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1

Modelling the Heat and Mass Transfer in Devices with Dense-Layer Dispersed Systems

Krenický Tibor, Dyadyura Kostiantyn, Kokhan Olexandr, Umynskyi Serhii

Management Systems in Production Engineering

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2025

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nr 4 (33)

470--477

EN

The work is devoted to the processes of heat and mass transfer in moving and stationary dense layers of dispersed materials. One and two-component models of heat and mass transfer in a layer with internal heat sources caused by chemical and phase transformations in the presence of submerged heat exchange processes are given. A review of the literature showed that for a layer containing heat sources, not only information on these parameters is missing, but also methods for their determination. This paper describes the theoretical basis that forms the analytical dependencies of such methods. Satisfactory qualitative and quantitative agreement between experimental and calculated data indicates that the models accurately describe the main patterns of heat transfer in a blown layer with submerged heat transfer surfaces. The research results showed that when calculating temperature fields, reliable information is needed on the heat transfer coefficients of the layer and its components.

2

Airlift bioreactor under bio-consumption environment: Mass transfer study of metabolic gases

Kadhim Ghasaq H. Abdul, Al-Mashhadani Mahmood K. H.

Journal of Ecological Engineering

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2025

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Vol. 26, nr 1

260--272

EN

The current study focused on tracking the biogas pathways in the internal loop airlift bioreactor under conditions of metabolic consumption. The focus of the investigation was simultaneously set on the wastewater produced by the dairy industry. Two stages were used to conduct this investigation. Using the Taguchi model, an optimization study of the bioreactor's operating conditions was conducted as the first step. The experimental findings demonstrated a distinct impact of the biogas flow rate on the overall mass transfer coefficient compared with the other operating parameters (liquid type and volume). By analyzing the S/N ratio and ANOVA analysis, the best level was determined for each parameter studied. The optimal factors were also identified (flow rate = 50, volume = 5.5, type of sol.= whey). These optimization values were then applied in real bacteria bio-consumption. The biogas consumed by the organism was also reduced from 50 to 25 liters/hour, thus saving 50 % of the energy consumed.

3

Considering uncertain quantities in the model of cryopreservation process of biological samples

Skorupa Anna, Piasecka-Belkhayat Alicja

Acta of Bioengineering and Biomechanics

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2025

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Vol. 27, no. 1

47--56

EN

This paper presents numerical modelling of the heat and mass transfer process in a cryopreserved biological sample. The simula-tion of the cooling process was carried out according to the liquidus-tracking (LT) protocol developed by Pegg et al., including eight stages in which both the bath solution concentration and temperature are controlled to prevent the formation of ice crystals. Methods: To determine the temperature distribution during cryopreservation processes, one uses the Fourier equation, while mass transfer was taken into account using an equation based on the Fick’s laws. This paper considers a model assuming fuzzy thermophysical parameters described by a triangu-lar and a Gaussian membership function. The numerical problem was solved using the finite difference method including fuzzy set theory. Results: The diagrams of temperature and mass distributions as a function on time and the distribution of the fuzzy variable at a given moment in time were prepared. Moreover, the fuzzy temperatures and concentrations were compared with experimental results from the literature in table. Conclusions: In the conclusions, two different types of membership functions were compared with each other, with which the fuzzy variables were described. It can be said that the Gaussian membership function works well for experimental data where the mean and standard deviation are known. In addition, the obtained results were confronted with experimental data. The calculated fuzzy temperatures are consistent with the temperature values occurring in the LT protocol. Larger differences between the experimental data and the calculated values are observed for the fuzzy dimethyl sulfoxide (DMSO) concentration.

