Abstract
In the present work, the interaction between non-gray radiation and forced convection in a laminar radiating gas flow over a recess including two backward and forward facing steps in a duct is investigated numerically. Distributions of absorption coefficients across the spectrum (50 cm−1 < η < 20,000 cm−1) are obtained from the HITRAN2008 database. The full-spectrum k-distribution method is used to account for non-gray radiation properties, while the gray radiation calculations are carried out using the Planck mean absorption coefficient. To find the divergence of radiative heat flux distribution, the radiative transfer equation is solved by the discrete ordinates method. The effects of radiation–conduction parameter, wall emissivity, scattering coefficient and recess length on heat transfer behaviors of the convection–radiation system are investigated for both gray and non-gray mediums. In addition, the results of gray medium are compared with non-gray results in order to judge if the differences between these two approaches are significant enough to justify the usage of non-gray models. Results show that for air mixture with 10 % CO2 and 20 % H2O, use of gray model for the radiative properties may cause significant errors and should be avoided.
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Abbreviations
- a :
-
Weight function for full-spectrum k-distribution method
- c p :
-
Specific heat (J kg−1 K−1)
- CR:
-
Contraction ratio
- ER:
-
Expansion ratio
- f :
-
k-Distribution (m)
- g:
-
Cumulative k-distribution
- I:
-
Radiation intensity (W m−2)
- k :
-
Absorption coefficient variable (m−1)
- k P :
-
Planck-mean absorption coefficient (m−1)
- Nu c :
-
Convective Nusselt number
- \(\overline{{Nu_{c} }}\) :
-
Average convective Nusselt number
- Nu r :
-
Radiative Nusselt number
- \(\overline{{Nu_{r} }}\) :
-
Average radiative Nusselt number
- Nu t :
-
Total Nusselt number
- \(\overline{{Nu_{t} }}\) :
-
Average total Nusselt number
- q c :
-
Convective heat flux (W m−2)
- q r :
-
Radiative heat flux (W m−2)
- q t :
-
Total heat flux (W m−2)
- Re:
-
Reynolds number
- RC:
-
Radiation–conduction parameter
- s:
-
Height of step (m)
- T:
-
Temperature (K)
- T ave :
-
Average temperature (K)
- \(U_{{^\circ }}\) :
-
Average velocity of the incoming flow at the inlet section (m/s)
- u, v:
-
x- and y-Components of velocity (m/s)
- U, V:
-
Dimensionless x- and y-component of velocity
- x, y:
-
Horizontal and vertical distance, respectively (m)
- X, Y:
-
Dimensionless horizontal and vertical coordinate, respectively
- x r :
-
Reattachment length (m)
- \(\alpha\) :
-
Thermal diffusivity (m2 s−1)
- \(\sigma\) :
-
Stefan Boatsman’s constant = 5.67 × 10−8 (W m−2 K−4)
- \(\sigma_{a\eta }\) :
-
Spectral absorbing coefficient (m−1)
- \(\sigma_{s}\) :
-
Scattering coefficient (m−1)
- \(\varepsilon\) :
-
Wall emissivity
- \(\varphi\) :
-
Step inclination angle
- \(\mu\) :
-
Dynamic viscosity (N s/m2)
- \(\rho\) :
-
Density (kg/m3)
- \(\Theta\) :
-
Dimensionless temperature
- \(\Theta_{b}\) :
-
Mean bulk temperature
- \(\kappa\) :
-
Thermal conductivity (W m−1 K−1)
- \(\theta_{1} ,\theta_{2}\) :
-
Dimensionless temperature parameters
- \(\eta\) :
-
Wavenumber (cm−1)
- b:
-
Black body
- c:
-
Convective, or cold wall
- g:
-
Cumulative k-distribution
- h:
-
Hot wall
- in:
-
Inlet section
- r:
-
Radiative
- t:
-
Total
- w:
-
Wall
- \(\eta\) :
-
Wavenumber (cm−1)
References
Armaly BF, Durst F, Pereira JCF, Chonung B (1983) Experimental and theoretical investigation of backward-facing step flow. J Fluid Mech 127:473–496
Tylli N, Kaiktsis L, Ineichen B (2002) Side wall effects in flow over backward facing step: experiments and numerical solutions. Phys Fluids 14(11):3835–3845
Abu-Mulaweh HI (2003) A review of research on laminar mixed convection flow over backward- and forward-facing steps. Int J Therm Sci 42:897–909
Yilmaz I, Öztop HF (2006) Turbulence forced convection heat transfer over double forward facing step flow. Int Commun Heat Mass Transf 33:508–517
