Difference between revisions of "Homework Assignment"

Revision as of 08:09, 14 March 2019

Aim of Assignment

Students will learn the basics of electromagnetic field calculations, their main steps, and gain practice in evaluating results and writing a Technical Report that meets international expectations.

Knowledge needed to solve the problem

• The main steps of the finite element method;
• Theoretical knowledge of the static magnetic field (for defining materials, for excitation);
• Knowledge of CAD system to create geometry;
• Download and install ANSYS AIM Student.

The Semester Assignment

The task consists of two parts, a basic task, with a faultless solution of up to 70%, and an extra task, with an additional maximum of 30%.

Part I of the Assignment

Calculating the force on the solenoid valve by finite element method

The geometry and dimensions of the task.

The task is cylindrical to the vertical ([math]z[/math]) axis, and the three-dimensional geometry must be prepared according to the specified dimensions (see figure).

Tasks

• Define the problem type based on the given parameters;
• Creating and specifying the task geometry in ANSYS Discovery AIM;
• Run the FEM simulation;
• Validation of results for a 2mm air gap. The value of the force acting on the plunger: [math]F(z=2\text{mm})=1.4611~\text{N}[/math] (inductance[math]L(z=2\text{mm}=21,27~\text{mH}[/math]);
• Test of Solution Performance (Solution performance tuning, Curved surface meshing) as a function of force;
• Number of finite elements (Tetrahedra), Energy (Total Energy), Energy Error and Delta Energy in the function of adaptive steps in two different cases;

• Postprocessing [at least two of the below]:

1) determination of force and inductance;

2) displaying equipotential lines;

3) display the minimum and maximum of the magnetic flux density;

4) display the magnetic field strength;

5) displaying magnetic flux density vectors.

• Preparation of a Technical Report based on the use of the above results.

Note: The “Part I of the Assignment” elements will be reviewed in detail during the exercise to prepare and run a simulation model for an electromagnetic task. On this basis, students can easily complete Part I of the Assignment by attending the exercises.

Parameters for this Assignment:

Relative permeability of air and coil [math]\mu_r = 1[/math];

The excitation of the coil (To validate the results): [math]I=0.76~\text{A}[/math], [math]N=789~{turns}[/math] (DC);

Magnetic curve of the core and plunge:

'Figure 1.' - Steel 1008 steel magnetization curve.

Part II. of the Assignment

Determining the force acting on the moving part of the problem (plunger) and the inductance of the coil as a function of displacement.

Note: This task corresponds to the solenoid valve in internal combustion engines that controls the injection.

Specific tasks

• Considering the plunger movement to the initial state (2mm air gap) from [math]-1.8\text{mm} \text{to} 10\text{mm}[/math] (at least in 7 positions). Detailed instructions on the solution will not be available.
• This part is intended to measure the degree of autonomy, initiative and diligence of the student, i.e.:
• # is the student able to do independent work;
• # to design, assemble and run the simulation alone.