Turbo - I looked back at Dan’s previous post in regard to this and he called it ‘fake news’ based on his error about the lower image being the Mercedes. That’s what I was triggered by. As you know I don’t come here these days and only did so on this occasion due to being pointed here by someone else.
@Just a fan - that was my exact line of enquiry, as without a bulkhead inside the rim you’d obviously get deflation. This only leaves the option of a cylindrical chamber for the air to circulate IMO and offers up the opportunity for heat to transfer between this chamber and the tyres volume and said heat then escapes through the gap in axle and wheel centre. Of course this creates a secondary aerodynamic effect but I think Mercedes had managed to convince the FIA that the effect was limited.
Ferrari have been quite clever here really, as they have not only been able to discern more about Mercedes ‘system’ through this consultation process but also created enough skepticism that they’d protest that Mercedes removed it anyway. It’s all smelling a bit like FRIC at the moment though, with this early system aimed at tyre temperature control but as you’ve noted, opening up the opportunity to use a similar system (perhaps more powerful) on the front hub, even though 2019’s rules are trying to prohibit that.
As for the actual way this system works, of course I can't be 100%, but this is how I understand it operates from the various interactions I've had with people on it.