ﺑﺮرﺳﯽ ﻋﺪدي ﺗﺎﺛﯿﺮ ارﺗﻔﺎع ﺻﻔﺤﺎت ﻣﺸﺒﮏ ﻗﺎﺋﻢ در اﺳﺘﻬﻼك اﻧﺮژي ﺷﯿﺐﺷﮑﻦ ﻗﺎﺋﻢ

Numerical Study of the Effect of Height of Vertical Screens on Vertical dro‎p Energy Dissipation

ﺻﻔﺤﺎت ﻣﺸﺒﮏ ﻗﺎﺋﻢ از ﺟﻤﻠﻪ ﻣﺴﺘﻬﻠﮏﮐﻨﻨﺪهﻫﺎي اﻧﺮژي ﻣﯽﺑﺎﺷﻨﺪ ﮐﻪ ﻣﯽﺗﻮان از آنﻫﺎ در ﭘﺎﯾﯿﻦدﺳﺖ ﺳﺎزهﻫﺎي ﻫﯿﺪروﻟﯿﮑﯽ ﮐﻮﭼﮏ ﻧﻈﯿﺮ ﺷﯿﺐﺷﮑﻦﻫﺎي ﻗﺎﺋﻢ اﺳﺘﻔﺎده ﻧﻤﻮد. در ﺗﺤﻘﯿﻖ ﺣﺎﺿﺮ ﺑﻪ ﺑﺮرﺳﯽ ﻋﺪدي ﺗﺎﺛﯿﺮ ارﺗﻔﺎع ﺻﻔﺤﺎت ﻣﺸﺒﮏ در ﭘﺎﯾﯿﻦدﺳﺖ ﺷﯿﺐﺷﮑﻦ ﻗﺎﺋﻢ ﭘﺮداﺧﺘﻪ ﺷﺪه اﺳﺖ. ﺑﺮاي اﯾﻦ ﻣﻨﻈﻮر ﺳﻪ ارﺗﻔﺎع ﻧﺴﺒﯽ 0/4 ،0/2 و 0/6 ﺑﺮاي ﺻﻔﺤﺎت ﻣﺸﺒﮏ و ﻣﺤﺪوده ﻋﻤﻖ ﺑﺤﺮاﻧﯽ ﻧﺴﺒﯽ ﺑﯿﻦ 0/12 ﺗﺎ 0/42 اﻧﺘﺨﺎب ﺷﺪه اﺳﺖ. ﺑﺮاي ﻣﺪلﺳﺎزي ﻋﺪدي از ﻧﺮم اﻓﺰار Flow-3D ﺑﺎ دو ﻣﺪل آﺷﻔﺘﮕﯽ k-E و )(RNG k-E و ﺳﻪ ﻧﻮع ﻣﺶ ﺑﻨﺪي اﺳﺘﻔﺎده ﺷﺪه اﺳﺖ. ﻧﺘﺎﯾﺞ ﺣﺎﺻﻞ ﻧﺸﺎن داد ﮐﻪ ﻣﺪل آﺷﻔﺘﮕﯽ )(RNG k-E در ﻣﻘﺎﯾﺴﻪ ﺑﺎ ﻣﺪل آﺷﻔﺘﮕﯽ k-E ﻣﻄﺎﺑﻘﺖ ﺑﻬﺘﺮي ﺑﺎ ﻣﺪل آزﻣﺎﯾﺸﮕﺎﻫﯽ داﺷﺖ. ﻫﻤﭽﻨﯿﻦ ﻧﺘﺎﯾﺞ اﺳﺘﻔﺎده از ﺻﻔﺤﺎت ﻣﺸﺒﮏ ﺑﺎ ارﺗﻔﺎعﻫﺎي ﻣﺘﻨﻮع در ﭘﺎﯾﯿﻦدﺳﺖ ﺷﯿﺐﺷﮑﻦ ﻗﺎﺋﻢ ﻧﺸﺎن داد ﮐﻪ اﯾﻦ ﺻﻔﺤﺎت ﺑﻪ ﺗﺮﺗﯿﺐ اﺳﺘﻬﻼك اﻧﺮژي ﻧﺴﺒﯽ و ﻋﻤﻖ ﻧﺴﺒﯽ ﭘﺎﯾﯿﻦدﺳﺖ را ﻧﺴﺒﺖ ﺑﻪ ﺷﯿﺐﺷﮑﻦ ﻗﺎﺋﻢ ﺳﺎده ﺑﻪ ﻃﻮر ﻣﺘﻮﺳﻂ 176 و 94 درﺻﺪ اﻓﺰاﯾﺶ ﻣﯽدﻫﺪ. ﺑﺎ ﺑﺮرﺳﯽ ﻣﯿﺰان اﻓﺰاﯾﺶ راﻧﺪﻣﺎن اﺳﺘﻬﻼك اﻧﺮژي ﻣﯽﺗﻮان درﯾﺎﻓﺖ ﮐﻪ ﺻﻔﺤﻪ ﻣﺸﺒﮏ ﺑﺎ ارﺗﻔﺎع ﻧﺴﺒﯽ 0/4 و 0/6 ﺑﺎ ﮐﺎﻫﺶ ﻣﯿﺰان اﺳﺘﻐﺮاق ﭘﺮش ﻫﯿﺪروﻟﯿﮑﯽ ﻧﺴﺒﺖ ﺑﻪ ﺻﻔﺤﻪ ﻣﺸﺒﮏ ﺳﺮﺗﺎﺳﺮي، اﻧﺮژي ﺑﯿﺸﺘﺮي را ﻣﺴﺘﻬﻠﮏ ﻣﯽﮐﻨﻨﺪ. در ﻧﻬﺎﯾﺖ ﺷﯿﺐﺷﮑﻦ ﻗﺎﺋﻢ ﻣﺠﻬﺰ ﺑﻪ ﺻﻔﺤﻪ ﻣﺸﺒﮏ ﺑﺎ ارﺗﻔﺎع ﻧﺴﺒﯽ 0/4 ﺑﺎ ﮐﺎﻫﺶ 66/3 و 10/3 درﺻﺪي ﻋﺪد ﻓﺮود ﭘﺎﯾﯿﻦدﺳﺖ و اﻓﺰاﯾﺶ 187 و 2/8 درﺻﺪي اﺳﺘﻬﻼك اﻧﺮژي ﻧﺴﺒﯽ، ﺑﻪ ﺗﺮﺗﯿﺐ ﻧﺴﺒﺖ ﺑﻪ ﺷﯿﺐﺷﮑﻦ ﻗﺎﺋﻢ ﺳﺎده و ﺷﯿﺐﺷﮑﻦ ﻗﺎﺋﻢ ﻣﺠﻬﺰ ﺑﻪ ﺻﻔﺤﻪ ﻣﺸﺒﮏ ﺳﺮﺗﺎﺳﺮي داراي ﺑﻬﺘﺮﯾﻦ ﻋﻤﻠﮑﺮد ﺑﻮد.

