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Summary of the Liquid-Gas Ejector Hydraulic Behavior - Theory and Practice
Gebouský, Ondřej ; Haidl, Jan
Liquid-gas ejectors (LGEs) are fascinating devices that use the kinetic energy of the liquid jet to entrain and eventually compress the gas. LGEs find applications in both industry and everyday life, e.g., as sprayers. However, a complex and reliable method for LGE design was not available in the open literature until recently. This contribution follows up on our recent works about the hydraulic behavior of LGE with undisturbed and destabilized liquid jets. This paper aims to summarize the device’s complicated hydraulics and characterize its optimal design for three industrially relevant applications - (a) LGE as the vacuum pump, (b) LGE as the gas purification equipment, and (c) LGE as the gas distributor for bioreactors.
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Mixing characteristics of a magnetically driven Rushton turbine in an unbaffled stirred tank reactor
Idžakovičová, Kristýna ; Haidl, Jan ; Gebouský, Ondřej ; Isoz, Martin
The standard and well-researched stirred vessel configuration comprises a tank equipped with one or more impellers positioned in the vessel’s axis and multiple wall-mounted baffles preventing the central vortex creation. However, particular industries, such as biotechnology, have an increased need for a sterile environment that often results in the usage of atypical stirred vessel configurations. An example of a commonly equipped atypical stirred vessel is an unbaffled stirred tank with an eccentric magnetically driven impeller. However, there is only a little knowledge about the mixing characteristics of such designs. In this work, we list experimental results for both the standard and atypical stirred vessel configurations. Furthermore, we present a CFD model of the atypical configuration. The model is used to calculate its mixing characteristics that are subsequently compared against our experimental results. It is shown that for the liquid height (H) to the vessel diameter (T) ratio H/T ≲ 1.2, the characteristics of both the standard and atypical designs coincide. For higher liquid heights (i) the characteristics of the atypical design decrease dramatically, and (ii) the characteristics estimates based on approaches developed for the standard configuration become unreliable.
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Experimental validation of granular flow kinetic theory under turbulent flow conditions
Haidl, Jan ; Chára, Zdeněk ; Matoušek, Václav
The mixed classical and extended kinetic theory of granular ows is used for modeling the characteristics of particles-water turbulent sheet ow. The open-source solver sedFoam v3.1 is used for the 1-D and 2-D ow simulations. The simulation results are compared to the experimental data measured in the open channel. After that, the simulation parameters are optimized to achieve the best possible agreement between the simulation and the experimental results. The unsatisfactory performance of the KT models and the observed simulation instabilities are discussed.
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Increasing Ejector Efficiency via Diffuser Shape Optimization
Kubíčková, Lucie ; Isoz, Martin ; Haidl, Jan
An ejector is a technologically simple and yet wide-application fluid machine. While it has favorable characteristics for a signifficant number of technological processes, its main downside is probably its high operational energy demands. The present paper is an initial result of an ongoing research aimed at improving energy e ciency of the ejector via optimization of its geometry. In the paper, we focus mostly on presenting a general multi-objective optimization framework usable for an ejector shape optimization. The approach applicability is illustrated on a simpli ed problem comprising only a single phase flow in an ejector mixing tube and diffuser. Nevertheless, the achieved simulation and optimization results are validated against experimental data. The proposed optimization method itself is based on multi-objective evolutionary algorithms (MOEAs) combined with computational fluid dynamics (CFD) for evaluation of the vector-valued objective function.
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Chemicko-technologický audit ÚV Tlumačov - posouzení technologie tvorby a separace suspenze
Pivokonský, Martin ; Čermáková, Lenka ; Prokopová, Michaela ; Fialová, Kateřina ; Sochorová, H. ; Haidl, Jan
Předložená zpráva se zabývá posouzením technologie tvorby a separace suspenze na ÚV Tlumačov ve dvou měřících cyklech (léto 2020 a jaro 2021) v profilech: i) za aerací, ii) odtok z reakční nádrže, iii) za flokulací, iv) nátok do sedimentace, v) za sedimentací, vi) nátok na filtraci, vii) za filtrací, a to na pravé i levé lince ÚV Tlumačov. V rámci zprávy byly posouzeny kvalita surové a upravené vody a účinnosti destabilizace a agregace. Zhodnocena byla příprava suspenze ve fázi rychlého a pomalého míchaní a separace vloček. K posouzení uvedeného byly použity testy agregace (sedimentometrická analýza).
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