بررسي آزمايشگاهي تأثير باكت پرتابي در انتهاي سرريز اوجي بر استهلاك انرژي و طول پرتابه

Experimental Study of Flip Bucket Effect at the End of Ogee Spillway on Energy Dissipation and Jet Length

در اين تحقيق تأثير باكت پرتابي در انتهاي سرريز اوجي بر ميزان استهلاك انرژي و طول پرتابه به­ صورت آزﻣﺎﯾﺸﮕﺎﻫﯽ ﺑﺮرﺳﯽ ﺷﺪ. آزﻣﺎﯾﺶﻫﺎ ﺑﺮ روي ﺳﺮرﯾﺰ اوﺟﯽ اﺳﺘﺎﻧﺪارد ﺑﺮاي ﺑﺎﮐﺖﻫﺎي ﺑﺎ زاوﯾﻪ ﺑﺮﺧﺎﺳﺖ 32 و 52 درﺟﻪ و ﺑﺪون ﺑﺎﮐﺖ اﻧﺠﺎم ﺷﺪ. ﻣﯿﺰان اﻓﺖ اﻧﺮژي در اﯾﻦ ﻧﻮع ﺳﺮرﯾﺰ ﺑﺎ اﻧﺠﺎم 21 آزﻣﺎﯾﺶ ﺑﺮاي دﺑﯽﻫﺎي ﺑﯿﻦ 330 ﺗﺎ 864 ﻟﯿﺘﺮ ﺑﺮ دﻗﯿﻘﻪ ﻣﻮرد ﺑﺮرﺳﯽ ﻗﺮار ﮔﺮﻓﺖ. ﻧﺘﺎﯾﺞ آزﻣﺎﯾﺶﻫﺎي اﻧﺠﺎم ﺷﺪه ﻧﺸﺎن داد در ﺳﺮرﯾﺰ ﺑﺎ ﺑﺎﮐﺖﻫﺎي ﭘﺮﺗﺎﺑﯽ ﺑﺎ زاوﯾﻪ ﺑﺮﺧﺎﺳﺖ 32 و 52 درﺟﻪ ﻧﺴﺒﺖ ﺑﻪ ﺳﺮرﯾﺰ ﺑﺪون ﺑﺎﮐﺖ، ﻣﯿﺰان اﺳﺘﻬﻼك اﻧﺮژي از 10 ﺗﺎ 20 درﺻﺪ اﻓﺰاﯾﺶ ﯾﺎﻓﺖ. ﻫﻢﭼﻨﯿﻦ ﺑﯿﺸﺘﺮﯾﻦ اﺳﺘﻬﻼك اﻧﺮژي ﻣﺮﺑﻮط ﺑﻪ ﺑﺎﮐﺖ ﭘﺮﺗﺎﺑﯽ ﺑﺎ زاوﯾﻪ ﭘﺮﺗﺎﺑﻪ 52 درﺟﻪ ﺑﻮد و اﻓﺖ ﻧﺴﺒﯽ اﻧﺮژي ﺑﺎ اﻓﺰاﯾﺶ دﺑﯽ در ﻫﺮ ﺳﻪ ﺣﺎﻟﺖ ﮐﻢ ﺷﺪ. ﺑﺮاي ﺑﺎﮐﺖﻫﺎي ﺑﺎ زاوﯾﻪ ﭘﺮﺗﺎب 32 و 52 درﺟﻪ، ﻃﻮل ﭘﺮﺗﺎﺑﻪ ﻧﯿﺰ اﻧﺪازهﮔﯿﺮي ﺷﺪ ﮐﻪ ﻃﻮل ﭘﺮﺗﺎﺑﻪ ﺑﺮاي ﺑﺎﮐﺖ 32 درﺟﻪ ﺑﯿﺸﺘﺮ از 52 درﺟﻪ ﺑﻮد. ﺑﺎ اﻓﺰاﯾﺶ دﺑﯽ، اﺧﺘﻼف ﻃﻮل ﭘﺮﺗﺎﺑﻪ ﺑﯿﻦ دو ﺑﺎﮐﺖ ﮐﻢ ﺷﺪه و در دﺑﯽ 864 ﻟﯿﺘﺮ ﺑﺮ دﻗﯿﻘﻪ ﻃﻮل ﭘﺮﺗﺎﺑﻪ ﺑﺮاي دو ﺑﺎﮐﺖ ﺗﻘﺮﯾﺒﺎً ﯾﮑﺴﺎن ﺷﺪ.

In this study, the effect of flip bucket at the end of ogee spillway on the energy dissipation rate and jet length has been investigated experimentally. Experiments on standard ogee spillway for buckets with take off angles of 32 and 52 and for no bucket condition were conducted. The rate of energy dissipation in this type of spillway was investigated with conducting 21 tests with discharge range between 330 to 864 L min-1 .The results showed that at the spillway with flip buckets and take off angles of 32 and 52 , the rate of energy dissipation was increased from 10 to 20 percent compared to the spillway having no bucket. The highest energy dissipation was occurred in the flip bucket with take off angle of 52 . Also the relative energy dissipation was decreased in all three modes with increasing discharge. The length of jet for flip buckets with angles of 32 and 52 was measured and it was releaved that the length of jet for bucket of 32 was greater than that for bucket of 52 . By increasing the discharge, the difference between the jet lengths of the two buckets was decreased and at the discharge rate of 864 L min-1, the length of jet was equal for the two buckets.