Discover the intricacies of simulating steady vortices in stirred tanks with the powerful Ansys Fluent software using a parametric workflow.
Challenges
Simulating steady vortices in stirred tanks presents a set of unique challenges. The complexities of fluid dynamics require precise modeling to accurately represent the behavior of vortices. Parameters such as stirrer speed, tank geometry, fluid properties, and boundary conditions need to be meticulously defined.
Additionally, ensuring computational efficiency while maintaining high accuracy is a critical challenge. Large-scale simulations can be resource-intensive, demanding robust computational power and optimized workflows. Identifying and mitigating potential sources of numerical errors or instabilities is essential to achieving reliable results.
Understanding the Importance of Vortex Simulation in Industrial Processes
Vortex simulation in stirred tanks is crucial for numerous industrial processes, including chemical mixing, pharmaceutical manufacturing, and food processing. Understanding the flow patterns and vortex formations helps in optimizing mixing efficiency, reducing energy consumption, and ensuring uniform product quality.
Accurate simulation allows engineers to predict potential issues such as dead zones, where mixing is insufficient, or excessive shear, which can damage sensitive materials. By leveraging vortex simulations, industries can enhance process control, reduce operational costs, and improve overall product consistency.
Engineering Solution
Ansys Fluent software provides a comprehensive solution for simulating steady vortices in stirred tanks through its parametric workflow. This powerful tool enables engineers to define a range of parameters and systematically explore their effects on vortex behavior.
The parametric workflow allows for automated simulations, where multiple scenarios can be evaluated efficiently. Engineers can adjust variables such as impeller type, rotation speed, and fluid properties, and analyze the resulting vortex structures. This approach ensures a thorough understanding of the system's dynamics and helps in optimizing design and operational parameters.
Application:
An unbaffled cylindrical tank agitated by a Rushton turbine impeller was used for this application. The computational domain is shown in Figure 1.
Figure 1. Computational Domain of the Stirred Tank
The "Volume of Fluid" multiphase model was applied with air as primary phase and water as secondary phase (Figure 2).
Figure 2. The Multiphase Model Settings
The agitation speed, density, liquid level, and viscosity were set as input parameters. The power, vortex depth, maximum liquid level rank height ratio, and minimum liquid level impeller height ratio were set as output parameters. Figure 3 shows the corresponding named selection used as input/output parameter, and depiction of the height related parameters.
Figure 3. The Input and Output Parameters
Since this is a steady-state application, "Frame Motion" option was used to define the rotation in the rotating domain. agitation speed input variable was set as the rotational speed (Figure 4).
Figure 4. Rotational Settings
A cell register was used to define the initial liquid height. In this example 0.19 m from the bottom of the tank will be assumed filled with liquid (Figure 5).
Figure 5. Initial Liquid Volume Settings
The simulation with the current settings indicated that, the steady-state solution could be approximately established with about 5000 iterations. The Residuals and the vortex depth monitor are shown in Figure 6.
Figure 6. The Simulation Residuals (Left), and the Vortex Depth Monitor (Right)
The below animation of the vortex formation also indicates a minor change towards the end of it to further support the established steady state. Note that, the impeller does not rotate in the animation as the rotation was modeled as moving frame for the steady solution.
The details of the model settings and post=processing steps can be found in the below video:
The video can further be reached from Ozen Engineering YouTube account: Simulation of Steady Vortex in a Stirred Tank using Ansys Fluent
Benefits
The utilization of Ansys Fluent's parametric workflow for vortex simulation offers several benefits. First, it significantly reduces the time required for design iterations by automating the simulation process. Engineers can quickly identify optimal configurations without manually adjusting each parameter.
Moreover, the high accuracy of simulations ensures that the results are reliable and can be confidently used for decision-making. This leads to improved process efficiency, cost savings, and enhanced product quality. Additionally, the ability to visualize complex flow patterns aids in better communication of design concepts and results to stakeholders.
Ozen Engineering Expertise
Ozen Engineering Inc. leverages it's extensive consulting expertise in CFD, FEA, thermal, optics, photonics, and electromagnetic simulations to achieve exceptional results across various engineering projects, addressing complex challenges like multiphase flows, erosion modeling, and channel flows using Ansys software.
We offer support, mentoring, and consulting services to enhance the performance and reliability of your hydraulic systems. Trust our proven track record to accelerate projects, optimize performance, and deliver high-quality, cost-effective results for both new and existing water control systems. For more information, please visit https://ozeninc.com.