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Special Issue "Practical and Scientific Aspects of Multiphase Systems"

A special issue of Energies (ISSN 1996-1073). This special issue belongs to the section "J: Thermal Management".

Deadline for manuscript submissions: 1 May 2023 | Viewed by 3954

Special Issue Editors

Prof. Dr. Marek Ochowiak
E-Mail Website
Guest Editor
Department of Chemical Engineering and Equipment, Poznan University of Technology, 60-965 Poznan, Poland
Interests: multiphase flows; separation processes; atomization; sprays; mixing; chemical technology
Special Issues, Collections and Topics in MDPI journals
Dr. Szymon Woziwodzki
E-Mail Website
Guest Editor
Institute of Chemical Technology and Engineering, Poznan University of Technology, 60-965 Poznan, Poland
Interests: mixing; multiphase flows; process simulation; plant design; separation
Special Issues, Collections and Topics in MDPI journals
Dr. Sylwia Włodarczak
E-Mail Website
Guest Editor
Department of Chemical Engineering and Equipment, Poznan University of Technology, 60-965 Poznan, Poland
Interests: multiphase flows; atomization; sprays; mixing; rheology
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

A multiphase system is characterized by the simultaneous presence of several phases, the two-phase system being the simplest case. The term two-component is sometimes used to describe flows in which the phases comprise different chemical substances. The analysis of multiphase systems can include consideration of multi-compound materials, multiphase flow, and multiphase heat and mass transfer.

The present Special Issue of Energies, entitled “Practical and Scientific Aspects of Multiphase Systems”, invites contributions on multiphase flows, multi-component systems, and chemical reactors of both experimental and computational studies. The Issue is focused on recent advances in conjunction to various practical aspects of chemical engineering, especially those related to the process intensification, process design, practical applicability of rheology, control systems, process safety, plant design, chemical technology, environmental engineering, materials, etc. We welcome communications, original research articles and review articles.

Prof. Dr. Marek Ochowiak
Dr. Szymon Woziwodzki
Dr. Sylwia Włodarczak
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Energies is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2200 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Practical aspects of the study
  • Computational fluid dynamics
  • Multiphase systems
  • Multiphase flow
  • Rheology
  • Mixing
  • Sedimentation
  • Fluidization
  • Sprays
  • Heat and mass transfer
  • Plant design
  • Process simulation
  • Wastewater treatment
  • Environmental engineering
  • Chemical engineering
  • Mechanics
  • Energy

Published Papers (6 papers)