4

Influence of wall temperature on condensation rate in duct flow of humid air : a comprehensive computational study

Bobrowski Jakub, Gutkowski Artur

Archives of Thermodynamics

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2024

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Vol. 45, no. 3

127--133

EN

In engineering phase-change phenomena are found in a multitude of applications, ranging from refrigeration and air conditioning to steam turbines and petroleum refining. This study investigates the flow of moist air in a circular duct where water vapour condenses in contact with the cold wall of the duct. The investigation delves into the relationship between the condensation mass transfer rate, the heat transfer between the bulk flow and the wall, and the temperature of the wall. The volume of fluid model coupled with the Lee evaporation-condensation model was employed. Five simulations were carried out, involving different wall temperatures while maintaining the same inlet conditions. Condensation was more pronounced at lower wall temperatures, which aligns with the expectations. The heat transfer between the bulk flow and the wall decreased with the decreasing temperature difference. Interestingly, the findings revealed that the surface heat transfer coefficient increased as the wall temperature approached the temperature of the bulk flow. The success of the study suggests potential applications in optimising thermal management systems, with implications for industries where accurate predictions of moisture behaviour and heat transfer are crucial.

5

CFD analysis of the effect of bed geometry on H2O adsorption and desorption efficiency

Janusz Szymon, Borcuch Marcin, Cyklis Piotr

Archives of Thermodynamics

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2024

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Vol. 45, no. 3

39--47

EN

The article presents a comprehensive computational fluid dynamics analysis of the adsorption and desorption cycles in adsorption refrigeration systems, focusing on the impact of the adsorbent bed geometry. The entire adsorption/desorption cycle has been modeled, allowing for the observation of events during the transitional period between processes and how these influence their progression. This approach is a novelty in the field. The developed numerical model was verified against experimental data available in the literature, demonstrating excellent convergence with the experiment, with a deviation not exceeding 2%. The study illustrates how the geometrical parameters such as height and length of the bed affect the efficiency of the adsorption and desorption processes, emphasizing the importance of bed geometry in the adsorption of heat and mass exchangers in energy and adsorbate transfer. The research findings provide valuable insights for designing more efficient cooling devices using adsorption technology, highlighting the role of bed geometry in optimizing these systems. Modeling the entire adsorption/desorption cycle is a novelty and allows for the observation of what happens during the transitional period between processes and how this influences their progression.

6

Analysis of unsteady heat and mass transfer in rotating MHD convection flow over a porous vertical plate

Narmatha Mohanasundaram, Kavitha R.

Archives of Thermodynamics

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2024

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Vol. 45, no. 4

179--187

EN

The aim of this research paper is to investigate the rotational flow of an unsteady magnetohydrodynamic heat and mass transfer flow due to convection over a vertical porous semi-infinite plate. The plate undergoes continuous circular motion, maintaining a constant velocity. To achieve this, we worked on both numerical methods and analytical techniques, particularly utilizing perturbation methods to solve the governing partial differential equations. Consequently, we derive an expression for the Nusselt and Sherwood numbers. We delve into the analysis of the velocity profile, temperature distribution, and concentration variation, exploring their behaviour under different physical parameters, including the magnetic field parameter, Grashof num-ber, Soret number and Schmidt number, as well as the Prandtl number. Our findings reveal that the velocity increases with rising values of Grashof, modified Grashof and Soret numbers, whereas it decreases with declining values of the magnetic field parameter, Prandtl number and Schmidt number. Additionally, as rotation gradually intensifies, the fluid velocity closely follows the boundary and becomes negligible as it moves away from it. To facilitate a comprehensive examination of the fluid flow and heat and mass transfer characteristics, we employ graphical representations. Furthermore, this paper offers an in-depth discussion of the underlying physical aspects and their implications.

7

Mathematical analysis of chemically reacting species and radiation effects on mhd free convective flow through a rotating porous medium

