Detailed film cooling effectiveness distributions were measured on the stationary blade tip and on the leading edge region of a rotating blade using a Pressure Sensitive Paint technique. Air and nitrogen gas were used as the film cooling gases and the oxygen concentration distribution for each case was measured. The film cooling effectiveness information was obtained from the difference of the oxygen concentration between air and nitrogen gas cases by applying the mass transfer analogy. In the case of the stationary blade tip, plane tip and squealer tip blades were used while the film cooling holes were located (a) along the camber line on the tip or (b) along the span of the pressure side. The average blowing ratio of the cooling gas was controlled to be 0.5, 1.0, and 2.0. Tests were conducted in a five-bladed linear cascade with a blow down facility. The free stream Reynolds number, based on the axial chord length and the exit velocity, was 1,100,000 and the inlet and the exit Mach number were 0.25 and 0.59, respectively. Turbulence intensity level at the cascade inlet was 9.7%. All measurements were made at three different tip gap clearances of 1%, 1.5%, and 2.5% of blade span. Results show that the locations of the film cooling holes and the presence of squealer have significant effects on surface static pressure and film-cooling effectiveness. Same technique was applied to the rotating turbine blade leading edge region. Tests were conducted on the first stage rotor of a 3-stage axial turbine. The Reynolds number based on the axial chord length and the exit velocity was 200,000 and the total to exit pressure ratio was 1.12 for the first rotor. The effects of the rotational speed and the blowing ratio were studied. The rotational speed was controlled to be 2400, 2550, and 3000 rpm and the blowing ratio was 0.5, 1.0, and 2.0. Two different film cooling hole geometries were used; 2-row and 3-row film cooling holes. Results show that the rotational speed changes the directions of the coolant flows. Blowing ratio also changes the distributions of the coolant flows. The results of this study will be helpful in understanding the physical phenomena regarding the film injection and designing more efficient turbine blades.

The leading edge of a turbine vane is subject to some of the highest temperature loading within an engine, and an accurate understanding of leading edge film coolant behavior is essential to efficient engine design. Although there have been many investigations of the adiabatic effectiveness for showerhead film cooling within the leading edge region, there have been no previous studies in which individual rows of the showerhead were tested with the explicit intent of validating superposition models. For the current investigation, a series of adiabatic effectiveness experiments were performed with a five-row showerhead, wherein each row of holes was operated in isolation. This allowed evaluation of superposition on both the suction side of the vane, which was moderately convex, and the pressure side of the vane, which was mildly concave. Superposition was found to accurately predict performance on the suction side of the vane at lower momentum flux ratios, but not for higher momentum flux ratios. On the pressure side of the vane, the superposition predictions were consistently lower than measured values, with significant under-prediction of adiabatic effectiveness occurring at the higher mass flow rates. Possible reasons for the under-prediction of effectiveness by the superposition model are presented. / text

Deposition of contaminant particles on gas turbine surfaces reduces the aerodynamic and cooling efficiency of the turbine and degrades its materials. Gas turbine designers seek a better understanding of this complicated phenomenon and how to mitigate its effects on engine efficiency and durability. The present study developed an experimental method in wind tunnel facilities to simulate the important physical aspects of the interaction between deposition and turbine cooling, particularly film cooling. This technique consisted of spraying molten wax droplets into the mainstream flow that would deposit and solidify on large scale, cooled, turbine airfoil models in a manner consistent with inertial deposition on turbine surfaces. The wax particles were sized to properly simulate the travel of particles in the flow path, and their adhesion to the surface was modeled by ensuring they remained at least partially molten upon impact. Initial development of this wax spray technique was performed with a turbine blade leading edge model with three rows of showerhead film cooling. It was then applied to turbine vane models with showerhead holes and row on pressure side consisting of either standard cylindrical holes or similar holes situated in a spanwise, recessed trench. Vane models were either approximately adiabatic or had a thermal conductivity selected to simulate the conjugate heat transfer of turbine airfoils at engine conditions. These models were also used to measure the adiabatic film effectiveness and overall cooling effectiveness in order to better assess how the cooling design interacted with deposition. Deposit growth was found to be sensitive to the mainstream air and the model surface temperatures and the solidification temperature of the wax. Deposits typically grew to an equilibrium thickness caused by a balance between erosion and adhesion. The existence of film cooling substantially redistributed deposit growth, but changes in blowing ratio had a minor effect. A hypothesis was proposed and substantiated for the physical mechanisms governing wax deposit growth, and its applicability to engine situations was discussed. / text

