Performance and optimum geometry of spines with simultaneous heat and mass transfer

2010

In this paper, constructal optimization of the twice Y-shaped assemblies of fins with six freedom degrees (characteristic parameters of geometry) is performed by employing finite element method and taking dimensionless maximum thermal resistance as a performance index, and the heat transfer performance of the twice Y-shaped assemblies of fins under various conditions with different freedom degrees are analyzed. The results show that the twice assemblies can improve the heat transfer performance of Y-shaped fin remarkably, and the minimum maximum thermal resistance of the twice Y-shaped assemblies of fins decreases by 36.37% compared with that of once Y-shaped assembly of fins. It is also proved again that the larger the number of freedom degrees for evolving is, the more perfect the system performance is. The effects of different characteristic parameters of geometry on the performance of the twice Y-shaped assemblies of fins are different, one should pay different attention to these parameters in practical engineering designs. The effects of two angles on the maximum thermal resistance are larger, but the optima of the two angles are robust. The effects of two height ratios on the maximum thermal resistance are more remarkable than those of two thickness ratios.constructal theory, fin, multi-scale, enhanced heat transfer, generalized thermodynamic optimization Citation:Xie Z H, Chen L G, Sun F R. Constructal optimization of twice Y-shaped assemblies of fins by taking maximum thermal resistance minimization as objective.

Section: Introductionmentioning

confidence: 94%

Constructal optimization of twice Y-shaped assemblies of fins by taking maximum thermal resistance minimization as objective

Xie

2010

“…Ref. [50] optimized a few spine fins of different configurations with simultaneous heat and mass transfer geometrically, and the obtained results include those obtained in a dry spine case just only with heat transfer. Xie et al [51] optimized second-order assembly of Y-shaped fins with maximum thermal resistance minimization.…”

Section: Introductionmentioning

confidence: 97%

“…In engineering, it is a common way to adopt fin for enhancing heat transfer with guidelines of theories involving constructal theory , entropy generation minimization theory [16,19,22,23] and field synergy principle [24][25][26][27][28][29][30][31][32][33][34][35][36][37]. Since Bejan put forward the constructal theory [1] in 1996, and applied it to optimization problem involving heat conduction, constructal theory has been developing rapidly in heat transfer optimization problems of fins [38][39][40][41][42][43][44][45][46][47][48][49][50][51]. Analytical and numerical methods are the two main methods for solving heat conduction problem.…”

Section: Introductionmentioning

confidence: 99%

“…However, constructal optimizations of fins do not reflect global heat conduction performances in heat transfer processes with heat transfer rate maximizations (maximum thermal resistance minimizations) or by introducing fin efficiency as performed in refs. [38][39][40][41][42][43][44][45][46][47][48][49][50][51]. Guo et al [52] introduced definitively a new physical quantity called "entransy" that describes the heat transfer ability (ref.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Constructal entransy dissipation rate minimization for umbrella-shaped assembly of cylindrical fins

Xiao

2010

Umbrella-shaped assembly of cylindrical fins is optimized by adopting analytical method and taking dimensionless mean thermal resistance (MTR) as performance index. The optimal construct of umbrella-shaped assembly is obtained. The results show that the heat conductance performance of the assembly becomes ever worse with ever greater number of elemental cylindrical fins, the umbrella-shaped assembly reduces to cylindrical fin in some values of design parameters, and the diameters' dependence on design parameters is weak for the optimized assembly. An equivalent thermal resistance defined based on entransy dissipation rate (EDR) reflects an average heat transfer effect of the assembly. The constructal design corresponding to the minimum EDR (or MTR) should be adopted for designing an assembly of fins in engineering at the limit safe condition.constructal theory, fin, entransy dissipation rate, intensifying heat transfer, generalized thermodynamic optimization

“…Fin and near fin structures are the effective cells and modules for controlling temperature, which are employed widely in the fields of energy, chemical industry, spaceflight, electronic industry, etc. The optimization studies for them are the important contents of heat transfer optimization all along [4,[7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

Comparative study on constructal optimizations of T-shaped fin based on entransy dissipation rate minimization and maximum thermal resistance minimization

Xie

2011

The constructal optimizations of T-shaped fin with two-dimensional heat transfer model are carried out by finite element method and taking the minimization of equivalent thermal resistance based on entransy dissipation and the minimization of maximum thermal resistance as optimization objectives, respectively. The effects of the global parameter a (integrating the coefficient of convective heat transfer, the overall area occupied by fin and its thermal conductivity) and the volume fraction  of fin on the minimums of equivalent thermal resistance and maximum thermal resistance as well as their corresponding optimal configurations are analyzed. The comparison of the results based on the above two optimization objectives is conducted. The results show that the optimal structures based on the two optimization objectives are obviously different from each other. Compared with the optimization result by taking the minimization of maximum thermal resistance as the objective, the optimization result by taking the equivalent thermal resistance minimization as the objective can reduce the average temperature difference in the fin obviously. The increases of a and  can all improve the working status of local hot spot and the global heat transfer performance of the system. But the improvement effects of the increases of a and  on the minimization of equivalent thermal resistance are different from those on the minimization of maximum thermal resistance. For either objective, the effect of a is different from that of . The T-shaped fin with minimum equivalent thermal resistance is much taller than that with minimum maximum thermal resistance; for either optimization objective, the stem of fin is thicker than the branches of fin, and the stem thickness is relatively close to branch thickness when the minimization of equivalent thermal resistance is taken as the optimization objective. The T-shaped fin with flat stem and slender branches can benefit the reduction of the maximum thermal resistance. constructal theory, entransy dissipation extremum principle, fin, multi-scale, generalized thermodynamic optimization Citation:Xie Z H, Chen L G, Sun F R. Comparative study on constructal optimizations of T-shaped fin based on entransy dissipation rate minimization and maximum thermal resistance minimization.