Erturk E (2008) Numerical solutions of 2-D steady incompressible flow over a backward facing step. Part I: high Reynolds number solutions. Comput Fluids 37:633–655
Atashafrooz M, Gandjalikhan Nassab SA, Ansari AB (2014) Numerical investigation of entropy generation in laminar forced convection flow over inclined backward and forward facing steps in a duct under bleeding condition. Therm Sci. doi:10.2298/TSCI110531026A
Selimefendigil F, Oztop HF (2013) Numerical analysis of laminar pulsating flow at a backward facing step with an upper wall mounted adiabatic thin fin. Comput Fluids 88:93–107
Abu-Nada E (2006) Entropy generation due to heat and fluid flow in backward facing step flow with various expansion ratios. Int J Exergy 3:419–435
Abu-Nada E (2008) Investigation of entropy generation over a backward facing step under bleeding conditions. Energy Convers Manag 49:3237–3242
Bahrami A, Gandjalikhan Nassab SA (2010) Study of entropy generation in laminar forced convection flow over a forward-facing step in a duct. Int Rev Mech Eng 4(4):399–404
Nie JH, Chen YT, Hsieh HT (2009) Effects of a baffle on separated convection flow adjacent to backward-facing step. Int J Therm Sci 48:618–625
Tsay YL, Chang TS, Cheng JC (2005) Heat transfer enhancement of backward-facing step flow in a channel by using baffle installation on channel wall. Acta Mech 174:63–76
Oztop HF, Mushatet KS, Yılmaz İ (2012) Analysis of turbulent flow and heat transfer over a double forward facing step with obstacles. Int Commun Heat Mass Transf 39(9):1395–1403
Chen YT, Nie JH, Hsieh HT, Sun LJ (2006) Three-dimensional convection flow adjacent to inclined backward-facing step. Int J Heat Mass Transf 49:4795–4803
Yan WM, Li HY (2001) Radiation effects on mixed convection heat transfer in a vertical square Duct. Int J Heat Mass Transf 44:1401–1410
Chiu HC, Jang JH, Yan WM (2007) Mixed convection heat transfer inhorizontal rectangular ducts with radiation effects. Int J Heat Mass Transf 50:2874–2882
Chiu HC, Yan WM (2008) Mixed convection heat transfer in inclined rectangular ducts with radiation effects. Int J Heat Mass Transf 51:1085–1094
Nouanegue H, Muftuoglu A, Bilgen E (2008) Conjugate heat transfer by natural convection, conduction and radiation in open cavities. Int J Heat Mass Transf 51:6054–6062
Ko M, Anand NK (2008) Three-dimensional combined convective–radiative heat transfer over a horizontal backward-facing step—a finite-volume method. Numer Heat Transf Part A 54:109–129
Ansari AB, Gandjalikhan Nassab SA (2011) Study of laminar forced convection of radiating gas over an inclined backward facing step under bleeding condition using the blocked-off method. ASME J Heat Transf 133(7):072702
Ansari AB, Gandjalikhan Nassab SA (2013) Forced convection of radiating gas over an inclined backward facing step using the blocked-off method. Therm Sci 17(3):773–786
Ansari AB, Gandjalikhan Nassab SA (2011) Combined gas radiation and laminar forced convection flow adjacent to a forward facing step in a duct. Int J Numer Method Heat fluid Flow 23(2):320–335
Atashafrooz M, Gandjalikhan Nassab SA (2012) Simulation of three-dimensional laminar forced convection flow of a radiating gas over an inclined backward-facing step in a duct under bleeding condition. Inst Mech Eng Part C J Mech Eng Sci 227(2):332–345
Atashafrooz M, Gandjalikhan Nassab SA (2012) Numerical analysis of laminar forced convection recess flow with two inclined steps considering gas radiation effect. Comput Fluids 66:167–176
Atashafrooz M, Gandjalikhan Nassab SA (2012) Combined heat transfer of radiation and forced convection flow of participating gases in a three-dimensional recess. J Mech Sci Technol 26(10):3357–3368
Farias TL, Carvalho MG (1998) Radiative heat transfer in soot-containing combustion systems with aggregation. Int J Heat Mass Transf 41:2581–2587
Solovjov VP, Webb BW (2005) The cumulative wavenumber method for modeling radiative transfer in gas mixtures with soot. J Quant Spectrosc Radiat Transf 93:273–287
