Flow simulations approach for flocculation tanks
Idžakovičová, Kristýna; Bílek, V.; Haidl, J.; Isoz, Martin; Pivokonský, M.
2024 - anglický Flocculation in water treatment facilities plays a key role in the separation of colloidal inorganic and organic substances. Its optimization leads to a significant increase in its efficiency and savings of operational costs. However, it is currently based on trial-and-error experimental approaches. In this contribution, we focus on flow modeling in stirred flocculation tanks that would, after coupling with a calibrated model of particle aggregation, enable simulationbased flocculation optimization. Despite the abundance of literature on stirred tank modeling, there is no universal agreement on the methodology used to describe turbulence nor on the approach to the computational mesh creation. Consequently, there is no unified methodology for simulations and their validation. To address this, we present a best-practice methodology for economical, yet reliable flow simulations in the said device. This methodology includes the choice of the turbulence model, the approach to the design of a high quality mesh suitable for arbitrary geometries, and results evaluation. It is developed based on an extensive literature review, a multitude of flow simulations using several meshes of progressively higher quality and resolution, and various strategies to converge to steady-state flow conditions. The simulation quality indicators used here involve comparison with the experimental data on fluid velocity, stirrer power output, and flow rate through the impeller zone. Additionally, the resulting flow simulation models are compared using tracer transport simulations, hinting at their potential for coupling with particle aggregation models. Klíčová slova: flocculation tank; stirring; MRF; CFD; OpenFOAM Plné texty jsou dostupné na jednotlivých ústavech Akademie věd ČR. Flow simulations approach for flocculation tanks

Flocculation in water treatment facilities plays a key role in the separation of colloidal inorganic and organic substances. Its optimization leads to a significant increase in its efficiency and ...

Idžakovičová, Kristýna; Bílek, V.; Haidl, J.; Isoz, Martin; Pivokonský, M.
Ústav termomechaniky, 2024

Improvement of an unbaffled stirred tank mixing characteristics using variable speed impeller
Gebouský, Ondřej; Haidl, Jan; Bodnár, J.; Pivokonský, Martin
2024 - anglický Unbaffled mixing tanks with magnetically driven impellers are increasingly used in biotechnological and pharmaceutical industries, combining the benefits of a closed, sterile environment with easy equipment cleanability. On the other hand, missing internals, such as baffles or cooling coils, have an adverse effect on the equipment mixing characteristics, namely the batch\nhomogenization time. In our previous research, we uncovered that the eccentricity and inclination of the impeller – both employed routinely to enhance the mixing characteristics of unbaffled vessels – are not fully effective in the suppression of central vortex formation resulting in the increase in the homogenization time. In this work, we propose a simple solution to counteract the central vortex formation – a periodical variation of impeller rotational speed. This approach destabilizes the central vortex, significantly reducing homogenization time while maintaining the benefits of the original unbaffled setup. This innovation can seamlessly integrate into existing industrial setups, promising efficiency gains for biotech and pharmaceutical production. Klíčová slova: unbaffled mixing tanks; variable rotational speed; vortex destabilization; mixing time improvement Plné texty jsou dostupné v digitálním repozitáři Akademie Věd. Improvement of an unbaffled stirred tank mixing characteristics using variable speed impeller

Unbaffled mixing tanks with magnetically driven impellers are increasingly used in biotechnological and pharmaceutical industries, combining the benefits of a closed, sterile environment with easy ...

Gebouský, Ondřej; Haidl, Jan; Bodnár, J.; Pivokonský, Martin
Ústav pro hydrodynamiku, 2024

A New Hollow Fiber-Based Liquid-Phase Microextraction Method for the Determination of Antihypertensive Drug Lercanidipine in Biological Samples
Labzova, O.; Hrdlička, Vojtěch; Navrátil, Tomáš; Šelešovská, R.
2024 - anglický A new hollow fiber-based liquid-phase microextraction (HF-LPME) method for the determination of antihypertensive drug lercandipine (LCN) in biological samples was developed. HF-LPME was\ncombined with optimized square wave voltammetry (SWV) on a cathodically pre-treated screenprinted boron-doped diamond electrode (SP-BDDE). Optimum HF-LPME conditions were:\nsupported liquid membrane (SLM) dodecane, 0.02 mol L-1 Britton-Robinson buffer (BRB, pH = 3) acceptor phase, BRB (pH = 7) donor phase, and time of extraction 30 min. Limits of quantification (LOQ) and detection (LOD) were 3.3 and 1.1 nmol L-1, respectively. The applicability of the developed method was verified on human urine, blood serum, and blood plasma with 20 and 100 nmol L-1 LCN addition. Klíčová slova: Lercanidipine hydrochloride; Hollow fiber liquid-phase microextraction; Screenprinted boron-doped diamond electrode Plné texty jsou dostupné na vyžádání prostřednictvím repozitáře Akademie věd. A New Hollow Fiber-Based Liquid-Phase Microextraction Method for the Determination of Antihypertensive Drug Lercanidipine in Biological Samples

A new hollow fiber-based liquid-phase microextraction (HF-LPME) method for the determination of antihypertensive drug lercandipine (LCN) in biological samples was developed. HF-LPME was\ncombined with ...

Labzova, O.; Hrdlička, Vojtěch; Navrátil, Tomáš; Šelešovská, R.
Ústav fyzikální chemie J. Heyrovského, 2024

The effect of trap type, season and baiting on the visitation of the trapping facility by black game
2024 - Klíčová slova: sus scrofa; prase divoké; odchyt; past; monitorování; vnadění; fotopast; les; poškození zvěře; hospodaření v lesích Plné texty jsou dostupné v knihovně ZČU. The effect of trap type, season and baiting on the visitation of the trapping facility by black game

Západočeská univerzita v Plzni, 2024

Paper foldink tasks – eye-tracking study
2024 - Klíčová slova: papírové skládanky; eye-tracking; manuální činnosti Plné texty jsou dostupné v knihovně ZČU. Paper foldink tasks – eye-tracking study

Západočeská univerzita v Plzni, 2024

School QR workshop
2024 - Klíčová slova: QR kód; webový návod; bezpečnost práce Plné texty jsou dostupné v knihovně ZČU. School QR workshop

Západočeská univerzita v Plzni, 2024

An outdoor game inspired by game shows and games from various corners of the world
2024 - Klíčová slova: terénní hra; herní show; zábava; učení hrou; kultura Plné texty jsou dostupné v knihovně ZČU. An outdoor game inspired by game shows and games from various corners of the world

Západočeská univerzita v Plzni, 2024

Stanovení ztratového součinitelé kónických redukcí ruzných rozměrů prostřednictvím numerických simulací
2024 - Klíčová slova: numerická simulace; redukce; ztrátový součinitel Plné texty jsou dostupné v knihovně ZČU. Stanovení ztratového součinitelé kónických redukcí ruzných rozměrů prostřednictvím numerických simulací

Západočeská univerzita v Plzni, 2024

Neautonomní dynamické systémy a jejich aplikace
2024 - Klíčová slova: dynamické systémy; neautonomní růstové modely; analýza Plné texty jsou dostupné v knihovně ZČU. Neautonomní dynamické systémy a jejich aplikace

Západočeská univerzita v Plzni, 2024

Komprese konektivity trojúhelníkovych sítí se známou geometrií s využitím neuronových sítí
2024 - Klíčová slova: neuronové sítě; geometrie; konektivita trojúhelníkové sítě Plné texty jsou dostupné v knihovně ZČU. Komprese konektivity trojúhelníkovych sítí se známou geometrií s využitím neuronových sítí

Západočeská univerzita v Plzni, 2024