پديد آورندگان :
ﺗﯿﻤﻮري ﯾﮕﺎﻧﻪ، ﻣﺮﯾﻢ داﻧﺸﮕﺎه رازي - ﮔﺮوه ﻋﻠﻮم و ﻣﻬﻨﺪﺳﯽ آب , ﺣﯿﺪري، ﻣﺤﻤﺪﻣﻬﺪي داﻧﺸﮕﺎه رازي - ﮔﺮوه ﻋﻠﻮم و ﻣﻬﻨﺪﺳﯽ آب , ﻗﺒﺎدﯾﺎن، رﺳﻮل داﻧﺸﮕﺎه رازي - ﮔﺮوه ﻋﻠﻮم و ﻣﻬﻨﺪﺳﯽ آب
كليدواژه :
حوضچه ترسيب مستطيلي , راندمان تله اندازي , مدل عددي يك بعدي , رسوبات غيريكنواخت
چكيده فارسي :
ﺳﺎﺑﻘﻪ و ﻫﺪف: روش ﻫﺎي ﻣﺨﺘﻠﻔﯽ ﺑﺮاي ﺟﻠﻮﮔﯿﺮي از ورود رﺳﻮﺑﺎت ﻣﻌﻠﻖ ﺑﻪ ﮐﺎﻧﺎل ﻫﺎي آﺑﯿﺎري وﺟﻮد دارد ﮐﻪ ﯾﮑﯽ از اﯾﻦ روش ﻫﺎ، اﺣﺪاث ﺣﻮﺿﭽﻪ ﻫﺎي ﺗﺮﺳﯿﺐ در اﺑﺘﺪاي ﺷﺒﮑﻪ آﺑﯿﺎري اﺳﺖ. ﺳﺮﻋﺖ آب در اﯾﻦ ﺳﺎزه ﺑﺎﯾﺪ آن ﻗﺪر ﮐﻢ ﺑﺎﺷﺪ ﮐﻪ رﺳﻮﺑﺎت ﻣﻌﻠﻖ ﺗﺎ ﻗﻄﺮ ﻣﺸﺨﺼﯽ در ﺣﻮﺿﭽﻪ ﻫﺎي ﺗﺮﺳﯿﺐ ﺗﻪ ﻧﺸﯿﻦ ﺷﻮد و ﻏﻠﻈﺖ رﺳﻮﺑﺎت در ﺟﺮﯾﺎن ﺧﺮوﺟﯽ ﺣﻮﺿﭽﻪ ﮐﺎﻫﺶ ﯾﺎﺑﺪ. راﻧﺪﻣﺎن ﺗﺮﺳﯿﺐ ﮐﻪ ﻧﺴﺒﺖ ﻏﻠﻈﺖ رﺳﻮﺑﺎت ﺧﺮوﺟﯽ ﺑﻪ ورودي اﺳﺖ ﺑﺎﯾﺪ ﻗﺒﻞ از ﻃﺮاﺣﯽ ﺣﻮﺿﭽﻪ ﺗﺮﺳﯿﺐ ﺑﺎ ﺗﻮﺟﻪ ﺑﻪ اﺑﻌﺎد ﻫﻨﺪﺳﯽ ﺳﺎزه، ﺧﺼﻮﺻﯿﺎت ﻫﯿﺪروﻟﯿﮑﯽ و ﻣﺸﺨﺼﺎت رﺳﻮﺑﺎت ورودي ﺗﻌﯿﯿﻦ ﺷﻮد ﺗﺎ ﺑﺮاي ﻣﺪﯾﺮﯾﺖ و ﺑﻬﺮه ﺑﺮداري از آن ﺑﺮﻧﺎﻣﻪ رﯾﺰي ﺷﻮد. ﻫﺪف از اﯾﻦ ﭘﮋوﻫﺶ، اراﺋﻪ ﻣﺪل ﻋﺪدي ﯾﮏ ﺑﻌﺪي رﺳﻮبﮔﺬاري در ﺣﻮﺿﭽﻪ ﺗﺮﺳﯿﺐ ﺑﺎ در ﻧﻈﺮ ﮔﺮﻓﺘﻦ داﻧﻪ ﺑﻨﺪي رﺳﻮﺑﺎت ورودي اﺳﺖ ﮐﻪ ﻋﻼوه ﺑﺮ ﺗﺨﻤﯿﻦ راﻧﺪﻣﺎن ﺗﻠﻪ اﻧﺪازي در ﺣﻮﺿﭽﻪ، ﺗﻐﯿﯿﺮات ﮐﻒ ﺣﻮﺿﭽﻪ، داﻧﻪ ﺑﻨﺪي رﺳﻮﺑﺎت ﺧﺮوﺟﯽ از ﺣﻮﺿﭽﻪ و ﻏﻠﻈﺖ رﺳﻮب در ﻫﺮ ﻣﻘﻄﻊ را ﻧﯿﺰ ﻣﺤﺎﺳﺒﻪ ﻣﯽ ﮐﻨﺪ.
