EVENTO
Advanced modeling strategies for crystallization fouling incorporating CaCO₃ polymorphism
Tipo de evento: Seminário de Avaliação - Série A
Crystallization fouling is a prevalent phenomenon in various industrial systems. This buildup reduces thermal efficiency by increasing thermal resistance in heat exchangers. Additionally, it results in higher maintenance and energy consumption costs. The net fouling rate on heat exchanger walls depends on the balance between deposition and removal rates. Deposition occurs when crystals, transported by diffusion from regions of high to low concentration, adhere to the heat transfer surface at a specific attachment reaction rate. In contrast, the removal process is governed by hydrodynamic forces and the break-off mechanisms acting on the deposited layer. Regardless of the fouling-type, it typically involves five key stages: initiation, transport, attachment, removal, and aging. The deposited material undergoes aging, leading to crystal size evolution and changes in its mechanical (e.g., material strength and Youngs modulus) and thermal (e.g., thermal conductivity and density) properties. Consequently, the break-off of crystalline deposits may take place when thermal stresses exceed the material strength. Building on the break-off model for CaCO3 reported by Babuka, Silva and Actor (2018), the present work aims to propose a new crystallization fouling model that enhances the aging treatment considering the CaCO3 polymorphs. This requires applying the population balance equation (PBE) to describe the crystal size evolution and the relative concentrations of the CaCO3 polymorphs over time, ensuring a consistent characterization of the aging process. The PBE is a hyperbolic integro-differential partial differential equation, which may lead to numerical complexities due to instabilities caused by steep solution gradients.To overcome these computational challenges, various Petrov Galerkin Finite Element Methods (PG-FEM) are considered. To approximate the scalar temperature fields of the fouling-wall structure and the water, the heat transfer models must be formulated using parabolic and hyperbolic partial differential equations. In addition, to consistently reproduce fouling evolution, we address the problem as a moving boundary problem, capturing the displacement of the fouling layer surface. Thus, a hybrid interface capturing strategy is proposed to approximate this movement. The proposed model enables an improved characterization of the crystallization fouling process.Evento HíbridoLocal: Auditório LNCCLink de transmissão: meet.google.com/ndx-qhgo-fbo
Data Início: 04/09/2026 Hora: 14:00 Data Fim: 04/09/2026 Hora: 17:00
Local: LNCC - Laboratório Nacional de Computação Ciêntifica - Auditorio B
Aluno: Andrés Mauricio Nieves Chacón - - LNCC
Orientador: Regina Célia Cerqueira de Almeida - Laboratório Nacional de Computação Científica - LNCC Renato Simões Silva - Laboratório Nacional de Computação Científica - LNCC
Participante Banca Examinadora: Alvaro Luiz Gayoso de Azeredo Coutinho - Universidade Federal do Rio de Janeiro - COPPE/UFRJ Diego Tavares Volpatto - Laboratório Nacional de Computação Científica - LNCC Renato Simões Silva - Laboratório Nacional de Computação Científica - LNCC
Suplente Banca Examinadora: José Karam Filho - Laboratório Nacional de Computação Científica - LNCC
