An analytical study of coupled heat and mass transfer freeze-drying with convection in a porous half body: A moving boundary problem

Chaurasiya, Vikas; Singh, Jitendra

doi:10.1016/j.est.2022.105394

Cited by 28 publications

(10 citation statements)

References 33 publications

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“…The increase in Re enhances tangential stress on the bottom disk whereas decreases on the top disc. The enhanced stretching rate urges the fluid to move quickly towards the disks and as a result heat exchange rate as well as couple stress decrease on both disks along with an enhancement in Re [54]. Furthermore, the viscous transporting extracts the heat from the flow region.…”

Section: Conclusion and Negotiationsmentioning

confidence: 99%

Retracted: Numerical study of heat and mass transfer for micropolar fluid flow due to two symmetrical stretchable disks

Amjad,

Ramzan,

Ahmad

et al. 2023

Phys. Scr.

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In this study, heat transfer is analyzed for an incompressible steady laminar micropolar fluid flow among two symmetrical stretchable disks. The associated Partial Differential Equations (PDEs) are converted into Ordinary Differential Equations (ODEs) through appropriate similarity transformations and then solved numerically through applying the quasi-linearization method along with the Finite Difference Method (FDM). This impact from certain inclusive parameters in the heat transfer and fluid flow is presented schematically. The results are tabulated and depicted that the shear stress rises for the upper disk and the opposite trend for the lower disk. It is also noted that a couple stress and heat transfer rate reduce across the disks.

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Section: Conclusion and Negotiationsmentioning

confidence: 99%

Retracted: Numerical study of heat and mass transfer for micropolar fluid flow due to two symmetrical stretchable disks

Amjad,

Ramzan,

Ahmad

et al. 2023

Phys. Scr.

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“…Several proposals have been made for the heat exchange with the environment along the side walls, which include radiation and conduction, e.g., [ 3 ]. Heat transfer inside the frozen region is based on conduction through the ice–solid mixture; in the dried region, heat transfer through the interconnected solid walls as well as heat convection are assumed [ 11 ]. At very low chamber pressure (below 10 Pa and in the absence of inert gases), the problem is simplified and heat convection is disregarded, e.g., [ 1 ].…”

Section: Introductionmentioning

confidence: 99%

“…The assumption of homogeneous domains that are assigned with effective, i.e., averaged properties, usually form the basis for further simplification of the problem to 1D, i.e., along the vertical height of the blocks [ 11 ]. This is surely accurate enough, when it can be expected that the sublimation of ice results in the formation of a flat (infinitesimally thin) phase boundary at the top side of the frozen block which moves downwards during the drying process.…”

Section: Introductionmentioning

confidence: 99%

A Non-Isothermal Pore Network Model of Primary Freeze Drying

Thomik,

Faber,

Gruber

et al. 2023

Pharmaceutics

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In this work, a non-isothermal pore network (PN) model with quasi-steady vapor transport and transient heat transfer is presented for the first time for the application of primary freeze drying. The pore-scale resolved model is physically based and allows for the investigation of correlations between spatially distributed structure and transport conditions. The studied examples were regular PN lattices with a significantly different structure, namely a spatially homogeneous PN, also denoted as monomodal PN, and a PN with significant structure variation, referred to as bimodal PN because of its bimodal pore size distribution. The material properties selected for the solid skeleton in this study are equivalent to those of maltodextrin. The temperature ranges applied here were −28 °C to −18 °C in the PN and −42 °C in the surrounding environment. The environmental vapor pressure was 10 Pa. The PNs were dried with constant temperature boundary conditions, and heat was transferred at the top side by the vapor leaving the PN. It is shown how the structural peculiarities affect the local heat and mass transfer conditions and result in a significant widening of the sublimation front in the case of the bimodal PN. The possibility of spatially and temporally resolved front structures is a unique feature of the PN model and allows the study of situations that are not yet described by classical continuum approaches, namely heterogeneous frozen porous materials. As demonstrated by the thin layers studied here, the pore-scale simulations are of particular interest for such situations, such as in lyomicroscopes or collagen scaffolds, where a length-scale separation between dry and ice-saturated regions is not possible.

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“…Recently, utilities have been obliged to change their operation techniques for generating electricity at a reduced pollution level due to growing concern about environmental issues and the implementation of the U.S. Clean Air Act amendments of 1990 [5]. Therefore, the necessity of considering emission dispatching is undeniable especially in modern societies.…”

Section: Introductionmentioning

confidence: 99%

A Multiobjective Evolutionary Approach for Solving the Multi-Area Dynamic Economic Emission Dispatch Problem Considering Reliability Concerns

Lotfi

2022

Sustainability

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Economic dispatch (ED) problems, especially in multi-area power networks, have been challenging concerns for power system operators for several decades. In this paper, we introduce a novel approach for solving the multiobjective multi-area dynamic ED (MADED) problem in the presence of practical constraints such as valve-point effect (VPE), prohibited operating zone (POZ), multi-fuel operation (MFO), and ramp rate (RR) limitations. Different objective functions including energy not supplied (ENS), generation costs, and emissions are investigated. The reliability objective, which has been less studied in economic dispatch area, distinguishes the proposed study from other studies. A compromise has been made from economic and reliability points of view. The MADED problem in the power system is inherently a complex and nonlinear problem, considering the operational constraint increments and the intricacy of the problem. Hence, the modified grasshopper optimization (MGO) algorithm based on a chaos mechanism is presented to prevent being trapped in local optima. The proposed method is tested on two systems including a 10 unit, 3-zone test system and a 40-unit 3-zone test system, and then, the outcomes are compared with those of other evolutionary techniques such as gray wolf optimization (GWO) and modified honey bee mating optimization (MHBMO). The simulation results demonstrate that the suggested strategy is successful in resolving both single-objective and multiobjective MADED problems.

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An analytical study of coupled heat and mass transfer freeze-drying with convection in a porous half body: A moving boundary problem

Cited by 28 publications

References 33 publications

Retracted: Numerical study of heat and mass transfer for micropolar fluid flow due to two symmetrical stretchable disks

Retracted: Numerical study of heat and mass transfer for micropolar fluid flow due to two symmetrical stretchable disks

A Non-Isothermal Pore Network Model of Primary Freeze Drying

A Multiobjective Evolutionary Approach for Solving the Multi-Area Dynamic Economic Emission Dispatch Problem Considering Reliability Concerns

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