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Item type:Publication, Access status: without files , A note on the analytical approach and its efficiency for solving multivariate breakage population balance equationsBreakage population balance equations are of significant importance in powder technology, specifically in the processes which involve reduction of particle size, milling, granulation and material refinement. The dynamics of breakage process can be captured well by multivariate formulations but are challenging to solve due to strong non-linearity and contributions from internal and external coordinates. To address these challenges, a semi-analytical technique based on the homotopy of functions is employed to solve linear and collisional breakage equations in a multivariate framework. Accuracy and computational performance of the proposed method are validated with respect to the Adomian decomposition method and finite volume method. Numerical results show that the proposed homotopy-based method outperforms both the existing techniques in terms of computational accuracy. Thus, homotopy analysis method can be considered as a robust and powerful tool to solve intricate multivariate particulate problems arising in scientific research and industrial applications.Publicationtype: Journal Article7 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , An improved meshfree approach for solving nonlinear multivariate models involving aggregation, breakage, growth and source(2026-01); ; The modeling of aggregation and collisional breakage phenomena remains largely unexplored due to nonlinearity and nonlocal nature of the model equation. This article discusses the performance and efficiency of a redefined homotopy-based method and generalized iteration method for solving bivariate aggregation-collision breakage model for several kinetic kernels. Solution for Brownian motion kernel and equi-partition of kinetic energy kernel are obtained to analyze the dynamics of bubble columns as well as the granular flow behavior. The iterative scheme is further extended to solve aggregation-breakage model with simultaneous growth and source terms. This model is also extended for solving bivariate cases.Publicationtype: Journal Article13 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Optimization of efficiency of lactose drying process in an industrial continuous fluidized bed dryer using dynamic flowsheet simulation(Elsevier, 2025-06-01); ; 28 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , An efficient approach to obtain analytical solution of nonlinear particle aggregation equation for longer time domains(Elsevier, 2024-03-01); ; Population balances commonly incorporate physical kernels such as polymerization, generalized bilinear, and Brownian aggregation kernels, which have found widespread application in aerosol physics, astrophysics, chemical engineering, mathematical biology, and pharmaceutical sciences to monitor the dynamics of particles. However, finding analytical solutions for physical relevant kernels over longer time domains in order to validate these models remains a challenging task. The aim of this note is to enhance the semi-analytical solutions obtained from the Adomian decomposition method (ADM) for solving the nonlinear aggregation population balance equation. The applicability of ADM is limited to shorter time domains, and the accuracy of its results decreases as the time domain increases, thereby restricting its potential applications. Therefore, a hybrid approach based on ADM and Padé approximant is proposed to find the solutions of the non-linear aggregation equation. The accuracy of the new technique is evaluated by considering Brownian, polymerization and generalized bilinear kernels for which new generalized series solutions are obtained and compared against the finite volume scheme [Kumar et al. (2015), Kinet. Relat. Models 9(2), 373–391]. In addition, the new series solutions for the sum kernel are computed corresponding to a Gamma initial distribution. Quantitative errors in the number density functions are calculated for sum and product aggregation kernels and shown in tables to assess the accuracy of the proposed technique. The results indicate that the new approach provides more accurate analytical solutions for longer time domains while using fewer terms in the truncated series than the ADM and Homotopy perturbation method [Kaur et al. (2019), J. Phys. A: Math. Theor. 52(38), 385201].Publicationtype: Journal Article11 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , A comparative study of the fixed pivot technique and finite volume schemes for multi-dimensional breakage population balances(Elsevier, 2023-12); ; ; Tiong, Simon Ing XunWhen modeling particle breakage, the use of a single dimension to characterize particulate systems becomes intractable when multiple dimensions (e.g., size and shape) are important. Amongst many potential numerical techniques, the Fixed Pivot Technique (FPT) and Finite Volume Schemes (FVS) are popular choices to resolve multi-dimensional breakage population balance equations (PBEs). However, whether there exists a general multi-purpose technique between the two remains unclear. Across all test cases with identical size domain and mesh, while both techniques demonstrate comparable accuracy in resolving the moments and number densities (with maximum difference in average relative errors of ∼O(100) and ∼O(102), respectively), and exhibit similar computational efficiency (time taken by FPT relative to FVS is of ∼O(100)), the choice of numerical technique is contingent upon the properties where accurate prediction is critical. To this end, FVS is the preferred choice when precise estimation of up to two properties is required owing to its simplicity, albeit requiring distinct schemes for different properties. Conversely, when more than two properties are crucial, the FPT is more suited as it preserves up to four properties in the internal 2D space. Overall, this work offers rational guidance for efficient and accurate modeling of multi-dimensional breakages.Publicationtype: Journal Article7 126 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Solid-fluid mixing behavior of conical spouted beds with internal devices(Elsevier, 2023-09-01); ; ; ; The effect of draft tubes and fountain confiner on the gas and solids mixing behavior is studied in conical spouted beds. Accordingly, the bed porosity has been determined in different hydrodynamic regimes of 1.1,1.25 and 1.5u/ums, with