This paper investigates the CO2 snow generation device in the
endoscopic system for medical application, and to explore the CO2 snow
freezing effect during in vitro test. A particle RT Sizer, Particle Image
Velocimetry system (PIV), Thermal Video System, and a hand-made CO2
snow scale system are used in this research. Effects of formation chamber
and bypass aperture on the quantity and quality of CO2 snow production are
investigated. Results show that CO2 snow has a superior freezing capability
in the application of cryosurgery, it is a potential star for the application of
cryosurgery guided by endoscopic. Results also show that the length of
formation chamber is an effective controlling parameter that has positive
effects on snow quantity (size and production rate), freezing capability
(freezing rate and minimum temperature) and impact area of snow ice.
Furthermore, the bypass aperture has negative effects both on nucleation
and agglomeration of small particles and on average size of CO2 snow
outside the chamber. However, it is an effective method to resolve the
problem of chamber frozen.