Effect of geometric variations on pressure loss for a model bifurcation of the human lung airway

Characteristics of pressure loss (Delta P) in human lung airways were numerically investigated using a realistic model bifurcation. Flow equations were numerically solved for the steady inspiratory condition with the tube length, the branching angle and flow velocity being varied over a wide range. In general, the Delta P coefficient K showed a power-law dependence on Reynolds number (Re) and length-to-diameter ratio with a different exponent for Re >= 100 than for Re < 100. The effect of different branching angles on pressure loss was very weak in the smooth-branching airways. (C) 2011 Elsevier Ltd. All rights reserved.