbine. Thermodynamic efficiency for single-cylinder turbine was calculated at 93,28 % with terminal power 136,2 MW. The design procedure was repeated for a double-cylinder body. Calculated terminal power for two-cylinder turbine was 134,4 MW with thermodynamic efficiency of 92.1%. By dividing turbine into two rotors resulting low-pressure turbine has a smaller rotor diameter, a longer blade and at the same time a larger number of stages. For double-cylinder turbine, it was necessary to consider twice the number of seals and radial bearings. Due to the increase in flow diameter of low-pressure turbine, losses related to the geometry of the stage increased. Thesis is supplemented by a section drawing of steam turbine with higher efficiency.
2

Experimental Study of the Wake behind a Circular Cylinder under Excitation

Chang, Tien-Li 30 July 2002 (has links)
This experiment is to investigate the effects of fluid with and without mass injection through a slit on the vortex shedding from a single cylinder. We research Reynolds Numbers on ranges from 800 to 4000. We used four kinds of ways which contain no mass injection, steady blowing, steady suction and oscillatory jet to study of the wake behind a circular cylinder under excitation in this experiment. No mass injection is measured for the sake of its reliability and comparability of experiment. Steady blowing and suction are applied to influence the wake flow. An oscillatory jet is used to influence the wake flow with varying frequencies and amplitudes. The experiment looks forward to use the results of this experiment so as to research into the effects on the wake flow, including the velocity values of fluctuation and turbulence intensity of the vortices structure, the dominant frequency in the flow pattern on a single cylinder. The main parameters in the study are the frequency, momentum and the location of the blowing and suction jet, which are a steady jet or unsteady oscillatory jet. Flow visualization has been carried out to investigate the interaction of steady or unsteady fluid perturbation and the vortex shedding of a cylinder.
3

Planar laser induced fluorescence imaging and analysis with ethanol blended fuels in a direct injection spark ignition engine

Liu, Quan January 2017 (has links)
The currently reported thesis was concerned with visualisation of the charge homogeneity and cyclic variations within the planar fuel field near the spark plug in an optical spark ignition engine fitted with an outwardly opening central direct fuel injector. Specifically, the project examined the effects of fuel type and injection settings, with the overall view to understanding some of the key mechanisms previously identified as leading to particulate formation in such engines. The three fuels studied included a baseline iso-octane, which was directly compared to two gasoline fuels containing 10% (E10) and 85% (E85) volume of ethanol respectively. The engine was a bespoke single cylinder with Bowditch style optical access through a flat piston crown. Charge stratification was studied over a wide spectrum of injection timings using the Planar Laser Induced Fluorescence (PLIF) technique, with additional variation in charge temperature due to injection also estimated when viable using a two-line PLIF approach. Overall, both gasoline-ethanol fuels generally exhibited a higher degree of stratification, albeit at least partly alleviated with elevated rail pressures. Under both warm and cold liner conditions the E10 fuel showed clear evidence of fuel droplets persisting up until ignition. Interestingly, with late injection timing the repeatability of the injection was superior (statistically) with higher ethanol content in the fuel, which may have been associated with the higher charge temperatures aiding control of the evaporation of the main mass of alcohol. The findings were corroborated by undertaking a comprehensive study of the influence of varying fuel type and injection settings on thermodynamic performance and engine-out emissions during firing operation, with additional gas exchange effects also influencing the optimum fuel injection timings.
4

An Experimental Investigation of Diesel-Ignited Gasoline and Diesel-Ignited Methane Dual Fuel Concepts in a Single Cylinder Research Engine

Dwivedi, Umang 17 August 2013 (has links)
Diesel-ignited gasoline and diesel-ignited methane dual fuel combustion experiments were performed in a single-cylinder research engine (SCRE), outfitted with a common-rail diesel injection system and a stand-alone engine controller. Gasoline was injected in the intake port using a portuel injector, whereas methane was fumigated into the intake manifold. The engine was operated at a constant speed of 1500 rev/min, a constant load of 5.2 bar IMEP, and a constant gasoline/methane energy substitution of 80%. Parameters such as diesel injection timing (SOI), diesel injection pressure, and boost pressure were varied to quantify their impact on engine performance and engineout ISNOx, ISHC, ISCO, and smoke emissions. The change in combustion process from heterogeneous combustion to HCCI like combustion was also observed.
5

Injection Timing Effects of Diesel-Ignited Methane Dual Fuel Combustion in a Single Cylinder Research Engine

