شبیه‌سازی سه‌بعدی انتقال حرارت و جرم در جریان آشفته دوغاب یخ در لوله‌های افقی

دوﻏﺎب ﯾﺦ ﺑﻪ ﺗﺮﮐﯿﺒﯽ از ذرات رﯾﺰ ﯾﺦ ﺑﺎ ﺳﯿﺎل ﺣﻤﻞ ﮐﻨﻨﺪه ﻣﺎﯾﻊ ﻣﺎﻧﻨﺪ آب ﮔﻔﺘﻪ ﻣﯽﺷﻮد. ﮐﻪ ﺑﻪﻋﻠﺖ ﺗﻮاﻧﺎﯾﯽ ﺗﻐﯿﯿﺮ ﻓﺎز، ﺑﻪﻋﻨﻮان ﻣﺒﺮد ﺳﺮﻣﺎﯾﺸﯽ ﻣﻮرد اﺳﺘﻔﺎده ﻗﺮار ﮔﺮﻓﺘﻪ اﺳﺖ. در ﻣﻄﺎﻟﻌﻪ ﺣﺎﺿﺮ ﺟﺮﯾﺎن ﺗﻐﯿﯿﺮ ﻓﺎز دﻫﻨﺪه دوﻏﺎب ﯾﺦ در داﺧﻞ ﻟﻮﻟﻪﻫﺎی اﻓﻘﯽ ﺑﻪﺻﻮرت ﻋﺪدی و ﺑﺎ اﺳﺘﻔﺎده از ﻧﺮماﻓﺰار ﻓﻠﻮﺋﻨﺖ ﻣﻮرد ﺑﺮرﺳﯽ ﻗﺮار ﮔﺮﻓﺘﻪ اﺳﺖ. ﻣﺎﻫﯿﺖ دوﻓﺎزی ﺗﺮﮐﯿﺐ دوﻏﺎب ﯾﺦ ﺑﺎ اﺳﺘﻔﺎده از ﻣﺪل دوﻓﺎزی اوﯾﻠﺮ-اوﯾﻠﺮ و ﺑﺮ ﭘﺎﯾﻪ ﺗﺌﻮری ﺟﻨﺒﺸﯽ ﺟﺮﯾﺎنﻫﺎی داﻧﻪای ﻣﻮرد ﺑﺮرﺳﯽ ﻗﺮار ﮔﺮﻓﺘﻪ اﺳﺖ. در اﯾﻦ ﭘﮋوﻫﺶ اﺛﺮ ﺗﻐﯿﯿﺮ ﻓﺎز ذرات ﯾﺦ ﺑﺮ روی ﻣﯿﺰان ﺣﺮارت و ﺟﺮم ﻣﺒﺎدﻟﻪ ﺷﺪه ﺑﯿﻦ ﻓﺎزی ﻣﻮرد ﺑﺮرﺳﯽ ﻗﺮار ﮔﺮﻓﺘﻪ و اﻓﺰاﯾﺶ 12 درﺻﺪی ﺿﺮﯾﺐ اﻧﺘﻘﺎل ﺣﺮارت ﻣﺤﻠﯽ ﺑﺮای اﺳﺘﻔﺎده از ﺗﺮﮐﯿﺐ دوﻏﺎب ﯾﺦ ﻧﺴﺒﺖ ﺑﻪ آب ﺧﺎﻟﺺ ﺗﮏﻓﺎز ﻣﺸﺎﻫﺪه ﺷﺪه اﺳﺖ. ﻫﻢﭼﻨﯿﻦ ﺑﺎ ﺑﺮرﺳﯽ ﻣﯿﺰان اﻧﺘﻘﺎل ﺟﺮم و اﻧﺘﻘﺎل ﺣﺮارت در ﻃﻮل ﻟﻮﻟﻪ ﻣﺸﺨﺺ ﺷﺪه اﺳﺖ ﮐﻪ ﺿﺮﯾﺐ ﺟﺎﺑﻪﺟﺎﯾﯽ ﺣﺮارﺗﯽ در ﻃﻮﻟﯽ از ﻟﻮﻟﻪ ﮐﻪ ﺑﺰرگﺗﺮ از 15-10 ﺑﺮاﺑﺮ ﻗﻄﺮ ﻟﻮﻟﻪ اﺳﺖ، ﺑﻪﺻﻮرت ﺛﺎﺑﺖ ﺑﺎﻗﯽ ﻣﯽﻣﺎﻧﺪ. در ﺣﺎﻟﯽ ﮐﻪ ﺗﻐﯿﯿﺮات ﻣﯿﺰان ﺟﺮم ﻣﯿﺎﻧﮕﯿﻦ ﻣﺒﺎدﻟﻪ ﺷﺪه در ﻃﻮل 10 اﻟﯽ 15 ﺑﺮاﺑﺮ ﻗﻄﺮ ﻟﻮﻟﻪ ﺑﻪ ﺑﯿﺸﺘﺮﯾﻦ ﻣﯿﺰان ﻣﻤﮑﻦ (ﺑﯿﻦ 5-2 ﺑﺮاﺑﺮ ﺧﺮوﺟﯽ) رﺳﯿﺪه و ﭘﺲ از آن ﮐﺎﻫﺶ ﻣﯽﯾﺎﺑﺪ ﺿﻤﻦ آنﮐﻪ ﮐﻪ در 20 درﺻﺪ اﻧﺘﻬﺎﯾﯽ ﻃﻮل ﻟﻮﻟﻪ، روﻧﺪ ﮐﺎﻫﺸﯽ ﺳﺮﯾﻊﺗﺮ اﺳﺖ.

3 D simulation of heat and mass transfer in turbulent flow of ice slurry in horizontal pipes

Ice slurry is called a mixture of fine ice particles with a fluid carrier such as water. The phase change ability of this mixture attracts the strong attention in the areas of thermal storage and refrigerant cooling of the secondary cycle. In this research, flow of ice slurry in horizontal tubes during the phase change is numerically investigated using FLUENT software. The twophase nature of ice slurry mixture is studied using the EulerEuler twophase model based on kinetic theory of granular flows. The effect of ice particles phase change on heat and mass transfer between phases are investigated, the obtained results show that the local heat transfer coefficient for the use of the icy slurry mixture is increased 12% compare to the pure water. It is also determined by examining heat and mass transfer rate along tube, that the heat transfer coefficient for the pipe lengths larger than 1015 times pipe diameter, remains constant. The variation of mean mass transfer is maximum at distance of 1015 times of pipe diameter. The maximum value is 25 times larger than mean mass transfer in the pipe outlet. At the 20% end of the pipe, the decreasing trend of mass transfer accelerates.