بررسی عددی میزان کاهش انتقال حرارت جابجایی و تشعشعی بین دو استوانه هم‌مرکز متناهی با استفاده از سپرهای تشعشعی

نوع مقاله: پژوهشی

نویسندگان

دانشگاه سمنان

چکیده

در این مقاله، مطالعه عددی تاثیر قرارگیری سپرهای تشعشعی در محفظه‌ای متشکل از دو استوانه متناهی هم‌محور در میزان تلفات حرارتی ناشی از جابجایی آزاد و انتقال حرارت تابش مورد بررسی قرار گرفته است. محفظه مورد مطالعه شامل دو استوانه هم‌محور بوده که استوانه داخلی دارای دمای بالاتری می‌باشد و بین این دو استوانه از یک و یا دو سپر تشعشعی با جنس‌های مختلف (آلومینیوم، مس و استیل) در فواصل مختلف استفاده شده است. تاثیر خواص فیزیکی (جنس سپرهای تشعشعی)، فاصله سپرهای تشعشعی، دمای استوانه داخلی و فشار محفظه بر میزان تلفات حرارتی مورد بررسی قرار گرفته است. نتایج به دست آمده برای دماهای مختلف استوانه داخلی (473.15 و 673.15 کلوین) و فشارهای مختلف محفظه (0.2 و 1.0اتمسفر) ارائه شده است، که نشان‌دهنده تاثیر مستقیم فشار محفظه و ضریب جذب سپر تشعشعی بر میزان تلفات حرارتی بین استوانه داخلی و خارجی می‌باشد.

کلیدواژه‌ها


عنوان مقاله [English]

Numerical Investigation of Convection and Radiation Heat Loss Reduction between Two Finite Concentric Cylinders Using Radiation Shields

نویسندگان [English]

  • Seyfolah Saedodin
  • Mohammad Sadegh Motaghedi Barforoush
چکیده [English]

Investigation of the radiation and natural convection heat losses from two finite concentric cylinders with radiation shields is performed numerically. The enclosure consists of two concentric cylinders with hotter inner cylinder and radiation shields with three different materials (aluminum, copper and steel) are inserted between the cylinders at different radial positions. The effects of physical properties (material), geometrical effects of radiation shields, inner cylinder temperature, and enclosure pressure on the heat losses have been investigated. The calculations were performed for two different inner temperatures as 473.15, and 673.15 K, and at two enclosure pressures of 0.2 and 1.0 atm. Results showed that the enclosure pressure and radiation shield emissivity together reduce the total heat loss from the inner cylinder.

کلیدواژه‌ها [English]

  • Free convection
  • radiation
  • Finite cylinders
  • Radiation shields
  • Enclosure
[1] A. Mezrhab, H. Bouali, H. Amaoui, M. Bouzidi, (2006),” Computation of combined natural-convection and
radiation heat-transfer in a cavity having a square body at its center”, Appl. Energy, 83, 1004– ه 1023
[2] V. Vivek, A.K. Sharma, C. Balaji, (2012),” Interaction effects between laminar natural convection and surface
radiation in tilted square and shallow enclosures”, Int. J. Therm. Sci. 60, 70– ه 84
[3] Semen G. Martyushev, Mikhail A. Sheremet, (2014), “Conjugate natural convection combined with surface
thermal radiation in a three-dimensional enclosure with a heat source, International Journal of Heat
and Mass Transfer”, 73 340– ه 353
[4] Menguc MP, Viskanta R. (1987), “Radiation heat transfer in combustion systems”, Prog Energy Combust
Sci;13: 97– ه 160
[5] Yang K.T., (1986), “Numerical modeling of natural convection–radiation interactions in enclosures, Int. Heat
Transfer Conf” , 131–ه 140
[6] G.V. Kuznetsov, M.A. Sheremet, (2009), “Conjugate natural convection with radiation in an enclosure”, Int.
J. Heat Mass Tran. 52 2215– ه 2223
[7] Anil Kumar Sharma, K. Velusamy, C. Balaji, S.P. Venkateshan, (2007),”Conjugate turbulent natural
convection with surface radiation in air filled rectangular enclosures”, Int. J. Heat Mass Tran. 50,
625– ه 639
[8] Seyfolah Saedodin, M.S. Motaghedi Barforoush, Mohsen Torabi, (2011), “Reducing Heat Transfer Between
Two Concentric Semi-Cylinders Using Radiation Shields with Temperature-Dependent Emissivity”,
Frontiers in Heat and Mass Transfer (FHMT), 2, ه 044001
[9] Seyfolah Saedodin, M. S. Motaghedi Barforoush, Mohsen Torabi, (2012),”Calculation of Reduction Heat
Transfer between Two Finite Concentric Cylinders Using Radiation Shields with Temperature-
Dependent Emissivity”, International Review of Mechanical Engineering, Vol. 6, N. 1
[10] Seyfolah Saedodin, M.S. Motaghedi Barforoush, Mohsen Torabi,(2011), “Calculation of radiation heat
transfer using hemisphere shields with temperature-dependent emissivity”, Journal of Applied
Sciences 11 (12), 2238-2243
[11] Seyfolah Saedodin, Mohsen Torabi, Jalal Moghimi Kandelousi and Nima Maghsodloo, (2010), “Application
of Net Radiation Transfer Method for Optimization and Calculation of Reduction Heat Transfer,
Using Spherical Radiation Shields”, World Applied Sciences Journal 11 (4): 457-461
[12] F.P. Incropera, D.P. Dewitt, T.L. Bergman, and A.S. Lavine,(2007), “Fundamentals of Heat and mass
transfer”, 6th ed., John Wiley and sons, New York
[13] Sparrow, E. M., and J. L. Gregg, (1956), “Laminar Free Convection Heat Transfer from the Outer Surface
of a Vertical Circular Cylinder”, Trans. ASME, 78 ,1823- ه 1828
[14] Churchill, S. W., and H. H. S. Chu, (1975), “Correlating Equations for Laminar and Turbulent Free
Convection from a Vertical Plate”, Int. J. Heat Mass Tran. 18 ,1323- ه 1329