ﻣﻮاد و روش ﻫﺎ: در اﯾﻦ ﭘﮋوﻫﺶ ﺑﻪ ﻣﻨﻈﻮر ﺷﺒﯿﻪ ﺳﺎزي رﺳﻮب ﮔﺬاري در ﺣﻮﺿﭽﻪ ﺗﺮﺳﯿﺐ اﺑﺘﺪا ﯾﮏ ﻣﺪل ﻋﺪدي ﺑﺮاﺳﺎس ﺷﻤﺎي ﺗﻨﺼﯿﻒ زﻣﺎن ﺗﻬﯿﻪ و ﺳﭙﺲ ﺑﻪ ﺑﺮرﺳﯽ ﺗﺄﺛﯿﺮ ﻋﻮاﻣﻞ ﻫﻨﺪﺳﯽ ﺣﻮﺿﭽﻪ ﺑﺮ راﻧﺪﻣﺎن ﺗﻠﻪ اﻧﺪازي رﺳﻮب ﭘﺮداﺧﺘﻪ ﺷﺪ. در ﻣﺪل ﻋﺪدي ﯾﮏ ﺑﻌﺪي ﺗﻮﺳﻌﻪ ﯾﺎﻓﺘﻪ، ﻣﻌﺎدﻻت ﺣﺎﮐﻢ ﺑﺮ ﺟﺮﯾﺎن و رﺳﻮب ﺑﻪ ﺗﺮﺗﯿﺐ ﺣﻞ ﮔﺮدﯾﺪ. ﺑﺮاي ﺻﺤﺖ ﺳﻨﺠﯽ ﻧﺘﺎﯾﺞ ﻣﺪل ﻋﺪدي از داده ﻫﺎي آزﻣﺎﯾﺸﮕﺎﻫﯽ اﻟﺒﺎرودي )1969( ﮐﻪ ﺷﺎﻣﻞ ﯾﮏ ﺣﻮﺿﭽﻪ ﺗﺮﺳﯿﺐ ﻣﺴﺘﻄﯿﻠﯽ ﺑﻪ ﻃﻮل 1/2446 ﻣﺘﺮ و ﻋﺮض 0/4572 ﻣﺘﺮ ﻣﯽ ﺑﺎﺷﺪ اﺳﺘﻔﺎده ﮔﺮدﯾﺪ. اﻟﺒﺎرودي ﺑﺮاي دﺑﯽ ﻫﺎي ﻣﺨﺘﻠﻒ ﻣﻘﺪار 200 ﻣﯿﻠﯽ ﮔﺮم ﺑﺮ ﻟﯿﺘﺮ رﺳﻮب ﺑﺎ ﻗﻄﺮ ﻣﺸﺨﺺ را ﺑﻪ درون ﺣﻮﺿﭽﻪ ﺗﺮﺳﯿﺐ وارد و ﺑﻌﺪ از ﻣﺪت زﻣﺎن ﻣﺸﺨﺼﯽ ﻣﻘﺪار ﻏﻠﻈﺖ ﺧﺮوﺟﯽ از ﺣﻮﺿﭽﻪ را اﻧﺪازه ﮔﯿﺮي ﮐﺮد. ﻫﻢ ﭼﻨﯿﻦ از داده ﻫﺎي ﺻﺤﺮاﯾﯽ ﺣﻮﺿﭽﻪ رﺳﻮب ﮔﯿﺮ ﻧﮑﻮآﺑﺎد اﺻﻔﻬﺎن )ﺷﺘﺎب ﺑﻮﺷﻬﺮي و ﻫﻤﮑﺎران، 2010( ﺑﻪ ﻣﻨﻈﻮر ﺻﺤﺖ ﺳﻨﺠﯽ اﺳﺘﻔﺎده ﮔﺮد ﯾﺎﻓﺘﻪ ﻫﺎ: ﻧﺘﺎﯾﺞ ﺻﺤﺖ ﺳﻨﺠﯽ ﻫﺎي راﻧﺪﻣﺎن ﺗﻠﻪ اﻧﺪازي ﻧﺸﺎن داد ﮐﻪ ﻣﻘﺪار ﺟﺬر ﻣﯿﺎﻧﮕﯿﻦ ﻣﺮﺑﻌﺎت ﺧﻄﺎ ﻣﺪل ﻋﺪدي ﺑﺮاي آزﻣﺎﯾﺶﻫﺎي اﻟﺒﺎرودي )6/15 (1969 درﺻﺪ و ﺑﺮاي ﺣﻮﺿﭽﻪ ﺗﺮﺳﯿﺐ ﺳﻤﺖ ﭼﭗ و راﺳﺖ ﺑﻪ ﺗﺮﺗﯿﺐ 8/13 و 6/77 درﺻﺪ اﺳﺖ. ﻫﻢ ﭼﻨﯿﻦ راﻧﺪﻣﺎن ﺗﻠﻪ اﻧﺪازي ﺑﺮاي ﻫﻤﻪ ذرات رﺳﻮب و ﺑﺮاي ﻫﺮ ﮔﺮوه ذرات ﻧﺴﺒﺖ ﺑﻪ ﻃﻮل ﺣﻮﺿﭽﻪ ﻣﻮردﺑﺮرﺳﯽ ﻗﺮار ﮔﺮﻓﺖ. ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد ﮐﻪ ﺑﺎ اﻓﺰاﯾﺶ ﻓﺎﺻﻠﻪ از اﺑﺘﺪا ﺣﻮﺿﭽﻪ، ﻣﻘﺪار راﻧﺪﻣﺎن ﺗﺮﺳﯿﺐ اﻓﺰاﯾﺶ ﻣﯽ ﯾﺎﺑﺪ ﺑﻪ ﻃﻮري ﮐﻪ در اﻧﺘﻬﺎي ﺣﻮﺿﭽﻪ ﺣﺪود 38/6 و 29/7 درﺻﺪ رﺳﻮﺑﺎت ﺑﻪ ﺗﺮﺗﯿﺐ در ﺣﻮﺿﭽﻪ ﭼﭗ و راﺳﺖ ﺗﻪ ﻧﺸﯿﻦ ﻣﯽ ﺷﻮد. ﺗﺮاز ﮐﻒ ﺣﻮﺿﭽﻪ ﺗﺮﺳﯿﺐ ﻧﯿﺰ ﺑﻪ دﻟﯿﻞ ﺗﻪ ﻧﺸﯿﻨﯽ رﺳﻮﺑﺎت ﺗﻐﯿﯿﺮ ﻣﯽ ﯾﺎﺑﺪ. ﻣﯿﺰان اﯾﻦ ﺗﻐﯿﯿﺮات در ﮐﻒ ﺣﻮﺿﭽﻪ ﻫﺎي ﺗﺮﺳﯿﺐ در اﺑﺘﺪاي ﺳﺎزه ﺑﻪ دﻟﯿﻞ ﻏﻠﻈﺖ ﺑﺎﻻي رﺳﻮﺑﺎت ورودي ﺑﯿﺶ ﺗﺮ از اﻧﺘﻬﺎ اﺳﺖ. ﻣﯿﺰان اﯾﻦ ﺗﻐﯿﯿﺮات در ﮐﻒ ﺣﻮﺿﭽﻪ ﻫﺎي ﺗﺮﺳﯿﺐ ﺳﻤﺖ ﭼﭗ و راﺳﺖ ﺑﺎ اﺳﺘﻔﺎده از ﺷﺒﯿﻪ ﺳﺎزي ﻣﺪل ﻋﺪدي ﭘﮋوﻫﺶ ﺣﺎﺿﺮ ﺑﻌﺪ از ﻣﺪت ﺳﻪ ﻣﺎه ﺑﻪ ﺗﺮﺗﯿﺐ ﺣﺪود 23/4 و 20 ﺳﺎﻧﺘﯽ ﻣﺘﺮ ﺑﻪ دﺳﺖ آﻣﺪ.
