Abstract
The influence of transverse leakage into a pressure-driven laminar flow in an infinitely long square duct is investigated. By a simple decomposition of the resulting three-dimensional pressure field, the leakage-induced secondary flow problem decouples from the primary flow problem. The numerical study reveals that two qualitatively different secondary flow patterns may occur, depending on the leakage flow rate. For a given streamwise pressure gradient it is observed that the axial mass flow rate may reduce by about 30 percent under certain leakage conditions, accompanied by a corresponding 50 percent increase in the Darcy-Weisbach friction factor.
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Abbreviations
- D :
-
duct height and width
- D h :
-
hydraulic diameter
- D i,j :
-
cell divergence
- F :
-
dimensionless pressure force
- h :
-
dimensionless slit height,H/D
- H :
-
slit height
- i,j :
-
indices
- K :
-
streamwise kinematic pressure gradient
- n :
-
summation index, time level
- p :
-
dimensionless pressure
- δp :
-
pressure increment
- P :
-
pressure
- \(\tilde P\) :
-
cross-sectional pressure variation
- q :
-
dimensionless volumetric axial flow rate
- Q :
-
leakage flow rate in m2/s
- Re:
-
leakage Reynolds number,U 0 D/v
- Re q :
-
primary flow Reynolds number
- δt :
-
time increment
- x, y :
-
dimensionless cross-sectional coordinates
- δx, δy :
-
cell widths
- X, Y :
-
cross-sectional coordinates
- z :
-
dimensionless axial coordinate
- Z :
-
axial coordinate
- u, v, w :
-
dimensionless velocity components
- U, V, W :
-
velocity components
- U 0 :
-
leakage velocity,Q/H
- V :
-
cross-sectional average velocity
- W 0 :
-
dummy velocity scale
- ρ :
-
density
- ν :
-
kinematic viscosity
- ω :
-
overrelaxation factor
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Andersson, H.I., Tiseth, K.L. Leakage effects in laminar duct flow: a numerical study. Appl. Sci. Res. 49, 117–134 (1992). https://doi.org/10.1007/BF02984173
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DOI: https://doi.org/10.1007/BF02984173