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Research

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Article
Design and Testing of Apparatus for Producing Dry Fog
Energies 2022, 15(24), 9296; https://doi.org/10.3390/en15249296 - 08 Dec 2022
Viewed by 280
Abstract
Dry fog is a specific form of aerosol that is used in many branches of industry and many aspects of everyday life. It can be used, inter alia, to disinfect rooms or to control the level of humidity. One of its greatest advantages [...] Read more.
Dry fog is a specific form of aerosol that is used in many branches of industry and many aspects of everyday life. It can be used, inter alia, to disinfect rooms or to control the level of humidity. One of its greatest advantages is undoubtedly its ability to work in the vicinity of electrical devices. Although the process of its formation and the very phenomenon of its occurrence are extremely simple things to describe, there are still many aspects that can be discovered, which are the focus of research by scientists around the world. One of the main parameters that influence the production process of dry fog is the pressure of the supplied gas, as well as the environmental conditions in which the aerosol is formed. This work focuses on the production of dry fog with the use of the designed and constructed apparatus, the structure of which is based on a jet nebulizer. The test and measurement stand is equipped with a compressor with a built-in pressure gauge for reading air pressure, a valve that allows the flow to be regulated, and an air supply and heating device that operates at various power values. The aim of this research was to check the impact of the power that is supplied to the system, as well as the impact of changing selected parameters such as gas pressure (which is one of the required media), on the liquid spraying process. The analysis of the results obtained during the experimental tests was based on the photographic method and allowed the mean Sauter volume–surface diameters of the obtained droplets to be compared. The analysis also showed that an increase in the power of the air supply and heating device translates directly into an increase in the ambient temperature in which the dry fog is formed, and contributes to the reduction of the diameter of the generated droplets. Changing the pressure of the atomized gas has a direct impact on the size of droplets in the generated aerosol—the higher the pressure, the smaller the droplets. Full article
(This article belongs to the Special Issue Practical and Scientific Aspects of Multiphase Systems)
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Article
Gas Hold-Up in Vessel with Dual Impellers and Different Baffles
Energies 2022, 15(22), 8685; https://doi.org/10.3390/en15228685 - 18 Nov 2022
Viewed by 334
Abstract
The influence of impellers system, baffles system and type of liquid on gas hold-up in a vessel has been presented in this paper. The analysis of gas hold-up was conducted on the basis of the data obtained in the vessel. The vessel used [...] Read more.
The influence of impellers system, baffles system and type of liquid on gas hold-up in a vessel has been presented in this paper. The analysis of gas hold-up was conducted on the basis of the data obtained in the vessel. The vessel used in the study was of inner diameter D = 0.288 m, and it was filled with liquid up to a height of H = 0.576 m. The vessel used in the study was equipped in four planar standard baffles or 24 vertical tubular baffles located on the circuit. A high-speed impellers system, consisting of two impellers located on the shaft, was used to agitate the liquid. The six gas–liquid systems were tested. The gas used in the study was air. The liquids were distilled water, aqueous solutions of NaCl (concentration c = 0.4 kmol/m3 or 0.8 kmol/m3), aqueous solution of sucrose (concentration c = 2.5% mass., 5% mass.), 5% mass. aqueous solution of sucrose and yeast suspension concentration ys = 1% mass. The obtained set of over 1600 experimental points allowed to derive the equations describing the effect of gas flow number Kg, Weber number We and parameter Y (for air–water and air–aqueous solution of NaCl) and Kg, We, c and ys (for air–water, air–aqueous solution of sucrose and air–yeast suspension–aqueous solution of sucrose) on gas hold-up. These equations do not have equivalents in the literature. Full article
(This article belongs to the Special Issue Practical and Scientific Aspects of Multiphase Systems)
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Article
Computational Fluid Dynamics of Influence of Process Parameters and the Geometry of Catalyst Wires on the Ammonia Oxidation Process and Degradation of the Catalyst Gauze
Energies 2022, 15(21), 8123; https://doi.org/10.3390/en15218123 - 31 Oct 2022
Viewed by 428
Abstract
The ammonia oxidation reaction on solid platinum–rhodium gauze is a critical step in nitric acid production. As the global demand for food and fertilisers keeps steadily growing, this remains an essential reaction in the chemical industry. However, harsh conditions inside ammonia burners lead [...] Read more.
The ammonia oxidation reaction on solid platinum–rhodium gauze is a critical step in nitric acid production. As the global demand for food and fertilisers keeps steadily growing, this remains an essential reaction in the chemical industry. However, harsh conditions inside ammonia burners lead to the degradation of catalytic meshes, severely hindering this process. This manuscript is focused on two issues. The first is the influence of catalyst gauze geometry and process parameters on the efficiency of ammonia oxidation on platinum–rhodium gauze. The second investigated problem is the influence of geometry on catalyst fibre degradation and the movement and deposition of entrained platinum particles. Computational Fluid Dynamics was utilised in this work for calculations. Different catalyst gauze geometries were chosen to examine the relationship between wire geometry and heat and mass transfer by analysing temperature and flow fields. Significantly, the analysis of the temperature gradient on the catalyst surface allowed us to estimate the spots of highest wire degradation and to track lifted platinum particles. The Discrete Phase Model was used to calculate entrained platinum particle trajectories and their deposition’s localisation and efficiency. Full article
(This article belongs to the Special Issue Practical and Scientific Aspects of Multiphase Systems)
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Article
The Fouling Effect on Commercial Ceramic Membranes during Filtration of Microalgae Chlorella vulgaris and Monoraphidium contortum
Energies 2022, 15(10), 3745; https://doi.org/10.3390/en15103745 - 19 May 2022
Viewed by 684
Abstract
Although interest in the use of membranes for the concentration of microalgal biomass has steadily been growing, little is known regarding the phenomena of membrane fouling. In addition, more attention has been given to polymeric membranes compared to ceramic membranes, which have a [...] Read more.
Although interest in the use of membranes for the concentration of microalgal biomass has steadily been growing, little is known regarding the phenomena of membrane fouling. In addition, more attention has been given to polymeric membranes compared to ceramic membranes, which have a longer life that is associated with a higher resistance to aggressive chemical cleaning. In this study, microfiltration (MF) and ultrafiltration (UF) of two microalgae species, Chlorella vulgaris and Monoraphidium contortum, were carried out using tubular crossflow ceramic membranes. Permeate flux was measured, resistance was calculated, and dissolved organic carbon (DOC) was determined. The flux reduction during the first 10 min of filtration was higher for MF than UF (>70% and <50%), and steady-state permeate fluxes were <5% (for MF) and <25% (for UF) of initial (in m3 m−2 s−1) 6.2 × 10−4 (for MF) and 1.7 × 10−4 (for UF). Total resistances (in m−1) were in the ranges of 4.2–5.4 × 1012 (UF) and 2.6–3.1 × 1012 (MF) for M. contortum and C. vulgaris, respectively. DOC reduction was higher for UF membrane (>80%) than for MF (<66%) and DOC concentrations (mg C L−1) in permeates following MF and UF were about five and two, respectively. In conclusion, we demonstrated: (i) higher irreversible resistance for UF and reversible resistance for MF; (ii) permeate flux higher for UF and for M. contortum; (iii) the significant role of dissolved organic compounds in the formation of reversible resistance for MF and irreversible resistance for UF. Full article
(This article belongs to the Special Issue Practical and Scientific Aspects of Multiphase Systems)
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Article
Effect of Adding Surfactants to a Solution of Fertilizer on the Granulation Process
Energies 2021, 14(22), 7557; https://doi.org/10.3390/en14227557 - 12 Nov 2021
Viewed by 1008
Abstract
Granulated chelates are innovative fertilizers that are highly effective and versatile, and they ensure the best start-up effect for plants. The final properties of granules are influenced by the method of their preparation and the used substances. The diameters of the obtained granules, [...] Read more.
Granulated chelates are innovative fertilizers that are highly effective and versatile, and they ensure the best start-up effect for plants. The final properties of granules are influenced by the method of their preparation and the used substances. The diameters of the obtained granules, their size range, and the final costs of the produced fertilizer are of great importance. The paper describes granules that were produced using an agglomeration of ZnIDHA in a fluidized bed with the aid of an aqueous solution of this substance with a high dry matter content. The aim of the study was to evaluate the effect of surfactant addition to the solution on the evolution of granule size distribution during the process carried out in a batch mode and to access the possibility of describing the process dynamics using population balance approach. A sieve analysis was performed in order to determine the size of the granulate, and numerical calculations were performed to determine the value of the constant aggregation rate. Based on experimental studies, it can be seen that the increase in the diameters of granules is mainly caused by the agglomeration process, and to a lesser extent by the coating process. The addition of surfactant increased the median size of the granules in the initial granulation stage, and also lowered the surface tension. This in turn enables a lower spraying pressure to be used. A comparison of different aggregation kernels constituting an integral part of the population balance model proved that the physically motivated equipartition kinetic energy kernel performs best in this case. Moreover, the computational results show an increase in the aggregation rate when the surfactant additive is used and confirm that population balance allows the extraction of physical information about the granulation. Full article
(This article belongs to the Special Issue Practical and Scientific Aspects of Multiphase Systems)
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Review

