Local entropy generation analysis for a single slope solar still (Numerical investigations)

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Abstract

In this research, the entropy generation is calculated locally in a single slope solar still by using computational fluid dynamics to improve the performance of this device. To benchmark the accuracy of the numerical method, the numerical results are compared with the experimental data obtained for a real solar still. The effects of aspect ratio (the ratio of length to the average height of the solar still) and the temperatures of glass cover and water surface on different types of entropy generation containing frictional, diffusive, and thermal entropy generations are investigated. Obtained results indicate that different types of entropy generation increase by increasing the temperatures of glass and water surfaces or increasing the aspect ratio. Moreover, the results showed that the aspect ratio affects considerably the performance of the solar still as it determines the distance between the evaporation (water surface) and condensation (glass surface) surfaces. Moreover, this parameter determines the time required for transferring the vapour from water surface to the glass surface. The regions around the water and glass surfaces have a high potential to generate the entropy and irreversibility. Finally, it is observed that the thermal entropy generation is dominant at all cases in comparison with two other types of entropy generation.

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References

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Journal of Solid and Fluid Mechanics
Volume 7, Issue 4
January 2018
Pages 279-291

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