تعليق و به دام انداختن ذرات با ضريب كنتراست مثبت و بررسي تاثير حجم در محيط مايع به وسيله پديده آكوستوفرتيك

Suspend and trap particles with a positive contrast ratio and investigate the effect of volume in a liquid medium by the acoustophoretic phenomenon

ﺗﻌﻠﯿﻖ ﻓﺮاﺻﻮت ﺑﻪ دﻟﯿﻞ ﻋﺪم واﺑﺴﺘﮕﯽ ﺑﻪ ﺟﻨﺲ و ﺧﻮاص ﻣﺎده، ﺟﻬﺖ اﻣﮑﺎن ﺗﻌﻠﯿﻖ، ﺑﺮاي ﻃﯿﻒ ﮔﺴﺘﺮده اي از ذرات ﻗﺎﺑﻞ اﺳﺘﻔﺎده اﺳﺖ و ﭘﺘﺎﻧﺴﯿﻞ ﺑﺎﻻﯾﯽ در اﻧﺘﻘﺎل و ﺟﺎﺑﺠﺎﯾﯽ ذرات ﺑﻪ ﺻﻮرت ﮐﻨﺘﺮل ﺷﺪه دارد. ﻫﺪف اﺻﻠﯽ در اﯾﻦ ﻣﻘﺎﻟﻪ، اﺳﺘﻔﺎده از روﺷﯽ ﺟﺪﯾﺪ ﺑﺮ ﭘﺎﯾﻪ اﻣﻮاج ﻣﺎﻓﻮق ﺻﻮت، ﺑﺮاي ﺗﻌﻠﯿﻖ و ﺟﺪاﺳﺎزي ﺑﺪون ﺗﻤﺎس ذرات از ﻣﺤﯿﻂ ﻣﻮردﻧﻈﺮ ﻣﯽﺑﺎﺷﺪ. ﺑﺎ اﺳﺘﻔﺎده از اﯾﻦ روش ﮐﻪ آﮐﻮﺳﺘﻮﻓﺮﺗﯿﮏ ﻧﺎﻣﯿﺪه ﻣﯽ ﺷﻮد، اﺑﺘﺪا ذره ﻫﺪف ﺑﻪ ﻣﺤﯿﻂ ﺳﯿﺎل ﺗﺰرﯾﻖ ﺷﺪه و ﭘﺲازآن ﺑﻪ ﺣﺎﻟﺖ ﺗﻌﻠﯿﻖ درآﻣﺪه و ﺟﺪاﺳﺎزي ذره ﺻﻮرت ﻣﯽﭘﺬﯾﺮد. ﻣﺤﯿﻄﯽ ﮐﻪ ﺟﻬﺖ اﯾﻦ ﺗﻌﻠﯿﻖ و ﺟﺪاﺳﺎزي اﻧﺘﺨﺎب ﮔﺮدﯾﺪ، آب ﻣﯽﺑﺎﺷﺪ. ﻋﻠﺖ اﯾﻦ اﻧﺘﺨﺎب، ﻧﻮ ﺑﻮدن اﻧﺠﺎم ﺗﻌﻠﯿﻖ و ﺟﺪاﺳﺎزي در اﯾﻦ ﻣﺤﯿﻂ ﺑﻪ دﻟﯿﻞ وﯾﺴﮑﻮزﯾﺘﻪ ﺑﺎﻻﺗﺮ و ﺳﺮﻋﺖ ﺻﻮت ﺑﺎﻻﺗﺮ آب ﻧﺴﺒﺖ ﺑﻪ ﻫﻮا و ﻧﺰدﯾﮏ ﺑﻮدن اﯾﻦ ﻣﺤﯿﻂ ﺟﻬﺖ ﮐﺎرﺑﺮد ﭘﺎك ﺳﺎزي آب، ﺟﺪاﺳﺎزي آب ﻣﻮﺟﻮد در ﻧﻔﺖ ﺧﺎم و ﺟﺪاﺳﺎزي ﭘﻼﮐﺖ از ﺧﻮن در ﻣﻘﯿﺎس ﻣﯿﮑﺮوﻓﻠﻮﺋﯿﺪﯾﮏ ﻣﯽﺑﺎﺷﺪ. ﻧﯿﺮوي آﮐﻮﺳﺘﻮﻓﺮﺗﯿﮏ ﺑﺎﯾﺪ از ﺑﺮآﯾﻨﺪ ﻧﯿﺮوي ﮔﺮاﻧﺶ و ﺷﻨﺎوري ﺑﯿﺸﺘﺮ ﺑﺎﺷﺪ ﮐﻪ ﺑﺘﻮاﻧﺪ ﺑﺮ آن ﻏﻠﺒﻪ ﮐﻨﺪ و ذره را ﺑﻪ ﺣﺎﻟﺖ ﺗﻌﻠﯿﻖ درآورد و ﺑﺮاي اﻓﺰاﯾﺶ اﯾﻦ ﻧﯿﺮو ﻧﯿﺎز اﺳﺖ ﻓﺸﺎر آﮐﻮﺳﺘﯿﮏ زﯾﺎد ﺷﻮد ﮐﻪ در ﺣﺎﻟﺖ ﻋﺎدي ﺑﺎ ﺗﻮﺟﻪ ﺑﻪ ﻓﺮﮐﺎﻧﺲ ﭘﺎﯾﯿﻦ (20kHz) ﻣﻮرداﺳﺘﻔﺎده و ﻣﻘﯿﺎس ﻣﺎﮐﺮو ﻗﺎﺑﻞ اﻧﺠﺎم ﻧﯿﺴﺖ و اﻓﺰاﯾﺶ ﺗﻮان ﻣﺼﺮﻓﯽ ﺗﺮاﻧﺴﺪﯾﻮﺳﺮ ﺑﺎﻋﺚ اﯾﺠﺎد ﮐﺎوﯾﺘﺎﺳﯿﻮن ﺷﺪه ﮐﻪ ﻣﺎﻧﻊ ﺗﻌﻠﯿﻖ ذرات ﻣﯽﺷﻮد، در اﯾﻦ ﻣﻘﺎﻟﻪ ﺟﻬﺖ اﻓﺰاﯾﺶ ﻓﺸﺎر آﮐﻮﺳﺘﯿﮏ و ﺗﻌﻠﯿﻖ ذرات از ﻣﺤﻔﻈﻪ ﺑﺴﺘﻪ و ﺑﺎ اﯾﺠﺎد ﺟﺮﯾﺎن اﯾﺴﺘﺎي رزوﻧﺎﻧﺲ اﺳﺘﻔﺎده ﺷﺪ ﮐﻪ ﺗﻌﻠﯿﻖ ذرات را ﺑﺎ ﻫﻤﯿﻦ ﻓﺮﮐﺎﻧﺲ ﭘﺎﯾﯿﻦ اﻣﮑﺎنﭘﺬﯾﺮ ﮐﺮد. در اﯾﻦ ﻣﺮﺣﻠﻪ ﺳﺮﻋﺖ اوﻟﯿﻪ ذرات در ﺣﺎﻟﺖ ﺷﺒﯿﻪﺳﺎزي و ﻋﻤﻠﯽ 0/4 ﻣﺘﺮ ﺑﺮ ﺛﺎﻧﯿﻪ داده ﺷﺪ و ﻧﺘﺎﯾﺞ ﻧﺸﺎن داد ﮐﻪ ﺑﯿﺸﺘﺮﯾﻦ اﺧﺘﻼف ﺳﺮﻋﺖ ﺑﯿﻦ ذرات ﺑﺎ ﺣﺠﻢ ﮐﻢ و زﯾﺎد 12.5 درﺻﺪ در ﺣﺎﻟﺖ ﺷﺒﯿﻪﺳﺎزي و 10 درﺻﺪ در ﺣﺎﻟﺖ ﻋﻤﻠﯽ ﺑﻮد؛ ﺑﻨﺎﺑﺮاﯾﻦ ذره ﺑﺎ ﺣﺠﻢ ﺑﯿﺸﺘﺮ ﻧﯿﺮوي ﺑﯿﺸﺘﺮي اﺣﺴﺎس ﮐﺮده و ﺳﺮﻋﺖ ﺑﯿﺸﺘﺮي ﻣﯽﮔﯿﺮد. ﺑﯿﺸﺘﺮﯾﻦ اﺧﺘﻼف ﺑﯿﻦ ﺷﺒﯿﻪﺳﺎزي و ﺗﺴﺖ ﻋﻤﻠﯽ ﻧﯿﺰ 8 درﺻﺪ ﺑﻮده ﮐﻪ در آزﻣﺎﯾﺶﻫﺎي ﺗﺠﺮﺑﯽ، ﺻﺤﺖ ﻃﺮاﺣﯽ اﻧﺠﺎم ﺷﺪه و ﻫﻤﭽﻨﯿﻦ ﻧﺘﺎﯾﺞ ﺷﺒﯿﻪﺳﺎزي ﺗﺎﯾﯿﺪ شد.

