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Numerical Optimization of MWCNT/Water Nanofluids in Turbulent Forced Convection: Trade-offs Between Thermal Enhancement and Hydraulic Penalty | ||
| Journal of Heat and Mass Transfer Research | ||
| مقالات آماده انتشار، پذیرفته شده، انتشار آنلاین از تاریخ 05 بهمن 1404 | ||
| نوع مقاله: Full Length Research Article | ||
| شناسه دیجیتال (DOI): 10.22075/jhmtr.2026.39756.1883 | ||
| نویسنده | ||
| Diaa Alkhateeb* | ||
| The Second Faculty of Mechanical and Electrical Engineering, Damascus University, Swaida, Syrian Arab Republic | ||
| تاریخ دریافت: 27 آبان 1404، تاریخ بازنگری: 03 دی 1404، تاریخ پذیرش: 05 بهمن 1404 | ||
| چکیده | ||
| This study revisits the turbulent forced‑convection performance of multi‑walled carbon nanotube (MWCNT)/water nanofluids. Building on a Eulerian–Eulerian two‑fluid framework, we couple a second‑order orientation tensor with population balance equations (PBEs) to simultaneously resolve shear‑induced alignment, anisotropic thermal conductivity and aggregation kinetics. A rigorous grid convergence study and quantitative comparisons with published experiments demonstrate root‑mean‑square errors below 5 % in Nusselt numbers and friction factors. Micro-level validation of the constitutive models is provided by comparing predicted orientation factors with rheo-optical measurements and simulated cluster size distributions with dynamic light scattering (DLS) data. The new coupled model predicts an optimal operating window (0.8–1.2 vol% % MWCNTs, Reynolds number 20 000–40 000) where the performance evaluation criterion (PEC) exceeds 1.3. Within this window, axial thermal conductivity increases by ~38 % and Nusselt numbers by ~24 % at 1 vol% %, while hydraulic penalties remain manageable. Concentrations above 1.2 vol% % trigger rapid aggregation that reduces thermal conductivity and increases viscosity, producing PEC values below unity. An economic analysis based on a 500-kW cooling system and realistic nanofluid preparation costs indicates payback periods of less than two years when operated in the high-PEC region. The paper closes with a balanced discussion of modelling limitations and future research directions. | ||
| کلیدواژهها | ||
| MWCNT/water nanofluids؛ turbulent forced convection؛ shear-induced alignment؛ aggregation dynamics؛ performance evaluation criterion (PEC)؛ high-flux cooling systems | ||
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آمار تعداد مشاهده مقاله: 28 |
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