Visualize the Flow

In this step, we use a results plane to view the flow through the valve.

  1. Click Planes from the Results tab:

    result planes

  2. To create a Plane, click Add on the Planes context panel:

    add plane

    You should see this:

    plane thru result

  3. To rotate the plane, left click on it, and click Z from the Context dialog:

    z plane

    You should see this (but without the letters):

    z plane done

    What is this image telling you?

    • The orange regions near the top of the poppet mean that the flow is accelerating through the gap.
    • The flow on the trailing side of the poppet seems to be recirculating. We'll be able to tell more when we look at vectors.
    • As the flow turns toward the outlet, it accelerates off the inside corner.
  4. To see the pressure drop through the valve, right click on the plane, click Plane result and Static Pressure:

    pressure plane

    You should see this:

    result pressure plane

Note: This is a plot of static gage pressure. Recall that the outlet boundary condition was set to 0 Pa gage, so everything in this plot is relative to the that value.

This plot shows the pressure drop through the valve. Because the pressure is 0 at the outlet, the pressure at the inlet is the overall pressure drop. Note that the pressure dips pretty low as it turns the inside corner near the outlet (position "C" from step 3). Fortunately it's not so low that cavitation is an issue.

In the next step, we use vectors to better understand the flow.

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