This work investigated a numerical approach to the search of a maximum heat transfer rate density (the overall heat transfer dissipated per unit of volume) from a two-dimensional laminar multiscale array of cylinders in cross-flow under an applied fixed pressure drop and subject to the constraint of fixed volume. It was furthermore assumed that the flow field was steady state and incompressible. The configuration had two degrees of freedom in the stationary state, that is, the spacing between the cylinders and the diameter of the smaller cylinders. The angular velocity of the cylinders was in the range 0 ≤ ϖ, ≤ 0.1. Two cylinders of different diameters were used, in the first case, the cylinders were aligned along a plane which lay on their centrelines. In the second case, the cylinder leading edge was aligned along the plane that received the incoming fluid at the same time. The diameter of the smaller cylinder was fixed at the optimal diameter obtained when the cylinders were stationary. Tests were conducted for co-rotating and counterrotating cylinders. The results were also compared with results obtained in the open literature and the trend was found to be the same. Results showed that the heat transfer from a rotating array of cylinders was enhanced in certain cases and this was observed for both directions of rotation from an array which was aligned on the centreline. For rotating cylinders with the same leading edge, there is heat transfer suppression and hence the effect of rotation on the maximum heat transfer rate density is insignificant. This research is important in further understanding of heat transfer from rotating cylinders, which can be applied to applications ranging from contact cylinder dryers in the chemical processes industry and rotating cylinder electrodes to devices used for roller hearth furnaces. / Dissertation (MEng)--University of Pretoria, 2011. / Mechanical and Aeronautical Engineering / unrestricted

This master thesis is devoded to examination of influence of bumped leading edge of hydraulic turbines ruber blade to characteristics of blade cascade. Thesis is based on hydraulic turbine which countoured/bumped leading edge of blade was created using previous studies on NACA profiles. The main goal of this thesis is to Compare shaped leading edge with flat leading edge using CFD calculations. Programms like SolidWorks and Gambit were used to calculate geometrics and meshes.

