top of page

This site was designed with the

website builder. Create your website today.Start Now

Ibai Mugica, PhD

Detailed numerical simulations of a single stage of rotatory active magnetic regenerators: influence of the pin geometry

Mugica, I., Poncet, S., Bouchard, J., 2020

International Journal of Thermal Sciences

The following paper examines different configurations of pin geometries for rotatory magnetocaloric regenerators, through detailed multiphysics simulations. The analysis is first done by characterizing the performance of each geometry against the multiple physical phenomena that intervene in a magnetocaloric regenerator: magnetic, fluid and thermal fields. Then, full 3D AMR cycles are simulated for a selected group of pin geometries, and conclusions are drawn between the temperature span of the regenerators and the separately analyzed physical phenomena. The main novelty of this study is the analysis of the tortuosity of the fluid flow, a characteristic parameter of porous media. One of the main conclusions is that an increased tortuosity might be a valid alternative strategy to increase the power of magnetocaloric regenerators.

An open source DNS solver for the simulation of Active Magnetocaloric Regenerative cycles

Mugica, I., Poncet, S., Bouchard, J., 2018

Applied Thermal Engineering

This paper describes the development of a new versatile multiphysics solver, whose final objective is to characterize Active Magnetocaloric Regenerative (AMR) cycles. The description is followed by a thorough validation divided in two parts. First, the separate simulations of the constituent physics are validated (porous geometry generation, fluid flow, Conjugated Heat Transfer and magnetic field). Then, the whole AMR code is compared to a measured prototype. The results are in all cases close to published numerical or experimental data. Also, two coupling mechanisms are studied, the temperature dependency of the viscosity of the Heat Transfer Fluid (HTF),and the influence of the magnetic permeability on the internal magnetic field of Gadolinium metal. Both effects prove to be negligible to compute the temperature field of a Magnetic Regenerator (MR). Moreover, by neglecting these effects the magnetic and flow fields of the MR can be computed beforehand, which reduces substantially the computational load at run time. Finally, the speed-up of the parallel multiphysics solver is evaluated.

dT (copy).png

Entropy generation in a parallel-plate active magnetic regenerator with insulator layers

Mugica, I., Poncet, S., Bouchard, J., 2017

Journal of Applied Physics

This paper proposes a feasible solution to diminish conduction losses in active magnetic regenerators. Higher performances of these machines are linked to a lower thermal conductivity of the Magneto-Caloric Material (MCM) in the streamwise direction. The concept presented here involves the insertion of insulator layers along the length of a parallel-plate magnetic regenerator in order to reduce the heat conduction within the MCM. This idea is investigated by means of a 1D numerical model. This model solves not only the energy equations for the fluid and solid domains but also the magnetic circuit that conforms the experimental setup of reference.

In conclusion, the addition of insulator layers within the MCM increases the temperature span, cooling load, and coefficient of performance by a combination of lower heat conduction losses and an increment of the global Magneto-Caloric Effect. The generated entropy by solid conduction, fluid convection, and conduction and viscous losses are calculated to help understand the implications of introducing insulator layers in magnetic regenerators. Finally, the optimal number of insulator layers is studied.

Exergy Analysis of a Parallel-Plate Active Magnetic Regenerator with Nanofluids

Mugica, I., Roy, S., Poncet, S., Bouchard, J., Nesreddine, H., 2017

Entropy

This paper analyzes the energetic and exergy performance of an active magnetic regenerative refrigerator using water-based Al2O3 nanofluids as heat transfer fluids. A 1D numerical model has been extensively used to quantify the exergy performance of a system composed of a parallel-plate regenerator, magnetic source, pump, heat exchangers and control valves. Al2O3 -water based nanofluids are tested thanks to CoolProp library, accounting for temperature-dependent properties, and appropriate correlations. The results are discussed in terms of the coefficient of performance, the exergy efficiency, and the cooling power as a function of the nanoparticle volume fraction and blowing time for a given geometrical configuration. It is shown that while the heat transfer between the fluid and solid is enhanced, it is accompanied by smaller temperature gradients within the fluid and larger pressure drops when increasing the nanoparticle concentration. It leads in all configurations to lower performance compared to the base case with pure liquid water.

bottom of page