Mass Transfer Parameters Research Articles

Williamson magneto nanofluid flow over partially slip and convective cylinder with thermal radiation and variable conductivity

This article is concerned with the study of MHD non-Newtonian nanofluid flow over a stretching/shrinking cylinder along with thermal radiation effects. Two-component slip mechanism models, namely Brownian motion and thermophoresis of nanofluid for the mass and energy transportation, developed by Buongiorno, are used. Convective heat transfer and nonuniform magnetic field are retained for the expanding/contracting cylinder. Variable thermal conductivity and heat generation effects along with slip boundary conditions are utilized over the cylinder surface. By utilizing the similarity transformation, these governing partial differential equations are converted into nonlinear ordinary differential equations (ODEs). To obtain numerical results, these ODE’S are solved by the shooting method using MATLAB software. The impact of different parameters like variable thermal conductivity, radiation parameter, magnetic parameter, Prandtl number, Brownian motion parameter, the magnetic parameter, Weissenberg number, the viscosity ratio parameter and mass transfer parameter, on the velocity, temperature and concentration is discussed graphically. Further, the Sherwood number, Nusselt number, the skin friction coefficient are also discussed through figures. It is noted through analysis that the speed of the nanofluid reduces for the higher Weissenberg number and expanding cylinder. For the contracting cylinder, i.e., for the negative unsteadiness parameter, the velocity increases.

Development of a Nondestructive Monitoring Technique for Vial Freeze-Drying Process using Microwave Resonance Spectroscopy

In this study, we developed a nondestructive monitoring technique for the drying progress of products in vials during the freeze-drying process using microwave resonance spectroscopy. An aqueous mannitol solution, commonly used as an excipient for injectable drugs, was used as the model material. The drying progress was determined using a mathematical model (i.e., Rp−Kv model), in which the parameters of mass and heat transfer were experimentally determined while considering the variation of the drying progress and position of the product on the drying shelf. A strong correlation was found between the extent of drying and changes in the microwave resonance spectrum. The simulation results were regressed against the changes in the resonance peak frequency and resonance intensity. Using this regression equation, the extent of drying could be predicted from the acquired spectral data. In this way, we were able to estimate the design space (the relationship between the operating conditions, internal temperature of the product, and sublimation rate), which changed with the extent of drying from the spectrum obtained inline, showing that it is possible to set the appropriate operating conditions based on the spectra.

Thermal diffusion of Maxwell nanoparticles with diverse flow features: Lie group simulations

The thermal onset of nanoparticles is quite impressive and dynamical and subsequently report significance in the thermal systems, heat transfer enhancement, engineering processes, cooling phenomenon, heating devices etc. Following such motivations in mind, current exploration reports the thermal impact of magnetized Maxwell nanofluid with mixed convection and radiative applications. The external source of heat and chemical reaction has also been introduced to report the thermal transportation phenomenon. The convective boundary conditions are entertained to investigate the problem. The system of partial differential equation is altered into ordinary differential equation by following the Li group approach. The numerical simulations computed by using the Runge–Kutta (RK-4) scheme. The eeffects of different controlling parameters are physically attributed flow fields. The results convey that a reduction in velocity is observed for mass transfer parameter and buoyancy constant while the reverse pattern of velocity is observed for Rayleigh number. Moreover, the presence of external heat source improves the thermal profile. The simulated results may present applications in enhancement of heat transfer, thermal systems, extrusion processes, solar energy, transportation systems, plasma etc.

Arrhenius energy on asymmetric flow and heat transfer of micropolar fluids with variable properties: A sensitivity approach

