Impact of inclination angle on thermo-bioconvection of nanofluid containing gyrotactic microorganisms saturated in porous square cavity
Abstract
This paper focuses on the result of inclined angle on bioconvection of porous media bounded by cavity wall square enclosure filled with both nanofluid and gyrotactic microorganisms passing through the media with pores. The dimensionless velocity, temperature, concentration, and mass transformation equations are solved by using the weighted residual Galerkin’s finite element method. The result of the inclination angle from δ=0∘ to δ=180∘ in a square cavity is interpreted. The outcomes of inclination on various key parameters, such as Rayleigh number, bioconvective Rayleigh number, Peclet number, Brownian motion, and the ratio of buoyancy, are discussed. Furthermore, the mean Nusselt number, Sherwood number, and density number are discussed at vertical walls.
Keywords: Nanofluid, Inclination angle, Buoyancy ratio, Peclet number, Square cavity, Bioconvection.
1 Introduction
The present problem is dealing with the nanofluid flow through the porous square cavity with temperature difference, which has a wide range of applications in recent years, such as geophysics, geothermal energy utilization, and many technologies. The bioconvection of the nanofluid containing gyrotactic microorganisms has a wide range of practical applications, such as chemical catalytic converters, buried electronic cables, pollutant dispersion in aquifers, food industrial forms, and so on. These types of many areas of applications are documented in these references [10, 24, 14, 15, 31].
The properties and utilization of the nanofluid were first introduced by Choi and Eastman [11] at ASME annual meeting. Many people have described the properties of nanofluids, such as [13, 30, 24, 23, 26]. In many electronic devices, like computers, boilers, converters, and so on, the angle of inclination to the surface affects the gravity force on the fluid, temperature gradient, and velocity of the fluid flow. In [32], the author expressed the free convection of the composite wall enclosure. Kuyper et al. [20] studied the effect of inclined angle on different flows in square cavity walls. Kuznetsov [21] explained the microscopic convection motion of the oxytactic microorganisms due to the temperature effect. Shermet and Pop [28] expressed that the result of the thermal movement of microorganisms in the nanofluid having gyrotactic microorganisms is a closed porous square cavity. Aziz, Khan, and Pop [5] presented the flow behavior of the nanofluid with gyrotactic microorganisms on a flat plate. At viscous dissipation, the behavior of oxytactic microorganisms in porous square cavities was discussed [2, 3]. Jamuna and Balla [17] discussed the behavior of the heat source and sink of the gyrotactic microorganisms in the square cavity. The activation energy effect on the gyrotactic microorganisms was discussed in [18]. The influence of Soret and Dufour on free convection of the fluid flow in the inclined four-side closed walls was explained in [8]. The MHD double-diffusion in the porous square enclosure with radiation and chemical reaction and the outcome inclination of the porous square cavity filled with gyrotactic microorganisms with the heat transformation was discussed in [6, 7]. Nanofluid movement in an inclined square cavity with gyrotactic microorganisms at MHD free convection was reported in [27].
The effect of angle movement of the square adiabatic wall on mixed convection of the nanofluid was explored in [16]. Aounallah et al. [4] explained the turbulent flow behavior of the nanofluid in an inclined square cavity on free convection, and Sheremet, Grosan, and Pop [27] investigated the free convective flow of nanofluid in inclined four-sided chamber with gyrotactic microorganisms. Tsai, Li, and Lin [29] discussed the inclination of the plate shield, and Aboueian-Jahromi, Hossein Nezhad, and Behzadmehr [1] studied the steady flow in inclined cylinders.
Rajarathinam and Nithyadevi [25] examined the movement of Cu-water nanofluid in inclined cavity walls with pores. The thermosolutal Maragoni effects of the bioconvective fluid flow with gyrotactic microorganisms on inclined sheets were explained in [19]. Recently, Varol, Oztop, and Koca [34] explained different fluids’ laminar flow in the different inclined enclosures.
Since, from the above literature survey, we note that many authors concentrated on the inclined angle of different geometries with convection of nanofluid with gyrotactic microorganisms. The novelty of this paper contains the square-shaped cavity enclosure with fluid containing nanoparticles and gyrotactic microorganisms. Galerkin’s finite-element method is used to solve the nondimensional governing equations.
