بررسی جریان سیال و انتقال حرارت جابجایی آزاد حفره مربعی با وجود مانع گرم مثلثی با روش المان محدود

نوع مقاله: مقاله مکانیک

نویسنده

دانشکده فنی و مهندسی ، دانشگاه دامغان

چکیده

در این مقاله، انتقال حرارت جابجایی طبیعی در یک حفرۀ مربعی بسته با وجود یک مانع مثلثی گرم در دمای TH، با استفاده از روش المان محدود شبیه سازی شده است. دیواره های بالا و پایین عایق بوده، در حالیکه دیواره های چپ و راست در دمای ثابت Tc (Tc <TH) نگه داشته شده است. روش مورد استفاده با نتایج عددی موجود اعتبار سنجی شده و تطابق بسیار خوبی بین نتایج به دست آمده است. جریان دو بعدی فرض شده و هوا به عنوان سیال عامل در نظر گرفته شده است. تاثیر پارامترهای مختلفی همچون عدد رایلی (Ra=103, 104, 105, 106)، موقعیت مختلف مانع در داخل حفره (H=L=0.1, 0.4, 0.7) و زوایای مختلف مانع (θ=00, 900, 1800, 2700) در نسبت های ابعادی متفاوت مانع (AR=0.2, 0.4, 0.6, 0.8) بر روی جریان سیال و انتقال حرارت داخل کانال بررسی شده است. نتایج نشان می‌دهد که با افزایش عدد رایلی و افزایش نسبت ابعادی، میزان نرخ انتقال حرارت افزایش می یابد. همچنین افزایش فاصله مانع از دیواره های چپ و پایین حفره، منجر به کاهش نرخ انتقال حرارت گشته و بیشترین مقدار عدد ناسلت متوسط به ترتیب در زوایای 0، 90، 270 و 180درجه مشاهده شده است.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Natural Convection Fluid Flow and Heat Transfer a Square Cavity with a Heated Triangular Obstacle Using Finite Element Method

نویسنده [English]

  • Rasul Mohebbi
Assist. Prof., Mech. Eng., Damghan Univ., Damghan, Iran.
چکیده [English]

In this paper, natural convection heat transfer in a closed square cavity with a hot triangular obstacle at temperature TH simulated by Finite Element Method. The top and the bottom walls are insulated while the left and the right walls are maintained at a constant temperature Tc (TH> Tc). The used method is validated against the existing numerical results and an excellent agreement between the results was found. The flow is assumed to be two-dimensional and air is chosen as a working fluid. The effect of different parameters such as Rayleigh number (Ra =103, 104, 105, 106), different position of obstacle inside cavity (H=L=0.1, 0.4, 0.7) and different angle of obstacle (θ'=00, 900, 1800, 2700) at different aspect ratio (AR =0.2, 0.4, 0.6, 0.8) on fluid flow and heat transfer inside the channel are investigated. The results showed that by increasing the Rayleigh number and increment of aspect ratio, the rate of heat transfer is increased. Also, enhancement the distance of obstacle from left and bottom walls of cavity, lead to decrement rate of heat transfer and the maximum values of mean Nusselt number are shown respectively at angles of 0, 90, 270, 180 degrees.

کلیدواژه‌ها [English]

  • Triangular Obstacle
  • finite element method
  • Natural convection
  • Square Cavity
 
