Three-dimensional numerical analyses of flow and transport characteristics in two representative multichamber ozone contactor models with different chamber width were conducted using large eddy simulation LES . Both time-averaged and instantaneous flow patterns suggest that the flow is characterized by the occurrence of large turbulent structures leading to extensive short-circuiting between ch...

This paper performs calculations of the recirculation factor in simulations of a flameless combustion furnace with different percentages of oxygen in air (from 21% to 100% O2). Results are compared with Magnussen’s recirculation theory and show that when there are chemical reactions, the recirculation results are overpredicted. An alternative correlation to Magnussen’s theory is proposed, usefu...

A recirculation microbial desalination cell (rMDC) was designed and operated to allow recirculation of solutions between the anode and cathode chambers. This recirculation avoided pH imbalances that could inhibit bacterial metabolism. The maximum power density was 931±29mW/m(2) with a 50mM phosphate buffer solution (PBS) and 776±30mW/m(2) with 25mM PBS. These power densities were higher than th...

Perfusion systems have the possibility to be operated continuously for several months. It is important that the performance of the cell retention device does not limit the operation time of a perfusion process used in the production of active pharmaceutical ingredients. Therefore, the aim of this study was to investigate the reliability and long-term stability of an acoustic perfusion process u...

In the framework of chaotic scattering we analyze passive tracer transport in finite systems. In particular, we study models with open streamlines and a finite number of recirculation zones. In the nontrivial case with a small number of recirculation zones a description by means of asymptotic quantities (such as the eddy diffusivity) is not appropriate. The nonasymptotic properties of dispersio...

Liquid recirculation is a method of improving evaporator performance by supplying the evaporator with more liquid than is evaporated. The excess liquid, which is generally provided by means of an externally-driven, mechanical pump, eliminates dryout and increases overall heat transfer coefficient in the evaporator. Liquid recirculation is common in large-scale industrial refrigeration systems, ...

This paper introduces the concept of residence-time, from the Eulerian view point, in a rigorous manner. The equations for various ow regimes are derived and a numerical solver is introduced based on Lax-Wendroo integration. An implementation is discussed that allows the coupling of this solver to any explicit CFD code. Examples of this concept are shown for extracting recirculation regions by ...

Rats were subjected to severe incomplete cerebral ischemia followed by recirculation. The levels of several of the cyclooxygenase products of arachidonic acid were measured at 5 and 15 minutes of ischemia and at 30 minutes of recirculation following 15 minutes of ischemia, PGE2 accumulated during the first 5 min. of ischemia and its level declined at 15 min. and returned to control level at 30 ...