Micropolar fluid flow in a channel with variable viscosity, variable thermal conductivity and activation energy is examined numerically using the Runge–Kutta Fehlberg method in this article. Two different boundary conditions are postulated in this study namely Prescribed Surface Temperature (PST) and Newtonian Heating (NH). The numerical outcomes are compared to check the precision of the suggested problem. Significant metrics like Reynolds number, Peclet number for heat and mass transfer, Schmidt number, Activation energy and chemical reaction parameter are graphically described. The influence of the parameters like spin gradient viscosity, vortex viscosity, micro-inertia density on the flow fields are discussed and shown. According to the graphic data, the velocity increases as the viscosity parameter increases whereas the temperature decays for larger values of variable thermal conductivity and also, activation energy enhances the concentration profile. The variation in viscosity parameter shows a significant effect on thermal distribution. The viscosity variation parameter enhances the shear stress and the couple stress. The Peclet number for heat transmission displays a changing effect for high and low Biot numbers regardless of the effect of variable thermal conductivity. This analysis tabulates the link between Nusselt number and Sherwood number over a Peclet number for heat and mass transfer. The skin friction coefficient increases with the viscosity parameter ∊ whereas enhancement in the thermal conductivity parameter decreases the Nusselt number. Furthermore, sensitivity analysis is carried here by developing RSM in order to identify the variations in the input values for the parameters Peh,Pem and N1. The response surface equation is created by using the software package MINITAB-16 by design of experiments. The regression model’s quality of fit is assessed by using the Analysis of Variance.

Alternative activated/KOH adsorbent for phenol adsorption: experimental, industrial case study and mass transfer interpretation.

Removal of phenol from wastewater is essential to achieve permitted concentrations according to the recommendations of USEPA. The adsorption capacity of phenol in activated adsorbent with KOH of Enterolobium contortisiliquum (TAC) was evaluated at different temperatures. The Langmuir isotherm represented the equilibrium data of this study. Thermodynamic process was endothermic, spontaneous, and reversible. The mass transfer parameters ranged from KE 0.68 to 0.96 × 10-3 (cm s-1), Ds 8.95 to 14.35 × 10-9 (cm2 s-1), and Dp 5.023 × 10-8 (cm2 s-1). The PVSDM model represented the adsorption kinetics. Intraparticle diffusion limits the mass transfer process Biot > 100. The two-stage process minimized the total amount of TAC required to achieve the permitted specification of phenol concentration in wastewater from different industrial sectors. TAC showed significant performance in the removal of phenol from wastewater.

Drying kinetics of blueberry pulp and mass transfer parameters: Effect of hot air and refractance window drying at different temperatures

Blueberry pulp was dried using hot air (HA) and refractance window (RW) methods at 55–95 °C, the drying kinetics were described by the Page (k and n) and Fick (Deff1) Models. In addition, mass transfer parameters (drying coefficient (S), lag factor (G), Biot number (Bi), effective diffusivity (Deff2), external mass transfer (hm)); and the activation energy were analysed. As results, the Page model showed the best fit, Deff1 and k parameters increased with temperature, especially for RW drying at 95 °C. RW method reduced the HA drying time by more than 30%. Furthermore, the 0<Bi<0.4 values were related to variations in internal resistance with temperature, except for HA drying at 95 °C, where the external resistance was also reduced. In conclusion, mass transfer parameters suggested that internal resistance was more important during HA drying, while RW was the most effective method since it needed lower time to dry samples.

Intrinsic insight of energy-efficiency optimization for CO2 capture by amine-based solvent: effect of mass transfer and solvent regeneration

Here the energy-efficiency performance of CO2 capture is investigated based on the combination of bench-scale experiments and simulated calculation. A comprehensive evaluation is performed by L25(56) orthogonal tests to analyze the effect of crucial operating conditions on CO2 capture. Experiments reveal desorption temperature and flue gas flow play a major role for CO2 capture efficiency. Rising flue gas flow could promote interfacial area, but decreases contact time, overally, net CO2 flow approximately determines the linear relationship of capture efficiency and absorption rate. With combination of Eulerian-Eulerian method with the population balance model, we predict the dynamics evolution process of dispersed bubble, in order to provide the detailed information of interphase contact area and multiphase flow for modelling complete mass transfer parameters. Meanwhile, rigorous process simulation is developed to analyze the energy consumption of carbon capture. Higher desorption temperature provides much leaner solvent, which is beneficial to CO2 absorption, but consumes greater energy penalty.