beds equipped with draft tubes of 0%,56% and 100% opening ratio. These devices significantly affect the gas residence time and particle cycle time distributions, which are further improved by using a fountain confiner, specially when high inlet gas flow rates are desired. The addition of this device was found to remove stagnant gas pockets over the annular zone, while reducing the particle cycle time by 15% with the OSDT configuration at 1.5u/ums. This reduction heavily depends on the distance between the bed surface and the fountain confiner. By including draft tubes, the expected particle cycle time can be more than doubled due to the reduced annular-spot solids circulation. Therefore, it was found that a combination of internal devices and operating flow rate present a promising strategy to control the gas flow pattern, while keeping the distribution of particles cycle times required for each application.Publicationtype: Journal ArticleScopus© Citations 4 33 98 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , CFD-aided population balance modeling of a spray drying processDue to the widespread application of spray dryers, the model-based optimization and control of the process are of great interest. Therefore, a reduced order model based on a population balance approach for the spray drying process is developed to accurately capture the shrinkage and drying mechanisms. The population balances describe the two-dimensional distribution of the moisture content and the granule size. The model is validated by experiments in a pilot scale spray dryer. Information from CFD simulations and previous single droplet experiments are used to determine suitable model parameters. The results show a good agreement of the model with experimental findings and promote the suitability of the population balance approach. Furthermore, a novel method of extracting information on the trajectories from detailed CFD simulations and inserting them into the reduced order model is presented. This increases the accuracy of the model without changing the computational complexity.Publicationtype: Journal Article79 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Investigation of the influence of impact velocity and liquid bridge volume on the maximum liquid bridge length(2022-06); ; ; Several models exist to predict the capillary forces due to liquid bridges during static particle contacts. However, for dynamic impacts, there is still a lack of knowledge to accurately describe the geometry and rupture of liquid bridges. This is essential in order to calculate correctly the energy dissipation in numerical models. Therefore, the liquid bridge volume during the rebound phase of collision, the restitution coefficient, the rupture time and the maximum liquid bridge length were analyzed for a wide range of contact velocities from 0.0001 to 4.0 m∙s−1. To perform experiments at different velocities three experimental setups were developed. First, free-fall experiments with spherical particles colliding on a glass pane covered with a water layer were performed at different impact velocities from 0.3 to 1.5 m∙s−1 and water layer thicknesses. Secondly, a pneumatic setup was developed for investigating the maximum liquid bridge length at constant liquid bridge volume and contact velocities from 0.3 to 4.0 m∙s−1. A third setup was used to investigate the liquid bridge behavior during low velocities from 0.0001 to 0.04 m∙s−1. Based on the experimental results, a new model is presented to account for the significant influence of impact velocity on the maximum liquid bridge length.Publicationtype: Journal Article23 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Novel approach for measurement of restitution coefficient by magnetic particle tracking(Elsevier, 2022-01); ; ; ; Inter particular contacts between particles are of great interest, as the intensity and quantity of contacts impact the behavior of a wide variety of industrial processes. The coefficient of restitution is commonly used to describe the collision of a particle either with other particles or with walls and components of plant equipment. The coefficient considers the amount of energy that is dissipated in the collision event. Usually the restitution coefficient is examined by the use of high speed cameras and image velocimetry. In this study a new method based on magnetic particle tracking (MPT) was developed to measure the restitution coefficient of magnetic particles. By performing simultaneous image velocimetry and MPT measurements, the novel approach is validated. The comparison shows a high coincidence of the results from both measurement methods, both for normal direction impacts as well as impacts on oblique surfaces. Furthermore, the rotation of particles was investigated (by rolling down a tilted plate), which has also shown the applicability of the MPT measurement method.Publicationtype: Journal ArticleScopus© Citations 11 129 307 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Material specific drying kinetics in fluidized bed drying under mechanical vibration using the reaction engineering approach(2020-11-25); ; ; ; The accurate modeling of vibrated fluidized bed dryers plays an important role in the design and optimization of industrial drying processes. Understanding the impact of vibration on the hydrodynamics of the bed, as well as the drying kinetics, is crucial for accurate modeling. The influence of vibration on the drying kinetics was investigated. It could be shown that vibration reduces the minimum fluidization velocity (umf) and thereby enables the operation of fluidized bed dryers at lower gas velocities. The reduction of umf is particularly pronounced at the resonance frequency of the bed material. However, once the powder was fully fluidized, no impact on the drying kinetics was observed. The Reaction Engineering Approach (REA) is one of the methods used to describe the drying kinetics with one material specific curve. In this work, it was shown that REA curves can be determined based on batch drying experiments in fluidized beds. Porous particles of Geldart groups A, B and D with particle sizes and densities similar to food products were investigated and their REA curves were experimentally determined. Comparison of the derived REA data with established material specific drying curves from literature shows high similarity. Hence, the REA data from fluidized bed experiments is suitable for the modeling and simulation of fluidized bed drying processes.Publicationtype: Journal Article85