Effect of the addition of pie-shaped ribs and parallelogram ribs in micro-channels on thermal performance using diamond-water nanofluid
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2021-02-12 |
| Journal | SN Applied Sciences |
| Authors | Kamel Chadi, Nourredine Belghar, Belhi Guerira, Mohammed Lachi, Mourad Chikhi |
| Institutions | University of Biskra |
| Citations | 2 |
| Analysis | Full AI Review Included |
Executive Summary
Section titled âExecutive SummaryâThis numerical study investigates the thermal performance of micro-channel heat sinks (MCHS) enhanced by internal ribs and cooled by a diamond-water nanofluid, targeting improved cooling for high-flux electronics.
- Optimal Design Identified: The micro-channel featuring wavy sidewalls and parallelogram ribs (Case 4) demonstrated superior thermal performance compared to smooth, wavy, or pie-ribbed designs.
- Temperature Reduction: Case 4 achieved the lowest maximum substrate temperature (Tmax = 317.91 K at Re=200), representing a 15.33 K drop compared to the smooth channel (Case 1, Tmax = 333.24 K).
- Heat Transfer Enhancement: The parallelogram rib configuration yielded the highest average Nusselt number (Nu) and average heat transfer coefficient (hav) across the tested Reynolds number range (200 < Re < 600).
- Thermal Resistance: The addition of ribs (Cases 3 and 4) significantly reduced the thermal resistance (Rth) of the heat sink, confirming better overall heat dissipation efficiency.
- Nanofluid Efficacy: A diamond-water nanofluid (5% volume concentration) was used, leveraging the high thermal conductivity of diamond (2300 W/mK) to enhance the coolantâs properties.
- Performance Trade-off: The superior thermal performance of Case 4 was accompanied by the highest friction factor (f), indicating increased pressure drop and higher pumping power requirements.
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| Coolant Material | Diamond-Water Nanofluid | N/A | 5% volume concentration (phi = 0.05) |
| Nanoparticle Thermal Conductivity (ks) | 2300 | W/mK | Diamond property at 300 K |
| Base Fluid Thermal Conductivity (kf) | 0.613 | W/mK | Water property at 300 K |
| Operating Reynolds Number (Re) | 200 to 600 | N/A | Laminar flow regime |
| Applied Heat Flux (Q) | 100 | W/cm2 | Constant flux on bottom substrate wall |
| Total Heat Sink Area (Aw) | 10 x 5 | mm2 | Total area being cooled |
| Channel Length (L) | 10 | mm | Micro-channel dimension |
| Channel Height (H) | 0.35 | mm | Micro-channel dimension |
| Optimal Tmax (Case 4) | 317.91 | K | Maximum temperature at Re=200 |
| Baseline Tmax (Case 1) | 333.24 | K | Maximum temperature at Re=200 |
| Rib Location (z) | 6.67 | mm | Distance from micro-channel exit (Cases 3 & 4) |
| Parallelogram Rib Width (Wr) | 0.05 | mm | Tested geometric parameter |
| Pie Rib Diameter (D) | 0.05 | mm | Tested geometric parameter |
Key Methodologies
Section titled âKey MethodologiesâThe study utilized a 3D numerical simulation approach to model the fluid flow and heat transfer characteristics within the micro-channels.
- Simulation Software and Method: Ansys Fluent software was used, employing the Finite Volume Method (FVM) for spatial integration of conservation equations.
- Flow Assumptions: The flow was modeled as stationary, laminar, incompressible, and Newtonian. Heat exchange by radiation was considered negligible.
- Nanofluid Modeling: Thermophysical properties (density, specific heat, thermal conductivity, viscosity) of the diamond-water nanofluid were calculated using established empirical correlations (e.g., Brinkman model for viscosity).
- Geometric Cases: Four distinct silicon micro-channel heat sink geometries were analyzed:
- Case 1: Smooth rectangular channel (Baseline).
- Case 2: Wavy sidewalls (2/3L).
- Case 3: Wavy sidewalls + Pie-shaped ribs.
- Case 4: Wavy sidewalls + Parallelogram ribs (Optimal).
- Boundary Conditions:
- Inlet: Uniform velocity (Winlet) and constant temperature (Tinlet).
- Bottom Wall: Constant heat flux (100 W/cm2) applied.
- Walls/Ribs: No-slip conditions (u=v=w=0) and continuity of heat flux at the fluid-solid interface.
- Top Wall: Adiabatic condition.
- Solution Algorithm and Convergence: The SIMPLE algorithm was used for pressure-velocity coupling. Mesh independence was confirmed, and convergence was achieved with residuals for continuity and velocity components in the order of 10-5.
Commercial Applications
Section titled âCommercial ApplicationsâThe findings are directly applicable to industries requiring high-efficiency thermal management solutions for high-power density electronics, particularly those leveraging the extreme thermal properties of diamond materials.
- High-Power Density Electronics: Cooling of advanced semiconductor devices (e.g., SiC, GaN) used in radar systems, 5G infrastructure, and high-frequency power amplifiers.
- Data Centers and HPC: Integration into next-generation server cooling loops to manage heat fluxes exceeding 100 W/cm2, improving reliability and reducing operational energy costs.
- Electric Vehicle (EV) Systems: Thermal management for EV battery packs, inverters, and motor controllers, where compact, high-performance cooling is critical for longevity and efficiency.
- Diamond-Enhanced Coolants: Development and deployment of diamond-based nanofluids for liquid cooling systems, capitalizing on diamondâs thermal conductivity (2300 W/mK) to achieve superior heat transfer coefficients.
- Micro-Electro-Mechanical Systems (MEMS): Design of integrated micro-channel heat sinks for localized cooling within miniaturized electronic packages and sensors.
View Original Abstract
Abstract In this paper, we numerically study the influence of the addition of parallelogram ribs and pie-shaped ribs in micro-channels on thermal exchange in three dimensions. We design four different silicon micro-channel heat sinks; the first and second cases without ribs, the third case with added pie-shaped ribs, and a fourth case containing parallelogram ribs. The main purpose of this research is to determine the best micro-channel heat sink in which the heat dissipation is sufficient to improve the heat exchange performance of the micro-channel, as well as to improve the cooling of the electronic components. A constant heat flux is applied to the bottom wall of the four micro-channels, and we use liquid diamond-water with a volume concentration of 5% diamond nanoparticles as a coolant, with a Reynolds number chosen between 200 and 600. The numerical results show that the Nusselt number (Nu) of the micro-channel that contains the parallelogram ribs is higher than that for the other cases, and it also yiels lower temperature values on the bottom wall of the substrate compared to the micro-channel containing pie ribs. When increasing the flow velocity, the thermal resistance of the micro-channel decreases in all cases, and we then find the largest value of the friction factor in the fourth case (with parallelogram ribs).
Tech Support
Section titled âTech SupportâOriginal Source
Section titled âOriginal SourceâReferences
Section titled âReferencesâ- 2016 - Electronics cooling