<p>This study investigates the effects of heat generation and magnetic fields on natural convection in a wavy porous cavity filled with a hybrid nanofluid (Al₂O₃-Cu/water), using the hybrid finite volume method (FVM) and XGBoost model within the local thermal non-equilibrium (LTNE) framework. The cavity contains inner heaters with variable lengths, positions, and heat generation/absorption coefficients. The primary objective is to analyze the interplay of key parameters, including heat source length (<InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="13538_2025_1747_Article_IEq1.gif" Format="GIF" Height="14" Rendition="HTML" Resolution="72" Type="Linedraw" Width="17" /> </InlineMediaObject> <EquationSource Format="TEX">\(B\)</EquationSource> <EquationSource Format="MATHML"><math> <mi>B</mi> </math></EquationSource> </InlineEquation>), position (<InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="13538_2025_1747_Article_IEq2.gif" Format="GIF" Height="14" Rendition="HTML" Resolution="72" Type="Linedraw" Width="19" /> </InlineMediaObject> <EquationSource Format="TEX">\(D\)</EquationSource> <EquationSource Format="MATHML"><math> <mi>D</mi> </math></EquationSource> </InlineEquation>), solid volume fraction (<InlineEquation ID="IEq3"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="13538_2025_1747_Article_IEq3.gif" Format="GIF" Height="17" Rendition="HTML" Resolution="72" Type="Linedraw" Width="16" /> </InlineMediaObject> <EquationSource Format="TEX">\(\phi\)</EquationSource> <EquationSource Format="MATHML"><math> <mi>ϕ</mi> </math></EquationSource> </InlineEquation>), porosity (<InlineEquation ID="IEq4"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="13538_2025_1747_Article_IEq4.gif" Format="GIF" Height="10" Rendition="HTML" Resolution="72" Type="Linedraw" Width="11" /> </InlineMediaObject> <EquationSource Format="TEX">\(\varepsilon\)</EquationSource> <EquationSource Format="MATHML"><math> <mi>ε</mi> </math></EquationSource> </InlineEquation>), Hartmann number (<InlineEquation ID="IEq5"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="13538_2025_1747_Article_IEq5.gif" Format="GIF" Height="14" Rendition="HTML" Resolution="72" Type="Linedraw" Width="28" /> </InlineMediaObject> <EquationSource Format="TEX">\(Ha\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi mathvariant="italic">Ha</mi> </mrow> </math></EquationSource> </InlineEquation>), Rayleigh number (<InlineEquation ID="IEq6"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="13538_2025_1747_Article_IEq6.gif" Format="GIF" Height="14" Rendition="HTML" Resolution="72" Type="Linedraw" Width="25" /> </InlineMediaObject> <EquationSource Format="TEX">\(Ra\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi mathvariant="italic">Ra</mi> </mrow> </math></EquationSource> </InlineEquation>), and the heat generation/absorption coefficient (<InlineEquation ID="IEq7"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="13538_2025_1747_Article_IEq7.gif" Format="GIF" Height="17" Rendition="HTML" Resolution="72" Type="Linedraw" Width="19" /> </InlineMediaObject> <EquationSource Format="TEX">\(Q\)</EquationSource> <EquationSource Format="MATHML"><math> <mi>Q</mi> </math></EquationSource> </InlineEquation>). The results provide insights into optimizing heat and mass transfer characteristics under varying conditions, with potential applications in thermal management systems. The mathematical model incorporates the governing equations for continuity, momentum, and energy for the fluid and solid phases. The LTNE approach accounts for separate temperature fields for the fluid and solid, enabling a detailed analysis of the thermal behavior. The numerical simulations were performed using dimensionless formulations, allowing the study of a wide range of physical and geometric parameters. The cavity geometry includes a wavy right wall maintained at a cold temperature (<InlineEquation ID="IEq8"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="13538_2025_1747_Article_IEq8.gif" Format="GIF" Height="16" Rendition="HTML" Resolution="72" Type="Linedraw" Width="18" /> </InlineMediaObject> <EquationSource Format="TEX">\({T}_{c}\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>T</mi> <mi>c</mi> </msub> </math></EquationSource> </InlineEquation>) and