What does a nose surgery have to do with a CFD simulation?

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About 20 years ago I underwent a nose operation myself in the Bundeswehrkrankenhaus in Ulm, because I got bad air on one side of my nose.

Since I like to know what happens, I followed the whole thing during the partial anaesthesia. The surgeon acted like a sculptor with a hammer and chisel. I wondered if he was working the right places and what would happen if he slipped. It’s not one of my most beautiful memories, but the subject has kept me busy.

To what extent these medieval methods may have made room for more modern procedures, I don’t know, but whether the bone is removed in the right place, we can tell you or the surgeon with the help of flow simulations today.

Figure 1: nasal cavity
Figure 2: Pressure distribution

At that time we had very long computation times with simple flow models and also the modelling expenditure was extremely long compared to today. A flow calculation would have been difficult to impossible, also the recording of the geometry and thus a CFD simulation would have been rather a matter of a pathologist.

Today we can model the exact geometry of the bone and cartilage structure of the respective patient with little effort using a CT scan and determine the pressure loss or volume flow of the two nostrils with a CFD simulation. Figure 2 shows the pressure curve, Figure 3 the flow lines.

The effects of a surgical intervention (expansion of the nasal space in the calculation model) can be simulated by locally changing the nasal structure.

The criterion as to whether the flow behaviour during surgery is better or worse can be evaluated on the basis of clear figures such as the volume flow through the two nostrils at the same differential pressures.

In addition, the CFD simulation can also be used to calculate and evaluate the distribution of water vapour in the breathing air.

Figure 3: Streamlines in the nasal cavity

If we inhale dry air, the lungs will not tolerate it so well. The breathing air must be humidified. The nose functions here like an air conditioner, which sets the right humidity. Figure 4 shows the dry air (blue) in the right nostril, which is sucked in and then moistened (red) towards the trachea.Maybe in a few years it will be possible to simulate snoring by coupled structure and flow simulation (FSI=Fluid-Structure-Interaction).  OP methods that provide relief would then be conceivable.

Figure 4: Humidification of the breathing air

In any case, we will continue to work on this topic at full speed.

In this sense I wish you a long breath.

If you are wondering whether a CFD simulation is also possible for your very personal project, we will be happy to advise you. Use our contact form here.

Your Stefan Merkle

One Response

  1. Hi Stefan,
    I love this blog – both as a CFD engineer and as someone who has a similarly non-functioning nose (it must be a sign of great intelligence or something).

    I’d like to feature it on the Simcenter Blog – either with you as a guest blogger, or with me writing a blog about your blog, and linking to this page in order to drive traffic. I would probably be good free advertising for your business.


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