VM122

VM122
Pressure Drop in a Turbulent Flowing Fluid

Overview

Reference:	R. C. Binder, Fluid Mechanics, 3rd Edition, 3rd Printing, Prentice-Hall, Inc., Englewood Cliffs, NJ, 1956, pg. 118, article 8-6.
Analysis Type(s):	Thermal (pressure) Analysis (ANTYPE = 0)
Element Type(s):	Coupled Thermal-Fluid Pipe Elements (FLUID116)
Input Listing:	vm122.dat

Test Case

Benzene at 50°F flows through a horizontal commercial steel pipe of diameter d, with an average velocity v. Determine the pressure drop, Δp, in a length of pipe. The pipe friction factor is f.

Figure 175: Turbulent Flowing Fluid Problem Sketch

Material Properties

Geometric Properties

f = 0.016

sp. gr. (specific gravity) = 0.9

= 200 ft = 2400 in

d = 6 in

v = 132 in/sec

Analysis Assumptions and Modeling Notes

The inlet flow rate w is input as a nodal quantity. The outlet pressure is defined to be zero for reference. An iterative solution is required to find the pressure drop. The following quantities are required for input and are calculated from the given data:

ρ = mass density	= sp. gr. x ρH₂0 = 0.9 x 62.4
	= /(386.4 x 12³) = 8.411 x 10^-5 lb_f-sec²/in⁴
w = mass flow rate	= ρvA = 8.411 x 10^-5 x 132 x π x 6 2/4
	= .3138 lb_f/sec/in

Results Comparison

	Target	Mechanical APDL	Ratio
Pressure Drop , psi	4.69	4.69[1]	1.00

Pressure drop Δp is given by PRES degree of freedom at node 1.