[1] Gebhart B, Jaluria Y, Mahajan R L, Sammakia B (1988) Buoyancy induced flows and transport. Hemisphere.
[2] Bejan A (1995) Convection Heat Transfer. Second ed, Wiley & Sons.
[3] Mohebbi R, Rashidi M M. (2017) Numerical simulation of natural convection heat transfer of a nanofluid in an L-shaped enclosure with a heating obstacle[J]. Journal of the Taiwan Institute of Chemical Engineers, 72: 70-84.
[4] Kumar De A, Dalal A (2006) A numerical study of natural convection around a square, horizontal, heated cylinder placed in an enclosure. Int J Heat Mass Trans 49: 4608–4623.
[5] Izadi M, Mohebbi R, Karimi D, Sheremet M A. (2018) Numerical simulation of natural convection heat transfer inside a ┴ shaped cavity filled by a MWCNT-Fe ⁠3 O ⁠4 /water hybrid nanofluids using LBM, Chemical Engineering & Processing: Process Intensification, DOI:10.1016/j.cep.2018.01.004
[6] Ostrach S (1988) Natural convection in enclosures. J Heat Trans 110: 1175–1190.
[7] Frederick R L (1989) Natural convection in an inclined square enclosure with a partition attached to its cold wall. Int J Heat Mass Trans 32: 87–94.
[8] House J M, Beckermann C, Smith T F (1990) Effect of a centered conducting body on natural convection heat transfer in an enclosure. Num Heat Trans  Part A 18: 213–225.
[9] Lee J R, Ha M Y (2005) A numerical study of natural convection in a horizontal enclosure with a conducting body. Int J Heat Mass Trans 48: 3308-3318.
[10] Bhave P, Narasimhan A, Rees D A S (2006) Natural convection heat transfer enhancement using adiabatic block: optimal block size and Prandtl number effect. Int J Heat Mass Trans 49: 3807–3818.
[11] Nada S A (2008), Experimental investigation of natural convection heat transfer in horizontal and inclined annular fluid layers. Heat Mass Trans  44: 929–936.
[12] Yang C S, Jeng D Z, Tang U H, Gau C (2009), Flowand heat transfer of natural convection in horizontal annulus with a heating element on inner cylinder. J Heat Trans 131: 082502.
[13] Butler C, Newport D,  Geron M (2013), Natural convection experiments on a heated horizontal cylinder in a differentially heated square cavity. Exp Therm Fluid Sci 44: 199–208.
[14] Abdallaoui M El, Hasnaoui M, Amahmid A (2015) Numerical simulation of natural convection between a decentered triangular heating cylinder and a square outer cylinder filled with a pure fluid or a nanofluid using the lattice Boltzmann method. Powder Tech 277: 193–205.
[15] A. Chamkha, M. Ismael, A. Kasaeipoor, T. Armaghani, (2016)  Entropy Generation and Natural Convection of CuO-Water Nanofluid in C-Shaped Cavity under Magnetic Field, Entropy 18 1-18.
[16] M.A.Ismael, T.Armaghani, A.J. Chamkha, (2016)Conjugate heat transfer and entropy generation in a cavity filled with a nanofluid-saturated porous media and heated by a triangular solid. J. Taiwan Institute of Chem. Eng., 59138-151.
[17] T. Armaghani, M. A. Ismael, A. J. Chamkha, (2017) Analysis of entropy generation and natural convection in an inclined partially porous layered cavity filled with a nanofluid, Canadian J Physics, 95238-252.
[18] A.J. Chamkha, A.M. Rashad, M.A. Mansour, T. Armaghani, M. Ghalambaz, (2017).Effects of heat sink and source and entropy generation on MHD mixed convection of a Cu-water nanofluid in a lid-driven square porous enclosure with partial slip, Physics of Fluids 29, 052001
[19] A.J. Chamkha, A.M. Rashad, T. Armaghani, M.A. Mansour, Effects of partial slip on entropy generation and MHD combined convection in a lid-driven porous enclosure saturated with a Cu–water nanofluid, Journal of Thermal Analysis and Calorimetry, accepted, DOI: 10.1007/s10973-017-6918-8.