Development of a spatially resolved technique for the measurement of effective diffusions and its application to the modelling of washcoated catalytic monoliths

A spatially resolved technique was developed as a novel methodology to investigate the process of effective diffusions in monolith catalysts. The technique was then applied to the investigation of methane oxidation inside a commercial 3 wt% Pd/Al2O3 monolith catalyst. The mass transfer parameters of O2 and CH4 were measured, and their effective diffusivities were calculated by a modified Bosanquet approach, which confirmed that the dominant diffusion regime in the substrate and the washcoat were molecular and Knudsen respectively. The applicability of this new approach was assessed via a comparison between simulations of the water-inhibited CH4 catalytic oxidation using either correlation or experimental-based mass transfer coefficients. This study demonstrates that careful measurement of diffusivity is essential to the accurate modelling of catalyst reaction rates.

Heat and mass transfer and hydrodynamics in cryogenic hydrogen fuel systems

The paper presents the results of experimental and theoretical studies and the development of methods to calculate the parameters of heat and mass transfer as well as hydrodynamic processes occurring during the following operations: filling of reservoirs and tanks with LH2; drain-free storage of LH2; saturation of LH2 with non-condensable gas (helium) during tank pressurization; drainage of hydrogen vapors and displacement of LH2 from the storage tank. It is noted that the main design parameters characterizing the process of filling cryogenic reservoirs and tanks are the following: the time of filling to the required level; LH2 evaporation losses during cooling; thermal stresses in the walls of reservoirs and tanks. The time of LH2 drain-free storage in real reservoirs and tanks is reduced due to thermal stratification in the liquid and gas–vapor phases compared to the time of LH2 drain-free storage under conditions of its complete mixing. The drainage of LH2 vapors is characterized by the following main design parameters: the rate of pressure change in the cryogenic tank; the flow rate of the drained mass; the degree of non-equilibrium during LH2 boiling; drop entrainment; an increase in the LH2 volume during boiling (“swelling”); the degree of pressure increase in case of a sudden termination of drainage. When LH2 is displaced, the following parameters of the feed system have a decisive influence on the heat and mass transfer characteristics: displacement pressure; LH2 thermal stratification; the degree of LH2 saturation with non-condensable gas; the maximum temperature of the tank wall; the mass of pressurizing gas. Liquid hydrogen (LH2) can be saturated during pressurization and displacement with helium and during other operations involving the use of non-condensable gas. The process of LH2 saturation with pressurizing gas (helium) is characterized by the following parameters: absorption coefficient that determines the efficiency of gas saturation and is equal to the ratio of the dissolved amount of helium to the entire mass of non-condensable gas that has passed through the solution; change in the LH2 temperature during gas saturation; helium concentration in the solution and its homogeneity. Based on the obtained experimental data and mathematical modeling, we determined relationships that make it possible to calculate the listed main parameters of heat and mass transfer as well as hydrodynamic processes at the main stages of the design and operation of cryogenic hydrogen tanks, systems of LH2 storage and feeding. The presented relationships can be used as reference data in the design and optimization of LH2 fuel systems.

Inverse problems in food engineering: A review

With the increase in the computational power, numerical simulations play an increasing role in designing, development, and optimization of various food processing operations. Inverse and ill-posed problems have been studied extensively in many branches of science and engineering, including mechanical, chemical, aerospace, biology, physics, and chemistry. The inverse techniques have been currently witnessing a growing trend in the food processing field for a decade. Inverse problems are usually performed when direct measurements of heat and mass transfer properties and boundary conditions, are not feasible. They are very sensitive to measurement errors; require optimization methods to tackle the inverse problem. It is necessary to consider the coupling heat and mass transfer for the solution of inverse problem since food process involves simultaneous heat and mass transfer within the food products. To date, inverse methods have been applied in few food processing operations, including drying, baking, freezing, and thermal processing. However, studies related to these areas on the estimation of unknown quantities for various fruits and vegetables, and food products are limited. This review covers the statistical concepts which include confidence interval, confidence region, model validation and minimization techniques discussed in detail. The optimal experimental design, D-optimality and Fisher Information Matrix, and sensitivity analysis are all extensively presented. The optimization techniques and their algorithms used in the area of food processing are explained. Finally, it mainly focuses on the inverse estimation of unknown quantities, namely, heat and mass transfer parameters in different food processing operations.