Guerry, Edward Scott 17 May 2014 (has links)
Diesel-ignited methane dual fuel combustion experiments were performed in a single cylinder research engine (SCRE). Methane was fumigated into the intake manifold and injection of diesel was used to initiate combustion. The engine was operated at a constant speed of 1500 rev/min, and diesel rail pressure was maintained at 500 bar. Diesel injection timing (SOI) was varied to quantify its impact on engine performance and engine-out ISNOx, ISHC, ISCO, and smoke emissions. The SOI sweeps were performed at different net indicated mean effective pressures (IMEPs) of 4.1, 6.5, 9.5, and 12.1 bar. Intake manifold pressure was maintained at 1.5 bar for the 4.1 and 6.5 bar IMEP SOI sweeps and 1.8 bar for the 9.5 and 12.1 bar IMEP SOI sweeps. Advancing SOI to 310º and earlier resulted in reduced ISNOx. However, high methane percent energy substitution (PES) resulted in high ISHC emissions especially at low IMEP.
6

Benchmarking, Characterization and Tuning of Shell EcoMarathon Prototype Powertrain

Griess, Eric J 01 March 2015 (has links)
With the automotive industry ever striving to push the limits of fuel efficiency, the Shell EcoMarathon offers a glimpse into this energy conserving mindset by challenging engineering students around the world to design and build ultra-efficient vehicles to compete regionally. This requires synchronization of engineering fields to ensure that the vehicle and powertrain system work in parallel to achieve similar goals. The goal for Cal Poly – San Luis Obispo’s EcoMarathon vehicle for the 2015 competition is to analyze the unique operating mode that the powertrain undergoes during competition and improve their current package to increase fuel efficiency. In this study, fuel delivery, ignition timing and engine temperature are experimentally varied to observe trends in steady state fuel consumption. A developmental simulation is then implemented with these trends to analyze potential differences in transient and steady state tuning targets. The engine is then tuned to finalized tuning targets and performance compared with benchmark values.
7

Konstrukční návrh standu pro zkoušení jednoválcového motoru / Stand for Single Cylinder Engine Testing

Sikora, Ondřej January 2018 (has links)
The diploma thesis deals with construction design of stand for testing single-cylinder turbocharged engine. The first part describes principles and possibilities of measuring the performance parameters of internal combustion engines. It also analyzes the issue of measuring single-cylinder combustion engine. The main part of thesis is about construction design of stand, which describes the individual technical solutions of the general construction parts. The last chapter deals with numerical simulation, which uses modern software tools. This software helps with verification of function design.
8

Návrh jednoválcového zážehového motoru / Design of Single Cylinder 4-stroke SI Engine

Číž, Petr January 2008 (has links)
Thesis deals with design of the experimental single-cylinder spark ignition engines for research purposes. The main purpose of this work is the design crankcase. Summary of possible constructions of spark ignition engines is included. Basic dimensions and 3-D design of the experimental engine resulted from the summary. The numerical analysis of proposed crankcase in ADAMS (MBS) and ANSYS (FEM) software environment is also part of the work. Generally, the proposed solution of the experimental engine was focused on the universality and simplicity of the design.
9

Čtyřdobý jednoválcový motor závodního motocyklu třídy MX1 / Four-stroke single cylinder engine of racing motorcycle for MX1 class

Kučera, Michal January 2012 (has links)
This thesis describes the design of single-cylinder four-stroke racing motorcycle with a displacement of 450 cm3. The introduction describes the MX1 class motorcycle engines design and basic parameters of the designed engine. This is followed by comparing construction of crank mechanism parts meeting strength calculations with components of contemporary racing engines. The next section describes the design of the timing mechanism, balance shaft, cylinder head, engine cylinder, gearbox shaft location and crankcase lubrication and cooling system.
10

Jednoválcový dvoudobý motor motocyklu třídy enduro / Single-Cylinder Two-Stroke Engine for Enduro Motorcycle

Koten, Stanislav January 2015 (has links)
This thesis deals with the construction of two-stroke motorcycle engine. Specifically, the racing engine for the Enduro class with a displacement of 250 cm3, adapted to be mounted in a chassis with extremely long swingarm according to patent of Frantisek Krnavek. The introduction briefly describes the E2 class rules and discussed design powertrain solutions of this class. Following design and calculation of required motor parameters. Further attention is devoted to detailed calculation of main bearings lifespan. The next section describes in detail the construction of the crank mechanism, cylinder head, exhaust pipe, power valve and reed valve. Conclusion deals with location of other engine parts.

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