| Popis: |
The paper presents the results of a study to obtain information on hydrodynamic features of trays that are suitable for use in heat and mass transfer processes with waste liquids and gases. Two types of so-called pasets – varieties of baffle tray – were considered. The first of them was a structure consisting of a funnel and a smaller diameter cone installed above it. The second type was distinguished by an element located above the funnel, which consisted of two cones joined by their bases. Descriptions of the fluid flow over these contact elements under irrigation conditions without and with a gas supply are given. The data on the pressure drop on dry and irrigated trays are obtained, which are summarized in the form of appropriate equations. A comparison of the hydrodynamic characteristics between the two types of pasets, as well as with the dual-flow tray, showed that there are no significant differences between the pasets. At the same time, the first of them has a simpler design and requires less metal. The pressure drop on both types of pasets is 1.6–1.9 times greater than on a dual-flow tray. However, since the pasets contain two stages of contact, it can be assumed that they offer less resistance to the passage of gas. Their advantage over the dual-flow tray is also a more stable hydrodynamic regime. The cause for the instability of the dual-flow tray regime was shown to be the hysteresis of the pressure drop dependence on the gas velocity. |