Reproducibility of Fruit Spirit Distillation Processes

Fruit spirit distillations processes are based on physical principles of heat and mass transfer. These principles are decisive for the separation of desired and undesired aroma compounds, which affect the quality of the distilled product. It is mandatory to control heat and mass transfer parameters to be able to perform fruit spirit distillation processes in a reproducible manner and to achieve equal products with similar volatile compound compositions repeatedly. Up to now, only limited information is available on the magnitude of reproducibility errors since fruit spirit distillation columns are typically not equipped with a suitable control or monitoring technique. We upgraded a batch distillation column with digitized instrumentation and a control technique to be able to control crucial parameters such as thermal energy inputs and reflux rates. This study aimed to identify whether control over two distillation parameters has the potential to enable us to perform distillation processes repeatedly. This study analyzed the magnitude of reproducibility errors for (i) six monitored distillation process parameters and (ii) 13 quantified volatile compounds in the product between duplicated distillation runs performed with equal setups. A total of eight different distillations were performed in duplicate (n = 16), while the six distillation parameters were monitored and logged every ten seconds. The produced distillates were equally subsampled into 20 fractions and each fraction analyzed for 13 volatile compound concentrations. Based on a dataset of 28,600 monitored duplicate distillation process data points, this study showed that process parameters can indeed be replicated with a median relative standard deviation (RSD) of &lt;0.1% to 7% when two crucial process parameters are controlled. The comparison of 1540 volatile compound concentrations in the product fractions showed a reproducibility error with an average median RSD of 9 ± 8%. This illustrated that by gaining control over thermal energy input and reflux rates, the reproducibility of fruit spirit distillation processes and their associated products can largely be met. It is advisable to equip distillation columns with a suitable control technique to be able to reproduce the performance of fruit spirit distillations.

Vacuum impregnation on apples with grape juice concentrate: Effects of pressure, processing time, and juice concentration

Apple cubes were subjected to vacuum impregnation using grape juice concentrate. The effect of pressure reduction (VP = 100–500 mmHg), immersion time (t = 10–30 min), and concentration of grape juice (C = 40–60°Brix) on impregnation parameters were evaluated using response surface methodology. Second-order polynomial equations were developed (R2 > 0.895) to describe the behavior of water loss, total soluble solids, L*, a*, Hue, total color difference, the color of impregnated/treated areas (AU/AOP), antioxidant activity, total monomeric anthocyanin, and dimensionless volume (V/Vo) in the impregnated product. VP had a significant (p ≤ 0.05) effect on mass transfer parameters, color parameters, AU/AOP, and bioactive compounds. However, at 60°Brix and 500 mmHg, the lower V/Vo values were reached due to cell disruption. Therefore, it is recommended to use a VP = 500 mmHg and t less than 20 min to significantly impregnate compounds and obtain a product without considerable morphometric modification.

Heat and mass transfer modeling and quality changes during deep fat frying: A comprehensive review

AbstractThe deep fat frying of food involves simultaneous heat and mass transfer between the food product and surrounding oil and hence the frying operation is complex in nature. Heat is transferred from the frying medium to the product surface by convection and from the surface to the core of the food through conduction. The specific heat, thermal conductivity, thermal diffusivity, and convective heat transfer coefficient are the major factors that greatly affect the rate of heat transfer. The heat transfer study for deep fat frying of food products revealed that the Fourier number was in the range of 0.1–0.5. The fat uptake and moisture loss are the primary modes of mass transfer during this process. For deep fat frying, the mass transfer coefficient for different food materials was found to be in the range of 10−4–10−6 m/s. The moisture diffusivity for various food materials was measured in the range of 10−6–10−10 m2/s. This review presents the different models implemented to assess the heat and mass transfer parameters during deep‐fat frying of different food materials. The effects of frying process parameters on color, texture, and different physical properties of fried food were discussed. Overall, this review includes information related to the frying of different food products that will assist the food processing connoisseurs and industries in predicting and optimizing the frying process parameters to obtain the desired quality in the product and make the process energy efficient.Practical ApplicationsFrying involves the convective heat transfer from the frying medium to the surface of the food product and conduction heat transfer within the food. During frying, the moisture and oil transport are controlled by diffusion gradient and capillary flow. Most of the oil penetrates into the food during cooling through the channels and pores of the product. The physicochemical changes in the fried product are regulated by frying process factors such as frying oil temperature, frying time, and thermal characteristics of the food. The intense heat of frying imparts a rich aroma and texture to fried foods. Modeling and optimization of frying is very important in order to produce high‐quality fried food products. Heat transfer parameters such as thermal diffusivity, heat transfer coefficient, Fourier number, and Biot number are important in analyzing and improving the product's frying operation. The food technologists would be able to analyze the mechanism of oil absorption and produce low‐oil fried food products if they had a better understanding of heat and mass transfer.

