本文以實驗方式探討蝴蝶閥在小開度下之壓損特性，受測蝴蝶閥口徑為５０公厘和１００公厘各一只，實驗採靜態體積檢驗法施測。
實驗結果顯示，５０公厘蝴蝶閥的能量損失係數明顯大於１００公厘者，尤其在小開度時的差異更為明顯，此現象顯示，不同口徑的蝴蝶閥，其能量損失係數隨著蝴蝶閥的構造、閥瓣的口徑、形狀等因素而異。另蝴蝶閥開度愈大，其能量損失係數相對減少，而能量損失係數雖會隨著下游流量控制閥開度減少而略微升高，但增值不大。
實驗結果另顯示，蝴蝶閥的能量損失係數隨著雷諾數增大而減小，即能量損失係數與雷諾數成負相關。蝴蝶閥的能量損失係數隨著壓力係數放大而增大，即能量損失係數與壓力係數成正相關。蝴蝶閥的能量損失係數隨著福祿數增大而減小，即能量損失係數與福祿數成負相關
。

　　This thesis studied the characteristics of energy loss coefficient (kc) of butterfly valve in small degree of opening by experiment. The diameters of tested butterfly valves are 50 and 100 millimeters respectively. The static cubage test method was adopted in measuring discharge.
　　The results showed that the kc of 50 mm is much larger than 100 mm’s, especially in small degree opening. This revealed that kc varied with the structure, diameter and disc shape of a butterfly valve. In addition, kc decreased as opening degree increased. The kc would increase slightly only as the discharge decreased.
　　Other experimental results revealed that the kc decreased as Reynolds number increased, i.e., kc had negative correlation with Reynolds　number. The kc increased in accompanying with pressure coefficient increased. It meaned kc had positive correlation with pressure coefficient. The kc increased as the Froude number increased, i.e., kc had negative correlation with Froude number.

【1】Morris M. J. and Dutton J. C. and Addy A. 　L. ,"An Investigation of　Compressible Flow Characteristic of Butterfly　Valves"Transactions of the ASME Journal of the　Fluid　Engineering , December , 1985 , Vol.107 ,p512-517
【2】Morris M. J. and Dutton J. C., "Aerodynamic
Torque Characteristic of　Butterfly Valves　in Compressible Flow " .Transactions of the　ASME, Journal of the Fluids Engineering, December, 1989,Vol.111, p392-399
【3】Morris M. J, and Dutton J.C., "Compressible
Flowfield Characteristic of Butterfly Valves
",Transactions of the ASME ,Journal of the　Fluids Engineering December , 1989, Vol.111, p400-407
【4】Morris M. J. and Dutton J. C., "An Experimental Investigation of Butterfly　Valve Performance Downstream of an Elbow ",Transactions
of the　ASME ,Journal of the Fluids Engineering, March , 1991 , Vol. 113, p81-85
【5】Chendong Huang and Rhyn H. Kirn ,"Three-
Dimensional Analysis of Partially Open Butterfly Valve Flows" .Transactions of the
ASME ,Journal of the Fluids Engineering ,
September , 1996 , Vol,118, p562-568
【6】Roberson and Crowe,Engineering Flow Mechanics, USA, p115,Third Edition
【7】Frank M.White,Fluid Mechanics,Southeast
Book Company ,Taiwan,p161,1980
【8】陳文龍，圓管內蝴蝶閥與流場交互作用之研究，成功大學工程科學所碩士論文，
第６９頁，民８８年。
【9】范德仙，流體力學，全華科技圖書公司，第３９１頁，民７７年。
【10】林國慶、蘇國欽，流體力學及其工程上之應用，大學圖書出版社，第２０３頁，
民６７年。
【11】張笑航，精密量具及機件檢驗，全華科技圖書公司，第４３頁，民８７年。
【12】阮光業、盛其安，品質管制與可靠性工程，超級科技圖書公司，第８６頁,
民７５年。