An experimental and theoretical analysis of convective reaction fronts in the chlorite tetrathionate (CT) reaction

The general objective of this research is the study the propagation of reaction fronts in moving fluids. We will conduct experiments in the chlorite tetrathionate (CT) equation in liquids confined in cylinders under different orientations with respect to the vertical direction. This reaction requires a combined analysis of thermal and compositional effects on the density gradient across the front. We will precisely locate the conditions where buoyancy forces can generate fluid motion. The propagation of the front will be tested under an external Poiseuille flow generated by injection pumps allowing control of the external flow rate. We will compare the experimental results with three-dimensional calculations in the correct cylindrical geometry. To this end, we will develop our own computational software based on mathematical algorithms that can be tailored to describe of this system in an efficient manner. In this work we will conduct the following theoretical and experimental research: 1) We will measure the speed of propagation and the shape of fronts in the CT reaction as they propagate inside vertical cylindrical tubes in the upward and downward direction, using tubes of different diameter. 2) We will conduct experiments the CT reaction for cylinders making an angle with the vertical direction. 3) We will develop a three-dimensional model in the cylindrical geometry coupling the eikonal equation with the Navier-Stokes equations, including density changes due to composition and temperature across the front. This will allow understanding of the transition to convection in CT reaction fronts as it relates to the experiments. 4) We will couple the nonlinear reaction-diffusion equation describing the CT reaction to the Navier-Stokes equation finding the changes in front and speed due to convection. 5) We will introduce an external fluid flow using injection pumps to understand the behavior of convective reaction fronts in a Poiseuille flow. The results will be compared with our theoretical calculations.

Experimental characterization of reaction fronts in the chlorite-tetrathionate (CT) reaction in aqueous solutions under different reactant concentration. Experimental observation of reaction fronts with convection in cylindrical tubes as a function of angle of inclination. Experimental measurements of front speeds under the action of an external Poiseuille flow. Theoretical modeling of the CT reaction front with density driven convection using an eikonal approximation. Reaction-diffusion model of the CT reaction front with convection due to thermal and concentration changes. Three-dimensional theory of the transition to convection for a CT reaction front in a cylinder. Theoretical description of the CT reaction fronts with convection in the presence of an external Poiseuille flow.

Investigacion basica

Disciplinario

Ciencias naturales - Otras ciencias naturales

PONTIFICIA UNIVERSIDAD CATÓLICA DEL PERÚ