Scale-up and mass transfer of the adsorption/desorption process of anthocyanins in amorphous silica

The purification and recovery of anthocyanins are important to maintain the stability of the purified solution, ensuring that the health-beneficial properties of this substance are not altered. This work aimed to obtain and compare solutions of commercial and natural grape and red cabbage anthocyanins, suitable process conditions, as well as purification and recovery through detailed analysis called two-stage, estimation of phenomenological parameters of mass transfer and scale-up using Bugram Protect® as amorphous silica. The adsorbent was characterized as amorphous and with a high silicon dioxide composition. The pH 3.0 potentiated the stability of flavylium cation in solution. The Freudlich isotherm represented the equilibrium data. The phenomenological parameters KE and Ds and the limiting step of mass transfer were estimated. Scale-up indicated dosages of adsorbents to meet the process specifications. This work presented additional results in phenomenological aspects and industrial scale in the recovery and purification of anthocyanins.

Correlation of the cell disintegration index with Luikov's heat and mass transfer parameters for drying of pulsed electric field (PEF) pretreated plant materials

Currently, the modelling of drying processes of plant tissues pre-treated by pulsed electric field (PEF) is following experimentally identified curves or separate heat and mass transfer and diffusion models with different levels of accuracy. This research had two major objectives: mathematical modeling and control of drying process of different vegetables pretreated by PEF during convective drying. The mathematical modeling was based on Luikov's heat and mass transfer model along with properties of different vegetables. Computer modelling was done using the difference method for predicting moisture and the temperature potentials of untreated and PEF-treated vegetables. The formulation and the solution procedures were applied to simulate the simultaneous heat and mass transfer in selected vegetables subjected to the convective drying. Suggested model had a good correlation with experimental results. Moreover, cell disintegration index can be used as a controllable parameter in heat and mass transfer models to predict drying behavior of potato, onion, and carrot tissues. Obtained drying models can be used as a mathematical tool to predict drying behavior for various types of agricultural products pre-treated by pulsed electric field. • Pulsed electric field (PEF) pre-treatment reduced the drying time. • Obtained methodology is a good tool for the analysis and modelling of PEF assisted drying. • Cell disintegration index is in relationship with the kinetics coefficients of Luikov's model. • Cell disintegration index can be used to predict drying behavior of plant tissues.

Modeling of the changes in some physical and chemical quality attributes of potato chips during frying process

In the present study, the heat and mass transfer parameters related to the potato chips and frying medium were determined, and the changes in some physical and chemical quality attributes of the potato chips were investigated during frying at 175 °C. The effective water diffusion coefficient-(Deff) was determined as 2.067×10−8 m2/s for potato chips, while the heat transfer coefficient-(h) was calculated as 251.5 W/m2.°C for the frying medium. The core temperature of the potato chips was equilibrated around 100 °C during frying, and under this constant temperature phase, the water evaporation rate was determined ∼8 g H2O/m2.s. HMF and furfural accumulations in the potato chips fit the best with the first-order mass formation kinetics model, and the formation rates were calculated as 0.1862 and 0.1386 1/min, respectively. High and significant correlations were determined between the color attributes of the potato chips and furfural derivatives. Consequently, the collected results by the suggested mathematical approaches can be used to optimize frying conditions along with obtaining the fried potato snacks compatible with consumer expectations.