2 Mathematical modeling
We consider the bioconvection flow in an inclined two-dimensional porous four-sided square cavity of dimension L containing nanofluid with gyrotactic microorganisms. Let us assume that δ is the inclination angle of the cavity wall with the horizontal surface. The vertical walls are maintained in various temperatures TC and TH, respectively ( TH>TC ). The remaining walls were kept perfectly insulated. The direction of gravity force g acts opposite to the vertical axis (Y-axis).
The steady-state Darcy–Boussinesq approximation governing equations are
∂u∂x+∂v∂y=0, | (1) |
μku=-∂p∂x-[(ρp-ρf)(C-Cmin)-(1-Cmin)ρfβ(T-TC)+γnΔρ]gsinδ, | (2) |
μkv=-∂p∂y-[(ρp-ρf)(C-Cmin)-(1-Cmin)ρfβ(T-TC)+γnΔρ]gcosδ, | (3) |
u∂T∂x+v∂T∂y=αm(∂2T∂x2+∂2T∂y2)+τDB(∂C∂x∂T∂x+∂C∂y∂T∂y)+τDTTC[(∂T∂x)2+(∂T∂y)2], | (4) |
u∂C∂x+v∂C∂y=Dm(∂2C∂x2+∂2C∂y2)+DTTc(∂2T∂x2+∂2T∂y2), | (5) |
∂∂x(un+u~n-Dn∂n∂x)+∂∂y(vn+v~n-Dn∂n∂y)=0. | (6) |
Here γ is the mean volume for microorganisms, Δρ=ρcell-ρf is the density difference of cell, TC is the cold wall temperature, TH is the hot wall temperature, αm is porous medium thermal diffusivity, C is the concentration of nanoparticles, C0 is nanoparticles average density, Cmin is minimum concentration of oxygen essential for microorganisms, Cp is specific heat at constant pressure, Dn is microorganisms diffusion coefficient, DB is the Brownian diffusion constant, DT is the thermophoretic diffusion coefficient, n is motile density number of microorganisms, g is the gravity force, chemotaxis constant is b, and the maximum speed of cell swims is wC. The average swimming velocities of microorganisms are u~ and v~ given as
u~=bwCΔC∂C∂x,v~=bwCΔC∂C∂y. | (7) |
Consider dimensional stream function ψ. Then u and v in x and y directions are considered as u=∂ψ∂y and v=∂ψ∂x by introducing the boundedless variables X=xH, Y=yH, Ψ=ψαm,θ=T-TCTH-TC, ϕ=C-CminΔC, and N=nn0, where n0 is the microorganism averaged density.
Substituting above unbounded variables into equation (1)–(7), then we get the following partial differential equations:
∂2Ψ∂X2+∂2Ψ∂Y2=RaNr(∂ϕ∂Xcosδ-∂ϕ∂Ysinδ)-Ra(∂θ∂Xcosδ-∂θ∂Ysinδ)+RaRb(∂N∂Xcosδ-∂N∂Ysinδ), | (8) |
(∂Ψ∂Y∂θ∂X-∂Ψ∂X∂θ∂Y)=(∂2θ∂X+∂2θ∂Y)+Nb(∂ϕ∂X∂θ∂X+∂ϕ∂Y∂θ∂Y)+Nt[(∂θ∂X)2+(∂θ∂Y)2], | (9) |
Le(∂Ψ∂Y∂ϕ∂X-∂Ψ∂X∂ϕ∂Y)=∂2ϕ∂X2+∂2ϕ∂Y2+NtNb(∂2θ∂X2+∂2θ∂Y2), | (10) |
∂Ψ∂X∂N∂Y-∂Ψ∂Y∂N∂X+PrPeSc(∂2ϕ∂X2+∂2ϕ∂Y2)=PrSc(∂2N∂X2+∂2N∂Y2), | (11) |
where Ra=gKβ(1-C0)ΔTLvαm, Rb=γΔρn0ρfβ(1-C0)ΔT, Le=αmDB, Pe=bwCDn, Nb=τDBΔCαm, Nt=τDT(TH-TC)αmTC, Pr=μfρfαf, Sc=μfρfDn, and Nr=(ρp-ρf)C0ρfβ(1-C0)ΔT.