Sharma Pawan Kumar, Sharma Bhupendra Kumar, Kumar Anil

Acta Mechanica et Automatica

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2024

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Vol. 18, no. 2

193--203

EN

The present study deals with the effects of radiation and mass transfer on a laminar unsteady free convective flow of a viscous, incompressible, electrically conducting and chemically reacting fluid past a vertical surface in a rotating porous medium. It is assumed that the surface is rotating with angular velocity . The governing mathematical equations are developed and solved by adopting complex variable notations and the analytical expressions for velocity, temperature and concentration fields are obtained. The effects of various parameters on mean primary velocity, mean secondary velocity, mean temperature, mean concentration, transient primary velocity, transient secondary velocity, transient temperature and transient concentration have been discussed and shown graphically. Further, the consequences of different parameters on rate of heat transfer coefficient (Nusselt number), rate of mass transfer coefficient (Sherwood number) and drag coefficient (mean skin-friction) are analysed. It is observed that the mean and transient primary velocities increase with the radiation parameter E, while reverse phenomena are observed for the Schmidt number, Sc, and the chemical reaction parameter, . The results may be useful in studying oil or gas and water movement through an oil or gas field reservoir, underground water migration, and the filtration and water purification processes.

8

Determination of the Specific Heat Flux During Boiling of the Dispersed Phase of the Emulsion

Pavlenkо Anatoliy, Koshlak Hanna, Basok Borys, Hrabova Tatiana

Rocznik Ochrona Środowiska

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2023

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Tom 25

16--24

EN

The intensity of heat exchange between the boiling emulsion and the enclosing surfaces is associated with the physical phenomena of the formation, growth, and destruction of vapour bubbles of the low-boiling component in the liquid phase. This article presents a methodology to assess the intensity of heat exchange processes. Using this technique, it is possible to predict the energy parameters of heat exchange equipment and the degree of intensification of heat transfer processes.

9

Verification of Dead Zones Generated in Bioreactors as a Proactive Stage in Bioreactor Design

Al-Mashhadani Mahmood K. H.

Journal of Ecological Engineering

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2023

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Vol. 24, nr 6

65--74

EN

The activity and growth of microorganisms for renewable energy production are still influenced by the dead zones created in bioreactors. These areas form a nutrient and thermal gradient, causing an abundance of food in certain areas compared to famines in other areas of same bioreactor. The current study is a step in identifying those dead zones, followed by another step in improving the flow of media inside the reactor. The results indicated that the inner parts of the bioreactor may be a crucial factor in the creation and spread of such dead zones. For example, the position of the disc-type diffuser contributes to the generation of those areas at the bottom of the reactor. It was inferred from the fluid movement in reactors using the annular-type diffuser proposed in the current study. The bubble size, gas mass flux, and radiuses of fillet, as the most important factors, were examined in both bioreactors. The results revealed a noticeable improvement in these parameters in this area of the reactor when the disc diffuser was replaced by the annular diffuser. For example, the average liquid velocity was recorded in the lower part of the modernized reactor at 0.0198 m/s, while the velocity was recorded in the conventional reactor at 0.00077 m/s under same bubbles diameter used in both reactors (0.125 mm). The inclusion of the effect of the presence of microorganisms in mathematical models was also addressed in the current study. The results showed that the amount of oxygen remaining at the bottom of the reactor after bio-consumption in the presence of the annular diffuser was higher than that in the conventional reactor. This clearly emphasizes the importance of the design of the internal parts of the bioreactor.

10

Impacts of chemical reactions on inclined isothermal vertical plate

Sundar Raj M., Nagarajan G., Murugan V. P., Muthucumaraswamy R.

International Journal of Applied Mechanics and Engineering

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2023

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Vol. 28, no. 2

64--76

EN

An accurate parameterization of an irregular surge across a continuously propelled circulation through an endless isothermal inclined plate has been investigated in the presence of a first-degree uniform chemical reaction. Both the plate’s temperature and the proximal intensity are increased systematically. To evaluate non-dimensional equations, the Laplace transform is utilized. The effect of velocity components on a range of physical parameters is investigated which include Sc, Pr, Gr, Gc, α, K and t. A proportionate increase of velocity with Gr and Gc was prominent. τ and Sh were mathematically determined.

