Session: K13-02 Pool Boiling Fundamentals

Paper Number: 107597

107597 - Experimental Study on Heat Transfer Characteristics of Carbon Dioxide Under Subcritical Pressures 

As a new type of refrigerant, carbon dioxide has been widely concerned due to its safety, stability and good heat transfer performance. The carbon dioxide refrigeration technology has broad application prospects. The deteriorated heat transfer is easily to be occurred even at low heat fluxes,  which will seriously damage the safe and stable operation of the refrigeration system. Howerver, the heat transfer deteriorated and critical heat flux of CO₂ under subcritical pressures has long been ignored. To study the heat transfer characteristics and heat transfer deterioration behavior of CO₂, a systematic analysis on heat transfer of CO₂ at subcritical pressures was implemented. Their heat transfer characteristics of carbon dioxide under subcritical pressures also compared with that in the supercritical pressure, the effects of mass flow rates and heat flux on the heat transfer characteristics was studied. The results show that the convection heat transfer performance of carbon dioxide under subcritical pressure is better than that under supercritical pressure, but the wall temperature peak is more likely to occur. The heat transfer deterioration will be aggravated by the decrease of mass flow rate and the increase of heat flow density. Based on the obtained experimental data, the correlation for predicting the critical heat flux is proposed as q_CHF/Gγ=e^-4.4189(ρ_L/ρ_V)^-0.7928We^-0.1730Ja^0.0838, with the maximum deviation of 15.6%.

Presenting Author: Qingjiang Liu Xi'an Jiaotong University