Assessing thermal and hydrodynamic performance of non-Newtonian nano-coolant flow through a porous backward-facing step channel with non-Darcian effects
This research examines the hydrodynamic and thermal characteristics of Al2O3-water as a shear-thinning non-Newtonian nano-coolant (NC) flowing through a porous structure. The rheological characteristics of the coolant have been deemed to be shear-thinning based on the weight percentage (ϕ) of suspen...
Saved in:
| Main Authors: | , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2025-09-01
|
| Series: | Results in Engineering |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2590123025020997 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1849415046441992192 |
|---|---|
| author | Zarin Akter Preetom Nag Hasina Akter Md. Mamun Molla Goutam Saha |
| author_facet | Zarin Akter Preetom Nag Hasina Akter Md. Mamun Molla Goutam Saha |
| author_sort | Zarin Akter |
| collection | DOAJ |
| description | This research examines the hydrodynamic and thermal characteristics of Al2O3-water as a shear-thinning non-Newtonian nano-coolant (NC) flowing through a porous structure. The rheological characteristics of the coolant have been deemed to be shear-thinning based on the weight percentage (ϕ) of suspended nanoparticles. The flow dynamics are examined within a homogeneous saturated porous substrate placed in a backward-facing step (BFS) channel featuring an expansion ratio of 1:2. The lengths of the upstream and downstream channels, before and after the step of height h, are maintained in a ratio of 6h:30h. The Darcy–Brinkman–Forchheimer (DBF) porous model, incorporating non-Newtonian viscous NC flow, has been numerically solved within the computational domain using a finite volume method with second-order accuracy. The investigations were conducted with varying key parameters, including Reynolds number (300≤Re≤1000), Rayleigh number (105≤Ra≤106), porosity (0.4≤ϵ≤0.99), and Darcy number (10−1≤Da≤10−3). Findings indicate a 50% reduction in skin friction coefficient (Cf) when doubling Re, highlighting the complex relationship between flow dynamics and thermal exchange within the porous substrate. The recirculation zone after the step shrinks with decreasing ϵ, emphasizing the improved heat transfer (HT) from the wall interface through a stronger porous medium. Increasing the porous strength by reducing ϵ from 0.9 to 0.4 leads to over 200% improvement in average thermal exchange rate (Nuavg) for the shear-thinning coolant (ϕ=4%) even at low permeability (Da=0.001). The study also evaluates the thermal performance criterion (PEC), which increases with higher Re but decreases with ϕ. The outcomes of PEC provide practical insights into the thermal engineering aspects, underscoring the significance of comprehending nano-coolant dynamics within a porous matrix for optimizing thermal transport processes. |
| format | Article |
| id | doaj-art-edb7fc9702324025b6da07ae36ff19d0 |
| institution | Kabale University |
| issn | 2590-1230 |
| language | English |
| publishDate | 2025-09-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Results in Engineering |
| spelling | doaj-art-edb7fc9702324025b6da07ae36ff19d02025-08-20T03:33:38ZengElsevierResults in Engineering2590-12302025-09-012710602710.1016/j.rineng.2025.106027Assessing thermal and hydrodynamic performance of non-Newtonian nano-coolant flow through a porous backward-facing step channel with non-Darcian effectsZarin Akter0Preetom Nag1Hasina Akter2Md. Mamun Molla3Goutam Saha4Department of Mathematics & Physics, North South University (NSU), Dhaka-1229, Bangladesh; Center of Applied & Computational Sciences (CACS), NSU, Dhaka-1229, BangladeshDepartment of Mathematics & Physics, North South University (NSU), Dhaka-1229, Bangladesh; Center of Applied & Computational Sciences (CACS), NSU, Dhaka-1229, Bangladesh; Corresponding author at: Department of Mathematics & Physics, North South University (NSU), Dhaka-1229, Bangladesh.Department of Mathematics & Physics, North South University (NSU), Dhaka-1229, Bangladesh; Center of Applied & Computational Sciences (CACS), NSU, Dhaka-1229, BangladeshDepartment of Mathematics & Physics, North South University (NSU), Dhaka-1229, Bangladesh; Center of Applied & Computational Sciences (CACS), NSU, Dhaka-1229, BangladeshDepartment of Mathematics, University of Dhaka, Dhaka-1000, BangladeshThis research examines the hydrodynamic