Vertical screens are energy dissipaters that can be used downstream of small hydraulic structures such as vertical drops. In the present study, the effect of the height of the screens on the downstream of the vertical drop has been investigated numerically. For this purpose, three relative heights of 0.2, 0.4 and 0.6 for the screens and the relative critical depth range between 0.12 and 0.42 have been selected. For numerical modeling, Flow- 3D software with two turbulence models 𝑘 −  and 𝑘 −  (𝑅𝑁𝐺) and three types of meshing has been used. The results showed that the 𝑘 −  (𝑅𝑁𝐺) turbulence model was better performance than 𝑘 −  model in comparison with experimental results. Also, the results of using screens with different heights in the downstream of the vertical drop showed that these plates increase the relative energy dissipation and relative depth of the downstream by 176% and 94% respectively compared to the simple vertical drop. Investigating of the increase in energy dissipation efficiency, it can be seen that the screens with relative heights of 0.4 and 0.6 dissipates more energy by reducing the immersion rate of the hydraulic jump compared to the overall mesh plate. Finally, the vertical drop equipped with screen with a relative height of 0.4 with a decrease of 66.3 and 10.3 percent of the Froude number of downstream and an increase of 187 and 2.8 percent relative energy consumption, had the best performance compared to the simple drop and vertical drop equipped with an overall screen, respectively.