The homogeneous reaction takes place in bulk of the fluid, while heterogeneous reaction occurs on some catalytic surfaces.
The polythermal method is used in various experiments using different temperatures in both cold finger and bulk of the fluid.
Besides, the nanoparticles with dispersion effect and Brownian motion hit the tube wall and absorb heat, and then mix back with the bulk of the fluid to cause a better heat transfer.
The pressure volume temperature (PVT) relationship of CO2 microbubbles is of particular interest, due to the presence of gas in the form of microbubbles in the bulk of the fluid.
In the latter two cases, the bulk of the fluid spins with the outer sphere, while the volume of fluid inside the tangent cylinder spins under the influence of both the inner and outer spheres, and the velocity jump across the tangent cylinder is accomodated by a thin shear layer (Fig. 5 b).
Assuming that it takes at least a year for the bulk of the fluid to move from the surface to the 5-way, the high temperatures at the 5-way soon after high rainfall (without a significant pH change) could simply be attributed to recharge-driven movement of fluids from hotter regions of the system.
Also, as already mentioned, the main effects of nanoparticles inside the fluid considering the Brownian motion and fluctuation are the change in the flow structure of fluid to semi-turbulence regime, and flattening of the transverse temperature gradient in the bulk of the fluid [9], and hence enhancing convective heat transfer of the nanofluid.
In this regime (with the relative sizes of the spheres also possibly playing a role), the bulk of the fluid is at rest in an inertial frame, and thus while the flow can be strongly driven, the influence of rotation is small (see, e.g., Guervilly and Cardin 2010).
However, it can be concluded that when the photocatalytic reaction is not fast, employing catalyst loadings below 1 g L 1, irradiation rates at the reactor wall below 1×10−6 Einstein cm−2 s−1 and good mixing operation (Re>1700) it will be always safe to assume that mass transport limitations in the bulk of the fluid are nonexistent.
An efficient way to quench such an uncontrolled chemical reaction is via the injection of a liquid jet containing a small quantity of a very active inhibiting agent (often called a stopper) that must be mixed into the bulk of the fluid to quench the reaction.