The dimensionless form of conditions at boundary is expressed in Figure 1.
We have Ψ=0 for all sides,
ϕ=1, θ=1, N=1 at X=0,
ϕ=1, θ=0, N=1 at X=1,
ϕ=1, ∂θ∂Y=0, Pe.N∂ϕ∂Y=∂N∂Y at Y=0, and
∂ϕ∂Y=∂θ∂Y=∂N∂Y=0 atY=1. |
Local solid Nusselt number, Sherwood number of nano particles and Sherwood microorganism are defined as
NuY=-(∂θ∂X)X=0,1, ShY=-(∂ϕ∂X)X=0,1, and NnY=-(∂N∂X)X=0,1.
The average quantities of Nusselt number, nanoparticle Sherwood number, and microorganism Sherwood number is defined as
Nuavg=∫01NuY𝑑Y,
Shavg=∫01ShY𝑑Y,
Nnavg=∫01NnY𝑑Y.
3 Numerical method
To find the numerical solution to (8)–(11), partial differential equations with boundary conditions Galerkin’s weighted residuals finite element method are solved with the help of MATLAB [9]. In this method, a two-dimensional field is divided into small triangular parts, in which each part is named an element. Over each element, assume a piecewise trial function.
Let Ψ, θ, ϕ, and N be approximated by Ψ=∑i=13Ψiξi, θ=∑i=13θiξi, ϕ=∑i=13ϕiξi, and N=∑i=13Niξi, where ξi is the linear interpolating functions over each triangular element. The FEM model matrix is as follows:
[[L11][L12][L13][L14][L21][L22][L23][L24][L31][L32][L33][L34][L41][L42][L43][L44]][{Ψ}{T}{C}{N}]=[{M1}{M2}{M3}{M4}],
where
L11=∬Ωe[∂ξj∂X∂ξi∂X+∂ξj∂Y∂ξi∂Y]𝑑x𝑑y,
L12=-Ra∬Ωe(ξj∂ξi∂Xcosδ-ξj∂ξi∂Ysinδ)𝑑X𝑑Y,
L13=RaNr∬Ωe(ξj∂ξi∂Xcosδ-ξj∂ξi∂Ysinδ)𝑑X𝑑Y,
L14=RaRb∬Ωe(ξj∂ξi∂Xcosδ-ξj∂ξi∂Ysinδ)𝑑X𝑑Y,
M1=0,
L21=0,
L22=∬Ωe[∂Ψ∂Y¯ξj∂ξi∂X-∂Ψ∂X¯ξj∂ξi∂Y+∂ξi∂X∂ξj∂X+∂ξi∂Y∂ξi∂Y-Nt(∂θ∂X¯ξj∂ξi∂X+∂θ∂Y¯ξj∂ξi∂Y)]𝑑X𝑑Y,
L23=-Nb∬Ωe[∂θ∂X¯ξj∂ξi∂X+∂θ∂Y¯ξj∂ξi∂Y]𝑑X𝑑Y,
L24=0, M2=0,
L31=0,
L32=-NtNb∬Ωe[∂ξi∂X∂ξj∂X+∂ξi∂Y∂ξj∂Y]𝑑X𝑑Y,
L33=∬Ωe[Le(∂Ψ∂Y¯∂ϕ∂X-∂Ψ∂X¯∂ϕ∂Y)+∂ξi∂X∂ξj∂X+∂ξi∂Y∂ξj∂Y]𝑑X𝑑Y ,
L34=0, M3=0,
L41=0, L42=0,
L43=∬ΩePePrSc(∂ξi∂X∂ξj∂X+∂ξi∂Y∂ξj∂Y)𝑑X𝑑Y,
L44=∬Ωe[∂Ψ∂Y¯ξj∂ξi∂X-∂Ψ∂X¯ξi∂ξj∂Y+PrSc(∂ξi∂X∂ξj∂X+∂ξi∂Y∂ξj∂Y)]𝑑X𝑑Y,
M4=0.
