HEAT-EXCHANGE IN HORIZONTAL HELIUM 2-PHASE FLOW

We studied heat transfer between copper tube and two-phase helium for different flow patterns. We can reach stratified wavy, intermittent an d dispersed flow. The copper cell have two temperature sensors placed on top and bottom of the tube. For all flow regimes the upper and lowe r sensors record different heating in spite of the copper high thermal conductivity. The temperature ratio between upper and lower sensors c an be up to 20. This difference vanishes for dispersed flow. Moreover, for both intermittent and stratified wavy flow, the boiling crisis oc curs for heat flux of about 2 000 Wm(-2) and for the whole section. As expected no boiling crisis appears for dispersed flow.