Pipe Flow Calculations Clarkson University（管流计算克拉克森大学）.pdf

Pipe Flow Calculations R. Shankar Subramanian Department of Chemical and Biomolecular Engineering Clarkson University We begin with some results that we shall use when making friction loss calculations for steady, fully developed, incompressible, Newtonian flow through a straight circular pipe. π 2 Volumetric flow rate Q D V where D is the pipe diameter, and V is the average velocity. 4  DV ρ DV 4Q 4m Reynolds Number: Re where ρ is the density of the µ ν π ν π µ D D fluid, µ is its dynamic viscosity, and ν µ/ ρ is the kinematic viscosity. The pressure drop ∆P is related to the loss in the Engineering Bernoulli Equation, or equivalently, the frictional head loss hf , through ∆P ρ=×loss γhf Here, the specific weight γ ρg , where g is the magnitude of the acceleration due to gravity. Power The power required to overcome friction is related to the pressure drop through Power =∆P Q or we can relate it to the head loss due to pipe friction via Power γ hf Q Head Loss/Pressure Drop The head loss hf is related to the Fanning friction factor f through 2   L V   hf 2 f    D g    L   2 or alternatively we can write the pressure drop as ∆P 2 f  (ρV ) D