Dear nThank you for getting back to me. nI actually have 20 points @ various locations near heat sinks as well as inlet and outlet. nAnd all those 22 points have somewhat similar air volume fraction : 1.0~1.5 %. nHowever according to the contour, even between the fins of heat sinks, air volume fraction seems to exceed 30%.nnCloud you please elaborate on 'check the area average of Volume of Fluid at the walls'?nWhich walls are you talking about; heatsink, cold plate or outer layer of cooling tank?nAnd what am I supposed to look for?.Kind regards,nNatn