Volume 51

Experimental investigation of the effects of transverse vibration on the supercritical CO2 heat transfer characteristics in a vertical/horizontal tube Lin-Cheng Han, Jian Chen, Kun-Ru Wang, Hua Chen, Wen-Long Cheng

Abstract

Heat transfer characteristics (HTC) of supercritical CO2 (SCO2) is crucial for many applications in the field of energy conversion. However, there are very few studies concerning the effects of vibration on the HTC of SCO2. In this paper, the effects of transverse vibration on the HTC of SCO2 flowing upward within a vertical tube (d=4.57 mm, L=1000 mm) are investigated experimentally and compared with a horizontal tube. The results reveal that vibration mitigates heat transfer deterioration (HTD) in the vertical tube, reduces the second peak of wall temperature along the channel significantly, and enhances heat transfer coefficient (htc). Vibration is more effective in enhancing heat transfer in the vertical tube compared to the horizontal tube. The vibration intensification mainly acts in the region before the mainstream enthalpy (hb) reaches the pseudo-critical enthalpy (hpc). Based on pseudo-boiling theory, vibration enhances heat transfer by inhibiting the growth of near-wall gas-like film and the temperature gradient inside the gas-like film.

Keywords Supercritical CO2, Vibration, Heat transfer characteristics, Heat transfer enhancement