Countercurrent exchange

About: Countercurrent exchange is a research topic. Over the lifetime, 2255 publications have been published within this topic receiving 28687 citations. The topic is also known as: Countercurrent exchange.

Erratum to: Counterflow, crossflow and cocurrent flow heat transfer in heat exchangers: analytical solution based on transfer units

Abstract: By means of analysis equations for heat transfer performance based on number of heat transfer units were found, that allow to solve in a simple way single-pass and multipass heat exchanger problems when there are counterflow, crossflow and cocurrent modes of flow in any combination. There is no need to use external information such as the effectiveness concept or the correction factor F. The analysis gives new results which are at variance with traditional heat exchanger analysis when crossflow or cocurrent flow is involved.

A Novel Countercurrent Fixed Bed Reactor

Abstract: A new three-phase reactor configuration having countercurrent flow of gas and liquid is proposed. The reactor had an internal diameter of 0.04 m and a catalyst bed height of 1 m. A spiral coil made out of wire gauge was inserted inside the fixed bed of catalyst. The gas preferentially passed through the void spaces created due to the presence of the coil. Hydrodynamic studies were conducted using water as liquid and air as gas. The effect of various parameters such as the configuration of the spiral coil, flow rate of gas and liquid on the pressure drop and liquid hold up of the catalyst bed were studied and were also compared with that of a conventional trickle bed reactor.

Stability of steam-water countercurrent stratified flow

Abstract: Two flow instabilities which limit the normal condensation processes in countercurrent stratified steam-water flow have been identified experimentally: flooding and condensation-induced waterhammer. In order to initiate condensation-induced waterhammer in nearly horizontal or moderately-inclined steam/subcooled-water flow, two conditions, the appearance of a wavy interface and complete condensation of the incoming steam, are necessary. Analyses of these conditions are performed on a basis of flow stability and heat transfer considerations. Flooding data for several inclinations and channel heights are collected. Effects of condensation, inclination angle and channel height on the flooding characteristics are discussed. An envelope theory for the onset of flooding in inclined stratified flow is developed, which agrees well with the experimental data. Some empirical information on basic flow parameters, such as mean film thickness and interfacial friction factor required for this theory are measured. The previous viewpoints on flooding appear not to conflict with the present experimental data in nearly horizontal flow but the flooding phenomena in nearly vertical flow appear to be more complicated than those described by these viewpoints because of liquid droplet entrainment.