Hagenbach correction

In other types of apparatus the liquid does not flow from a tube into the air with a finite velocity but into a bulb filled with liquid. Its velocity is then practically zero and, according to Griineisen, i the Hagenbach correction should not then be applied, although most other experimenters think it... 

Batschinski, Z. phys, Chem, 1913, 84, 643 Dorsey, Phys, Rev, 1926, 28, 833 Jones and Fornwalt, J.A.C,S, 1938, 60, 1683. Stockl, in Landolt-Bornstein, Tabellen, 5th edit., 1923, 126, recalculated Thorpe and Rodger s results by omitting the Hagenbach correction, and says Thorpe was in agreement with this procedure. See Hatschek, The Viscosity of Liquids, 1928, 22. 

Ubbelohde, Handbuch der Chemie und Technologic der Oele, 1908, 1, 341 Zur Viskosimetrie, 2nd edit., Leipzig, 1936 Hatschek, The Viscosity of Liquids, 1928, 29 Fajans and Wust, Practical Physical Chemistry, 1930, 51 van der Wyk and Meyer, Chem, Weekbl, 1935,32,548 (no Hagenbach correction necessary accuracy 4x 10 ) Westphal, Z, techn, Phys, 1941, 22, 305. 

Critical shear rate of the onset of non-Newtonian flow behavior Maximum shear rate Hagenbach correction Dynamic viscosity... 

The actual correction found experimentally is k2V Qjn R rather than v Q l7fiR where k2 is a constant, nearly equal to unity, called the Hagenbach coefficient which depends on the form of the apparatus and must be determined by calibration in accurate, work. According to Boussinesqi its average value is M2. Poiseuille s formula (2) is thus modified to ( =1) ... 

There is a rather troublesome correction for surface tension, the theory of which is discussed by Jones and Fornwalt and by Barr." Variation in the Hagenbach coefficient 2 i ay occur if the direction of flow is reversed, and it must be determined for each rate of flow. Wetzstein found an apparent variation in viscosity with pressure, the observed being less than the calculated value at higher pressures, but reaching a limiting value at higher pressures, r)=ri +blp, where b is a constant. 

Hagen-Poiseuille law, 72 Hagenbach coefficient, 74 correction, 73, 75 hanging drop, 183, 189 level viscometer, 80 Hare s apparatus, 12 Harkins s equation, 155 heat capacity of electrolyte solution, 225 content of electrolyte and non-electrolyte solutions, 225-6 content of vapour, 348 Heilborn s specific heat formula, 218 Henning s latent heat formula, 307 Herwig s method for density of saturated vapour, 325... 

The viscosity of a 0.02% solution of polyethylene powder in decahydronapthalene was measured by means of an Ubbelohde capillaiy viscometer. The measurement yielded an average solution flow time of 124 seconds vs. 72.3 seconds for the pure solvent. A Hagenbach (k) correction factor of 2.02 seconds was previously determined for this particular viscometer. What is the nominal molecular weight of the polyethylene sample Would this polyethylene be classified as an UHMWPE ... 

The correction factor m can be determined by comparing measurements of capillaries with the same diameter but different lengths. Generally, the Hagenbach-Couette correction term comes in a table together with commercially available capillaries. 

The running times have to be corrected afterwards. For short running times this is to be done according to Hagenbach (see Capillary viscosimeter above). In practice, this is usually not done according to Eq. (3.6) though, but correction times are listed by the manufacturer for the particular capillary and have to be subtracted from the measured running times t ... 

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