High Gravity Influence on Boiling Heat Transfer in Helical Coils
Experiments were conducted to investigate the flow boiling heat transfer in helical coils under high gravity operating conditions. The centrifuge used for this study has a two meter-long arm allowing providing the high gravity up to 11 g. The heat flux can be up to 15100 W m−2 and the mass velocity ranging from 40 to 200 kg m−2 s−1, and the outlet quality ranging from 0% to 50%. Flow visualization and wall superheat in two high gravity direction configurations were analyzed. Experimental results showed that the high gravity acceleration had an adverse superheat influence on the flow boiling heat transfer, particularly at the low mass and the low vapor quality. The heat transfer in radial acceleration configuration was found to be superior to that in axial configuration. The helical coil curvature in itself could be utilized as a high gravity resistance.