78,408 research outputs found

    Experimental Investigations of Exciting Forces Caused by Flow in Labyrinth Seals

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    The interaction of the flow through the labyrinth seals with the shaft of the rotor can have an effect on the stability of turbomachines. Thus, the excited forces, so-called cross forces or nonconservative forces, arise, which act perpendicular to the rotor eccentricity. This effect is caused by an unsymmetrical pressure distribution within the labyrinth cavities. Experimental studies were carried out for different types of labyrinth geometries: two staggered labyrinths with teeth on the stator and grooved rotor as well as a full and a convergent stepped labyrinth. These labyrinths can be found on the tip shrouding of bladings in steam or gas turbines. The following parameters were varied in the test facility: geometry of the labyrinth seals (number of cavities, inlet region), shaft rotation, pressure difference on the seal, entry swirl and eccentricity of the rotor. The results are presented for stiffness coefficients of the labyrinth seals, leakage flow and circumferential flow in each cavity which was measured with special probes. Generally, the inlet swirl has the greatest influence on the coefficients of the seals. The experimental results were compared with theoretical results and were in good agreement

    The Labyrinth

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    The Labyrinth is a puzzle video game meant to be experienced with a virtual reality headset. It aims to differ from typical puzzle games by being simultaneously fun, immersive, and mentally stimulating. The game consists of three unique level types, with room for further development to create more complex versions of said levels. In this document, we discuss how we developed the game environment to effectively engage the player in enjoyable and engaging problem-solving challenges. The game has been rigidly tested and play-testers were surveyed on their experiences, in order to improve the game

    Inside the labyrinth : the thematics of space in the fiction of Paola Capriolo

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    In Capriolo's fiction we see, above all, the centrality of place in the minds and lives of her protagonists, often linked with the idea of the labyrinth: labyrinth as endless tortuous passageways, enclosed place, puzzle, quest. The stories, built around the obsessions of their protagonists, transcend normal temporal and spatial boundaries, and reflect the labyrinth in various forms: as a physical maze; as mirror reflections, sometimes infinitely receding; as a remote, closed-off place; and as a metaphor suggesting confusion of the mind or of ideas. As well as a considerable degree of overlap within these areas, there is a pervading, underlying sense of ambiguity, and the idea of permanence and of eternal 'being'

    Theoretical approach to labyrinth seal forces - cross-coupled stiffness of a straight-through labyrinth seal

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    Two kinds of three dimensional flows in a labyrinth seal, a jet flow and a core flow, are considered and theoretical equations are set up concerning the motion of each flow. The pressure distribution within the labyrinth is calculated, when the rotor shaft makes a small displacement from the center line of the casing, keeping parallel with it. The theoretical values of cross coupled stiffness obtained by integrating the pressure under different labyrinth geometries and operating conditions through these formulas are compared with the experimental data

    Analysis of dynamic characteristics of fluid force induced by labyrinth seal

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    Flow patterns of the labyrinth seal are experimentally investigated for making a mathematical model of labyrinth seal and to obtain the flow induced force of the seal. First, the flow patterns in the labyrinth chamber are studied on the circumferential flow using bubble and on the cross section of the seal chamber using aluminum powder as tracers. And next, the fluid force and its phase angle are obtained from the measured pressure distribution in the chamber and the fluid force coefficients are derived from the fluid force and the phase angle. Those are similar to the expression of oil film coefficients. As a result, it is found that the vortices exist in the labyrinth chambers and its center moves up and down periodically. The pressure drop is biggest in the first stage of chambers and next in the last stage of chambers

    Circumferential pressure distributions in a model labyrinth seal

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    A research program to isolate and study leakage flow through labyrinth glands was initiated. Circumferential pressure distributions were measured in the labyrinth glands with geometry appropriate to the high pressure labyrinths in large steam turbines. Knowledge of this pressure distribution is essential as it is this unequal pressure field that results in the destabilizing force. Parameters that are likely to affect the pressure distributions are incorporated into the test rig. Some preliminary pressure profiles are presented

    Annular honeycomb seals: Test results for leakage and rotordynamic coefficients; comparisons to labyrinth and smooth configurations

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    Test results are presented for leakage and rotordynamic coefficients for seven honeycomb seals. All seals have the same radius, length, and clearance; however, the cell depths and diameters are varied. Rotordynamic data, which are presented, consist of the direct and cross-coupled stiffness coefficients and the direct damping coefficients. The rotordynamic-coefficient data show a considerable sensitivity to changes in cell dimensions; however, no clear trends are identifiable. Comparisons of test data for the honeycomb seals with labyrinth and smooth annular seals show the honeycomb seal had the best sealing (minimum leakage) performance, followed in order by the labyrinth and smooth seals. For prerotated fluid entering the seal, in the direction of shaft rotation, the honeycomb seal has the best rotordynamic stability followed in order by the labyrinth and smooth. For no prerotation, or fluid prerotation against shaft rotation, the labyrinth seal has the best rotordynamic stability followed in order by the smooth and honeycomb seals
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