Centripetal comes from the latin words "centrum" - centre and "petere" which means to seek. I can assure you that when using centrifuges the contents do indeed fly away from the centre, not towards.
If you have any doubt, at the next carnival you can attend, take a ride on a horizontal spinning wheel and leave your seatbelt off. Then you can report back to us whether you flew back towards the centre or indeed away from the centre.