Experimental and theoretical study on the co-current two-phase downflow regime transition in open solid foam packed reactors

The main objective of this Diploma thesis was to determine the regime transition between trickling and pulsing flow for solid ceramic foams made of silicium carbid with extra silicium coating (SiSiC). Two pressure transducers were used in order to determine this transition. Additional to the experimental determination, a predictive model was developed after the idea of Grosser et al. (1988) as well as Attou and Ferschneider (2000). Therefore, bed specific parameters (specific surface area, pressure drop parameters, static liquid holdup, porosity of the bed) and fluid specific parameters (gas and liquid density and viscosity, surface tension) had to be known. Since these models were only validated for conventional FBRs with a packing of spheres, modifications have been carried out in order to fit the model to foam related parameters.
In order to describe the regime transition through the models, further experiments had been carried out. The static liquid holdup as well as the singe phase (gas phase) pressure drop were investigated and afterwards modeled though different approaches.
To obtain the influences of changing the surface tension as well as the viscosity on the regime transition, additional experiments with tergitol and glycerin were carried out.
Three different pore sizes (20 PPI, 30 PPI and 45PPI) as well as two different foam diameters (0.05m and 0.1 m) were investigated with two different spray systems. For the change of viscosity and surface tension, only foams with a diameter of 0.1m had been used.