INTRODUCTION AND USE OF THE ITEM This Item extends the application of the friction factor data in Item No. 66027 (Reference 2) to two cases of subsonic compressible flow. Whilst the flow of liquids may almost always be considered incompressible (and the friction losses therefore calculated as in Item No. 66027)@ the flow of gases may only be considered incompressible if the Mach number is low (M less than about 0.2) and if the pressure drop is also a small proportion of the initial static pressure (less than about 5 per cent) so that changes in density are small. Two methods of using this Item are presented. Firstly@ a hand calculation approach is considered using the graphs provided and Section 5 gives two worked examples using this method. Secondly@ Appendix B presents a Fortran 77 computer program designed to solve the full equations as derived in Appendix C. The same examples from Section 5@ along with an additional example to illustrate choking@ are then solved using these equations.
ESDU 74029 D-1993 history
1993ESDU 74029 D-1993 FRICTION LOSSES FOR FULLY-DEVELOPED FLOW IN STRAIGHT PIPES OF CONSTANT CROSS-SECTION - SUBSONIC COMPRESSIBLE FLOW OF GASES