Eventos Anais de eventos
ENCIT 2016
16th Brazilian Congress of Thermal Sciences and Engineering
SIMULATION OF A HYDRAULIC CIRCUIT FOR A MAGNETIC REFRIGERATOR
Submission Author:
Thiago Ebel , SC , Brazil
Co-Authors:
Pedro Cardoso, Jaime Lozano, Jader Riso Barbosa Jr.
Presenter: Thiago Ebel
doi://10.26678/ABCM.ENCIT2016.CIT2016-0065
Abstract
The flow distribution system plays a key role in the operation and the overall performance of a magnetic refrigerator [1]. However, there are few works in the literature dedicated to the design and evaluation of hydraulic circuits for magnetic refrigerators [2]. Therefore, the focus of this work is to evaluate flow management systems by means of an initial qualitative analysis and numerical simulations. In this study, different fluid switching devices were evaluated to propose a new hydraulic circuit for a rotary magnetic refrigeration system. There are two main solutions for the fluid switching device employed up to date in rotary magnetic refrigerators: (i) face-to-face sealing (rotary valves), the most common solution, and (ii) cam systems, as proposed in Ref. [3]. In this work, an electronic driven fluid switching device is proposed as a suitable solution to manage the flow in a magnetic refrigeration system. Three solutions were ranked in an adapted Pugh Matrix in terms of the energy consumption, versatility and other key parameters. The electronic system was chosen as the most suitable solution to be employed in a hydraulic circuit for a rotary magnetic refrigerator. Numerical simulations of a simplified hydraulic circuit of the system developed by [4] were performed in a commercial CFD software [5] to better understand the transient behavior of the hydraulic circuit in terms of different operating conditions. The analysis was carried out for different mass flow rates, operating frequencies and valve opening ramps. Water hammers were predicted to occur after switching the fluid flow direction, and depended chiefly on the operating frequency and the mass flow rate. The performance of the hydraulic system showed a dependence on the valve opening ramp. It has been demonstrated that fast ramps increase the water hammer and slow ramps allow the fluid bypassing the AMR. The numerical simulation enabled the estimation of the behavior of the hydraulic circuit at different operating conditions, thus helping the design of a novel hydraulic system and the selection of the solenoid valves. The desirable hydraulic system presents moderate water hammer, low pumping power and low power to operate the switching devices (valves). The use of a return valve upstream of the high pressure valves is recommended to reduce the water hammer.
Keywords
Numerical simulation, HVAC, magnetic refrigeration, Numerical simulation, HVAC, magnetic refrigeration
