A critical transition rule for broadening exponent of fluctuation and its effect on dissipation in chemical reaction-heat conduction coupling systems

A stochastic model of chemical reaction-heat conduction-diffusion for a one-dimensional gaseous system under Dirichlet or zero-fluxes boundary conditions is proposed in this paper. Based on this model,we extend the theory of the broadening exponent of critical fluctuations to cover the chemical reaction-heat conduction coupling systems as an asymptotic property of the corresponding Markovian master equation (ME),and establish a valid stochastic thermodynamics for such systems. As an illustration,the non-isothermal and inhomogeneous Schl-gl model is explicitly studied. Through an order analysis of the contributions from both the drift and diffusion to the evolution of the probability distribution in the corresponding Fokker-Planck equation(FPE) in the approach to bifurcation,we have identified the critical transition rule for the broadening exponent of the fluctuations due to the coupling between chemical reaction and heat conduction. It turns out that the dissipation induced by the critical fluctuations reaches a deterministic level,leading to a thermodynamic effect on the nonequilibrium physico-chemical processes.

Numerical study on heat and mass transfer mechanisms of Janus particle sedimentation considering corrosion

Janus particle is a research hotspot due to its novelty and settlement in acid liquid during wastewater treatment.Heat and mass transfer mechanisms of Janus particle sedimentation considering corrosion are numerically investigated based on immersed boundary lattice Boltzmann method.Chemical reaction heat ratio,Damkohler number,Peclet number,and particle number effects on temperature field,concentration field,Janus particle mass reduction,position,and velocity are investigated.The uniform particle has an equilibrium position of about 1/4 times the channel width for two corroded uniform particle settlement processes.The Janus particle horizontal position deviates from the uniform particle equilibrium position due to the force caused by nonuniform buoyancy and particle rotation.When the chemical reaction heat ratio is more than 1,the Janus particle horizontal position is closer to the channel centerline and has a positive deviation.However,the converse trend happens when the chemical reaction heat ratio is less than 1,and the Janus particle horizontal position has a negative deviation.The Janus particle horizontal position deviation magnitude increases with increasing Damkohler number and decreasing Peclet number.The horizontal position deviation phenomenon exists for the single corroded Janus particle and two corroded Janus particle settlement processes.