Measurement of the densities of complex fluids: apparatus, validation, and results for water and for each of three complex mixtures (retrograde condensates)

(p,ρ,T) of liquidn-octane obtained with a spherical pycnometer at temperatures of 298.03 K and 313.15 K and pressures in the range 0.7 MPa to 32 MPa

“…The experimental procedures have been described in detail elsewhere, (1) and only the important differences from our earlier work are given here. The spherical pycnometer was constructed, by the National Engineering Laboratory, U.K., as two hemispheres from a single cylindrical bar of Inconel 625.…”

“…Figure 1 also shows the 100 cm 3 positive-displacement pump mounted inside the stirred fluid bath; we did this to reduce the effects of mercury migration discussed above and elsewhere. (1,2) The effective area of the positive displacement pump piston was determined by auxiliary experiments at a pressure of 13.789 MPa. The linear displacement l of the piston was obtained with a precision of 0.001·l, from a scale mounted on the pump.…”

“…Recently, (1,2) we published densities of five complex and compositionally characterized fluids obtained with a ''cylindrical'' pycnometer. Here we present measurements of mass density for n-octane obtained with a spherical pycnometer.…”

“…This geometry was chosen because we can, with linear thermal expansion and elastic constants of the cell wall material taken from the literature, more easily calculate the internal cell volume V c at a given temperature and pressure from one gravimetrically determined value of V c (T,p). In our previous work, (1,2) the mercury was expelled from a positive-displacement pump situated at ambient temperature into a cell located in a thermostat; the pycnometer and pump were separated by a valve. During these previous experiments the mass of mercury injected into the cell was compared with that determined gravimetrically and, usually, the value obtained by weighing was greater than that calculated from pump displacements.…”

Memorial Issue in Honor of Anthony R. H. Goodwin: Preface

“…The paper by Hellmann and Vogel on the viscosity of water vapor intersects Tony's interest in both the vibrating wire technique and his earlier studies at British Petroleum and NIST of the properties of water. 9,10 Accurate density measurements of complex fluids were an early quest of Tony's 9 which he revisited in later work on down-hole fluids. 11 The papers by Marsh and Brown on excess volumes of mixtures of n-alkanes by dilution dilatometry as well as the papers by Regueira et al on hexane + decane and + hexadecane and by Bi et al on the densities of various acetates are fitting extensions of that work, especially given the wide temperature and pressure ranges studied.…”