Considerations on the thermal performances of ribbed channels by means of a novel dynamic method for hierarchical clustering

A Niro,P Gramazio,S Ciminà,F Vignati,D Fustinoni

doi:10.1088/1742-6596/745/3/032076

A Niro, P Gramazio + Show 3 more

Open Access

https://doi.org/10.1088/1742-6596/745/3/032076

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Abstract

The investigation of ribbed surfaces for the enhancement of heat transfer in forced convection allowed to observe that different geometries may lead to comparable performances. Due to the lack of an underlying structure of the data, a novel method for data clustering is introduced here, to assess to what extent comparable performances can be achieved using different rib geometries. The clustering method is an agglomerative technique, based on the inclusion of each configuration in another ones bounding box, whose size depends dynamically on the Nusselt number and the pumping power. The method is applied to a large database experimentally obtained at ThermALab of Politecnico di Milano, in order to identify the Nusselt number and the friction factor for diverse-rib configurations in a large-aspect ratio channel with low-Reynolds flows. The clusters are determined, and the resulting families of configurations are used to assess the possible effects of the rib geometry on the thermal and fluid-dynamic performances. The clustering analysis results suggest interesting considerations.

Highlights

Enhancing heat transfer in forced convection has always raised a paramount interest in industrial research, as the applications range from gas-turbine blade cooling to plate-fin compact heat exchangers, including electronic components [1, 2]
Conclusions and final remarks A novel method was introduced for the statistical analysis of experimental data, to investigate the performances of ribs with different geometry used to enhance heat transfer in forced convection
This analysis is motivated by the empirical evidence that quite different rib geometries may often result in similar performances, despite the lack of an evident correlation between their geometry and thermal-fluid-dynamic effects

Summary

Introduction

Enhancing heat transfer in forced convection has always raised a paramount interest in industrial research, as the applications range from gas-turbine blade cooling to plate-fin compact heat exchangers, including electronic components [1, 2]. The large number of experimental studies performed on ribbed channels confirms their effectiveness, and shows that the geometric factors, which condition heat transfer lead to a very large number of possible results.

Results

Conclusion