Der TRPV3 (transient receptor potential vanilloid 3)-Kanal ist ein nicht-selektiver, Kalzium-permeabler Kationenkanal, der hauptsächlich in epidermalen Keratinozyten exprimiert wird (Peier et al., 2002). Eine genaue Regulierung der Kalzium-Dynamik in der Epidermis der Haut spielt bei der Bildung der Hautbarriere eine entscheidende Rolle, wodurch viele Aspekte der Epidermisfunktion, einschließlich der Proliferation, Differenzierung und Migration der Keratinozyten, kontrolliert werden (Bikle & Mauro, 2014; S. E. Lee & Lee, 2018). Bei näherer Betrachtung des Einflusses des TRPV3-Kanals auf die Hauthomöostase deuten aktuelle Studien darauf hin, dass der TRPV3-vermittelte Einstrom von Kalziumionen in Keratinozyten die Freisetzung von pro-inflammatorischen Zytokinen und Wachstumsfaktoren induziert (Cheng et al., 2010; Xu et al., 2006). Daher kann jedes Ungleichgewicht in der TRPV3-Aktivität drastische Auswirkungen auf die gesunde Funktion der Haut haben, wobei eine Kanalüberaktivität mit Hyperkeratose und Entzündungen der Haut in Verbindung gebracht werden kann. Diese Störungen der Haut sind unter anderem für Hauterkrankungen wie der atopischen Dermatitis und dem schwerwiegenden Olmsted-Syndrom, das durch gain-of-function-Mutationen des TRPV3-Kanals verursacht wird, charakteristisch (Lin et al., 2012; Yamamoto-Kasai et al., 2013). Darüber hinaus kann eine Kanalunterfunktion mit einer beeinträchtigten Hautregeneration und Wundheilung korreliert werden (Aijima et al., 2015; Miyamoto et al., 2011). Diesbezüglich wurde gezeigt, dass der TRPV3-Kanal mit dem Rezeptor für den epidermalen Wachstumsfaktor (EGF-Rezeptor) einen Signalkomplex bildet, um die Bildung der Hautbarriere zu regulieren, wobei die Aktivität von TRPV3 wahrscheinlich durch die Aktivierung des EGF-Rezeptors verstärkt wird (Cheng et al., 2010). Der TRPV3-Kanal wird ebenso durch verschiedene natürliche Verbindungen, wie Carvacrol und Thymol, oder durch synthetische Substanzen, wie 2-Aminoethoxy-diphenylborat (2-APB) aktiviert, wobei 2-APB häufig zur Untersuchung der Funktion von TRPV3 in vitro angewendet wird, da es sich hierbei um einen kostengünstigen und relativ potenten TRPV3-Aktivator handelt. 2-APB wirkt jedoch auch auf eine Vielzahl anderer TRP-Kanäle, sodass es schwierig ist, die Effekte, die durch 2-APB in nativen Geweben ausgelöst werden, auf eine Aktivierung des TRPV3-Kanals zurückzuführen (Hinman, Chuang, Bautista, & Julius, 2006; Hu et al., 2004; M. Li, Jiang, & Yue, 2006; Togashi, Inada, & Tominaga, 2008; Vogt-Eisele et al., 2007; Chokshi, Fruasaha, & Kozak, 2012; Lievremont, Bird, & Putney, 2005). Bei der früheren Durchführung eines Wirkstoffscreenings einer ChemBioNet Substanzbibliothek wurde der TRPV3-selektive Inhibitor 26E01 identifiziert (Bischof et al., 2020). Um weitere potente und spezifische TRPV3-Modulatoren zu identifizieren, wurde eine hausinterne Substanzbibliothek bestehend aus 50 chemischen Verbindungen, die im Labor von Thomas Magauer synthetisiert wurden, und die SelleckChem-Substanzbibliothek L1700 bestehend aus 4718 Verbindungen gescreent. In dieser Arbeit ist die Identifizierung, Validierung und erste Anwendung des neuen, potenten, TRPV3-selektiven Aktivators KS0365 beschrieben. Durch die Anwendung dieses neuartigen TRPV3-Aktivators konnte im Rahmen dieser Studie gezeigt werden, dass TRPV3-Aktivatoren den Reepithalisierungsprozess nach einer Verletzung der Haut fördern könnten. Diese Schlussfolgerung ist auf die in dieser Studie festgestellte Beobachtung zurückzuführen, dass infolge der Aktivierung des TRPV3-Kanals mit KS0365 in den Leading-Edges von Keratinozyten und in migrierenden Keratinozyten, die im Rahmen von Migrationsassays am Rande der erzeugten Lücke lokalisiert waren, die stärksten Anstiege der intrazellulären Kalziumionenkonzentration ausgelöst wurden und KS0365 wahrscheinlich aufgrund dieser Effekte eine Beschleunigung der Keratinozytenmigration bewirkte.:Inhaltsverzeichnis 1. Abkürzungsverzeichnis 1 2. Einleitung 5 2.1 Die Funktion von Kalzium in der Haut 5 2.2 Ionenkanäle in Keratinozyten 8 2.3 Der TRPV3-Kanal 10 3. Zielstellung und Methodenwahl 17 4. Materialien und Methoden 21 4.1 Kultivierung immortalisierter Zelllinien 21 4.2 Isolierung primärer Keratinozyten 22 4.3 Erzeugung einer stabilen m308kTRPV3-YFP-Zelllinie 23 4.4 Interne Totalreflexionsfluoreszenz (TIRF)-Mikroskopie 24 4.5 Small-interfering RNA (siRNA)-vermittelter Knockdown 24 4.7 Wirkstoffscreening 26 4.8 Hit-Validierung durch Erstellung von Konzentrations-Wirkungsbeziehungen 27 4.9 Selektivitätstestung 27 5.0 Analyse von synergistischen Wirkungen von TRPV3-Aktivatoren 27 5.1 Ratiometrisches Kalzium-Imaging 28 5.2 Elektrophysiologische Untersuchungen 29 5.3 Bestimmung der metabolischen Zellaktivität 29 5.4 Zellmigrations-Assays 30 5.5 Kalzium- Imaging mittels interner Totalreflexionsfluoreszenz-Mikroskopie 30 5.6 Daten-Analyse 31 6. Ergebnisse 33 6.1 Wirkstoffscreening und Bestimmung von Konzentrations-Wirkungsbezie- hungen 33 6.2 Selektivitätstestung des neuen TRPV3-Aktivators KS0365 38 6.3 Validierung des siRNA-vermittelten TPRV3-Knockdowns 42 6.4 Kalzium-Imaging in primären Keratinozyten 44 6.5 Elektrophysiologische Untersuchungen 45 6.6. Analyse von synergistischen Wirkungen von TRPV3-Aktivatoren 49 6.7 Evaluierung der Langzeit-Tolerabilität von TRPV3-Modulatoren 50 6.8 Zellmigrations-Assays 53 6.9 Kalzium-Imaging in migrierenden Keratinozyten 58 7.0 Analyse von Kalzium-Signalen in der Leading-Edge von Keratinozyten mittels TIRF-Mikroskopie 60 8. Diskussion und Ausblick 63 9. Zusammenfassung der Arbeit 75 10. Referenzen 79 11. Erklärung über die eigenständige Abfassung der Arbeit 95 12. Lebenslauf 96 13. Publikationen 96 14. Wissenschaftliche Poster und Vorträge 96 15. Danksagung 97