To linearize the system of equations, the functions are incorporated, which are assumed to be known. After applying the boundary conditions, a matrix of system of linear equations is formed, which is solved by using the Gauss–Seidel iteration method. The convergence of the solution is assumed when the relative error for each variable between two consecutive iterations is observed below the convergence criteria such that |ψn+1-ψn|≤10-5, where n is the number of iterations and ψ stands for Ψ,θ,C.
To choose the grid size, the grid independence test is performed for 21×21,41×41,61×61,71×71,81×81,91×91 grid sizes. The grid independence test reveals that the grid size 81×81 is sufficient to study in the the bioconvection phenomena.
4 Result and discussion
The present equations (8)–(11) are numerically investigated and analyzed in the porous square cavity filled with nanofluid and gyrotactic microorganisms at different inclination angles. The numerical investigation is carried out with the following parameters considered Rayleigh number (Ra=25), bioconvection Rayleigh number (Rb=15), Lewis number (Le=1), Peclet number, thermophoresis parameter, Brownian parameter, buoyancy ratio parameter, Schmidt number 0.1, Prandtl number 6.9, and inclination angle (δ=30∘) unless when it is mentioned.
Streamlines are presented in Figure 2 for various values of inclination angle (δ). When δ=0∘, the cells moved in the clockwise direction in the square enclosure. The absolute maximum of the stream function is |Ψmax|=1.56. At 30∘, inclination angle the maximum stream function value is |Ψmax|=2.0435, and the rotation of the cell moves in the same direction. The inclination angle increased to 90∘, and the velocity of the fluid flow is reduced. At 120∘, the intensity of the flow increased to |Ψmax|=2.0421. In this, the cell moves to the center regime with the intensity of the gravitational force. At 150∘ inclination angle, the flow strength is low and the cell moves near to corners of the left down wall and right top walls. At 180∘, the fluid flow velocity is less with the strength of cell |Ψmax|=1.5629.
Isotherms are demonstrated in Figure 3 for various inclination angles from 0∘ to 180∘. At inclination 30∘, the temperature distribution is indicating the stratified diagonally. At 180∘, isotherms are parallel to the vertical walls, which shows the transfer of heat in the mode of heat conduction.
Nanoparticle isoconcentrations of the fluid for various angles are expressed in Figure 4. At 0∘ to 30∘ inclination angle, the nanoparticle volume fraction was raised near the bottom cavity wall. When the square enclosure was moved from angle 90∘ to 120∘, the nanoparticle isoconcentration decreased. When the angle is 120∘ to 150∘, again the concentration of nanoparticles increases. When the angle of inclination is inclined from 150∘ to 180∘, the concentration of nanoparticles is decreased. In these all angles, the cell is divided into two different parts: one is formed near the bottom adiabatic wall and the other part is formed as a semi-opened vertex close to the top adiabatic wall.
Figure 5 displays isoconcentrations of microorgnisms for the various inclination angles. At 0∘ to 30∘ inclination angle, two types of cells are formed: one cell is near the bottom adiabatic wall and the cell moves from the cold wall to the hot wall, the second is an open semi vertex formed at the top cavity wall, and it moves from the hot wall to the cold wall. When the inclination varies from 0∘ to 180∘, the movement of cells in the isoconcentrations of microorganisms and nanoparticle volume fraction is the same. The concentration of microorganisms’ maximum value is found at δ=30∘, 120∘.
In Figure 6, the effect of Rb and Nt on average Nusselt number, Sherwood numbers of nanoparticles, and Sherwood number of microorganisms is discussed. Moreover, Rb increases Nuavg and Shavg from 0∘ ≤ δ ≤ 90∘, 90∘ ≤ δ ≤ 180∘, and it reaches high. Indeed, at 0∘, 90∘, and 180∘ the average Nusselt number and average Sherwood number values are low. Also, Rb increases Nnavg from 0∘ to 180∘. In addition, Nt increases Nuavg from 0∘ to 180∘, and it shows wavy behavior, and Shavg and Nnavg are also increased with the increase of thermophoresis parameter.
5 Conclusion
The effect of porous square cavity inclination with the horizontal surface with nanofluid and gyrotactic microorganisms was analyzed with the streamlines, isotherms, nanoparticle volume fraction, and microorganism isoconcentration from 0∘ to180∘.
