simulation of mixing processes<\/strong>. The degree of modeling complexity largely depends on problem-specific parameters and the simulation’s objective. It is often possible to reduce the complexity of a problem by making appropriate assumptions. <\/p>\n\nRegarding the design of mixing vessels<\/strong>, these can be divided into two different categories: stirred tanks and jet-mixed tanks.<\/p>\n\n1. Stirred Tanks In stirred tanks<\/strong>, as the name suggests, mechanical components, typically a set of blades connected to a power source, are used to move the fluid. In contrast, in jet-mixed tanks, the fluid is continuously drawn from the tank and pumped back in a closed loop, providing energy for stirring. <\/p>\n\n2. Jet-Mixed Tanks <\/h3>\n\n Especially in jet-mixed tanks<\/strong>, higher mixing times occur if operating parameters such as flow rate and nozzle diameter are not optimally defined. In such cases, it is therefore advisable to perform a CFD calculation to optimize or initially determine the operating parameters. Furthermore, CFD simulations are helpful in the design of mixing vessels, among other things. They can help identify so-called dead zones where no mixing is achieved. The geometric parameters can then be adjusted in the design to minimize or completely avoid these zones. This is particularly critical for jet-mixed tanks that are reused within an industry and are not optimized for their current application. Often, significant process improvements can be achieved by cleverly adding baffles or making other minor design changes. <\/p>\n\nChallenges in CFD Simulation of Mixing Processes<\/h2>\n\n What influences the complexity and effort of a CFD simulation?<\/strong><\/p>\n\nThe complexity of the CFD model also depends on the type of mixture. For example, it is much simpler and more cost-effective to simulate a single-phase mixture than a multiphase system. Sometimes it makes sense to assume multiphase systems as single-phase if the mixture types have similar viscosity and density with negligible surface tension at the interphase. Different models are used for the simulation of miscible and immiscible liquids<\/strong>. The main difference lies in the surface tension at the interface of an immiscible mixture, which restricts diffusion. However, for stirred tanks, the modeling complexity depends on the size and speed of the rotating components. <\/p>\n\nModeling Approaches for Mixing Vessels: Efficiency vs. Accuracy<\/h2>\n\n When simulating mixing processes, there are various modeling approaches<\/strong>, each representing a compromise between computational effort and accuracy. The choice of the correct method depends on the specific conditions in the mixing vessel, particularly the rotational speed and the overlap of the moving regions. <\/p>\n\nHere is an overview of common approaches:<\/p>\n\n
1. MRF (Multiple Reference Frame) <\/h3>\n\n The MRF approach offers the most computationally cost-effective solution. However, it is only suitable for processes with higher rotational speeds and non-overlapping rotational zones. <\/p>\n\n
2. Sliding Mesh <\/h3>\n\n Sliding or moving mesh approaches are suitable for lower rotational speeds and in cases where the rotating blades are in an overlapping zone.<\/p>\n\n
3. Moving Mesh<\/h3>\n\n The animation in this article shows the mixing of two immiscible liquids. The model consists of two blades moving at a low rotational speed and enclosing an overlapping region. The mixing phenomenon is simulated with a moving mesh. <\/p>\n\n<\/video><\/figure>\n\nelbcore engineers \u2013 Your Partner for the Simulation and Modeling of Mixing Processes<\/h2>\n\n We have experienced that when experienced employees leave a company, valuable knowledge is lost and not replaced. To prevent such a situation or to bridge such a gap, elbcore engineers can provide support and advice. Through our many years of experience in the field of simulations, we are able to develop tailor-made optimizations to always achieve the best solution for our clients. Therefore, if you are faced with the task of improving one of your systems or require deeper insight into your processes, please feel free to request a free and non-binding consultation appointment<\/a>. <\/p>\n","protected":false},"excerpt":{"rendered":"Mixing is a prevalent phenomenon in industries such as food and chemical manufacturing. Although widely used, the physics involved are quite complex and, in some areas, still unexplored. This presents a particular challenge when it comes to reliable and accurate predictions of relevant parameters (e.g., mixing time). A few analytical models exist in the literature, […]<\/p>\n","protected":false},"featured_media":561,"template":"","class_list":["post-1253","blog","type-blog","status-publish","has-post-thumbnail","hentry"],"_links":{"self":[{"href":"https:\/\/www.elbcore-engineers.de\/en\/wp-json\/wp\/v2\/blog\/1253","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.elbcore-engineers.de\/en\/wp-json\/wp\/v2\/blog"}],"about":[{"href":"https:\/\/www.elbcore-engineers.de\/en\/wp-json\/wp\/v2\/types\/blog"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.elbcore-engineers.de\/en\/wp-json\/wp\/v2\/media\/561"}],"wp:attachment":[{"href":"https:\/\/www.elbcore-engineers.de\/en\/wp-json\/wp\/v2\/media?parent=1253"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}