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1

High flow, low shear impellers versus high shear impellers; dispersion of oil drops in water and other examples

Pacek Andrzej W., Nienow Alvin W.

Chemical and Process Engineering

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2021

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Vol. 42, nr 2

77–-90

EN

Flow patterns generated by two ChemShear impellers, CS 2 and CS 4 have been measured and flow numbers calculated; Fl = 0.04 for both impellers. Transient and equilibrium drop sizes, d32 μm of 3 different viscosity silicone oils agitated by a high-shear Rushton turbine, RT, a low-shear, high-flow HE3 impeller and the two ChemShears were determined. The equilibrium d32 are correlated for all impellers, by d32 = 1300(εT )−0.58 max.svv0.14 with an R2 = 0.94. However, the time to reach steady state and the equilibrium size at the same specific power do not match the above descriptors of each impeller’s characteristics. In other literature, these descriptors are also misleading. In the case of mixing time, a high shear RT of the same size as a high flow HE3 requires the same time at the same specific power in vessels of H/T = 1. In bioprocessing, where concern for damage to cells is always present, free suspension animal cell culture with high shear RTs and low-shear impellers is equally effective; and with mycelial fermentations, damage to mycelia is greater with low shear than high. The problems with these descriptors have been known for some time but mixer manufacturers and ill-informed users and researchers continue to employ them.

2

Application of turbiscan lab to study the effect of emulsifier content on the stability of plant origin dispersion

Zalewska Anna, Kowalik Joanna, Grubecki Ireneusz

Chemical and Process Engineering

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2019

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Vol. 40, nr 4

399-–409

EN

The effect of emulsifier volume on emulsion system stability of plant origin being the basis of diet supplements for animals in winter season was analyzed. For this purpose, measurements of the backscattered light intensity as the function of the measuring cell height were conducted with a Turbiscan LAB optical analyzer. System stability was analyzed on the basis of Turbiscan Stability Index values. A Helos laser analyzer and a Nikon Eclipse E400 POL optical microscope were used to investigate drop size distribution and analyze microscopic pictures. It was shown that emulsion with 10% (w/w) of the emulsifier was the most stable one.

3

Variability of the diesel fuel spray microstructure during the injection into stagnant air by a typical diesel engine injector

Krause P., Kidacki G., Klyus O.

Journal of Machine Construction and Maintenance - Problemy Eksploatacji

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2018

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no. 2

101--107

EN

The article presents the results of a study on the distribution of Sauter Mean Diameter (SMD) along the axis of an atomized diesel oil spray and changes in SMD occurring during the injection in selected cross-section of the spray. A piston fuel pump was used for atomization, while atomization quality measurements were made using a Malvern Spraytec particle analyzer. The results show that adopting averaged SMD values for the whole fuel spray charge does not reflect the actual range of droplet sizes in the area of highest volume concentration of droplets in a spray, i.e. the area having the greatest impact on the evaporation and combustion of fuel. It can be useful to designers of diesel engines and simulation of processes in combustion chamber.

PL

W artykule przedstawiono możliwości doboru średnic kropli rozpylonego paliwa do badań modelowych lub jako wartość wzorcową (reprezentatywną) dla strugi rozpylonego paliwa w komorze spalania silnika z zapłonem samoczynnym. Zamieszczono wyniki badań rozkładu średniej średnicy Sautera (SMD) wzdłuż osi strugi rozpylanego oleju napędowego oraz zmian SMD zachodzących w czasie wtrysku w wybranym przekroju strugi. Do rozpylania użyto tłokowej pompy paliwowej, a do pomiarów jakości rozpylania przyrządu Spraytec firmy Malvern. Przedstawione rezultaty wskazują, że przyjmowanie uśrednianych wartości SMD dla zakresu rozpylania całej dawki paliwa nie odzwierciedla rzeczywistego obrazu rozmiarów kropli w obszarze najwyższego stężenia objętościowego kropel w strudze, czyli mającego największy wpływ na proces odparowania i spalania paliwa.

4

Wytwarzanie emulsji wielokrotnej z zastosowaniem emulgatora naturalnego

Major-Godlewska M., Draus P.

Inżynieria i Aparatura Chemiczna

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2015

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Nr 6

336--337

PL

Badania miały na celu wytworzenie emulsji wielokrotnej z użyciem lecytyny sojowej jako emulgatora. Do wytworzenia emulsji wielokrotnej zastosowano mieszadło magnetyczne. Zdjęcia uzyskanej emulsji wykonywano za pomocą diagnostycznego mikroskopu odwróconego OPTATECH MW-100, z oprogramowaniem i kamerą cyfrową OPTATECH 5 MP. Na podstawie otrzymanych zdjęć, korzystając z oprogramowania OptaView, wyznaczono powierzchnie poszczególnych kropel emulsji i obliczono średnice zastępczych kropel.

EN

The aim of this study was to obtain experimentally multiple emulsion with soya lecithin as the emulsifier. A magnetic stirrer was used for the production of multiple emulsion. The pictures of emulsion were made using the diagnostic microscope OPTA-TECH MW-100 with software and digital camera OPTA-TECH. On the basis of obtained pictures, using the software OptaView, the surface areas of individual emulsion drops were determined and drop diameters were calculated.

5

Relationship between the dispersed droplet diameter and the mean power input for emulsification in several types of motionless mixers

Yamamoto T., Kawasaki H., Kumazawa H.

Environment Protection Engineering

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2010

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Vol. 36, nr 4

5-21

EN

Continuous emulsification of low-viscosity liquids was investigated with three different types of motionless mixers, i.e., Needle Jetting Mixer (NJM), Kenics Static Mixer ® (KSM) and Ramond Supermixer ® (RSM). Kerosene and n-heptane were used as the continuous phase, in which nonionic surfactant (Span80) was dissolved, and deionized water was the dispersed phase. The size distributions of water droplets in emulsions were normalized by the Sauter mean diameter (d32), and then they obeyed a log-normal distribution function with an upper-limit. The correlations of d32 with the mean power input per unit mass of the media within the region where the drop dispersion mainly occurred (PM) were derived. The PM levels of these motionless mixers were the same as these of agitation vessel. The slopes of the correlation lines on the log (d32) - log (PM) correlation chart took almost the same value of -0.4, which agreed with the value derived from isotropic turbulence law in low-viscosity liquids. As the line for RSM was located below those for NJM and KSM, RSM may be the most energy-efficient device of the three.