A 2D hybrid model of the fluid flow and heat transfer in a reciprocating active magnetic regenerator

Oliveira, Pablo A. de; Trevizoli, Paulo V.; Barbosa, Jader R.; Prata, A. T.

doi:10.1016/j.ijrefrig.2011.08.009

Cited by 34 publications

(15 citation statements)

References 32 publications

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“…However, few authors of AMR models specify which numerical approach they employ. , Oliveira et al (2012) and Tušek et al (2011) apply the finite differences method with an implicit scheme while Nikkola et al (2014) employ an explicit scheme and Nielsen et al (2009) adopt the ADI method. On the other hand, Petersen (2007) and Dikeos and Rowe (2013) employ a finite element approach.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

An efficient numerical scheme for the simulation of parallel-plate active magnetic regenerators

Torregrosa-Jaime

Corberán

Payá

et al. 2015

International Journal of Refrigeration

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A one-dimensional model of a parallel-plate active magnetic regenerator (AMR) is presented in this work. The model is based on an efficient numerical scheme which has been developed after analysing the heat transfer mechanisms in the regenerator bed. The new finite difference scheme optimally combines explicit and implicit techniques in order to solve the one-dimensional conjugate heat transfer problem in an accurate and fast manner while ensuring energy conservation. The present model has been thoroughly validated against passive regenerator cases with an analytical solution. Compared to the fully implicit scheme, the proposed scheme achieves more accurate results, prevents numerical errors and requires less computational effort. In AMR simulations the new scheme can reduce the computational time by 88%.

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Section: Accepted Manuscriptmentioning

confidence: 99%

An efficient numerical scheme for the simulation of parallel-plate active magnetic regenerators

Torregrosa-Jaime

Corberán

Payá

et al. 2015

International Journal of Refrigeration

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“…[16,[38][39][40][41][42][43][44][45][46][47][48]. Recently, also a few 2-D models have been applied [49][50][51][52]. The 2-D model generally assumes a twodimensional fluid velocity profile and includes the longitudinal and transversal thermal conductivity of the magnetocaloric material and the heat-transfer fluid (parallel and perpendicular to the direction of the fluid flow).…”

Section: A Brief Review Of Amr Numerical Modelsmentioning

confidence: 99%

“…A more straightforward and simple way to include the magnetocaloric effect is to apply the adiabatic temperature change of the magnetocaloric material during the magnetization and demagnetization processes, as was done by, e.g. [43,49,52]. In doing so, the term _ q MCE is not included in Eq.…”

Section: Mathematical (Physical) Model Of An Amr (Basic Energy Balancmentioning

confidence: 99%

“…As recently shown [42,52,80], the number of independent parameters can be reduced by the application of the dimensionless AMR model. It is based on a dimensionless length (and thickness in the 2-D model), time, temperature and magnetic field, as well as different dimensionless numbers, like NTU, utilization factor, thermal capacity ratio, Fourier number, Peclet number, etc.…”

Section: Mathematical (Physical) Model Of An Amr (Basic Energy Balancmentioning

confidence: 99%

“…If, on the other hand, more than the optimum amount of fluid is pumped through the AMR, this can cause fluid from the hot end of the AMR (or even from the HHEX) to be transported into the CHEX. This of course reduces the temperature span as well as the total cooling power of the AMR [52]. Under such conditions, the temperature span between the heat source and heat sink will be small and the operation will be similar to one without regeneration (single-stage device).…”

Section: The Impact Of the Operational Parameters And Geometry On Thementioning

confidence: 99%

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Active Magnetic Regeneration

Kitanovski

Tušek

Tomc

et al. 2014

Green Energy and Technology

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It is well known that the magnetocaloric effect of most magnetocaloric materials at moderate magnetic fields (up to 1.5 T) is limited to a maximum adiabatic temperature change of 5 K [1,2]. This value is not sufficient for such materials to be directly implemented into a practical cooling or heating device where temperature span over 30 K is required. Therefore, in order to increase the temperature span, one and so far the best option is for a heat regenerator to be included in the magnetic thermodynamic cycle.A heat regenerator is a type of indirect heat exchanger where the heat is periodically stored and transferred from/to a thermal storage medium (regenerative material) by a working (heat-transfer) fluid. The regenerative material usually has a porous structure, through which a working fluid is pumped in an oscillatory, counter-flow manner (which is more efficient than a parallel flow system). During the 'hot period', a warmer fluid flows through the regenerative material, which cools down, while the material heats up. As a result, heat is stored in the material. During the 'cold period', a cooler fluid flows through previously heated regenerative material, so the fluid heats up, while the material cools down. The heat is therefore transferred back to the fluid (the same fluid or a different one) at a different phase of the thermodynamic cycle. After a certain number of such steps, a periodic steady state is reached and, as a result, a temperature profile can be established along the length of the regenerator [3].The need to apply heat regenerators in a magnetic refrigerator was already realized by Brown [4] in the first prototype of a magnetic refrigerator, built in 1976. He applied a regenerative Stirling-like thermodynamic cycle (very similar to AMR), which significantly increased the temperature span of the device [4,5]. A few years later Steyert [6] and Barclay and Steyert [7] presented and explained the active magnetic regenerator, which remains the most applied method for the exploitation of the magnetocaloric effect at room temperature. Furthermore, all prototypes of magnetic refrigerators built since then have been based on the AMR process [5]. An AMR, unlike a passive (regular) heat regenerator, contains a magnetocaloric material as the regenerative material. It has a double function in a magnetic regenerator, i.e. it works as a regenerator and enables an increase in the temperature span as well as working as a coolant and generating/absorbing heat between the particular phases of the

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Caloric devices: A review on numerical modeling and optimization strategies

2021

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Summary The discovery of giant caloric effects and further investigation on device systems that can compete with current heat management technologies in terms of efficiency have led to a major increase in modeling investigations. These models have been crucial in designing the most efficient, cheap, and robust setups with reliable performances. One example is the modeling of magnetic refrigerators and heat pumps that has been used in the optimization of critical geometrical parameters of magnetocaloric regenerators. In this paper, we review the model components of caloric heat pump and refrigerator systems, including field generation, heat transfer, caloric effects, fluid dynamics, and loss mechanisms. We also review the optimization strategies used so far, which are based on sensitive analysis, brute force approaches, statistical learning, and genetic algorithms. The analysis is applied to magnetocaloric, electrocaloric, elastocaloric, and barocaloric systems.

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A 2D hybrid model of the fluid flow and heat transfer in a reciprocating active magnetic regenerator

Cited by 34 publications

References 32 publications

An efficient numerical scheme for the simulation of parallel-plate active magnetic regenerators

An efficient numerical scheme for the simulation of parallel-plate active magnetic regenerators

Active Magnetic Regeneration

Caloric devices: A review on numerical modeling and optimization strategies

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