and thermal characteristics of Al2O3-water as a shear-thinning non-Newtonian nano-coolant (NC) flowing through a porous structure. The rheological characteristics of the coolant have been deemed to be shear-thinning based on the weight percentage (ϕ) of suspended nanoparticles. The flow dynamics are examined within a homogeneous saturated porous substrate placed in a backward-facing step (BFS) channel featuring an expansion ratio of 1:2. The lengths of the upstream and downstream channels, before and after the step of height h, are maintained in a ratio of 6h:30h. The Darcy–Brinkman–Forchheimer (DBF) porous model, incorporating non-Newtonian viscous NC flow, has been numerically solved within the computational domain using a finite volume method with second-order accuracy. The investigations were conducted with varying key parameters, including Reynolds number (300≤Re≤1000), Rayleigh number (105≤Ra≤106), porosity (0.4≤ϵ≤0.99), and Darcy number (10−1≤Da≤10−3). Findings indicate a 50% reduction in skin friction coefficient (Cf) when doubling Re, highlighting the complex relationship between flow dynamics and thermal exchange within the porous substrate. The recirculation zone after the step shrinks with decreasing ϵ, emphasizing the improved heat transfer (HT) from the wall interface through a stronger porous medium. Increasing the porous strength by reducing ϵ from 0.9 to 0.4 leads to over 200% improvement in average thermal exchange rate (Nuavg) for the shear-thinning coolant (ϕ=4%) even at low permeability (Da=0.001). The study also evaluates the thermal performance criterion (PEC), which increases with higher Re but decreases with ϕ. The outcomes of PEC provide practical insights into the thermal engineering aspects, underscoring the significance of comprehending nano-coolant dynamics within a porous matrix for optimizing thermal transport processes.http://www.sciencedirect.com/science/article/pii/S2590123025020997Non-Newtonian fluidNanofluidPorous mediumBackward facing stepFinite volume methodPerformance evaluation criteria |
| spellingShingle | Zarin Akter Preetom Nag Hasina Akter Md. Mamun Molla Goutam Saha Assessing thermal and hydrodynamic performance of non-Newtonian nano-coolant flow through a porous backward-facing step channel with non-Darcian effects Results in Engineering Non-Newtonian fluid Nanofluid Porous medium Backward facing step Finite volume method Performance evaluation criteria |
| title | Assessing thermal and hydrodynamic performance of non-Newtonian nano-coolant flow through a porous backward-facing step channel with non-Darcian effects |
| title_full | Assessing thermal and hydrodynamic performance of non-Newtonian nano-coolant flow through a porous backward-facing step channel with non-Darcian effects |
| title_fullStr | Assessing thermal and hydrodynamic performance of non-Newtonian nano-coolant flow through a porous backward-facing step channel with non-Darcian effects |
| title_full_unstemmed | Assessing thermal and hydrodynamic performance of non-Newtonian nano-coolant flow through a porous backward-facing step channel with non-Darcian effects |
| title_short | Assessing thermal and hydrodynamic performance of non-Newtonian nano-coolant flow through a porous backward-facing step channel with non-Darcian effects |
| title_sort | assessing thermal and hydrodynamic performance of non newtonian nano coolant flow through a porous backward facing step channel with non darcian effects |
| topic | Non-Newtonian fluid Nanofluid Porous medium Backward facing step Finite volume method Performance evaluation criteria |
| url | http://www.sciencedirect.com/science/article/pii/S2590123025020997 |
| work_keys_str_mv | AT zarinakter assessingthermalandhydrodynamicperformanceofnonnewtoniannanocoolantflowthroughaporousbackwardfacingstepchannelwithnondarcianeffects AT preetomnag assessingthermalandhydrodynamicperformanceofnonnewtoniannanocoolantflowthroughaporousbackwardfacingstepchannelwithnondarcianeffects AT hasinaakter assessingthermalandhydrodynamicperformanceofnonnewtoniannanocoolantflowthroughaporousbackwardfacingstepchannelwithnondarcianeffects AT mdmamunmolla assessingthermalandhydrodynamicperformanceofnonnewtoniannanocoolantflowthroughaporousbackwardfacingstepchannelwithnondarcianeffects AT goutamsaha assessingthermalandhydrodynamicperformanceofnonnewtoniannanocoolantflowthroughaporousbackwardfacingstepchannelwithnondarcianeffects |