Siemens Industrial Turbomachinery AB produce five gas turbines models. The SGT-700 can currently only start on gases which contain low amounts of inert gases. It is therefore of interest to widen the fuel range which the SGT-700, as well as other gas turbines, can start on. This report investigates the maximum limit of inert gases the SGT-700 will be able to start on, but also investigates if it is possible to start on liquid fuel (diesel) by making a few modifications to the gas turbine. To investigate this, the atmospheric combustion rig available at Siemens in Finspång has been used with a standard burner, igniter and ignition unit for the SGT-700. For the liquid fuel, the igniter was replaced by a torch igniter specially made for liquid fuels. Four different gases were evaluated; methane, propane, CO2 and N2 in order to see the effect of both various hydrocarbons and various inert gases. A model was developed for the gaseous experiments to estimate the limit for the maximum amount of inert gases the gas turbine would be able to start on. The model suggested that CO2 would require a larger amount of energy than N2 for the same amount in the composition, but that varying hydrocarbons did not have any effect if looking at the mass % of inert gas in the composition. The model was also extended with ethane and hydrogen but no experiments were performed with these gases. The model gave satisfying results. It overestimated the maximum amount of inert gases which could be mixed with propane, but agreed well when comparing the two inert gases with each other. Other interesting results were that an increased fuel flow decreased the minimum ignition energy and that an increased air flow gave a minor decrease in the maximum amount of inert gases that was possible to ignite. The torch igniter for the liquid fuel worked in a satisfying way. The ignition energy was however too low, so the ignition reliability was low. A new ignition unit with larger energy output therefore needs to be implemented. The igniter was fairly insensitive to variations in burner air flow and the ignition delay was small enough to provide a sustainable flame.

This thesis investigates the oxidation chemistry and ignition properties of formic acid (FA). The study reports experimental measurements of ignition delay time (IDT) and CO/CO2 time histories during FA oxidation in a shock tube. The initial concentration of FA was measured with a laser to minimize uncertainties arising from its low vapor pressure and tendency to form dimers. Shock tube experiments were carried out at two pressures, around 1.7 and 3.5 bar, and temperatures ranging from 1194 to 1658 K, with two equivalence ratios, 0.72 and 1.47. The results show a noticeable dependence of IDTs on temperature and pressure, while there was insignificant dependence on equivalence ratio. Six kinetic models for FA oxidation available in the literature were tested against the obtained data to evaluate their accuracy and suggest potential improvements. We found that 4 models performed well in predicting IDTs and CO/CO2 profiles with some overprediction at certain conditions. Sensitivity analysis revealed that the IDTs of FA are governed by unimolecular decomposition, H abstraction, and radical consumption (HOCO) reactions. The concentration of HO2 is higher at low temperatures, which is favorable for the system’s reactivity as it makes IDTs more sensitive to the reaction HOCHO + HO2 = H2O2 + HOCO. CO formation is controlled by two reactions: CO + OH = HOCO and HOCHO (+M) = CO + H2O, while the second reaction is more pronounced at high temperatures. Moreover, the dissociation of HOCO is faster at higher pressures, leading to higher initial CO concentrations. The formation of CO2 is determined by CO + OH = CO2 + H, while at higher temperatures, HOCHO (+M) = CO2 + H2 (+M) becomes more important, resulting in higher initial CO2 concentrations.

Nuclear physics experiments typically involve the collection and analysis of detector signals produced by the interaction of subatomic particles with matter to deduce various quantities. When heavy ions are involved, Si Detector signals are distorted by the formation of a plasma-like cloud from the interaction between the heavy ions and the detector material. The signal amplitude is reduced and delayed, two effects known as Pulse Height Defect (PHD) and Plasma Delay Time (PDT). A recent experiment was performed at the Institut Laue-Langevin(ILL) experimental nuclear reactor facility in Grenoble, using the LOHENGRIN mass spectrometer, to study these walk effects. The purpose of this project is to use a subset of the data to perform pulse shape analysis and develop a parametrization of the pulse waveform in order to better understand the PDT and PHD and how the pulses are affected. Initially, the PDT and PHD are estimated for masses 90, 100, 130 and 143 u using already established methods. The pulse waveforms are then investigated and a suitable parametrization of the pulse waveform is developed. The region around the pulse onset, which is important in extracting the timing characteristics of the pulse, is found to be described rather well by the Landau function. The Landau function parameters are further investigated and correlations with pulse shape characteristics are discussed. Finally, this novel parametrization is used as an alternative approach to estimate the PDT for the same masses as initially. Comparisons between the two methods indicate that the PDT is actually a combined effect of the physical plasma delay and the walk effects introduced by the underlying triggering routine that is used during offline analysis.