11

Investigations of mass transfer in simulated biomedical systems

Adach-Maciejewska Anna, Kopka Klaudia

Chemical and Process Engineering : New Frontiers

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2023

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Vol. 44, nr 4

art. no. e46

EN

The work motivation was to investigate in vitro system simulating drug release from Drug Eluting Stent (DES). The experiments were conducted in a custom designed unit simulating drug release from polymer covering DES in a simplified way. The active substance diffuses from a thin, internal annular layer of hydrogel (imitating “stent”) to the outer cylindrical layer of hydrogel (“artery wall”) and is at once drifted away by coaxially flowing solution (“blood”). The conducted research proved functionality of the experimental unit. The rate of mass transfer depends considerably on the mass driving force and on the affinity of substance-hydrogel. The volumetric flow rate and liquid viscosity did not affect the process significantly. The effective diffusion coefficient was calculated as a process parameter and then used in the other variants. Diffusion in hydrogel is the mechanism limiting the mass transfer in the examined system. For the first attempt, the diffusive model used in literature was employed. The provided calculations are consistent with experimental data and therefore show that despite its simplifications the model allows to estimate the amount of released substance. In conclusion, the relative substance mass, changing over time, was estimated in the respective parts of the unit. The prospect of determining the relative mass of the substance appearing in the subsequent parts of the system over time provides the opportunity to adjust the respective process parameters, which will facilitate control over the rate of mass release.

12

Analysis of heat and mass transfer in an adsorption bed using CFD methods

Janusz Szymon, Szudarek Maciej, Rudniak Leszek, Borcuch Marcin

Archives of Thermodynamics

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2023

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Vol. 44, no. 2

177--194

EN

The trend of reducing electricity consumption and environmental protection has contributed to the development of refrigeration technologies based on the thermal effect of adsorption. This article proposes a methodology for conducting numerical simulations of the adsorption and desorption processes. Experimental data available in the literature were used as guidelines for building and verifying the model, and the calculations were carried out using commercial computational fluid dynamics software. The simulation results determined the amount of water vapor absorbed by the adsorbent bed and the heat generated during the adsorption process. Throughout the adsorption process, the inlet water vapor velocity, temperature, and pressure in the adsorbent bed were monitored and recorded. The results obtained were consistent with the theory in the literature and will serve as the basis for further, independent experimental studies. The validated model allowed for the analysis of the effect of cooling water temperature on the sorption capacity of the material and the effect of heating water temperature on bed regeneration. The proposed approach can be useful in analyzing adsorption processes in refrigeration applications and designing heat and mass exchangers used in adsorption systems.

13

Thermal and physical properties and heat-mass transfer processes of drying pumpkin seeds

Paziuk Vadim, Snezhkin Yurii, Dmytrenko Natalia, Ivanov Sergiu, Tokarchuk Oleksiy, Kupchuk Ihor

Przegląd Elektrotechniczny

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2022

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R. 98, nr 7

154--157

EN

We have investigated pumpkin seed heat capacity influenced by the two factors of the heat agent temperature and the moisture content of the material. The difference between the heat of evaporation when drying pumpkin seeds in a differentiated microcalorimeter DMKI 01 from the tabular value is 6%. Increasing the temperature of the heat agent from 40 to 60°C reduces the drying process by 8 times, but the most appropriate is the drying mode at 40°C, under which the germination of pumpkin seeds is 98%. The study of heat and mass transfer during drying shows that active heat up process takes place at the beginning, then there is an intensive moisture evaporation from the material as evidenced by the value of the Rehbinder test, which is close to zero.

PL

Badano pojemność cieplną pestek dyni, na którą wpływają dwa czynniki: temperatura czynnika grzewczego oraz wilgotność materiału. Różnica pomiędzy ciepłem parowania podczas suszenia pestek dyni w zróżnicowanym mikrokalorymetrze DMKI 01 od wartości tabelarycznej wynosi 6%. Podwyższenie temperatury czynnika grzewczego z 40 do 60°C skraca proces suszenia 8-krotnie, ale najbardziej odpowiedni jest tryb suszenia w 40°C, w którym kiełkowanie pestek dyni wynosi 98%. Z badań wymiany ciepła i masy podczas suszenia wynika, że na początku zachodzi proces aktywne(go nagrzewania, następnie następuje intensywne odparowywanie wilgoci z materiału, o czym świadczy bliska zeru wartość testu Rehbindera.