1. The velocity of the nanofluid flow is high at the angle 30∘, 120∘ and in the remaining angles, the flow intensity is low.
2. The temperature distribution of the nanofluid is affected by the square cavity inclination.
3. Nanoparticle isoconcentration and microorganism isoconcentrations are high at the 30∘ and 120∘, and at the remaining angles, the value is low.
4. Thermophoresis parameter increases Nuavg, Shavg, and Nnavg from 0∘≤δ≤180∘. Also, Nt increases Nuavg from 0∘≤δ≤180∘, but at 0∘ and 180∘, the value is low. 5. Bioconvection Rayleigh number increases Nuavg, Shavg, and Nnavg.
Acknowledgements
Authors are grateful to there anonymous referees and editor for their constructive comments.
References
- [1] Aboueian-Jahromi, J., Hossein Nezhad, A. and Behzadmehr, A.Effects of inclination angle on the steady flow and heat transfer of power-law fluids around a heated inclined square cylinder in a plane channel, J. Nonnewton Fluid Mech., 166 (23-24) (2011) 1406–1414.
- [2] Alluguvelli, R., Balla, C.S. and Naikoti, K. Bioconvection in porous square cavity containing oxytactic microorganisms in the presence of viscous dissipation, Discontinuity, Nonlinearity, and Complexity, 11(02) (2022) 301–313.
- [3] Alluguvelli, R., Balla, C.S., Naikoti, K. and Makinde, O.D. Nanofluid bioconvection in porous enclosure with viscous dissipation, Indian J. Pure Appl. Phys. 60(1) (2022) 78–89.
- [4] Aounallah, M., Addad, Y., Benhamadouche, S., Imine, O., Adjloit, L. and Laure, D. Numerical investigation of turbulent natural convection in an inclined square cavity with a hot wavy wall, Int. J. Heat Mass Transf. 50(9) (2007) 1683–1693.
- [5] Aziz, A., Khan, W.A. and Pop, I. Free convection boundary layer flow past a horizontal flat plate embedded in porous medium filled by nanofluid containing gyrotactic microorganisms, Int. J. Therm. Sci. 56 (2012) 48–57.
- [6] Balla, C.S., Chinthapally Haritha and Kishan, N. Magnetohydrodynamic double-diffusive convection in fluid saturated inclined porous cavity with thermal radiation and chemical reaction, J. Chem. Technol. Metall. 53 (2018) 518–536.
- [7] Balla, C.S., Jamuna, B., Krishna Kumari, S.V.H.N. and Rashad, A.M. Effect of inclination angle on bioconvection in porous square cavity containing gyrotactic microorganisms and nanofluid, J. Mech. Eng. Sci. 236(9)(2021), 4731–47470.
- [8] Balla, C.S. and Kishan, N. Soret and Dufour effects on free convective heat and solute transfer in fluid saturated inclined porous cavity, Int. J. Eng. Sci. Technol. 18(4) (2015) 543–554.
- [9] Balla, C.S., Ramesh, A., Kishan, N. and Rashad, A.M. Impact of Soret and Dufour on bioconvective flow of nanofluid in porous square cavity, J. Heat transfer, 50(5) (2021) 5123–5147.
- [10] Bejan, A. On the boundary layer regime in a vertical enclosure filled with a porous medium, Lett. Heat Mass Transf. 6(2) (1979) 93–102.
- [11] Choi, S.U.S. and Eastman, J A. Enhancing thermal conductivity of fluids with nanoparticles, International mechanical engineering congress and exhibition, San Francisco, CA . United States, 1995.
- [12] Cross, R.J., Bear, M.R. and Hickox, C.E. The application of flux-corrected transport (FCT) to high Rayleigh number natural convection in a porous medium. Proceedings of 8th International Heat Transfer Conference, San Francisco (1986).
- [13] Das, S.K., Choi, S.U.S., YU, W., and Pradeep, T. Nanofluids: Science and Technology, Mater. Manuf. Process. 24(5) (2009) 600–601.
- [14] Ingham, D.B., Bejan, A., Mamut, E. and Pop, I. Emerging technologies and techniques in porous media, 3rd Edition, Kluwer, Dordrecht, 2004, 93–117.