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Review
The D2-Law of Droplet Evaporation When Calculating the Droplet Evaporation Process of Liquid Containing Solid State Catalyst Particles
Energies 2022, 15(20), 7642; https://doi.org/10.3390/en15207642 - 16 Oct 2022
Cited by 1 | Viewed by 424
Abstract
The review presents the D2-law of droplet evaporation, which is used to describe the spraying process involving the evaporation of droplets. This law, the subject of numerous publications, can be successfully applied to describe the droplet evaporation process under various conditions, [...] Read more.
The review presents the D2-law of droplet evaporation, which is used to describe the spraying process involving the evaporation of droplets. This law, the subject of numerous publications, can be successfully applied to describe the droplet evaporation process under various conditions, including the calculations of the process of feeding the boiler with a liquid that contains catalyst particles. To date, not a lot of work has been devoted to this issue. The paper is a continuation of previous research concerning the spraying of liquids with a catalyst, which improves the efficiency of the process. The conducted analysis showed that the experimental data from previously published work are very compatible with the data obtained from the D2-law of droplet evaporation. At the standard speed of about 20 m/s of an aerosol flowing through a dust duct, droplets in the stream should be observed up to a distance of 1 m from the outlet of the apparatus supplying the system. Under such flow conditions, a droplet’s lifetime must be above 0.05 s. The dependence between a droplet’s lifetime and its diameter and temperature was determined. The obtained results confirmed that the effective droplet diameter is above 30 µm. Such droplets must be generated and then fed to the boiler for the catalyst to work properly. This law is an engineering approach to the problem, which uses relatively simple model equations in order to determine the evaporation time of a droplet. Full article
(This article belongs to the Special Issue Practical and Scientific Aspects of Multiphase Systems)
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