a flat left wall with localized heat sources (<InlineEquation ID="IEq9"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="13538_2025_1747_Article_IEq9.gif" Format="GIF" Height="16" Rendition="HTML" Resolution="72" Type="Linedraw" Width="20" /> </InlineMediaObject> <EquationSource Format="TEX">\({T}_{h}\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>T</mi> <mi>h</mi> </msub> </math></EquationSource> </InlineEquation>). The findings reveal the significant influence of <InlineEquation ID="IEq10"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="13538_2025_1747_Article_IEq10.gif" Format="GIF" Height="14" Rendition="HTML" Resolution="72" Type="Linedraw" Width="17" /> </InlineMediaObject> <EquationSource Format="TEX">\(B\)</EquationSource> <EquationSource Format="MATHML"><math> <mi>B</mi> </math></EquationSource> </InlineEquation>, <InlineEquation ID="IEq11"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="13538_2025_1747_Article_IEq11.gif" Format="GIF" Height="14" Rendition="HTML" Resolution="72" Type="Linedraw" Width="19" /> </InlineMediaObject> <EquationSource Format="TEX">\(D\)</EquationSource> <EquationSource Format="MATHML"><math> <mi>D</mi> </math></EquationSource> </InlineEquation>, <InlineEquation ID="IEq12"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="13538_2025_1747_Article_IEq12.gif" Format="GIF" Height="17" Rendition="HTML" Resolution="72" Type="Linedraw" Width="16" /> </InlineMediaObject> <EquationSource Format="TEX">\(\phi\)</EquationSource> <EquationSource Format="MATHML"><math> <mi>ϕ</mi> </math></EquationSource> </InlineEquation>, and <InlineEquation ID="IEq13"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="13538_2025_1747_Article_IEq13.gif" Format="GIF" Height="17" Rendition="HTML" Resolution="72" Type="Linedraw" Width="19" /> </InlineMediaObject> <EquationSource Format="TEX">\(Q\)</EquationSource> <EquationSource Format="MATHML"><math> <mi>Q</mi> </math></EquationSource> </InlineEquation> on the flow structure and thermal distribution. An increase in <InlineEquation ID="IEq14"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="13538_2025_1747_Article_IEq14.gif" Format="GIF" Height="14" Rendition="HTML" Resolution="72" Type="Linedraw" Width="17" /> </InlineMediaObject> <EquationSource Format="TEX">\(B\)</EquationSource> <EquationSource Format="MATHML"><math> <mi>B</mi> </math></EquationSource> </InlineEquation> intensifies convective currents and enhances heat transfer efficiency, while the position of the heat source (<InlineEquation ID="IEq15"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="13538_2025_1747_Article_IEq15.gif" Format="GIF" Height="14" Rendition="HTML" Resolution="72" Type="Linedraw" Width="19" /> </InlineMediaObject> <EquationSource Format="TEX">\(D\)</EquationSource> <EquationSource Format="MATHML"><math> <mi>D</mi> </math></EquationSource> </InlineEquation>) modulates the distribution of buoyancy forces. The addition of nanoparticles (<InlineEquation ID="IEq16"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="13538_2025_1747_Article_IEq16.gif" Format="GIF" Height="17" Rendition="HTML" Resolution="72" Type="Linedraw" Width="16" /> </InlineMediaObject> <EquationSource Format="TEX">\(\phi\)</EquationSource> <EquationSource Format="MATHML"><math> <mi>ϕ</mi> </math></EquationSource> </InlineEquation>) improves the effective thermal conductivity of the hybrid nanofluid, enhancing both fluid and solid phase heat transfer. Positive values of <InlineEquation ID="IEq17"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="13538_2025_1747_Article_IEq17.gif" Format="GIF" Height="17" Rendition="HTML" Resolution="72" Type="Linedraw" Width="19" /> </InlineMediaObject> <EquationSource Format="TEX">\(Q\)</EquationSource> <EquationSource Format="MATHML"><math> <mi>Q</mi> </math></EquationSource> </InlineEquation> further amplify buoyancy-driven convection, resulting in higher Nusselt numbers (<InlineEquation ID="IEq18"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="13538_2025_1747_Article_IEq18.gif" Format="GIF" Height="14" Rendition="HTML" Resolution="72" Type="Linedraw" Width="28" /> </InlineMediaObject> <EquationSource Format="TEX">\(Nu\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi mathvariant="italic">Nu</mi> </mrow> </math></EquationSource> </InlineEquation>). The impact of porosity (<InlineEquation ID="IEq19"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="13538_2025_1747_Article_IEq19.gif" Format="GIF" Height="10" Rendition="HTML" Resolution="72" Type="Linedraw" Width="11" /> </InlineMediaObject> <EquationSource Format="TEX">\(\varepsilon\)</EquationSource> <EquationSource Format="MATHML"><math> <mi>ε</mi> </math></EquationSource> </InlineEquation>) and Rayleigh number (<InlineEquation ID="IEq20"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="13538_2025_1747_Article_IEq20.gif" Format="GIF" Height="14" Rendition="HTML" Resolution="72" Type="Linedraw" Width="25" /> </InlineMediaObject> <EquationSource Format="TEX">\(Ra\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi mathvariant="italic">Ra</mi> </mrow> </math></EquationSource> </InlineEquation>) was also evaluated. Higher porosity values promote fluid permeability, facilitating stronger convective currents and more uniform temperature profiles. Similarly, increasing <InlineEquation ID="IEq21"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="13538_2025_1747_Article_IEq21.gif" Format="GIF" Height="14" Rendition="HTML" Resolution="72" Type="Linedraw" Width="25" /> </InlineMediaObject> <EquationSource Format="TEX">\(Ra\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi mathvariant="italic">Ra</mi> </mrow> </math></EquationSource> </InlineEquation> shifts the dominant heat transfer mechanism from conduction to convection, enhancing thermal mixing and efficiency. The Hartmann number (<InlineEquation ID="IEq22"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="13538_2025_1747_Article_IEq22.gif" Format="GIF" Height="14" Rendition="HTML" Resolution="72" Type="Linedraw" Width="28" /> </InlineMediaObject> <EquationSource Format="TEX">\(Ha\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi mathvariant="italic">Ha</mi> </mrow> </math></EquationSource> </InlineEquation>) was found to suppress convection due to magnetic damping effects, reducing heat transfer rates. However, this damping can be partially offset by the enhanced thermal conductivity from higher nanoparticle concentrations (<InlineEquation ID="IEq23"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="13538_2025_1747_Article_IEq23.gif" Format="GIF" Height="17" Rendition="HTML" Resolution="72" Type="Linedraw" Width="16" /> </InlineMediaObject> <EquationSource Format="TEX">\(\phi\)</EquationSource> <EquationSource Format="MATHML"><math> <mi>ϕ</mi> </math></EquationSource> </InlineEquation>). AI-based models, specifically XGBoost, were employed to predict the Nusselt number for nanofluid and solid phases and the average heat transfer characteristics. The predictions align well with the numerical results, validating the model’s applicability for optimizing thermal systems. Overall, the study demonstrates that careful selection of parameters such as <InlineEquation ID="IEq24"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="13538_2025_1747_Article_IEq24.gif" Format="GIF" Height="14" Rendition="HTML" Resolution="72" Type="Linedraw" Width="17" /> </InlineMediaObject> <EquationSource Format="TEX">\(B\)</EquationSource> <EquationSource Format="MATHML"><math> <mi>B</mi> </math></EquationSource> </InlineEquation>, <InlineEquation ID="IEq25"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="13538_2025_1747_Article_IEq25.gif" Format="GIF" Height="14" Rendition="HTML" Resolution="72" Type="Linedraw" Width="19" /> </InlineMediaObject> <EquationSource Format="TEX">\(D\)</EquationSource> <EquationSource Format="MATHML"><math> <mi>D</mi> </math></EquationSource> </InlineEquation>, <InlineEquation ID="IEq26"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="13538_2025_1747_Article_IEq26.gif" Format="GIF" Height="17" Rendition="HTML" Resolution="72" Type="Linedraw" Width="16" /> </InlineMediaObject> <EquationSource Format="TEX">\(\phi\)</EquationSource> <EquationSource Format="MATHML"><math> <mi>ϕ</mi> </math></EquationSource> </InlineEquation>, <InlineEquation ID="IEq27"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="13538_2025_1747_Article_IEq27.gif" Format="GIF" Height="10" Rendition="HTML" Resolution="72" Type="Linedraw" Width="11" /> </InlineMediaObject> <EquationSource