# How to Model High Viscosity Layered Waste Pumping in CFD?

• sergkras2000
In summary, the conversation is discussing a problem related to modeling liquid flows during the process of pumping from open storages. The liquid is a high viscous waste and is stored in natural reservoirs. The proposed formulation for the problem is to investigate the liquid flow of viscous incompressible layered waste in 2-D stationary laminar flow during the pumping process. The participants also discuss the potential addition of a heating process and the use of Navier-Stokes equations for the problem. The speaker suggests specifying the geometry and flow more and not worrying about heating if the viscosity depends on temperature.
sergkras2000
Please, can somebody help in a problem related to FD and outlined below.
I need to formulate a problem for the following question: modeling of liquid flows during a process of pumping from open storages. A liquid is high viscous waste similar to highly viscous oils. It is layered waste from coke making and petroleum refining plants. The waste are stored in nature reservoirs like a lagoons having three layers and it must be pumped with partly heating in predetermined depth.
Is the following formulation right and can be solved using current CFD codes: "Investigation of liquid flow of viscous incompessible layered waste in 2-D stationary laminar flow during a process of pumping from storages of industrial plants"?
Please, maybe somebody can suggest how to correct or complicate the formulation, may be by addition heating process problem or other definition for the Navier-Stokes equations?

Maybe it is a bit complex for me giving you the OK for your problem. You should specify more the geometry and flow.

At first sight I think that Incompressible Flow N-S equations are accurate for your purposes. Don't worry about heating. The heating will only affect to temperature field, only and only if the viscosity doesn't depends on temperature. If viscosity depends on temperature, then both momentum, continuity and energy equations are coupled.

The formulation for the CFD problem you have outlined seems appropriate and can be solved using current CFD codes. However, there are a few ways in which you can further refine and complicate the problem to make it more challenging and realistic.

Firstly, you can consider incorporating turbulence effects into the model, as real-life flows are often turbulent in nature. This would require the use of the Reynolds-averaged Navier-Stokes (RANS) equations and a suitable turbulence model.

Secondly, you can also include the effects of heat transfer in the problem. This would involve solving the energy equation along with the Navier-Stokes equations, and considering the temperature variations in the liquid as it is being pumped from the storage.

Additionally, you can also consider the presence of solid particles in the liquid waste, which can affect the flow behavior and require additional modeling techniques such as the Euler-Lagrange approach.

Overall, incorporating these additional complexities will make the problem more challenging and closer to real-life scenarios, and will require advanced CFD techniques and codes to solve it accurately. I hope this helps in refining your CFD formulation problem. Good luck!

## 1. What is a CFD formulation problem?

A CFD formulation problem refers to the process of mathematically modeling a fluid flow system using computational fluid dynamics (CFD) techniques. It involves creating a set of equations and numerical methods to accurately simulate and analyze fluid flow behavior.

## 2. What are the main challenges in formulating a CFD problem?

The main challenges in formulating a CFD problem include selecting the appropriate mathematical model, discretization method, and boundary conditions, as well as ensuring the accuracy and convergence of the solution. It also requires a thorough understanding of the physics of the problem and the limitations of the CFD software.

## 3. How do you validate a CFD formulation?

CFD formulation can be validated by comparing the results with experimental data or analytical solutions, if available. It is also important to conduct a grid independence study to ensure that the solution is not affected by the grid resolution. Additionally, sensitivity analysis can be performed to assess the impact of changing input parameters on the results.

## 4. What are some common sources of error in CFD formulation?

Common sources of error in CFD formulation include inadequate grid resolution, improper boundary conditions, and simplifications made in the mathematical model. Other sources of error can include numerical instabilities, convergence issues, and human error in inputting data.

## 5. How can CFD formulation be applied in real-world problems?

CFD formulation has a wide range of applications in various industries, such as aerospace, automotive, and energy. It can be used to optimize the design of aerodynamic components, study the flow behavior in internal combustion engines, and simulate heat transfer in power plant systems, among many others. CFD formulation can also be used to predict and analyze the effects of natural disasters, such as hurricanes and tsunamis, on structures and buildings.

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