Abstract

The performance and thermal properties of convective–radiative rectangular and moving exponential porous fins with variable thermal conductivity together with internal heat generation are investigated. The second law of thermodynamics is used to investigate entropy generation in the proposed fins. The model is numerically solved using shooting technique. It is observed that the entropy generation depends on porosity parameter, temperature ratio, temperature distribution, thermal conductivity and fins structure. It is noted that entropy generation for a decay exponential fin is higher than that of a rectangular fin which is greater than that of a growing exponential fin. Moreover, entropy generation decreases as thermal conductivity increases. The results also reveal that entropy generation is maximum at the fin’s base and the average entropy production depends on porosity parameters and temperature ratio. It is further reveal that the temperature ratio has a smaller amount of influence on entropy as compared to porosity parameter. It is concluded that when the temperature ratio is increases from 1.1 to 1.9, the entropy generation number is also increase by 30% approximately. However, increasing porosity from 1 to 80 gives 14-fold increase in average entropy generation.

Highlights

  • The performance and thermal properties of convective–radiative rectangular and moving exponential porous fins with variable thermal conductivity together with internal heat generation are investigated

  • To obtain the governing equation, it is supposed that the fin is isotropic, homogeneous and saturated with single-phase fluid, and the Darcy model is used to investigate the fluid-porous medium interaction.it is considered that both the solid and fluid bodies are in thermal balance with one another

  • We have studied entropy generation in a variety of porous fins having temperature dependent thermal conductivity together with convection, radiation and internal heat generation

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Summary

Mathematical formulation

Moving exponential perforated fin with and variable thermal conductivity and internal heat generation is considered. To obtain the governing equation, it is supposed that the fin is isotropic, homogeneous and saturated with single-phase fluid, and the Darcy model is used to investigate the fluid-porous medium interaction.it is considered that both the solid and fluid bodies are in thermal balance with one another. It should be noted that ξ ∗ = 0 indicate rectangular fin and |ξ ∗| = 0 represent exponential fin, while τb is the semi-fin thickness. Based on Darcy’s model and the aforementioned assumptions the energy equation for porous fin can be expressed as qx − qx + ∂q dx − m Cp T − Ta dx − h(1 − φ)P T − Ta dx + UρCpf (x) dT dx + qf (x) − εσ P T4 − Ta4 dx = 0,.

Entropy generation
Numerical results and discussion
Conclusion
Findings
Additional information
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