Format="TEX">\(\varepsilon\)</EquationSource> <EquationSource Format="MATHML"><math> <mi>ε</mi> </math></EquationSource> </InlineEquation>, and <InlineEquation ID="IEq28"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="13538_2025_1747_Article_IEq28.gif" Format="GIF" Height="17" Rendition="HTML" Resolution="72" Type="Linedraw" Width="19" /> </InlineMediaObject> <EquationSource Format="TEX">\(Q\)</EquationSource> <EquationSource Format="MATHML"><math> <mi>Q</mi> </math></EquationSource> </InlineEquation>, coupled with the use of hybrid nanofluids, can significantly improve the thermal performance of porous cavities under MHD conditions.</p>

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XGBoost Predictions of Heat Generation in MHD Natural Convection of Hybrid Nanofluid in a Wavy Porous Cavity

  • Noura Alsedais,
  • Mohamed Ahmed Mansour,
  • Abdelraheem M. Aly

摘要

This study investigates the effects of heat generation and magnetic fields on natural convection in a wavy porous cavity filled with a hybrid nanofluid (Al₂O₃-Cu/water), using the hybrid finite volume method (FVM) and XGBoost model within the local thermal non-equilibrium (LTNE) framework. The cavity contains inner heaters with variable lengths, positions, and heat generation/absorption coefficients. The primary objective is to analyze the interplay of key parameters, including heat source length ( \(B\) B ), position ( \(D\) D ), solid volume fraction ( \(\phi\) ϕ ), porosity ( \(\varepsilon\) ε ), Hartmann number ( \(Ha\) Ha ), Rayleigh number ( \(Ra\) Ra ), and the heat generation/absorption coefficient ( \(Q\) Q ). The results provide insights into optimizing heat and mass transfer characteristics under varying conditions, with potential applications in thermal management systems. The mathematical model incorporates the governing equations for continuity, momentum, and energy for the fluid and solid phases. The LTNE approach accounts for separate temperature fields for the fluid and solid, enabling a detailed analysis of the thermal behavior. The numerical simulations were performed using dimensionless formulations, allowing the study of a wide range of physical and geometric parameters. The cavity geometry includes a wavy right wall maintained at a cold temperature ( \({T}_{c}\) T c ) and a flat left wall with localized heat sources ( \({T}_{h}\) T h ). The findings reveal the significant influence of \(B\) B , \(D\) D , \(\phi\) ϕ , and \(Q\) Q on the flow structure and thermal distribution. An increase in \(B\) B intensifies convective currents and enhances heat transfer efficiency, while the position of the heat source ( \(D\) D ) modulates the distribution of buoyancy forces. The addition of nanoparticles ( \(\phi\) ϕ ) improves the effective thermal conductivity of the hybrid nanofluid, enhancing both fluid and solid phase heat transfer. Positive values of \(Q\) Q further amplify buoyancy-driven convection, resulting in higher Nusselt numbers ( \(Nu\) Nu ). The impact of porosity ( \(\varepsilon\) ε ) and Rayleigh number ( \(Ra\) Ra ) was also evaluated. Higher porosity values promote fluid permeability, facilitating stronger convective currents and more uniform temperature profiles. Similarly, increasing \(Ra\) Ra shifts the dominant heat transfer mechanism from conduction to convection, enhancing thermal mixing and efficiency. The Hartmann number ( \(Ha\) Ha ) was found to suppress convection due to magnetic damping effects, reducing heat transfer rates. However, this damping can be partially offset by the enhanced thermal conductivity from higher nanoparticle concentrations ( \(\phi\) ϕ ). AI-based models, specifically XGBoost, were employed to predict the Nusselt number for nanofluid and solid phases and the average heat transfer characteristics. The predictions align well with the numerical results, validating the model’s applicability for optimizing thermal systems. Overall, the study demonstrates that careful selection of parameters such as \(B\) B , \(D\) D , \(\phi\) ϕ , \(\varepsilon\) ε , and \(Q\) Q , coupled with the use of hybrid nanofluids, can significantly improve the thermal performance of porous cavities under MHD conditions.