Difference between revisions of "Homework Assignment"

Revision as of 06:10, 16 March 2021

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 Agros2D or FEMM.

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%.

Deadline	May 11, 2020, 23:59
Output Form:	PDF format. Color drawings should be made so that their contents are clear to the reader in black and white.
Language	English
Place of submission:	In Moodle system.
Late submission:	After every day started, a 5% deduction from the achieved result (i.e. after 5 days delay 100% can only be obtained up to 100% - 5x5% = 75%).
Evaluation:	0 - 48% - Insufficient [F] (1)
	50 - 59% - Sufficient [D] (2)
	60 - 70% Satisfactory [C] (3)
	71 - 84% Good [B] (4)
	85 - 100% - Very good [A] (5)
For the formal requirements, the requirements of CFD and mechanics are also valid here.

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 Agros2D(2D) or FEMM(2D);
• Run the FEM simulation;
• Validation of results for a 2mm air gap.

The results of the simulations.

Software	Discovery AIM	Maxwell 3D	FEMM	Maxwell 2D
Force [N]	3,586	3,582	3,542	3,587
Inductance [mH]	39,88	39,84	39,71	39,84

• 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~\text{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.:
  1. is the student able to do independent work;
  2. to design, assemble and run the simulation alone.

References