ﻧﺘﯿﺠﻪ ﮔﯿﺮي: ﭘﺲ از ﺗﻮﺳﻌﻪ و ﺻﺤﺖ ﺳﻨﺠﯽ ﻣﺪل ﻋﺪدي، ﻋﻤﻠﮑﺮد ﺣﻮﺿﭽﻪ ﻫﺎي ﺗﻪ ﻧﺸﯿﻨﯽ ﻧﮑﻮآﺑﺎد و ﻣﺪل آزﻣﺎﯾﺸﮕﺎﻫﯽ اﻟﺒﺎرودي ﺑﺎ اﺳﺘﻔﺎده از ﻣﺪل ﻋﺪدي ﻣﻮردﺑﺮرﺳﯽ ﻗﺮار ﮔﺮﻓﺖ. ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد ﮐﻪ ﻣﺘﻮﺳﻂ راﻧﺪﻣﺎن ﺗﻠﻪ اﻧﺪازي رﺳﻮب ﺑﺮاي ﺣﻮﺿﭽﻪ ﺗﺮﺳﯿﺐ ﺳﻤﺖ ﭼﭗ و راﺳﺖ 36/5 و 27/3 درﺻﺪ اﺳﺖ. ﺑﻨﺎﺑﺮاﯾﻦ ﻣﻘﺪار زﯾﺎدي رﺳﻮب ﺑﻪ داﺧﻞ ﺷﺒﮑﻪ آﺑﯿﺎري وارد ﻣﯽ ﺷﻮد. ﺑﻪ ﻣﻨﻈﻮر اﺻﻼح ﺣﻮﺿﭽﻪ ﻫﺎي ﺗﺮﺳﯿﺐ ﻧﮑﻮآﺑﺎد و اﻓﺰاﯾﺶ راﻧﺪﻣﺎن ﺗﻠﻪ اﻧﺪازي رﺳﻮب ﻣﯽ ﺗﻮان ﻃﻮل، ﻋﺮض و ﯾﺎ ﻋﻤﻖ ﺣﻮﺿﭽﻪ را اﻓﺰاﯾﺶ داد. ﺑﺪﯾﻦ ﻣﻨﻈﻮر ﺑﺎ اﻓﺰاﯾﺶ ﯾﮑﯽ از ﻣﺘﻐﯿﺮﻫﺎي ﻓﻮق و ﺛﺎﺑﺖ ﻧﮕﻪ داﺷﺘﻦ ﺑﻘﯿﻪ ﭘﺎراﻣﺘﺮﻫﺎ، ﻣﺪل ﻋﺪدي اﺟﺮا و راﻧﺪﻣﺎن ﺗﻠﻪ اﻧﺪازي ﻣﺤﺎﺳﺒﻪ ﺷﺪ. ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد ﮐﻪ اﻓﺰاﯾﺶ ﻃﻮل ﺣﻮﺿﭽﻪ ﺗﺮﺳﯿﺐ ﺳﻤﺖ ﭼﭗ و اﻓﺰاﯾﺶ ﻋﺮض ﺣﻮﺿﭽﻪ ﺳﻤﺖ راﺳﺖ ﺳﺪ ﻧﮑﻮآﺑﺎد ﺑﯿﺶ ﺗﺮﯾﻦ ﺗﺄﺛﯿﺮ را ﺑﺮ راﻧﺪﻣﺎن ﺗﻠﻪ اﻧﺪازي دار
چكيده لاتين :
Background and objectives: There are various methods to prevent the entry of suspended sediments into the irrigation canals, one of which is the construction of sedimentation ponds at the beginning of the irrigation network. Sediment efficiency, which is the ratio of the concentration of outlet sediments to inlet, should be determined before designing the sedimentation pond according to the geometric dimensions of the structure, hydraulic properties and characteristics of inlet sediments to be planned for management and operation. The purpose of this study is to present a one-dimensional model of sedimentation in the sedimentation pond by considering the sedimentation of inlet sediments, which in addition to estimating the trapping efficiency in the pond, also calculates changes in the pond floor, sedimentation of sediment outlet and sediment concentration in each section.
