Abstract
Inter-particle and particle-wall connectivity in suspension flow has profound effects on thermal and electrical conductivity. The spectral impulse generation and the imparting of kinetic energy on the particles is shown through a mathematical analysis to be effective as a means of achieving an approximate equivalent of a Langevin thermostat. However, with dilute suspensions, the quadratic form of the thermal pulse spectra is modified with a damping coefficient to achieve the desired Langevin value. With the dense suspension system, the relaxation time is calculated from the non-linear differential equation, and the fluid properties were supported by the viscosity coefficient. A “smoothed” pulse is used for each time-step of the flow simulation to take care of the near-neighbor interactions of the adjacent particles. An approximate optimal thermostat is achieved when the number of extra pulses introduced within each time step is found to be nearly equal to the co-ordination number of each particle within the assembly. Furthermore, the ratio of the particle kinetic energy and the thermal energy imparted is found to be never quite equal to unity, as they both depend upon the finite values of the pulse duration and the relaxation time.
Highlights
The shallow flows of nano-particles in planar conduits is a common feature of many industrial device applications, as well as being one of the primary generic routes used for transporting reagents and products to and from structured material surfaces as part of selective heterogeneous surface interactions, ranging from adsorptive separations to reaction catalysis; see for example (Pawar andLee, 2015) [1], (Merino-Garcia et al 2018) [2].The more efficient alignment of particle layers adjacent and in contact with a reactive surface, such as found in fuel cell, bio-catalysis and electrochemical surface coating applications, is profoundly important to the efficiency of the processes required to generate, store and release renewable energy, asAppl
Has investigated the effects of varying the direction of the acceleration due to gravity on colloidal suspensions from orthogonal to parallel to the fluid flow direction, and the resulting impact on Brownian motion and particle settling
(see Equation (9)), presented in the thermal pulse intensity spectra analysis presented nanoparticle above, gains further prominence by these results reported on the conductivity of Keblinksi et al (2005)
Summary
The more efficient alignment of particle layers adjacent to, and in contact with, a reactive surface, such as found in a fuel cell, bio-medical and electrochemical device, is often reliant upon the effective control of the dynamics of particle assembly in narrow conduits. One such control is possible by spectral thermal pulsing to generate a controlled Brownian motion of particles. This is demonstrated by numerical simulation here to be highly effective when particles are conveyed in viscous fluids close to a neutrally buoyant condition
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