Fire Sprinkler with Flow Simulation

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For this post, I decided to take the fire sprinkler that I posted on December 18th and run a flow simulation with it.  In order to do this I first had to suppress the glass tube that would hold the water back.  This simulates the heat from a fire expanding the liquid inside and breaking the glass.  Before being able to run the simulation I needed to make a containment part around the head of the sprinkler and also put a lid on the open end by the threads.  This was done in order to run the analysis as an internal flow.  To set up the actual simulation I first set up the computational domain so that it was a little larger then my whole assembly.  For the general settings I set the analysis type to internal, the fluid to water, and left the rest of the settings to their defaults.  From there, I needed to set up my boundary conditions.  These specify what the input and outputs to the system are.  For the input of the system, I selected the inside face of the lid and used a static pressure that was in a normal direction to the lid.  I then selected the internal faces of the containment part and set those to the environmental pressure which I left set to the default.  I also set the faces that were in the direct line parallel to the lid as an ideal wall.  From there I meshed and ran the simulation.  Once it had finished solving I inserted a flow trajectory using the internal face of the lid with 500 points showing the pressure of the water.  This is seen in the image above.  The result has some abnormalities that aren’t what I expected  but that could be caused by how I set up the simulation.  I hope you enjoy.

 

Ian Jutras

Worcester Polytechnic Institute

Mechanical Engineering 2013

Download Fire Sprinkler with simulation