• The KSFM Journal of Fluid Machinery
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• v.2 no.3 s.4
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• pp.52-58
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• 1999

The leakage and rotordynamic coefficients of see-through type gas labyrinth seals are determined using a two-control-volume-model analysis with Moody's wall-friction-factor formula which is defined with a large range of Reynolds number and relative roughness. Jet flow theory are used for the calculation of the recirculation velocity in the cavity. For the reaction force from the labyrinth seal, linearized zeroth-order and the first-order perturbation equations are developed for small motion about a centered position. The leakage and rotordynamic coefficient results of the present analysis are compared with Scharrer's theoretical analysis using Blasius' wall-friction-factor formula and Pelletti's experimental results. The comparison shows that the present analysis using Moody's wall-friction-factor formula and Scharrer's theoretical analysis using Blasius' wall-friction-factor formula give the same results for a smooth seal surface and the range of Reynolds number less than $10^5$.

• 유체기계공업학회:학술대회논문집
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• 2002.12a
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• pp.465-470
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• 2002

For measuring friction-factor of artificially-roughened surfaces which are usually applied on damper seals, flat plate test apparatus is designed and fabricated. the measurement of leakage and pressure distribution through round-hole pattern specimen with different hole area is described and a method is discussed for determining the friction-factor experimentally. Results show that the friction-factor of the round-hole pattern surfaces is bigger than that of smooth surface and increases as increasing the hole area. A empirical friction factor model for round-hole pattern surface is defined as the Moody's friction factor formula.

• The KSFM Journal of Fluid Machinery
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• v.6 no.3 s.20
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• pp.15-20
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• 2003

For measuring friction factor of artificially-roughened surfaces which are usually applied to damper seals, flat plate test apparatus is designed and fabricated. The measurements of leakage flow and pressure distribution through round-hole patterned specimen with different hole areas are described, and a method is discussed for determining the friction factor experimentally. Results show that the friction factor of the round-hole patterned surface is bigger than that of smooth surface, and increases as increasing the hole area. A empirical friction factor model for the round-hole patterned surface can be descrived by the Moody's friction factor formula.