Smooth pipe frictional pressure loss

Following are some rules and equations for calculating friction pressure losses in pipes and ducts. Consider a Newtonian fluid of density p, flowing at the average velocity u into a smooth... 

Frictional Pressure Loss in Rough and Smooth Pipe... 

We also have the Fanning friction factor,/, which equals 2(j) and the Moody friction factor/, which equals 8(, just as we saw earlier when discussing frictional pressure loss in rough and smooth pipe for Newtonian fluids. 

The Beggs and Brill correlation significantly underpredicts pressure loss (34%) due to the assumption of smooth pipe friction factors. The smooth pipe friction factors in the original correlations were substituted with rough pipe friction factors to produce revised Beggs and Brill correlations. 

A large body of literature is available on estimating friction loss for laminar and turbulent flow of Newtonian and non-Newtonian fluids in smooth pipes. For laminar flow past solid boundaries, surface roughness has no effect (at least for certain degrees of roughness) on the friction pressure drop of either Newtonian or non-Newtonian fluids. In turbulent flow, however, die nature... 

Hydraulic Losses.—The hydraulic losses are the losses in pressure caused by the gas friction and by the sudden changes in the gas velocity or direction of flow. On the basis of D. W. Taylor s experiments on the flow of air in pipes, the pressure drop in the suction and in the discharge pipes (pounds per square inch) = L = lv s/4 00,-GOOD, where I is the length of pipe, feet, v the velocity of gas, feet per second, s the specific gravity of gas referred to free air (0.0764) as unity, and D the diameter of pipe, inches. For pipes of first-class workmanship and in very best condition, this loss may be reduced by about 20 per cent. The same care to have smooth pipe walls and to avoid too short bends should be taken with gases as with liquids. 

Design a positive pressure dilute-phase pneumatic transport system to carry 500 kg/h of a powder of particle density 1800 kg/m and mean particle size 150 pm across a horizontal distance of 100 m and a vertical distance of 20 m using ambient air. Assume that the pipe is smooth, that four 90° bends are required and that the allowable pressure loss is 0.7 bar. See below for Blasius correlation for the gas-wall friction factor for smooth pipes. 

Values of k and k for various polymer/tube systems are given in Table 5.10. (Values of k and ki can be determined for a given polymer solution from laboratory measurements of pressure drop in smooth tubes at two flow rates in the turbulent range.) These values can be used with the model to predict friction loss for that solution at any Reynolds number in any size pipe. If the Colebrook equation for smooth tubes is used, the appropriate generalized expression for the friction factor is... 

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