14

Mathematical analysis of mass and heat transfer through arterial stenosis

Hussain Azad, Sarwar Luba, Akbar Sobia, Malik M. Y.

Journal of Power Technologies

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2022

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Vol. 102, nr 3

88--95

EN

The article investigates the steady state flow of an incompressible fluid which is treated as a Williamson fluid through a stenoised region in the shape of cosine constriction. Blood is taken as a Williamson fluid. Mathematical formulation leads us to nonlinear compatibility and energy equations, which are then deciphered by the shooting technique to obtain the numerical solution. Suitable resemblance transformations are used to change partial differential equations into an embellished form of ordinary differential equations. Further, the consequences of the different parameters involved are shown by graphs and a conclusion is presented. Velocity and temperature fields are canvassed graphically for the distinct values of emerging parameters and discussed in tabular form. Skin friction and the coefficient of heat transfer are also covered in the discussion. The resulting Nusselt number curve exhibits negative deflection for variational values of λ and height of the stenosis δ.

15

Thermo-diffusion MHD convection in enclosure using heat and mass lines visualization techniques

Kushawaha Durgesh, Yadav Sushil, Singh Dwesh K., Behera Pravata Kumar

Journal of Applied Mathematics and Computational Mechanics

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2022

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Vol. 21, nr 2

63--76

EN

The numerical study of two-dimensional laminar thermo-diffusion natural convection in an exponentially heated and concentrated square enclosure of unit length in the presence of a uniform horizontal magnetic field is presented in this paper. The left and right vertical walls are assumed to have higher and lower temperatures and concentrations, respectively, and are governed by exponential functions, whereas the horizontal walls are assumed to be adiabatic and non-diffusive. The mathematical formulation of heat and mass functions has been completed, and heat and mass line contours have been drawn based on these functions to investigate the behavior of heat and mass in the cavity. The flow governing equations were solved using a finite difference method in conjunction with the Successive Over-Relaxation (SOR) technique and then converted to a vorticity-stream function form. A detailed comparison of isotherms with heatlines and isosolutes with masslines has been performed. Furthermore, the reduction for lower Rayleigh numbers Ra surpassing the reduction for higher values of Ra. The maximum reduction in overall heat and mass transfer has been observed for higher Hartmann (Ha = 8).

16

Heat and mass transfer in a vertical channel flow through a porous medium in the presence of radiation

Guria M.

International Journal of Applied Mechanics and Engineering

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2022

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Vol. 27, no. 3

63--78

EN

An analysis is made of heat and mass transfer in a three dimensional flow between two vertical porous plates through a porous medium. Analytical solutions have been obtained using the perturbation technique. The effect of non-dimensional parameters on velocity, temperature and concentration field are shown graphically. It is seen that the main flow velocity decreases with an increase in both the radiation parameter and Schmidt number but increases with an increase in the thermal Grashoff number, mass Grashoff number as well as the permeability parameter. Variations of the shear stress at the left plate are given in a tabular form. It is seen that the shear stress due to the primary flow at the left plate increases with an increase in the Reynolds number but decrease with an increase in the Schmidt number. With the increase of both the radiation parameter and Reynolds number the temperature decreases. The concentration field also decreases with an increase of the Schmidt number. Variations of mass flux at the left plate are given in tabular form. It is seen that the mass flux at the left plate increases with increase in both Schmidt number or Reynolds number.

