Journal of Xi'an Jiaotong University

Feasibility Investigation on Vacuum Liquid CO₂ Cryoprobe
Yan Jia，Tong Mingwei，Xu Guangcai，Hu Yinping
(College of Power Engineering，Chongqing University，Chongqing 400044，China)

Abstract：Heat transfer of creature tissues is largely related to blood perfusion，and then minishing blood perfusion has double senses in the cryotherapy．Based on the theoretical analysis，a vacuum liquid CO₂ cryoprobe was proposed and its feasibility was investigated using capillary tubes，with external diameters were of 3.0 mm，2.2 mm and 1.7 mm respectively．The results of experimental study show that mass flow rate of liquid CO₂ was related to lengths，internal diameters，and pressure drop of capillary tubes．Blocking problem which arose from CO₂’s three phases point was solved by adopting gradual pressure drop．In addition，the temperature of liquid CO₂ was lower than the ‘frozen dangerous temperature zone’ after its pressure decreased，and CO₂-consuming quantity was only 7 kg/h．Therefore it would be quite economical and feasible in cryosurgery．
Keywords：cryosurgery；feasibility investigation；liquid carbon dioxide；vacuum cryoprobe