低温治疗仪的改进研究-制冷及低温工程专业论文.docxVIP

II II 浙江大学硕士学位论文 Abstract Improved study on a cryosu咆ery app盯atus WuDongbo (Insti阳te of Refriger;刽ion and Cryogenics，Zhejiang University ，310027) ABSTRACT Cryosurgery employs low tempera阳reωdes甘oy dise邸ed tissues.ηl?s technology has been developed 出 part of modern medicine. It is an alternative of traditional surgery and has advantages of easy operation，no bleeding ，low side effect and high security. So far，cηosu鸣eηcan be applied to many clinical departments inc1uding general surgery，neurosurgery，urology，bone，chest heart surge.町， dermatology and oncology. An auto-cascade re企igeration system utilizes only one compressor wi也 zeotropic re仕igerant as the working fluid It can reach temperature of below 斗。O.C.The system is simple，compact and reliable. As a cooling source for cηosurgery app缸a阳乳 白e auto-cascade re仕igeration system can bring about many benefits. In thls 由esis，improved experimenta1 studies WI町e carried out on an existing apparatus，and simulation W拙 done with 由.e cryoprobe.ηle mamωn臼nts were as follows: (1)ηle connecting 阳be wω replacedωoffer better thermal insu1ation and flexibility. A new cryoprobe was designed. 白rrough test 让 wωfound 由at the 企eezing capacity of the cryoprobe w邸 obviously improved. (2) After choosing appropriate ratio of a quaternary re企igerant mixture，the lowest temperature at the cryoprobe could reach as low 邸 -130.C ，and 18W re企igeration c叩acity could be obtained at _90 o?.The impacts of the fluid composition on 也e system performanωwere studied. (3)ηle influences of the ambient temperature on 伽e operation par即neters of the system，suchω 伽e cryoprobe temperature，suction and discharge pressure，e对mωt temperature ，were investigated. ( 4) Numerical simulations on the heat transfer and fluid flow around the cryoprobe were done wi由 Fluent so仕ware. How the 仕eezing capacity and 吐le re仕igerant pressure drop were affected by 由e inlet s阳te of the re仕igerant was discussed. KEYWORDS: Cryosurgery，Auto-Cascade Re仕iger