Numerical Study of Inclination Effect of the Floating Solar Still Fitted with a Baffle in 3D Double Diffusive Natural Convection
Abstract
:1. Introduction
2. Physical Model and Governing Equations
2.1. Physical Model
2.2. Governing Equations, Assymtions, and Boundary Conditions
- Concentration and temperature: , .
- Velocity: on all walls.
- Vorticity and vector potential:
- Vector potential: at and 1, at and 1, at and 1.
3. Numerical Method, Validation, and Grid Sensitivity
3.1. Numerical Method
- ○
- Step 1: Initializing;
- ○
- Step 2: Resolution of the energy equation;
- ○
- Step 3: Resolution of the concentration equation
- ○
- Step 4: Resolution of the vorticity equation;
- ○
- Step 5: Resolution of the potential vector equation.
3.2. Validation
3.3. Grid Sensitivity
4. Results and Discussion
4.1. Flow Structure, Iso-Temperatures, and Iso-Concentrations
4.2. Heat and Masse Transfer Rates
4.3. Sensitivity Analysis
5. Conclusions
- ○
- Uncooled air-vapor leakage was observed during tilting for the solar still equipped with a small flat baffle (reference case) at the cooling zone.
- ○
- The triangular and curvilinear baffle design assisted the air-vapor mixture to cool down before the exit.
- ○
- When Ra = 2 × 104 and θ = 0°, from N = 0.5, the average heat transfer rate is highest in case 2, for triangular baffle. A 12% improvement in the average heat transfer rate compared to the reference case is observed.
- ○
- When Ra = 5 × 104 and N = 0, an improvement of the air-vapor convection is observed in the heating zone for all the new baffles designs studied at θ = 15°. The thermal gradient is enhanced in the cooling zone mainly in the middle of the cold surfaces for cases 2 and 3. When the inclination is less than 18°, all cases studied have higher average Nusselt values than the reference case. And case 2 has higher values of average heat transfer rate. For cases 2 and 3, triangular and curvilinear baffle design, the evolution is parabolic with a maximum of the average transfer rate observed for θ = 5°. In the range of angles between 5° and 20°, case 2 has the highest average mass transfer rate.
- ○
- When Ra = 5 × 104 and N = 1, the heat transfer rate for cases 1, 2, and 3 is higher than the reference case only when θ is lower than 5°. Cases 2 and 3 exhibit higher average Sherwood values than the reference case from θ = 12°. Increasing the angle from 0° to 25° exhibits for case 2 an increase in the average mass transfer rate of 35%.
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
Nomenclature
C | Dimensionless concentration |
D | Mass diffusivity (m2/s) |
Gr | Grashof number |
K | Thermal conductivity (W/m·K) |
H | Height from the base surface to the top (m) |
L | Baffle width (m) |
Le | Lewis number |
N | Buoyancy ratio |
Nu | Nusselt number |
Pr | Prandtl number |
Ra | Rayleigh number |
Sh | Sherwood number |
T | Dimensionless time (=) |
T | Dimensionless temperature |
Dimensionless velocity vector (=) | |
Greek symbols | |
Thermal diffusivity (m2/s) | |
Coefficient of thermal expansion (K−1) | |
Coefficient of solutal expansion (K−1) | |
Dynamic viscosity (kg/m.s) | |
Kinematics viscosity (m2/s) | |
Dimensionless vector potential () | |
Dimensionless vorticity (=) | |
Θ | Angle of inclination of still |
Subscripts | |
x, y, z | Cartesian coordinates |
h | hot, high |
c | Cold |
l | Low |
av | average |
0 | reference |
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Mesh Size | Shav | Percentage Increase | Incremental Increase |
---|---|---|---|
413 | 2.697 | - | - |
513 | 2.733 | 1.33481646 | - |
613 | 2.854 | 5.82128291 | 4.48646644 |
713 | 2.8578 | 5.9621802 | 0.14089729 |
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Almeshaal, M.A.; Maatki, C. Numerical Study of Inclination Effect of the Floating Solar Still Fitted with a Baffle in 3D Double Diffusive Natural Convection. Processes 2022, 10, 1607. https://doi.org/10.3390/pr10081607
Almeshaal MA, Maatki C. Numerical Study of Inclination Effect of the Floating Solar Still Fitted with a Baffle in 3D Double Diffusive Natural Convection. Processes. 2022; 10(8):1607. https://doi.org/10.3390/pr10081607
Chicago/Turabian StyleAlmeshaal, Mohammed A., and Chemseddine Maatki. 2022. "Numerical Study of Inclination Effect of the Floating Solar Still Fitted with a Baffle in 3D Double Diffusive Natural Convection" Processes 10, no. 8: 1607. https://doi.org/10.3390/pr10081607