Péclet Number

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Peclet number

[pə′klā ‚nəm·bər]
(chemical engineering)
Dimensionless group used to determine the chemical reaction similitude for the scale-up from pilot-plant data to commercial-sized units; incorporates heat capacity, density, fluid velocity, and other pertinent physical parameters.

Péclet Number


a dimensionless number that is a similarity criterion for processes of convective heat exchange; named after the French physicist J. C. Péclet (1793–1857). The Péclet number Pe = vl/a = Cpρvl/γ, where l is the characteristic linear dimension of the surface of heat exchange, v is the fluid velocity relative to the heat exchange surface, a is the thermal diffusivity, Cp is the specific heat at constant pressure, ρ is the density, and λ is the thermal conductivity of the fluid. The number Pe characterizes the relationship between the convective and molecular processes of heat exchange in the flowing fluid. The process of molecular conduction predominates at low Pe values, and the process of heat exchange by convection of the fluid predominates at high Pe values. The relation between the Péclet number, the Reynolds number Re, and the Prandtl number Pr is given by the equation Pe = Re × Pr.

References in periodicals archive ?
b] Particle porosity [xi] Dimensionless mass transfer constant h Step size for z and r K Mass transfer coefficient for Malathion K Step size for [tau] L Length of study area(cm) MW Molecular Weight (g/mol) n Dimensionless constant for Malathion Pe Peclet number Q Mobile phase volumetric flow rate (mL/min) [tau] Dimensionless time t Time (s) r Dimensionless particle radio R Radial coordinate (cm) v Interstitial velocity (cm/s) [V.
so, according to (25), the asymptotic behavior for large Peclet number within the grinding zone is
However, the relatively small Peclet numbers, <v>x/<D>-x/[lambda], are around one for x > 0.
The experimental data were used to calculate overall heat transfer coefficient, convective heat transfer coefficient, and Nusselt number of nanofluids with various particle volume concentrations and Peclet numbers.
These two assumptions are justified on the basis of the calculated particle Peclet number and particle density and size, respectively (see below):
Figure 7 suggests an inverse relationship between effective Peclet number, P, and [beta] for the results in Fig.
The above formulation identifies a non-dimensional group which may be termed as the Local Peclet number given by
Taking into account methodology of estimation using Peclet number [10, 11], one may state that in the process of nitrogen mass transfer in slag the share of molecular diffusion, in comparison with the convective one, is negligently small.
where Pe is Peclet number, v is dynamic viscosity, [[eta].
m], and the time scale of advection to l/U, the Peclet number also is accurately viewed as an index of diffusive to advective time scales.