Quote:
Originally Posted by Bavafa
Can you please elaborate on this and what is it involved in getting the data?
Thinking out loud, I would think that a good set of data would be driven by first having it flying with the stock size, 2.5" and then enlarge it to the FM150 size of 3" and then get the performance data.
I am also wondering if the shape of it will make much of difference, although we are only enlarging it by .5"
Am I off the mark on this?
|
Mehrdad,
The idea would be to send samples to Don Rivera at Air Flow Performance and have him test them on the flow bench. He would measure the pressure drop across various snorkel configurations.
The shape of the transition between the 2.5" and 3" bores certainly matters a lot. Nothing worse than an aft-facing step -- that is, having the tube abruptly expand from 2.5" to 3" diameter going downstream with a square step.
Ideally, go farther upstream in the snorkel where the diameter is bigger, and make a smooth transition without any restriction/reduced diameter. Second best is to gently expand out from the smaller diameter to the 3" diameter over as much length as you can.
The need for the gentle transition is that you are making a diffuser that is slowing the flow down from the higher velocity in the smaller diameter section, and you want to effectively slow it down with no flow separation to get the full available pressure increase. What happens with the aft-facing step is that the flow separates and you just have a jet of the higher velocity going into the larger diameter tube. The jet breaks down through turbulence so that you end up with the slower velocity, but no pressure increase. The available pressure increase was wasted in viscous dissipation.
At the same time, I would love to have Don test with and without the filter, and with the filter with a small radius lip around the perimeter to help the flow turn over the corners and down into the filter.