FLOW BOILING HEAT TRANSFER OF ELECTRONIC CHIPS IN HORIZONTAL CHANNELS

The heat transfer from silicon chips to a forced convection two-phase flow has been studied. The study has been a part of the tremendous research activities due to the now approved Large Hadron Collider (LHC) at CERN. The present study is related to the cooling of the innermost silicon detector region which will surround the collision point. Due to the specific application, the present work contains several important characteristics which are somewhat different to most of the previous work on two-phase cooling. The main emphasis has been to minimize the temperature variations and mechanical vibrations along the channel, and to reduce the total mass in the detector. We have therefore used a very narrow channel combined with a low liquid flow velocity. Silicon chips were mounted at the bottom part of a 300 mm-long horizontal channel. During the set of experiments, the liquid flow rate was changed within 0.43 to 1.54 × 10−6m3/s. At a heat flux of 1 watt per cm channel length, which is the anticipated heat load, we were able to keep the temperature variations between the different silicon chips to less than two degrees centigrade.