[20] A.J. Chamkha, A.M. Rashad, T. Armaghani, M.A. Mansour, (2018) Entropy Generation and MHD Natural Convection of a Nanofluid in an Inclined Square Porous Cavity: Effects of a Heat Sink and Source Size and Location, Chinese J of Physics, 56193-211.
[21] Abbassi H, Turki S, Ben Nasrallah S (2001) Mixed convection in a plane channel with a built-in triangular prism. Numer Heat Transfer 39: 307–320.
[22] Chattopadhyay H (2007), Augmentation of heat transfer in a channel using a triangular prism. Int J Therm Sci 46: 501–550.
[23] Xu X, Sun G, Yu Z, Hu Y, Fan L, Cen K (2009) Numerical investigation of laminar natural convective heat transfer from a horizontal triangular cylinder to its concentric cylindrical enclosure. Int J Heat Mass Trans 52: 3176–3186.
[24] Farhadi M, Sedighi K, Korayem A M (2010) Effect of wall proximity on forced convection in a plane channel with a built-in triangular cylinder. Int J Therm Sci 49: 1010–1018.
[25] Alansary H, Zeitoun O, Ali M (2012) Numerical modeling of natural convection heat transfer around horizontal triangular cylinders. Numer Heat Trans Part A 61: 201–219.
[26] Saadedin S, Hemmat-Asafe M (2012) Heat transfer and properties of synthetic convection around hot obstacles inserted in sloped square cavity filled with nanofluid . Modeling in engineering.
[27] Fereydoun A, Abbasian-Arani A, Hemmat-Asafe M, Zare-Ghadi A (2013) Natural convection around hot cylinder inserted in square cavity filled with nanofluid with change of radius and location of cylinder . Modeling in engineering.
[28] El Abdallaoui M, Hasnaoui M, Amahmid A (2014) Lattice-Boltzmann modeling of natural convection between a square outer cylinder and an inner isosceles triangular heating body. Numer Heat Trans Part A 66: 1076–1096.
[29] Sheikholeslami M, Gorji-Bandpy M, Vajravelu K (2015) Lattice Boltzmann simulation of magnetohydrodynamic natural convection heat transfer of Al2O3–water nanofluid in a horizontal cylindrical enclosure with an inner triangular cylinder. Inte J  Heat Mass Trans 80: 16–25.
[30] Hoseini H, Mohaseli A (2016) Heat transfer in bubble kip gas-solid to solid particles inside it using dynamic of computational fluid. Modeling in engineering.
[31] Nazari M, Kayhani M H, Mohebbi R. (2013) Heat transfer enhancement in a channel partially filled with a porous block: lattice Boltzmann method[J]. International Journal of Modern Physics C, 24(09): 1350060.
 [32]  Nazari M, Mohebbi R, Kayhani M H. (2014) Power-law fluid flow and heat transfer in a channel with a built-in porous square cylinder: Lattice Boltzmann simulation[J]. Journal of non-Newtonian fluid mechanics, 204: 38-49.
 [33]  Mohebbi R, Nazari M, Kayhani M H. (2016) Comparative study of forced convection of a power-law fluid in a channel with a built-in square cylinder[J]. Journal of Applied Mechanics and Technical Physics, 57(1): 55-68.
[34]   Mohebbi R, Heidari H. (2017) Lattice Boltzmann simulation of fluid flow and heat transfer in a parallel-plate channel with transverse rectangular cavities[J]. International Journal of Modern Physics C, 28(03): 1750042.
[35]   Mohebbi R, Lakzayi H, Sidik N A C, et al. (2018) Lattice Boltzmann method based study of the heat transfer augmentation associated with Cu/water nanofluid in a channel with surface mounted blocks[J]. International Journal of Heat and Mass Transfer, 117: 425-435.
[36]   Mohebbi R, Rashidi M M, Izadi M, et al. (2018) Forced convection of nanofluids in an extended surfaces channel using lattice Boltzmann method[J]. International Journal of Heat and Mass Transfer, 117: 1291-1303.
[37] Jani S, Mahmoodi M, Amini M (2013) Natural convection at different Prandtl numbers in rectangular cavities with a fin on the cold wall. J Energy: Eng Manag 2: 58-69.