SALOME : impeller design

Salome : Free and Open source cad and meshing software. Today I tried using salome to model a impeller. The model was not an accurate design but an approximate to the actual one. Salome lacks a majot feature for blade designing i.e "loft". This was the only issue which I faced while creating the geometry.

Now let me explain you the steps in salome for making this design.

P.S. : The dimensions are in mm and other dimensions are just taken randomly.

Step 1.

In salome go to  " New Entities > 2D Sketch " and create a 2D image for the impeller as shown.

Step 2.

Click on the  " Reset Axis " to change the view of the sketch.

Create a face for the sketch using  " New Entity > Build > Face ".

Select the edges of the sketch and then click on Apply.

Step 3.

We need to revolve the face along an axis to complete the impeller design.

Go to " New Entity > Generation > Revolution ".

Click on the face and the axis along which we want to revolve and provide the input for revolution. In this case it is 360 deg.

Step 4.

Now we need to create the blades for the impeller.

Note that : The blades here are not having the perfectly aerofoil design shape as expected. The Salome seems to be lagging the lost function or may be I am not able to find it and hence its just an approximate design which I have come up with.

The thickness of the blade is 4mm and the top and bottom part of the blades are having a length of 58 mm and 80 mm.

To create the blade go to points and then create the points at the top surface of the impeller and at the bottom surface where the impeller blades cut the impeller.

Twist the bottom surface of the blade by and angle of 45 deg and having some curved surface.

STEP 5.

Similarly create a face for the blade and not extrude it along the Z axis.The blade has a thickness of 4 mm.

STEP 6.

To make multiple blades we need to create multiple copies of the blade. This can be done as follows :

Go to "Operation > Transformation > Multi-rotation"

Now create about 22 such copies of the blade with an angle of 25 deg in between each blade.

Now to make the geometry as a single model fuse the impeller and the blade using the fuse option. (" Operation > Boolean > Fuse ")

Save the mesh as impeller.msh (save it in ascii format)

This completes our geometry although not exact, but still an effort to create a impeller blade. I hope the loft option gets updated in the new release of Salome.( I am currently using Salome 7.2.0)

Meshing might take a while....so stay updated.. :)

Using Latex

For the time being please go through these spoken tutorials which are made by my Project Invigilator Prof. Kannan Modugalya. Simple 10 minutes tutorial will not only help you to learn latex but will help you learn it really quickly.

LINK : http://www.spoken-tutorial.org/tutorial-search/?foss=LaTeX&language=English

Plotting a variable against time in paraview 4.1.0

Paraview is really awesome and I bet once you start using it you would actually love it. Few things have changed in the new version of paraview and some I, myself had issues in dealing with some of the features. So my professor told me to get a plot of a scalar quantity v/s time and zoinks!!!..I gave a yes nod , but when I actually went and tried doing it I wasn't able to locate the option for plotting it. So after spending a quality 48 hours I realized it was a bit tricky and there was no good link/ forum / user manual available for doing it. So make life easier for beginners and paraview lovers and my friends these are the steps of creating a plot a graph with time.

STEP 1.

Open your OpenFOAM or any other format that you wish to open in Paraview.

STEP 2.

View your geometry along any direction you wish to.

STEP 3.

Now click if your geometry is 2D, you need not worry. But if it's 3D I would suggest to make the opacity of your geometry to 0.7/0.6 and and take a cut section at that location.


STEP 4.

After this now the real change comes into picture. In all the older versions of paraview we had Selection Display Inspector for selecting a location in the geometry, which is disabled in the latest version. In place of which a new option is provided just above the user interface window..which has a small icon named "SELECT POINTS ON". Click on this.

STEP 5.

Now place the point in your desired location and now select PlotSelectionoverTime.

STEP 6.

Click Apply and then wait for some time. For simple simulations it may be work quite fast and you will get a plot of various quantities v/s time. But for complex geometries it may take a while as it may consume more a greater chunk of your RAM.

STEP 7.

This end up the plotting . Now label your axis and use these graphs for your Reports. Happy plotting... :) !!!!

FOSS family just keeps growing...

It has been a fantastic journey with the FOSSEE (Free and Open Source Software for Science and Education ) team and it still continues to grow. Since I joined the team way back in 2011 and now when I see it today there is a lot of increase in the entropy of the whole project. With FOSS spreading like a wild fire in Indian Universities these days the addition of new FOSS tools has certainly bolstered the mission in a great way. From learing Scilab, Python to doing doing simulations using OpenFOAM to building a Inhouse Electrical software CAD tool, OR tools for optimization ,it really shows the efforts put up by every one.

I really wish the use of FOSS tools reaches every nooks and corners of India to save lot's of money that we invest on commercial tools and thus by investing the same money to develop the man power required to make FOSS more effective.

More information : http://fossee.in/