Ultrasonic suspension can be used for a wide range of particles due to its independence from the material and properties of the material, and has a high potential for the transfer and manipulation of particles in a controlled manner. The main purpose of this paper is to use a new method based on ultrasonic waves, for suspension and noncontact separation of particles from the desired environment. Using this method, called acoustic acoustophoretic, the target particle is first injected into the fluid medium and then it is suspended and is separated. The environment chosen for this suspension and separation is water. The reason for this choice is the novelty of the suspension and separation in this environment due to the higher viscosity and speed of sound of water than air and the proximity of this environment for water purification, separation of water in crude oil and microfluidic scale separation of platelets from blood. The acoustic force must be greater than the resultant of the gravitational and buoyancy force so that it can overcome it and suspend the particle. In order to increase this force it is necessary to increase the acoustic pressure, which is not normally feasible due to the low frequency in macro scale (20 kHz) and increasing the power consumption of the transducer causes cavitation that prevents the suspension of particles. At this stage, the initial velocity of the particles in the simulation and practical mode was given as 0.4 m / s and the results showed that the largest difference in velocity between the particles with low and high volume was 12.5% in the simulation and 10% in the experiment; Therefore, the larger the particle, the more force it feels and the faster it gets. The largest difference between simulation and experimental test was 8%, therefore, experimental tests confirmed the design accuracy and also the simulation results.