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Test results of friction factor for round-hole roughness surfaces in closely spaced channel flow of water

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Abstract

For examining friction-factor characteristics of round-hole pattern surfaces which are usually applied on damper seals, flat plate test apparatus is designed and fabricated. The measurement method of leakage and pressure distribution along round-hole pattern specimen with different hole area is described and a method for determining the Fanning friction factor is discussed. Results show that the round-hole pattern surfaces provide a much larger friction factor than smooth surface, and the friction factor vs. clearance behavior yields that the friction factor generally decreases as the clearance increases unlike the results of Nava’s flat plate test. As the hole depth is decreased, the friction factor is increased, and maximum friction factor is obtained for 50% of hole area. Since the present experimental friction factor results show coincident characteristics with Moody’s friction factor model, empirical friction factors for round-hole pattern surfaces are obtained by using the Moody’s formula based on curve-fit of the experimental data. Results of Villasmil’s 2D CFD simulation support the present experimental test result.

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Abbreviations

A:

Cross-sectional area (m2)

a, b, c:

Coefficients of Moody’ friction factor model in Eq. (2)

c1 :

Clearance of test section (m)

d:

Hole depth (m)

D:

Pipe diameter (m)

Dh :

Hydraulic diameter in Eq. (4) (m)

e:

Absolute roughness (m)

f:

Fanning friction factor in Eq. (7)

fB :

Blasius model of friction factor in Eq. (1)

fM :

Moody model of friction factor in Eq. (2)

hf :

Pressure loss due to friction effect in Eq. (3) (Pa)

1:

Total distance of ΔP (m)

ΔP:

Pressure drop (Pa)

Q:

Flow rate (m3/s)

Re:

Reynolds number in Eq. (6)

v:

Flow velocity in Eq. (5) (m/s)

w:

Width of test section (m)

:

(hole area/total area) x 100(%)

γ :

Fluid viscosity (N-s/m2)

ρ :

Fluid density (kg/m3)

φ :

Hole diameter (m)

References

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  1. Mechanical Engineering Department, Kyungwon University, 461-701, Sungnam, Korea

    Tae Woong Ha

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  1. Tae Woong Ha
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Correspondence to Tae Woong Ha.

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Ha, T.W. Test results of friction factor for round-hole roughness surfaces in closely spaced channel flow of water. KSME International Journal 18, 1849–1858 (2004). https://doi.org/10.1007/BF02984333

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  • DOI: https://doi.org/10.1007/BF02984333

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