Showing papers by "Sankaran Sundaresan published in 1988"

Onset of pulsing in two‐phase cocurrent downflow through a packed bed

Abstract: In cocurrent downflow of a gas and a liquid through a packed column, a transition from trickling flow to pulsing flow is observed as one increases the flow rates. A simple macroscopic model for the two-phase flow is analyzed to examine whether this regime transition should be viewed as the loss of stability of a steady state or the loss of existence of any solution for the steady-state equations of motion. The former appears to be a more reasonable interpretation and an explicit algebraic criterion for the onset of pulsing is presented.

Oxygen transfer between metals and oxygen-ion conducting supports

Abstract: The charge-transfer reactions in the three-phase interfacial region, between a platinum catalyst, an yttria-stabilized zirconia (YSZ) support, and the gas phase, were studied electrochemically during carbon monoxide oxidation. From electrochemical and reaction-rate measurements, it appeared that oxygen was being removed from the support by carbon monoxide adsorbed on the platinum, while being supplied to the support by atomic oxygen adsorbed on either the platinum or the YSZ. Highly disperse Pt/YSZ catalyst outperformed a Pt/Al2O3 catalyst, the rate difference being explained in terms of interfacial reactions. Even in the presence of species such as water and sulfur dioxide, catalysts with YSZ supports outperformed those with alumina supports.

Oxygen transfer between rhodium and an oxygen‐ion conducting support

Abstract: Etude comparative de l'activite catalytique d'un catalyseur rhodium sur support d'alumine et sur support de zircone stabilisee a l'Yttrium. Application a la conversion catalytique des echappements automobiles