本研究主要探討醫用水刀噴嘴出口外型成為30度角的漸張噴嘴時，噴嘴出口流場的定性及定量分析，包括平均流量、平均流速、衝擊力、輸出功率及流場觀測與高速攝影拍照，對此改良式漸張噴嘴與傳統式直管噴嘴進行相關性能比較。實驗結果顯示在相同操作壓力下的水刀流量、衝擊力、功率以及凝膠體切割深度，漸張式噴嘴皆比直管式噴嘴為大，而噴流水柱的流場結構方面，漸張式噴嘴有比直管式噴嘴穩定，能夠維持較長的未擴長度。因此在相同水刀操作壓力下時，使用漸張式的噴嘴便能有效增強水刀出口能量，進而提升水刀切割效能。

The experimental investigation on the performance of a cone-down nozzle water jet cutter for surgical application has been done in the Institute of Aeronautics and Astronautics of National Cheng-Kung University. By using various nozzles with different nozzle diameters and a fixed cone-down angle of 30o , the jet flow characteristics have been measured and the jet flow pattern have been observed by high speed photography. The results show that under the same operational pressure the cone-down nozzle has a higher flux, a higher impinging force and a higher cutting depth on phantom tissue on comparing with the straight-tube nozzle. The cone-down nozzle offers the outlet flow flied in a much stable and longer breakup length than the straight-tube nozzle. Thus, it concludes that the cone-down geometry can improve the efficiency of a water jet cutter.

[1]M.O. Schurr, M. Wehrmann, W. Kunert, A. Melzer, M.M. Lirici, R. Trapp, E. Kanehira, G. Buess ,“Histologic effects of different technologies for dissection in endoscopic surgery: Nd:YAG laser, high frequency and water-jet,” Endoscopic Surgery Allied Technologies, Vol. 2, No. 3-4 , pp. 195-201, 1994.
[2]王詩誠, “脈衝式醫用水刀性能之改進研究,” 成功大學航太研究所碩士論文, 2006.
[3] I.W. Farmer, P.B. Attewell, “Rock penetration by high velocity water jet,” International Journal Rock Mechanics and Mining Science, Vol. 2, pp.135-153, 1964.
[4] N. Brook, D.A. Summers, “The penetration of rock by high-speed water jet,” International Journal Rock Mechanics and Mining Science, Vol. 6, pp.249-258, 1969.
[5] D.N. Papachristou, R. Barters, “Resection of the liver with a water jet,” British Journal of Surgery, Vol. 69, No. 2, pp.93-94, 1982.
[6] R. Izumi, K. Yabushita, K. Shimizu, M. Yagi, A. Yamaguchi, K. Konishi, T. Nagakawa, I. Miyazaki, “Hepatic resection using a water jet dissector,” Surgery Today, Vol. 23, No. 1, pp.31-35, 1993.
[7] I. Lipshitz, R. Bass, A. Loewenstein, “Cutting the cornea with a waterjet keratome,” Journal of Refractive Surgery, Vol. 12, No. 1, pp.184-186, 1996.
[8] H.G. Rau, E.R. Buttler, G. Baretton, H.M. Schradey & F.W. Schildberg, “Jet-cutting supported by high frequency current: New technique for hepatic surgery,” World Journal of Surgery, Vol. 21, pp.254-260, 1997.
[9] R. Magritz, V. Jurk, E. Reusche, R. Siegert, “ Water-jet dissection in parotid surgery: an experimental study in dogs,” Laryngoscope, Vol. 111, No. 9, pp.1579-1584, 2001.
[10] M. Wanner, S. Jakob, F. Schwarzl, M. Oberholzer and G. Pierer, “ Optimizing the Parameters for Hydro-Jet Dissection in Fatty Tissue – A Morphological Ex Vivo Analysis,” European Surgery, Vol. 34, No. 2, pp.137-141, 2002.
[11] C. Kortan, N.Y. Bayramov, T.M. Rzaev, A. Tas, U. Abbasov, “Diameter and Pressure of the Water-Jet For Liver Resection,”Eastern Journal of Medicine, Vol. 6, No. 2, pp.43-47, 2001.
[12] J. Oertel, M.R. Gaab, A. Knapp, H. Essig, R. Warzok, J. Piek, “Water Jet Dissection in Neurosurgery: Experimental Results in the Porcine Cadaveric Brain,” Neurosurgery, Vol. 52, No. 1, pp. 153-159, 2003.
[13]K. Yanaida, “ Flow Characteristics of Water Jets,” Proceeding second International Symposium on Jet Cutting Technology BHRA Fluid Engineering, Cranfield, pp. A2/19~A2/32, 1974.
[14]D.S. Shavlosky, “Hydrodynamics of high pressure fine continuous jets,” Proceeding first International Symposium on Jet Cutting Technology, BHRA Fluid Engineering, Cranfield, pp. A6-A81, 1972.
[15]H. Hiroyasu, “Spray Breakup Mechanism from the Hole Type Nozzle and Its applications,” Atomization and Sprays, Vol. 10, pp.511-527, 2000.
[16]B.R. Munson, D.F. Young, T.H. Okiishi, “Fundamentals of Fluid Mechanics” 4th Edition, John Wiley & Sons, Inc.
[17]Robert W. Fox, Alan T. McDonald, “Introduction to Fluid Mechanics” 5th Edition, John Wiley & Sons, Inc.
[18]許朝洋, “醫學用水刀的研究開發與測試,” 成功大學航太研究所碩士論文, 2003.
[19]H. Vahedi Tafrreshi, B. Pourdeyhimi, R. Holmes, D. Shiffler, “Simulating and Characterizing Water Flows Inside Hydroentangling Orifices,” Textile Research Journal, Vol.73, No. 3, pp.256-262, 2003.
[20]E. Ghassemieh, H. K. Versteeg, M. Acar, “Effect of Nozzle Geometry on the Flow Characteristics of Hydroentangling Jets,” Textile Research Journal, Vol.73, No.5, pp.444-450, 2003.