Ludwig CB, Malkmus W, Reardon JE, Thomson JAL (1973) Handbook of infrared radiation from combustion gases. Technical report SP-3080, Scientific and Technical Information Office. National Aeronautics and Space Administration (NASA), Washington, DC
Edwards DK, Balakrishnan A (1973) Thermal radiation by combustion gases. Int J Heat Mass Transf 16(1):25–40
Edwards DK (1976) Molecular gas band radiation. Adv Heat Transf 12:115–193
Liu F, Smallwood GJ (2004) An efficient approach for the implementation of the SNB based correlated-k method and its evaluation. J Quant Spectrosc Radiat Transf 84(4):465–475
Modest MF (2003) Narrow band and full spectrum k-distributions for radiative heat transfer-correlated-k vs., scaling approximation. J Quant Spectrosc Radiat Transf 76(1):69–83
Denison MK, Webb BW (1993) A spectral line based weighted sum of gray gases model for arbitrary RTE solvers. ASME J Heat Transf 115(4):1004–1012
Solovjov VP, Webb BW (2000) SLW modeling of radiative transfer in multi component gas mixtures. J Quant Spectrosc Radiat Transf 65:655–672
Modest MF (2003) Radiative heat transfer, 2nd edn. McGraw-Hill, New York)
Pierrot L, Soufiani A, Taine J (1999) Accuracy of narrow-band and global models for radiative transfer in H2O, CO2, and H2O–CO2 mixtures at high temperature. J Quant Spectrosc Radiat Transf 62:523–548
Colomer G, Consul R, Oliva A (2007) Coupled radiation and natural convection: different approaches of the SLW model for a non-gray gas mixture. J Quant Spectrosc Radiat Transf 107:30–46
Ibrahim A, Lemonnier D (2009) Numerical study of coupled double-diffusive natural convection and radiation in a square cavity filled with a N2–CO2 mixture. Int Commun Heat Mass Transf 36:197–202
Modest MF, Zhang H (2002) The full-spectrum correlated-k distribution for thermal radiation from molecular gas-particulate mixtures. ASME J Heat Transf 124(1):30–38
Tencer J, Howell JR (2013) A multi-source full spectrum k-distribution method for 1-D inhomogeneous media. J Quant Spectrosc Radiat Transf 129:308–315
Porter R, Liu F, Pourkashanian M, Williams A, Smith D (2010) Evaluation of solution method for radiative heat transfer in gaseous oxy-fuel combustion environments. J Quant Spectrosc Radiat Transf 111:2084–2094
Lari K, Baneshi M, Gandjalikhan Nassab SA, Komiya A, Maruyama S (2012) Numerical study of non-gray radiation and natural convection using the full-spectrum k-distribution method. Numer Heat Transf Part A 61:61–84
Keshtkar MM, Gandjalikhan Nassab SA (2009) Theoretical analysis of porous radiant burners under 2-D radiation field using discrete ordinates method. J Quant Spectrosc Radiat Transf 110:1894–1907
Patankar SV, Spalding DB (1972) A calculation procedure for heat, mass and momentum transfer in three-dimensional parabolic flows. Int J Heat Mass Transf 15(10):1787–1806
Rothman LS, Gordon IE, Barbe A, ChrisBenner D, Bernath PF, Birk M, Boudon V, Brown LR, Campargue A, Champion J-P, Chance K, Coudert LH, Dana V, Devi VM, Fally S, Flaud J-M, Gamache RR, Goldman A, Jacquemart D, Kleiner I, Lacome N, Lafferty WJ, Mandin J-Y, Massie ST, Mikhailenko SN, Miller CE, Moazzen-Ahmadi N, Naumenko OV, Nikitin AV, Orphal J, Perevalov VI, Perrin A, Predoi-Cross A, Rinsland CP, Rotger M, Simeckova M, Smith MAH, Sung K, Tashkun SA, Tennyson J, Toth RA, Vandaele AC, VanderAuwera J (2009) The HITRAN 2008 molecular spectroscopic database. J Quant Spectrosc Radiat Transf 110:533–572
Patankar SV (1981) Numerical heat transfer and fluid flow, chap 7. Taylor & Francis, Philadelphia
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Atashafrooz, M., Gandjalikhan Nassab, S.A. & Lari, K. Numerical analysis of interaction between non-gray radiation and forced convection flow over a recess using the full-spectrum k-distribution method. Heat Mass Transfer 52, 361–377 (2016). https://doi.org/10.1007/s00231-015-1561-z
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DOI: https://doi.org/10.1007/s00231-015-1561-z