Effect of Boundary Conditions and Turbulence Treatment on the Simulated Performance of a Ribbed Heat Exchanger

Abstract

Ribbed surfaces are widely employed in heat exchangers to enhance the convective heat transfer and hence the overall thermal efficiency. This study aims to investigate the effect of two important assumptions made in computational fluid dynamics simulations, i.e. the thermal boundary conditions and the turbulence modeling, using a popular test case for the heat transfer over a continuous ribbed plate was taken as a reference. Numerical simulations were performed both neglecting and considering the conduction within the solid, to verify the effect of different thermal boundary conditions on the fluid domain, and with several turbulence treatments, ranging from common Reynolds-averaged Navier-Stokes approaches to higher fidelity but more computationally intensive Large Eddy Simulations. The results demonstrate that both aspects are important for an accurate prediction of the thermal performance of ribbed channels.

Acknowledgments

This project has received funding from the Regione Autonoma della Sardegna within the project “Heated-Air Plug&Play” (project code RICERCA_1C-83).

Disclosure statement

None to declare.

Additional information

Notes on contributors

Marco Bertoli

Marco Bertoli obtained his Batchelor and Masters’ Degree in Mechanical Engineering from the University of Cagliari. He collaborated with the Centro Sviluppo Materiali (CSM) - Structural Integrity and Reliability Department until 2015, mainly involved on fluid dynamics issues related to the oil & gas transportation in pipelines. His research activities were devoted to the study of the ductile fracture propagation, focusing on gas decompression behavior for the driving force evaluation, as part of research projects funded by European Community (SARCO2 and INDUSE2). In 2015, he founded Astarte Strategies, a spin-off of the University of Cagliari which offers consultancy services for technological innovation of industrial products and processes. In Astarte, he is a specialist in numerical and experimental methods. His main activities are focused on modeling, analysis, and optimization of heat exchange processes as well as combustion, internal flows, aerodynamics and environmental dispersion of pollutants. He is also expert in biomed/vascular 3D modeling and simulation.

Francesco Cambuli

Francesco Cambuli obtained a degree in Mechanical Engineering in 1994 and a Ph.D. in Mechanical Design in 1998, both from the University of Cagliari (Italy). Since January 2022 he is an Associate Professor at the Department of Mechanical, Chemical and Materials Engineering (DIMCM), University of Cagliari. His research activities are focused on the field of turbomachinery, developed with experimental and numerical (CFD) methods. Currently, the main topics are the aerodynamic analysis of Wells turbines, the study of the aerothermal behavior of gas turbine blades and the performance evaluation of commercial pumps when used as turbines.

Roberto Baratti

Roberto Baratti is a Full Professor at the Department of Mechanical, Chemical and Materials Engineering, University of Cagliari. He obtained the Laurea degree (summa cum laude) from University of Cagliari in 1982 and the Dottorato di Ricerca (Ph.D.) from University of Pisa in 1986. Presently, his interests are in the field of process modeling and control of industrial processes and stochastic modeling of chemical, and biochemical reactor.

Tiziano Ghisu

Tiziano Ghisu is an Associate Professor at the Department of Mechanical, Chemical and Materials Engineering, University of Cagliari. He obtained a Masters’ degree in Aerospace Engineering from the University of Turin, a Masters’ degree from the University of Cranfield and a Ph.D. from the University of Cambridge. His main research interests cover the numerical simulation of complex fluid dynamics problems through high-performance computing, the development and application of optimization methods to problems of industrial relevance, uncertainty quantification and optimization in presence of uncertainty. He is Principal Investigator for the Cagliari Unit in the projects Madeleine and NextAir, funded by the European Union through the Horizon 2020 Program.