To monitor the gas and solid streams in a downcomer of a J-valve in a CFB, the simultaneous measurement technique using the oxygen gas tracer, the hot particle tracer and the pressure drop was developed. By using this novel measurement technique, the dependence of the solid flow on the gas flow in the moving bed in the downcomer of J-valve was investigated. The pressure profile and the pressure...

Detailed simulation of the thermal stresses of the reactor pressure vessel (RPV) wall in case of pressurized thermal shock (PTS) requires the simulation of the thermal mixing of cold high-pressure safety injection (HPI) water injected to the cold leg and flowing further to the downcomer. The simulation of the complex mixing phenomena including e.g. stratification in the cold leg and buoyancy dr...

An accurate description of the fluid flow and heat transfer within a Pressurized Water Reactor (PWR), for the safety analysis and reactor performance is always desirable. In this paper a mathematical model of the fundamental physical phenomena which are associated to a typical PWR is presented. The mathematical model governs the fluid dynamics in the reactor. Using commercial software CFX, a co...

A gas-liquid-solid inverse  uidization airlift bioreactor was proposed by combining advantages of external-loop airlift reactors and inverse  uidized beds. This airlift bioreactor comprises a gas-liquid riser, a gas separator, a liquid-solid inverse  uidized downcomer and a bottom connector. The effects of the gas velocity and the particle loading on the gas holdup in the riser and the liqui...

One of the OECD ROSA project tests, investigating temperature stratification in the cold legs and the downcomer during ECCS water injection under single-phase natural circulation conditions was analysed with the FLUENT code. The guidance given in the „Best Practice Guidelines for the Use of CFD in Nuclear Reactor Safety Applications” of the OECD GAMA group was followed. Steady-state calculation...

From a design and hydraulic standpoint, trays are relatively complex distillation internals. In the ongoing search for higher performance trays, one first must understand the hydraulic and mass transfer aspects of the tray operation such as entrainment, downcomer flooding, and vapor liquid contact. When this is well understood, then various aspects of the deck and/or downcomer designs can more ...

Efficiency data for MVG trays with truncated downcomers are presented for the first time. Various operating conditions including vacuum and high pressure are considered. While 7 bar and 11 bar data are very promising it has been possible to show that a uniform liquid flow pattern does indeed affect the efficiency at atmospheric pressure positively. A special downcomer outlet device has been dev...

Confined plunging jets are investigated as potential outfalls for the discharge of desalination brine. Compared to offshore submerged that rely on momentum induce mixing, released above water surface utilize both and negative buoyancy. Plunging also introduce air into column, which can reduce possibility hypoxic zones. In contrast unconfined jets, confined include a confining tube, or downcomer...

nowadays distillation is recognized as one of the economical and the most trustable separation methods in chemical, petroleum, gas and petrochemical industries. it is almost used as a first and the most applicable choice in separation methods. in this article the effect of inlet downcomer on the hydrodynamics of industrial sieve tray has been elaborated. the study was carried out by using a 3-d...