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Investigation of Pressure Drop Through Helical Coils


McElligott, Richard Hardy (1949) Investigation of Pressure Drop Through Helical Coils. Engineer's thesis, California Institute of Technology. doi:10.7907/0S5A-NH14.


This investigation was conducted to determine the character of the pressure drop through helically wound pipes by comparing the pressure drops of straight pipes and helically wound pipes of comparable relative roughness. The scope of the study was limited to Reynolds Numbers below 10[superscript 5] and to flow through 3/8 and 1/2 inch stainless steel tubing of circular cross section. It was further limited by the use of water as the only working fluid and by the fact that no control was established over the exact character of the surface roughness. The results show that the correction factor Hc' is rather insensitive to Reynold's number and that it has greater dependence upon roughness and less dependence upon curvature than was previously thought probable. In addition, it is shown that an empirical formula of the type Hc = 1 + K(r/D)[superscript a](D/Dh)[superscript b] where a >> b, is probably more realistic than the Ac = 1 + 3.5 D/Dh expressed in current literature. It is further shown that within the scope of this study, the relative roughness, r/D, as determined by the profilometer and the relative roughness ε/D as used by L. F. Moody correspond, and r/D may be used to determine a friction factor from the Moody curves.

Item Type:Thesis (Engineer's thesis)
Subject Keywords:Aeronautics
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Aeronautics
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Unknown, Unknown
Thesis Committee:
  • Unknown, Unknown
Defense Date:1 September 1948
Record Number:CaltechETD:etd-02132009-131121
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:631
Deposited By: Imported from ETD-db
Deposited On:19 Feb 2009
Last Modified:28 Mar 2023 22:04

Thesis Files

PDF (McElligott_rh_1949.pdf) - Final Version
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