Numerical study of natural convection in a vertical porous annulus with discrete heating

Sankar, M.; Park, Youngyong; Lopez, Juan M.; Do, Younghae

doi:10.1016/j.ijheatmasstransfer.2010.11.043

Cited by 117 publications

(39 citation statements)

References 38 publications

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“…The numerical technique implemented in this study has been successfully employed in our recent papers to investigate the effects of magnetic field on the double-diffusive convection (Venkatachalappa et al 2011) and thermocapillary convection (Sankar et al 2011b) in a vertical non-porous annulus, and also to understand the effect of discrete heating on the natural convection in a vertical porous annulus (Sankar et al 2011a). Further, in order to verify the accuracy of the current numerical results, simulations of the present model are tested and compared with different reference solutions available in the literature for pure thermal convection, and thermosolutal convection in a cylindrical porous annulus.…”

Section: Validationmentioning

confidence: 99%

“…Other notable studies involving the discrete heating of a rectangular cavity are due to Saeid and Pop (2004) and Sivasankaran et al (2011). Recently, Sankar et al (2011a) reported on the effects of size and location of a discrete heater on the natural convective heat transfer in a vertical annulus. Natural convection resulting from thermal and solutal buoyancy forces in rectangular and annular cavities has also been investigated (Trevisan and Bejan 1986;Goyeau et al 1996;Sivasankaran et al 2008;Shipp et al 1993a,b;Chen et al 2010).…”

Section: Introductionmentioning

confidence: 99%

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Double-Diffusive Convection from a Discrete Heat and Solute Source in a Vertical Porous Annulus

et al. 2011

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This article reports a numerical study of double-diffusive convection in a fluidsaturated vertical porous annulus subjected to discrete heat and mass fluxes from a portion of the inner wall. The outer wall is maintained at uniform temperature and concentration, while the top and bottom walls are adiabatic and impermeable to mass transfer. The physical model for the momentum equation is formulated using the Darcy law, and the resulting governing equations are solved using an implicit finite difference technique. The influence of physical and geometrical parameters on the streamlines, isotherms, isoconcentrations, average Nusselt and Sherwood numbers has been numerically investigated in detail. The location of heat and solute source has a profound influence on the flow pattern, heat and mass transfer rates in the porous annulus. For the segment located at the bottom portion of inner wall, the flow rate is found to be higher, whereas the heat and mass transfer rates are higher when the source is placed near the middle of the inner wall. Further, the average Sherwood number increases with Lewis number, while for the average Nusselt number the effect is opposite. The average Nusselt number increases with radius ratio (λ); however, the average Sherwood number increases with radius ratio only up to λ = 5, and for λ > 5 , the average Sherwood number does not increase significantly.123 754 M. Sankar et al.

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Section: Validationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Double-Diffusive Convection from a Discrete Heat and Solute Source in a Vertical Porous Annulus

et al. 2011

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“…Hasil penelitian ini menunjukkan kenaikan koefisien perpindahan panas konveksi 2 -50%. Sankar dkk [9] telah melakukan eksperimen perpindahan panas konveksi alamiah aliran di dalam anulus vertikal, sedangkan Kamajaya dkk [10] telah melakukan eksperimen perpindahan panas konveksi alamiah aliran nanofluida Al 2 O 3 -air di dalam sub-buluh vertikal. Hasil penelitian-penelitian ini memperlihatkan bentuk-bentuk persamaan korelasi numerik perpindahan panas konveksi alamiah aliran nanofluida di dalam subkanal vertikal.…”

Section: Pendahuluanunclassified

Karakteristik Perpindahan Panas Konveksi Alamiah Aliran Nanofluida Al2o3-Air Di Dalam Pipa Anulus Vertikal

