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The accuracy of the final viscosity of the CS method needs a very accurate density prediction of the reference fluid. The molar volume of the reference fluid methane is therefore calculated by a special EOS, and the Benedict-Webb-Rubin (1940) [ 20 ] equation of state variant suggested by McCarty (1974), [ 21 ] and abbreviated BWRM, is ...
Physically, volume viscosity represents the irreversible resistance, over and above the reversible resistance caused by isentropic bulk modulus, to a compression or expansion of a fluid. [1] At the molecular level, it stems from the finite time required for energy injected in the system to be distributed among the rotational and vibrational ...
One of the key predictions of the theory is the following relationship between viscosity , thermal conductivity, and specific heat : k = f μ c v {\displaystyle k=f\mu c_{v}} where f {\displaystyle f} is a constant which in general depends on the details of intermolecular interactions, but for spherically symmetric molecules is very close to 2. ...
Dimensionless numbers (or characteristic numbers) have an important role in analyzing the behavior of fluids and their flow as well as in other transport phenomena. [1] They include the Reynolds and the Mach numbers, which describe as ratios the relative magnitude of fluid and physical system characteristics, such as density, viscosity, speed of sound, and flow speed.
Viscosity is a measure of a fluid's rate-dependent resistance to a change in shape or to movement of its neighboring portions relative to one another. [1] For liquids, it corresponds to the informal concept of thickness; for example, syrup has a higher viscosity than water. [2]
μ is the dynamic viscosity of the fluid (Pa·s = N·s/m 2 = kg/m·s) ρ is the density of the fluid (kg/m 3) Pe is the Peclet Number; Re is the Reynolds Number. The heat transfer analog of the Schmidt number is the Prandtl number (Pr). The ratio of thermal diffusivity to mass diffusivity is the Lewis number (Le).
is the bulk fluid density; is the boundary layer density = (), the temperature difference between boundary layer and bulk fluid. There are two different ways to find the Grashof number from this point.
The following table lists historical approximations to the Colebrook–White relation [23] for pressure-driven flow. Churchill equation [ 24 ] (1977) is the only equation that can be evaluated for very slow flow (Reynolds number < 1), but the Cheng (2008), [ 25 ] and Bellos et al. (2018) [ 8 ] equations also return an approximately correct ...