- [15] Ingham, D.B. and Pop, I. Transport phenomenon in porous media, Pergamon, Oxford, 1998.
- [16] Izadi, M., Behzadmehr, A. and Shahmardan, M.M. Effect on inclination angle on mixed convection heat transfer of a nanofluid in a square cavity, International Journal for Computational Methods in Engineering Science and Mechanics, 16(1) (2015) 11–12.
- [17] Jamuna, B. and Balla, C.S. Bioconvection in a porous square cavity containing gyrotactic microorganisms under the effects of heat generation/absorption, Proc. Inst. Mech. Eng. E: J. Process Mech. Eng. 235(5) (2021), 1534–1544.
- [18] Jamuna, B., Mallesh, M.P. and Balla, C.S. Activation energy process in bioconvection nanofluid flow through porous cavity, Journal of Porous Media, 25(4) (2022) 37–51.
- [19] Kairi, R.R., Roy, S. and Raut, S. Thermosolutal Marangoni impact on bioconvection in suspension of Gyrotactic microorganisms over an inclined stretching sheet, J. Heat Transfer, 143(3) (2021) 031201 (10 pages).
- [20] Kuyper, R.A., Van Der Meer, TH.H., Hoogendoorn, C.J. and Henkes, R.A.W.M. Numerical study of laminar and turbulent natural convection in an inclined square cavity, Int. J. Heat Mass Transf. 36 (11)(1993) 2899–2911.
- [21] Kuznetsov, A.V. Thermo-bioconvection in a suspension of oxytactic bacteria, Int. Commun. Heat Mass Transf. 32 (8) (2005) 991–999.
- [22] Manole, D.M. Numerical benchmark results for natural convection in a porous medium cavity. Heat and Mass Transfer in Porous Media, ASME Conference 1992, vol. 216 (1992) 55–60.
- [23] Minkowycz, W.J., Sparrow, E.M. and Abraham, J.P. Nanoparticle neat transfer and fluid flow, CRC Press, New York,2013.
- [24] Nield, D.A., and Bejan, A. Convection in porous media, 4th ed., Springer, New York, 2013.
- [25] Rajarathinam, M. and Nithyadevi ,N.Heat transfer enhancement of Cu-water nanofluid in an inclined porous square cavity with internal heat generation, Therm. Sci. Eng. Prog. 4 (2017) 35–44.
- [26] Shenoy, A., Sheremet, M. and Pop, I. Convective flow and heat transfer from wavy surfaces: Viscous fluids, porous media and nanofluids, CRC Press, New York, 2016.
- [27] Sheremet, M., Grosan, T. and Pop, I.MHD free convection flow in an inclined square cavity filled with both nanofluids and gyrotactic microorganisms, Int. J. Numer. Methods Heat Fluid Flow. 29(12) (2019) 4642–4659.
- [28] Sheremet, M.A. and Pop, I.Thermobioconvection in a square porous cavity filled by oxy-tactic microorganisms, Transp. Porous Media, 103 (2014) 191–205.
- [29] Tsai, G.-L., Li, H.-Y. and Lin, C.-C. Effect of the angle of inclination of a plate shield on the thermal and hydraulic performance of a plate-fin heat sink, Int. Commun. Heat Mass Transf. 37(4) (2010) 364–371.
- [30] Vadasz, P. Heat conduction in nanofluid suspensions, J. Heat Transf. 128(5) (2006) 465–477.
- [31] Vafai, K. Hand book of Porous media, 2nd Edition, Taylor and Francis, New York, 2005.
- [32] Varol, Y., Oztop, H. and Koca, A. Effect of inclination angle on natural convection in composite walled enclosures, Heat Transf. Eng. 32(1)(2011) 57–68.
- [33] Varol, Y., Oztop, H. and Pop, I. Influence of inclination angle on buoyancy-driven convection in triangular enclosure filled with a fluid-saturated porous medium, Heat Mass Transf. 44(5) (2008) 617–624.
- [34] Varol, Y., Oztop, H.F. and Koca, A. Effects of inclination angle on conduction—natural convection in divided enclosures filled with different fluids, Int. Commun. Heat Mass Transf. 37(2) (2010) 182–191.
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