There is a great interest to develop biomass combustion systems for industrial and utility applications. Improved biomass energy conversion systems are designed to provide better combustion efficiencies and environmental friendly conditions, as well as the fuel flexibility options in various applications. The gas derived from the gasification process of biomass is considered as one of the potential candidates to substitute traditional fuels in a combustion process. However, the gascomposition from the gasification process may have a wide range of variation depending on the methods and fuel sources. The better understanding of the combustion features for the Gasified Biomass Gas(GBG) is essential for the development of combustion devices to be operated efficiently and safely at the user-end. The objective of the current study is therefore aiming to achieve data associated with the combustion features of GBG fuel for improving the efficiency and stability of combustion process. The numerical result is achieved from the kinetic models of premixed combustion with a wide range of operating ranges and variety of gas compositions. The numerical result is compared with experimental data to provide a better understanding of the combustion process for GBG fuel. In this thesis the laminar flame speed and ignition delay time of the GBG fuel are analyzed, using 1-D premixed flame model and constant volume model respectively. The result from different kinetics are evaluated and compared with experimental data. The influences of initial temperature, pressure and equivalence ratio are considered, as well as the variation of gas compositions. While the general agreement is reached between the numerical result and experimental data for laminarflame speed prediction, deviations are discovered at fuel-rich region and increased initial temperature. For the ignition delay time, deviations are found in the low-temperature and low pressure regime. The empirical equations considering the influence of initial temperature,pressure and equivalence ratio are developed for laminar flame speed and ignition delay times. The influence of major compositions such as CO, H2 and hydrocarbons are discussed in details in the thesis. Furthermore, a simplified kinetic model is developed and optimized based on the evaluation of existing kinetics for GBG fuel combustion. The simplified kinetic model is expected to be used for simulating the complexc ombustion process of GBG fuel in future studies. / <p>QC 20150511</p>

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Increased trends towards servitization within previously exclusively manufacturing industries makes a larger part of maintenance become the responsibility of the manufacturer. This increased responsibility makes it more important for suppliers to know how different parameters contribute to cost, to be able to price their contracts correctly. Systems Engineering (SE) and Integrated Logistics Support (ILS) are two current methodologies on how to manage large systems. These methodologies are mainly used within defence industries and large capital-intensive infrastructure projects but are today also utilised in civilian industries. With the new methodology of Model Based Systems Engineering (MBSE) and the new demands of servitization it becomes more important to know how different parameters affect the final cost of a project during the very early phases of development. Within ILS the parameters Administrative Delay Time (ADT) and Logistics Delay Time (LDT) have previously not received attention proportional to their contribution to overall availability in projects. This thesis is based in literature, interviews of industry professionals, and the study of a real case of an electrical charging infrastructure project currently in development. From these sources multiple paths to resolve the issues with support from ILS, MBSE, SE, and other management literature are explored. Several attributes of the case, and characteristics of MBSE and ILS leads to the conclusion that coupling the methodologies with Lean methods would lead to better insight into where critical points in the explored system are and give ways of resolving issues with ADT and LDT that exist. The combination of MBSE and Lean methods could successfully identify possible critical points in the error handling of the electrical charging infrastructure system early in the process of implementation. Conclusionary the combination of MBSE, ILS, and Lean is a possibly powerful way to identify and improve the availability and consequently the cost of a project in the early stages. / Tjänstefiering är en trend som gör att en allt större del av underhåll inom tidigare endast tillverkande industrier blir tillverkarens ansvar. När detta ansvar ökar blir det viktigare för tillverkaren and veta vilka parametrar som är kostnadsdrivande. Detta för att kunna prissätta sina tjänster korrekt. Systemteknik (SE) och Integrerat Logistikstöd (ILS) är två metodologier som används till att hantera underhåll av stora system. Dessa nyttjas främst inom försvarsindustrin och inom kapitalintensiva infrastrukturprojekt, men används även i privat industri. Med hjälp av en utveckling inom SE, Modellbaserad Systemteknik (MBSE), och med de krav som tjänstefiering innebär så blir vikten av att ha korrekt angivna parametrar tidigt i projektet mer tydlig. Inom ILS är särskilt parametrarna administrativ väntetid (ADT) och logistisk väntetid (LDT) särskilt eftersatta med hänsyn till hur mycket de påverkar tillgängligheten och kostnaderna för systemet. Detta examensarbete baseras på tillgänglig litteratur inom nämnda områden, intervjuer med industrirepresentanter, och dokumentation och intervjuer i ett riktigt fall. Det riktiga fallet är ett pågående projekt för uppbyggnad och underhåll av laddningsinfrastruktur för eldrivna fordon. Från dessa källor utforskades och analyserades flera vägar för hur man skulle kunna förbättra hanteringen av ADT och LDT med grund i litteraturen kring ILS, MBSE, och SE med annan litteratur inom mangament som stöd. Fallets egenskaper, och egenskaper hos ILS och MBSE leder till slutsatsen att en kombination av MBSE och Lean skulle leda till att man lättare kan utforska kritiska delar av ett underhållssystem, och åtgärda existerande problem med ADT och LDT. En kombination av dessa principer kunde identifiera kritiska punkter i felhanteringssystemet hos laddarna i infrastrukturprojektet trots att projektet befann sig tidigt i implementationen. Slutligen kan konstateras att MBSE, ILS och Lean är en möjlig kraftfull kombination för att förbättra tillgängligheten tidigt i ett projekts livscykel.