Nazar

2016

Tri Dasa Mega

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ABSTRAKKARAKTERISTIK PERPINDAHAN PANAS KONVEKSI ALAMIAH ALIRAN NANOFLUIDA AL 2 O 3 -AIR DI DALAM PIPA ANULUS VERTIKAL. Hasil beberapa penelitian menunjukkan bahwa nanofluida memiliki karakteristik termal yang lebih baik dibandingkan dengan fluida konvensional (air). Berkaitan dengan hal tersebut, saat ini sedang berkembang pemikiran untuk menggunakan nanofluida sebagai fluida perpindahan panas alternatif pada sistem pendingin reaktor. Sementara itu, konveksi alamiah di dalam pipa anulus vertikal merupakan salah satu mekanisme perpindahan panas yang penting dan banyak ditemukan pada reaktor riset TRIGA, reaktor daya generasi baru dan alat konversi energi lainnya. Namun di sisi lain karakteristik perpindahan panas nanofluida di dalam pipa anulus vertikal belum banyak diketahui. Oleh karena itu penting dilakukan secara berkesinambungan penelitian-penelitian untuk menganalisis perpindahan panas nanofluida di dalam pipa anulus vertikal. Pada penelitian ini telah dilakukan analisis numerik menggunakan program computer CFD (computational of fluids dynamic) terhadap karakteristik perpindahan panas konveksi alamiah aliran nanofluida Al 2 O 3 -air konsentrasi 2% volume di dalam pipa anulus vertikal. Hasil kajian ini menunjukkan terjadi peningkatan kinerja perpindahan panas (bilangan Nuselt-N U ) sebesar 20,5% -35%. Pada moda konveksi alamiah dengan bilangan 2,471e +09 ≤ R a ≤ 1,955e ABSTRACT THE CHARACTERISTICS OF NATURAL CONVECTION HEAT TRANSFER OF AL 2 O 3 -WATER NANOFLUID FLOW IN A VERTICAL ANNULUS PIPE. Results of several researches have shown that nanofluids have better thermal characteristics than conventional fluid (water). In this regard, ideas for using nanofluids as an alternative heat transfer fluid in the reactor coolant system have been well developed. Meanwhile the natural convection in a vertical annulus pipe is one of the important mechanisms of heat transfer and is found at the TRIGA research reactor, the new generation nuclear power plants and other energy conversion devices. On the other hand, the heat transfer characteristics of nanofluids in a vertical

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“…Moreover, transient natural convection in porous vertical annuli has not been extensively investigated: only Sankar et al [19] and Jha and Yusuf [20] derived numerical [19] and semianalytical [20] solutions for time-dependent problems.…”

Section: Introductionmentioning

confidence: 99%

Influence of one porous layer insert on the transient heat transfer in a tall annulus in presence of large source terms

Arpino¹,

Ciccolella²,

Cortellessa³

et al. 2017

IJHT

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This paper provides a sensitivity analysis on the influence of one porous layer insert on the transient behavior of natural convection in a tall annular enclosure in presence of large source terms. The porous medium which partially fills the cavity is characterized by a low value of the Darcy number, typical of insulating materials and metallic foams, often employed in heat exchangers and other engineering applications. A stabilized, fully explicit version of the Compressibility Based Scheme is here employed and validated against experimental data available in the scientific literature for steady and unsteady convection in vertical cylindrical enclosures. Several analyses are presented here by changing both the geometrical features of the cavity and the properties of the porous domain. The results of these analyses demonstrate that not only the thermo-physical properties of the porous medium but also the position and the thickness of the porous layer strongly affect the transient behavior of the convective phenomena occurring in the cavity.

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Numerical study of natural convection in a vertical porous annulus with discrete heating

Cited by 117 publications

References 38 publications

Double-Diffusive Convection from a Discrete Heat and Solute Source in a Vertical Porous Annulus

Double-Diffusive Convection from a Discrete Heat and Solute Source in a Vertical Porous Annulus

Karakteristik Perpindahan Panas Konveksi Alamiah Aliran Nanofluida Al2o3-Air Di Dalam Pipa Anulus Vertikal

Influence of one porous layer insert on the transient heat transfer in a tall annulus in presence of large source terms

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