# Simulation Electrical Heating of a Channel Flow using a Scott Circuit with four Rod Electrodes

In this case study we consider a simulation of a channel flow heated by four rod electrodes using a Scott circuit. Here the rod electrodes are not computed as solid bodies, i.e. their geometric shell is the boundary of the channel model. The electrical potential is applied to the rod electrode boundary. Since this Scott circuit involves two separate (phase-shifted) circuits, two separate electric fields have to be computed in this simulation. Depending on the flow rate and the arrangement of the electrodes, the electrical resistance in the fluid sets a specific temperature distribution in the fluid.

Figure 1: CAD created in NOGRID's COMPASS

Figure 2: Electrical potential circuit A

Figure 3: Electrical power circuit B

Figure 4: Temperature after 360 seconds

Figure 5: Fluid velocity field including velocity vectors

Figure 6: Temperature distribution including electrical current field vectors for circuit A

If you want to perform a simulation 'electrical heating of a channel flow by using a Scott circuit with four rod electrodes' you can use the CFD software NOGRID points. Based on the geometrical model which can either be imported from your CAD or created with our CAD preprocessor COMPASS you can generate a computer model of a specific geometry in a very short time (compared to mesh-based methods) and see its thermal characteristics in advance.

The following equation is used within NOGRID points to solve the electrical potential u in liquids and solids:

u electrical potential u = u (x, y, z)
σ electrical heat conductivity
q source term

In the field of electrostatics, the electrical potential does not change with time and the valid differential equation for the electrical potential u is the Poisson equation

Conduction in solids and liquids is described by Ohm's law, which states that current is proportional to the applied electric field. The current density (current per unit area) j in an area is directly proportional to the electric field E and the proportionality factor is the electric conductivity σ:

The electric field E can be calculated directly from the electric potential u by

In this simulation, the Navier-Stokes equations together with the temperature equation and the Poission equation for electrical potential are computed. Due to the Scott circuit, two phase-shifted circuits are required, i.e. the above equations are solved twice in the simulation. The temperature in the flow is influenced by the magnitude of the electrical current, the arrangement of the rod electrodes and the temperature-dependent electrical resistance of the fluid. If, for example, the viscosity of the fluid depends on the temperature, the temperature distribution naturally has a direct influence on the flow in the channel.

NOGRID points helps to understand the flow by visualization of the mass, momentum and heat transfer of single and multiple phases. You receive integral quantities which you can use to analyze the heat exchange efficiency. NOGRID unites abilities to handle free surface flow and moving parts in the domain and allows the simulation of any conceivable geometry and operation modes such as

• computation is in full 3D solving complete Navier-Stokes-Equations
• easy and intuitive setup also for FSI (Fluid-Structure-Interaction) cases
• free definable material properties by equations or curves
• coupled solutions for electrical heating and fluid mechanic cases
• open or closed domains including inflow and outflow areas (non-batch mode)
• moving of parts and flexible thermal contact behaviour

## Nogrid's strengths

Particular strengths of NOGRID's fluid flow CFD software are the rapid preprocessing (no fluid grid needs to be generated, only the boundary mesh, inner finite points are generated automatically depending on User setting initially and during computation), and the outstandingly short computation time even for complicated cavities.
As you can see in the image below, the boundary of the geometry still requires a mesh to allow the interior finite points to detect the boundary. The boundary must therefore be meshed and the finite points inside are automatically generated during the simulation controlled by User specifications.

## What is CFD from NOGRID?

CFD solves the fundamental equations that define the fluid flow process. With CFD software from NOGRID every engineer makes better decisions by predicting, analyzing and controlling fluid flow, heat and mass transfer or chemical reaction. By using NOGRID software for flow modeling you receive information on essential flow characteristics as for example flow distribution. Using it additional to testing and experimentation NOGRID software helps to improve the evaluation of your design – resulting in better construction and operation parameters, increasing planning security and money savings due to faster time to the marketplace for your product or process.

## Choose NOGRID

With NOGRID, you choose professional CFD software and services – our aim is helping you to be successful. When you decide to work with NOGRID you choose close cooperation with a dynamic, flat hierarchies-organization. Short information channels result in quick and accurate professional support and service. Our team consists of highly qualified employees, who are experts in fields such as numerical simulation or computational fluid dynamics. Based on our know-how, we are pleased to offer the following services, responding to your individual requirements:

## TRAINING

In our two-days training courses you will learn, how to use NOGRID CFD software efficiently. Our technical support team will teach you how to handle and solve different cases.

For more details please refer to Training Courses →

## Technical Support

We offer full professional support from the minute you start using our software, by telephone or by email. Contact us, when ever needed.

For more details please refer to Software Support

## Service

Lack of time or resources and other constraints often make outsourcing an attractive solution. We help you with your flow modeling needs. Based on our engineering expertise in this field we offer individual numerical simulation services matching the unique needs of your organization.

For more details please refer to Simulation Services →

Göttelmannstr. 13B
55130 Mainz, Germany
info@nogrid.com