Kommt es zu einer akuten respiratorischen Insuffizienz, stellt die Beatmung einen wichtigen Eckpfeiler der Therapie dar. Da eine invasive Beatmung über einen endotrachealen Tubus mit Risiken verbunden ist, sollte wann immer möglich, eine nicht-invasive Beatmung eingesetzt werden. Neben den absoluten Kontraindikationen limitieren Undichtigkeit, Ulzerationen im Gesichtsbereich und ein schlechter Tragekomfort die Praktikabilität der Gesichtsmasken. Ziel dieser Arbeit war die Evaluation eines neuartigen Beatmungshelms in einem Lungenmodell und einer Probandenstudie im Hinblick auf Beatmungsparameter (Beatmungsdruck, AZV, AMV, PEEP) Resistance, Compliance, Delay-Zeiten, CO2, SpO2, Triggerzeit und Komfort. Es zeigte sich, dass eine Steigerung des PEEP auf 8 mbar zu einer signifikanten Reduktion der DelayTrigger und DelayPeep-Zeiten führte. Höhere PEEP-Werte gingen hingegen mit einer zunehmenden Leckage und Gefahr einer Desynchronität zwischen Proband und Ventilator einher. Eine zusätzliche Druckunterstützung konnte das AMVLunge signifikant steigern, was zu einem Abfall der CO2-Konzentration sowohl in der transkutanen Messung als auch im Helm führte. Problematisch zeigte sich aufgrund der Compliance des Helms, dass ein hoher Anteil des AMV zum Druckaufbau im Helm verloren geht. Dieser Effekt war abhängig von PEEP, ASB sowie Compliance und Resistance der Lunge. Der Beatmungshelm ist als eine gute Alternative zu betrachten, wenn eine Aufrecherhaltung eines PEEPs im Vordergrund steht, wie etwa bei einer Oxygenierungstörung bei Parenchymversagen.

Applications of natural gases that contain high levels of hydrogen have become a primary interest in the gas turbine market. For reheat gas turbines, understanding of the ignition delay times of high-hydrogen natural gases is important for two reasons. First, if the ignition delay time is too short, autoignition can occur in the mixer before the primary combustor. Second, the flame in the secondary burner is stabilized by the ignition delay time of the fuel. While the ignition delay times of hydrogen and of the individual hydrocarbons in natural gases can be considered well known, there have been few previous experimental studies into the effects of different levels of hydrogen on the ignition delay times of natural gases at gas turbine conditions. In order to examine the effects of hydrogen content at gas turbine conditions, shock-tube experiments were performed on nine combinations of an L9 matrix. The L9 matrix was developed by varying four factors: natural gas higher-order hydrocarbon content of 0, 18.75, or 37.5%; hydrogen content of the total fuel mixture of 30, 60, or 80%; equivalence ratios of 0.3, 0.5, or 1; and pressures of 1, 10, or 30 atm. Temperatures ranged from 1092 K to 1722 K, and all mixtures were diluted in 90% Ar. Correlations for each combination were developed from the ignition delay times and, using these correlations, a factor sensitivity analysis was performed. It was found that hydrogen played the most significant role in ignition delay time. Pressure was almost as important as hydrogen content, especially as temperature increased. Equivalence ratio was slightly more important than hydrocarbon content of the natural gas, but both were less important than pressure or hydrogen content. Further analysis was performed using ignition delay time calculations for the full matrix of combinations (27 combinations for each natural gas) using a detailed chemical kinetics mechanism. Using these calculations, separate L9 matrices were developed for each natural gas. Correlations from the full matrix and the L9 matrix for each natural gas were found to be almost identical in each case, verifying that a thoughtfully prepared L9 matrix can indeed capture the major effects of an extended matrix.

