From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Mathematical rules for the flow of liquids through pipes, orifices and jets.
| Identifier | ExFiles\Box 36\1\ scan 025 | |
| Date | 21th February 1917 | |
| To E.{Mr Elliott - Chief Engineer} from EFC. EFC4/T21217. 21st February 1917. X.2907 - FLOW OF LIQUIDS THROUGH ORIFICES, PIPES AND JETS OF VARIOUS SHAPES. In answer to your memo E2/B16217, I admit that my memo EFC5/T9217, was a little badly worded. What I really wished to know was your reasons for using the rule area^2/perimeter as applied to any case whatever, I do not know of, and cannot see any justification for this rule. I attach herewith two sheets on the "Flow of Liquids through Pipes" from which you will see that such flow varies as sqrt(area^3/perimeter) other things being the same, and since the flow through simple orifices, having no appreciable length in comparison with the diameter, varies as area, we should expect the flow through an outlet which is intermediate in form between a pipe and a simple orifice, to vary as some function of A and p intermediate between these two. Your rule, area^2/perimeter lies outside this range, but of course it is still true that if the delivery actually lies within my range, it also lies within yours. (In the case of an outlet of circular form my range would become d^(5/2) to d^2 and yours would be d^3 to d^2, d being the diameter). I have noted your suggestion of making experiments of such outlets with different values of the ratio length:diameter and may possibly do something in this way sometime soon. I think possibly I can find out for you how the law of variation depends upon the ratio length : diameter, by attacking this problem mathematically, but it will be necessary to know | ||