Materials and methods: n this study, in order to simulate sedimentation in the sedimentation pond, first a numerical model was developed and then the effect of the geometric factors of the pond on the sediment trapping efficiency was investigated. In the developed one-dimensional numerical model, the governing equations of flow and sediment were solved, respectively. To validate the results of the numerical model, El-Baroudi (1969) laboratory data were used, which include a rectangular sedimentation pond with a length of 1.2446 m and a width of 0.4572 m. For different discharges, El-Baroudi deposited 200 mg/l of sediment with a specified diameter into the sedimentation pond and after a certain period of time measured the concentration of the effluent from the pond. Also, field data of Nekoabad sediment catchment area of Isfahan (Shetab-Boushehri et al., 2010) were used for validation.
Results: The results of trap efficiency verifications showed that the mean value of the square root of the mean square error of the numerical model for El-Baroudi (1969) experiments was 6.15% and for the left and right sedimentation ponds were 8.13 and 6.77%, respectively. Also, the trapping efficiency was investigated for all sediment particles and for each group of particles in relation to the length of the pond. The results showed that with increasing the distance from the beginning of the pond, the amount of sedimentation efficiency increases so that at the end of the pond The sediments are deposited in the left and right basins, respectively. The floor level of the sedimentation pond also changes due to sedimentation of sediments. The rate of these changes in the floor of sedimentation ponds at the beginning of the structure is higher than the end due to the high concentration of inlet sediments. The amount of these changes in the bottom of the left and right sedimentation ponds using the numerical model simulation of the present study after three months was about 23.4 and 20 cm, respectively.
Conclusion: After developing and validating the numerical model, the performance of Nekoabad sedimentation ponds and El-Baroudi laboratory model were investigated using the numerical model. The results showed that the average sediment trapping efficiency for the left and right sedimentation ponds was 36.5% and 27.3%. Therefore, a large amount of sediment enters the irrigation network. In order to improve Nekoabad sedimentation ponds and increase sediment trapping efficiency, the length, width or depth of the pond can be increased. For this purpose, by increasing one of the above variables and keeping the other parameters constant, the numerical model was executed and the trapping efficiency was calculated. The results showed that increasing the length of the left sedimentation pond and increasing the width of the right pond of Nekoabad Dam has the greatest effect on the trapping efficiency