Man has always been fascinated by the flight of birds and insects. First attempts at flight involved flapping wings to mimic the birds and insects that had been observed in flight. Fixed wings proved to be a more practical approach and have been used for over 100 years for manned flight. Emphasis has been placed on flapping wing designs for micro air vehicles (MAVs) as research has shown that challenges arise in lift generation and stability in fixed wing flight as the scale decreases [1].This research explores the use of 3D, time-resolved, Synthetic Aperture PIV (SAPIV) in measuring flow velocities on the mechanical flapping wing of a MAV in tethered flight. The vortical structures on the MAV are measured using both SAPIV and 2DPIV to be able to analyze 2D and 3D velocity fields. The 3D vorticity plots and 2D slice vorticity plots show the three-dimensional nature of the Leading Edge Vortex (LEV) and Trailing Edge Vortex (TEV). 2DPIV plots and 2D slices from the 3D data show general agreement in the structure and behavior of the flow around the flapping wing. The lift and thrust generated by the MAV are measured using a force gauge. The wing tip is tracked in 2D and 3D for synchronization of the measured lift forces with the flow field measurements from the SAPIV. The positive and negative circulation are plotted against the measured lift and thrust forces. The measured lift and thrust forces from the force gauge are then compared to the calculated lift and thrust forces from the measured 3D circulation found through the SAPIV flow field measurements. A plane measured parallel to the LEV and TEV vortex cores allows the defining of a unit vector that is directed normal to the top of the wing and the LEV and TEV cores. The decomposition of the unit vector allows for the calculation of the lift and thrust generated by the circulation around the wing. The comparisons between the measured and calculated forces show good agreement in the case of the measured and calculated lift forces.

In summary the tilting mechanism helps to explain the overall flow structure and the stability of the leading edge vortex.; The leading edge vortex has been identified as the most critical flow structure for producing lift in flapping wing flight. Its stability depends on the transport of the entrained vorticity into the wake via spanwise flow. This study proposes a hypothesis for the generation and enhancement of spanwise flow based on the chordwise vorticity that results from the tilting of the leading edge vortex and trailing edge vortex. We investigate this phenomenon using dynamically scaled robotic model wings. Two different wing shapes, one rectangular and one based on Drosophila melanogaster (fruit fly), are submerged in a tank of mineral oil and driven in a flapping motion. Two separate kinematics, one of constant angular velocity and one of sinusoidal angular velocity are implemented. In order to visualize the flow structure, a novel three dimensional particle image velocimetry system is utilized. From the three dimensional information obtained the chordwise vorticity resulting from the vortex tilting is shown using isosurfaces and planar slices in the wake of the wing. It is observed that the largest spanwise flow is located in the area between the chordwise vorticity of the leading edge vortex and the chordwise vorticity of the trailing edge vortex, supporting the hypothesis that the vortex tilting enhances the spanwise flow. Additionally the LEV on the rectangular wing is found to detach at about 80% span as opposed to 60% span for the elliptical wing. Also, two distinct regions of spanwise flow, one at the base and one at the tip, are observed at the beginning of the sinusoidal kinematic, and as the velocity of the wing increases these two regions unionize into one. Lastly, the general distribution of vorticity around each wing is found to be nearly the same, indicating that different wing shapes do not greatly affect the distribution of vorticity nor stability mechanisms in flapping flight.

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