Simulation Electrical Heating Water in Continuous Flow Mode

The simulation of electrical heating of water in a continuous flow mode can be performed with NOGRID points CFD software.

Directly electrically heated liquids are found in many industrial processes and apparatuses. In this case study, a continuously operated immersion heater is computed. Devices that provide a continuous supply of a heated liquid are also called water heaters or boilers or simply heat exchangers in the case of water. The immersion heater used in this study has an electrical resistance heating element enclosed in a container. The liquid to be heated flows through the container. The heating element is simulated as a separate solid and is in direct contact with the liquid. Due to the electrical resistance of the metal, the liquid is heated to varying degrees depending on the thickness distribution, geometry and position of the immersion heater. Since several materials are computed simultaneously in this simulation and are in contact, this is also referred to as a multi-phase simulation.

Figure 1: CAD created in NOGRID's COMPASS

Figure 2: Electrical potential for the heater

Figure 3: Electrical power density for the heater

Figure 4: Temperature in the heater after 100 seconds

Figure 5: Temperature distribution for the water and the heater

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:

electricHeating equn 01

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

electricHeating equn 02

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:

electricHeating equn 03

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

electricHeating equn 04

The metal of the heater in this study is treated as a solid, i.e. only the temperature equation and the Poission equation for electrical potential are computed. The fluid within the chamber is of course in contact with the heater and heat can be exchanged, i.e. the temperature in the flow is affected by the temperature in the heater and vice versa. If, for example, the viscosity of the fluid depends on the temperature, then the temperature distribution of the heater has a direct influence on the flow in the nozzle.
The heat can be transferred either by heat conduction and/or heat radiation or by convection by means the flow of a fluid. You can couple also all kinds of heat transfer mechanisms. In the example ideal thermal contact between the nozzle and the fluid is specified.

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

NOGRID's particular strengths 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.
Easy Modelling with NOGRID CFD Software

Easy and fast modelling: Build geometry, mesh boundary, setup the case and start computation

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 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.

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