Prediction of mass transfer and kinetic behavior during the extraction of high added‐value products from sour cherry ( Prunus cerasus L.) peels

In this study, deep eutectic solvent has been used in order to propose an environmentally and green method for conversion of biowaste into high added-value products. A deep eutectic solvent system consisting of citric acid/ethylene glycol mixture (1/4, molar ratio) has been prepared to extract total polyphenols from sour cherry (Prunus cerasus L.) peels. Deep eutectic solvent-based microwave-assisted extraction has been used in order to evaluate mass transfer, kinetic, and thermodynamic parameters. According to the high Biot number values (1,487.23, 2,970.83, 3,974.28), an efficient contact between the total polyphenols and the deep eutectic solvent system has been confirmed. It is observed that the total amount of phenolic substances varies between 4.29 and 33.61 mg-GAE/g of fresh material. In this study, the pseudo-second-order kinetic model (R2 > 0.90) has been successfully applied for the extraction of TPC during MAE. ∆H > 0, ∆S > 0, and ∆G < 0 denote an endothermic and spontaneous microwave-assisted extraction system for the solid–liquid extraction of TPC from sour cherry (Prunus cerasus L.) peels. Novelty impact statement Polyphenolic compounds (anthocyanins and antioxidants) were extracted from sour cherry (Prunus cerasus L.) peels. Extraction kinetics of economical and environmental MAE method has been investigated for natural antioxidants. The structure of the DES-based MAE of bioactive substances from sour cherry peels will be able to understand comprehensively according to the thermodynamic parameters.

On the Decreasing Mismatch-Induced Stresses in a Heterostructure During Growth of the Structure from Gas Phase

In this paper, we introduce an approach to decrease mismatch-induced stress in a heterostructure by using radiation processing during growth from gas phase. We build a framework for the approach of the mismatch-induced stresses in the heterostructure decreasing simultaneously with an acceleration of recombination and diffusion of radiation defects in the damaged region. An analytical approach for analyzing of mass and heat transfer is also introduced. The approach gives a possibility to take into account simultaneously spatial and temporal variations of parameters of mass transfer. At the same time, the approach gives a possibility to take into account nonlinearity of considered processes.

Chemisorption of CO2 in a gas–liquid vortex reactor: An interphase mass transfer efficiency assessment

AbstractTo develop cost‐effective CO2 capture technology process intensification will play a vital role. In this work, the capabilities of a gas–liquid vortex reactor (GLVR) as novel process intensification equipment are evaluated by studying its interphase mass transfer parameters to build up the fundamentals for its future application to for example, CO2 capture. The NaOH‐CO2 chemisorption system and Danckwerts' model are applied to obtain the effective interfacial area and liquid‐side mass transfer coefficient. Results show that the gas–liquid contact in the GLVR is capable of both generating a large interfacial area in a small reactor volume and creating a region with high‐energy dissipation to improve mass transfer. A comparison of the volumetric mass transfer coefficients with data reported in literature for conventional and intensified reactor types confirms a superior mass transfer efficiency and, most importantly, a favorable energetic efficiency of the GLVR.

Elucidating the mass transfer mechanism of CrVI adsorption by encapsulated chitosan-carbon nanotubes-iron beads in packed-bed columns

This study evaluates the CrVI breakthrough behaviors of a continuous-flow column packed with composite chitosan-MWCNTs‑iron beads under various operating conditions. Under the tested range of experimental parameters, a maximum of 54% of CrVI removal was achieved at: water flow rate, 1 mL/min, feed CrVI concentration, 30 mg/L; and packed bed height 8 cm. A homogeneous surface diffusion model (HSDM) involving convection-dispersion and diffusion equations was formulated, numerically solved, and experimentally validated. The high degree of conformity between the calculated and experimental breakthrough curves facilitated the determination of mass transfer parameters including axial dispersion DL, (1.30 × 10−8 to 1.56 × 10−7 m2/s) and surface diffusion Ds, (7.28 × 10−11 to 1.80 × 10−10 m2/s) via an error minimizing approach. The DL value was a function of molecular diffusion, which varied with the flow velocity, mass loading, and bed height. The Ds values were slightly higher than those previously reported, owing to the heterogeneous nature of the adsorbent. The external film diffusion coefficient (kf) was also determined by using Wilson-Geankoplis empirical correlation, which was recognized as a rate-controlling factor during CrVI mass transfer to the adsorbent beads. Furthermore, sensitivity analysis showed that a transition from diffuse- to shock-front occurred with a decreasing DL, while a decrease in the slope of breakthrough curves was observed by decreasing Ds and bed porosity, and increasing kf and Langmuir parameters. Lastly, the study demonstrated a high correlation between utilization of fractional bed capacity and axial Peclet number. This method is suitable for optimizing operating conditions to maximize the utilization of a fixed-bed columns.