The goal of the project was to simulate a typical silicon detectorresponse in an experiment made at the Tandem lab in Uppsala. The plasma delay time was analyzed by simulating the experiment. Three different models of the plasma delay time were introduced and their effects on time of flight measurements were studied. A continuation of the main goal was to see if the inserted PDT models could be extracted from the simulations when being treated as a pseudo experiment, to see theoverall effectiveness of the experiment. When comparing the final simulations with actual measurements, it was concluded that the main properties of the detector response had been featured and that the simulations were successful. The successful extraction of the inserted plasma delay times and their dependencies on energy also proved that the experiment was a good one. The result of the project was that one of the models seemed to have a strong mass dependence, however with no clear dependence on the energy. The other two models showed a somewhat similar dependence on energy. One of the two models also showed a relatively weak mass dependence.

Indiana University-Purdue University Indianapolis (IUPUI) / Investigations of a constant-volume combustor ignited by a penetrating transient jet (a puff) of hot reactive gas have been conducted in order to provide vital data for designing wave rotor combustors. In a wave rotor combustor, a cylindrical drum with an array of channels arranged around the axis spins at a high rpm to generate high-temperature and high-pressure product gas. The hot-gas jet ignition method has been employed to initiate combustion in the channels. This study aims at experimentally investigating the ignition delay time of a premixed combustible mixture in a rectangular, constant-volume chamber, representing one channel of the wave rotor drum. The ignition process may be influenced by the multiple factors: the equivalence ratio, temperature, and the composition of the fuel mixture, the temperature and composition of the jet gas, and the peak mass flow rate of the jet (which depends on diaphragm rupture pressure). In this study, the main mixture is at room temperature. The jet composition and temperature are determined by its source in a pre-chamber with a hydrogen-methane mixture with an equivalent ratio of 1.1, and a fuel mixture ratio of 50:50 (CH4:H2 by volume). The rupture pressure of a diaphragm in the pre-chamber, which is related to the mass flow rate and temperature of the hot jet, can be controlled by varying the number of indentations in the diaphragm. The main chamber composition is varied, with the use of four equivalence ratios (1.0, 0.8, 0.6, and 0.4) and two fuel mixture ratios (50:50, and 30:70 of CH4:H2 by volume). The sudden start of the jet upon rupture of the diaphragm causes a shock wave that precedes the jet and travels along the channel and back after reflection. The shock strength has an important role in fast ignition since the pressure and the temperature are increased after the shock. The reflected shock pressure was examined in order to check the variation of the shock strength. However, it is revealed that the shock strength becomes attenuated compared with the theoretical pressure of the reflected shock. The gap between theoretical and measured pressures increases with the increase of the Mach number of the initial shock. Ignition delay times are obtained using pressure records from two dynamic pressure transducers installed on the main chamber, as well as high-speed videography using flame incandescence and Schileren imaging. The ignition delay time is defined in this research as the time interval from the diaphragm rupture moment to the ignition moment of the air/fuel mixture in the main chamber. Previous researchers used the averaged ignition delay time because the diaphragm rupture moment is elusive considering the structure of the chamber. In this research, the diaphragm rupture moment is estimated based on the initial shock speed and the longitudinal length of the main chamber, and validated with the high-speed video images such that the error between the estimation time and the measured time is within 0.5%. Ignition delay times decrease with an increase in the amount of hydrogen in the fuel mixture, the amount of mass of the hot-jet gases from the pre-chamber, and with a decrease in the equivalence ratio. A Schlieren system has been established to visualize the characteristics of the shock wave, and the flame front. Schlieren photography shows the density gradient of a subject with sharp contrast, including steep density gradients, such as the flame edge and the shock wave. The flame propagation, gas oscillation, and the shock wave speed are measured using the Schlieren system. An image processing code using MATLAB has been developed for measuring the flame front movement from Schlieren images. The trend of the maximum pressure in the main chamber with respect to the equivalence ratio and the fuel mixture ratio describes that the equivalence ratio 0.8 shows the highest maximum pressure, and the fuel ratio 50:50 condition reveals lower maximum pressure in the main chamber than the 30:70 condition. After the combustion occurs, the frequency of the pressure oscillation by the traversing pressure wave increases compared to the frequency before ignition, showing a similar trend with the maximum pressure in the chamber. The frequency is the fastest at the equivalence ratio of 0.8, and the slowest at a ratio of 0.4. The fuel ratio 30:70 cases show slightly faster frequencies than 50:50 cases. Two different combustion behaviors, fast and slow combustion, are observed, and respective characteristics are discussed. The frequency of the flame front oscillation well matches with that of the pressure oscillation, and it seems that the pressure waves drive the flame fronts considering the pressure oscillation frequency is somewhat faster. Lastly, a feedback mechanism between the shock and the flame is suggested to explain the fast combustion in a constant volume chamber with the shock-flame interactions.