17

Application of chromatographic plate theory on the weathered crust elution-deposited rare earth ore with carboxylate

Zhang Zhenyue, Wang Guangshuai, Li Chunhua, Chi Ruan, Long Fei, Chen Zhuo, Chi Xiao Wang, Liu Defeng

Physicochemical Problems of Mineral Processing

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2021

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Vol. 57, iss. 4

48--62

EN

To improve the leaching process of rare earth and reduce the impurities in the leachate, the carboxylate ammonium, such as ammonium acetate, ammonium citrate and ammonium tartrate, were selected as lixiviant to compare the effects of concentration, flow rate, pH and temperature on leaching mass process of rare earth and aluminum. Meanwhile, the leaching behaviors of rare earth and aluminum leached by three kinds of carboxylate ammonium were analyzed by chromatographic plate theory. The relationship between the flow rate and height equivalent (HETP) could fit well with the Van Deemter equation and there was an optimal flow rate (uopt) for the leaching of the rare earth and aluminum. Besides, the conditions of carboxylate ammonium lixiviant were optimized. The optimum concentrations of ammonium acetate, ammonium tartrate and ammonium citrate were 15 g/L, 25 g/L and 5 g/L respectively, the leaching flow rate was 0.50 mL/min, the pH value was approximatively 7.00 and the leaching temperature was 293 K to 303 K. At these conditions, the mass transfer efficiencies of three ammonium carboxylates for rare earth and aluminum was in the order of ammonium acetate > ammonium tartrate > ammonium citrate. Moreover, the ammonium acetate could commendably inhibit aluminum ions entering the lixivium.

18

Review on the numerical investigations of mass transfer from drug eluting stent

Song Jianfei, Kouidri Smaine, Bakir Farid

Biocybernetics and Biomedical Engineering

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2021

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Vol. 41, no. 3

1057--1070

EN

Drug-eluting stent (DES) as the newly developed treatment for the cardiovascular disease has been the preferred treatment option for most of the patients with significant reduction of restenosis incidents. However, the follow-up complications such as late thrombosis after stent implantation limit the further widespread use of DES which has caused extensive attention from the researchers. Numerical method has been widely employed to predict the DES performance in human body during the past decades, contributing to the stent design optimization and a better understanding of drug release mechanisms in a cost-effective way compared to the experiments. Among the existing numerical investigations, different modelling methods of DES inside artery can be found to study the drug transport process, and adopting the proper models physically and mathematically plays a key role to obtain the results well fitting with the practical case. Therefore, in this review article, the existing numerical researches regarding DES mainly in the last two decades have been focused and summarized including the established modeling methods and the controlling parameters investigations related to drug release from DES. In addition, the common results obtained have been discussed collectively aiming to guide the following researches.

19

Preparation of a solid product with high water content and water retention properties

Cvijić Marko, Golob Janvit

Polish Journal of Chemical Technology

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2020

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Vol. 22, nr 3

17--23

EN

This work presents the development of a solid product with a high water content (99.08%) and water retention properties. Water was chosen as a potential carrier of a volatile active substance and water retaining properties of material were studied at a temperatures and relative air humidity values with the support of the theory of drying. The study first confirmed the role of Gibbs’ phase rule in the research of solid-gas phase equilibrium, and second presented drying kinetics developed from Fick’s second law and expressed with the first term of the Fourier equation. Solutions of equations for phase equilibrium and mass transfer enabled the calculation of Luikov’s parameters, which are important for equilibrium relations and for the diffusivity of water in a solid for mass transfer prediction. The obtained thermodynamic and kinetic parameters enabled product characterisation that may be important for the prediction of retention times.

20

Influence of chemical reaction on the heat and mass transfer of nanofluid flow over a nonlinear stretching sheet: a numerical study

Misra Santoshi, Govardhan K.

International Journal of Applied Mechanics and Engineering

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2020

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Vol. 25, no. 2

103--121

EN

A numerical study on a steady, laminar, boundary layer flow of a nanofluid with the influence of chemical reaction resulting in the heat and mass transfer variation is made. The non-linear governing equations with related boundary conditions are solved using Adam’s predictor corrector method with the effect of a Brownian motion and thermophoresis being incorporated as a model for the nanofluid, using similarity transformations. Validation of the current numerical results has been made in comparison to the existing results in the absence of chemical reaction on MHD flows. The numerical solutions obtained for the velocity, temperature and concentration profiles for the choice of various parameters are represented graphically. Variations of heat and mass transfer across a Brownian motion and thermophoresis are studied and analyzed.