scholarly journals Experimental and numerical study on the thermal control strategy for a gas foil bearing enhanced with thermoelectric modules

2020 ◽  
Vol 138 ◽  
pp. 106581 ◽  
Author(s):  
Adam Martowicz ◽  
Jakub Roemer ◽  
Michał Lubieniecki ◽  
Grzegorz Żywica ◽  
Paweł Bagiński
Keyword(s):  
Control Strategy ◽  
Numerical Study ◽  
Thermal Control ◽  
Thermoelectric Modules ◽  
Foil Bearing

A Numerical Study on the Thermal Control of Lithium Batteries by Composite Phase Change Materials and Metal Foams

2021 ◽  
Author(s):  
Bernardo Buonomo ◽  
Oronzio Manca ◽  
Ferdinando Menale ◽  
Francesco Moriello ◽  
Simone Mancin
Keyword(s):  
Control System ◽  
Phase Change ◽  
Metal Foam ◽  
Numerical Study ◽  
Liquid Fraction ◽  
Convective Heat Transfer Coefficient ◽  
Thermal Control ◽  
Temperature Fields ◽  
Local Thermal Equilibrium ◽  
Thermal Control System

Abstract This study attempts to control the temperature peaks due to the operation of the battery itself by examining a two-dimensional model to numerically investigate the thermal control of a lithium battery of a commercial electric car. The battery has the dimensions of 8 cm × 31 cm × 67 cm and its capacity is equal to 232 Ah with 5.3 kWh. Thermal control is achieved by means of an internal layer of copper or aluminum foam and phase change material (paraffin), placed on the top of the battery and the external surfaces are cooled by a convective flow. The governing equations, written assuming the local thermal equilibrium for the metal foam, are solved with the finite volume method using the commercial code Ansys-Fluent. Different cases are simulated for different thicknesses of the thermal control system and external convective heat transfer coefficient. The results are given in terms of temperature fields, liquid fraction, surface temperature profiles as a function of time and temperature distributions along the outer surface of the battery for the different cases. In addition, some comparisons with pure PCM are provided to show the advantages of the composite thermal control system with PCM inside the metal foam.

scholarly journals Development of a mathematical model for the numerical study of a thermal control system fluid circuit

2019 ◽  
Vol 537 ◽  
pp. 022003
Author(s):  
F V Tanasienko ◽  
Yu N Shevshenko ◽  
M G Melkozerov ◽  
A A Kishkin ◽  
A V Delkov ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Control System ◽  
Numerical Study ◽  
Thermal Control ◽  
Thermal Control System

scholarly journals Numerical Study of Lorentz Force Interaction with Micro Structure in Channel Flow

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4286
Author(s):  
Shabbir Ahmad ◽  
Kashif Ali ◽  
Sohail Ahmad ◽  
Jianchao Cai
Keyword(s):  
Heat Transfer ◽  
Differential Equations ◽  
Viscous Dissipation ◽  
Numerical Study ◽  
Nonlinear Differential Equations ◽  
Thermal Control ◽  
Shear Stresses ◽  
Fluid Temperature ◽  
X Rays ◽  
Micro Particles

The heat transfer Magnetohydrodynamics flows have been potentially used to enhance the thermal characteristics of several systems such as heat exchangers, electromagnetic casting, adjusting blood flow, X-rays, magnetic drug treatment, cooling of nuclear reactors, and magnetic devices for cell separation. Our concern in this article is to numerically investigate the flow of an incompressible Magnetohydrodynamics micropolar fluid with heat transportation through a channel having porous walls. By employing the suitable dimensionless coordinates, the flow model equations are converted into a nonlinear system of dimensionless ordinary differential equations, which are then numerically treated for different preeminent parameters with the help of quasi-linearization. The system of complex nonlinear differential equations can efficiently be solved using this technique. Impact of the problem parameters for microrotation, temperature, and velocity are interpreted and discussed through tables and graphs. The present numerical results are compared with those presented in previous literature and examined to be in good contact with them. It has been noted that the imposed magnetic field acts as a frictional force which not only increases the shear stresses and heat transfer rates at the channel walls, but also tends to rotate the micro particles in the fluid more rapidly. Furthermore, viscous dissipation may raise fluid temperature to such a level that the possibility of thermal reversal exists, at the geometric boundaries of the domain. It is therefore recommended that external magnetic fields and viscous dissipation effects may be considered with caution in applications where thermal control is required.

A Gasless Reservoir Solution for Electro-Hydraulic Compact Drives With Two Prime Movers

2020 ◽  
Author(s):  
Søren Ketelsen ◽  
Damiano Padovani ◽  
Morten Kjeld Ebbesen ◽  
Torben Ole Andersen ◽  
Lasse Schmidt
Keyword(s):  
Control Strategy ◽  
Numerical Study ◽  
Mimo System ◽  
Chamber Pressure ◽  
Gas Leakage ◽  
Reservoir Volume ◽  
Reservoir Solution ◽  
Flow Imbalance ◽  
Prime Movers ◽  
Gas Volume

Abstract Due to an increased focus on improving the energy efficiency and compactness of hydraulic linear actuators, the electro-hydraulic compact drive (ECD) has received increased attention lately. In this study the ECD consists of variable-speed electric motors and fixed-displacement pumps, which are directly connected to the cylinder, thus controlling the linear motion in a throttleless manner. Furthermore, ECDs are self-contained systems, i.e. based on a fully enclosed oil circuit, in order to avoid external contamination and air to enter the system and to increase system compactness. Conventionally a low-pressure gas-loaded accumulator is used as an oil reservoir to compensate for the flow imbalance occurring whenever utilizing single-rod cylinders in closed systems. The accumulator pressure is to be kept relatively low to stay within the required limits governed by the permitted pump housing’s pressure. Generally, this pressure is not allowed to exceed 1–3 bar. To avoid violating this limitation, the gas volume must be significantly larger than the actual oil volume, which needs to be stored in the accumulator. This requirement decreases the obtainable compactness of the ECD, especially for systems with a large cylinder stroke. Furthermore, the accumulator represents a potential of gas leakage, which ultimately could result in the ECD being non-functional. This paper presents a gasless reservoir solution, improving the system compactness and avoiding the risk of gas leakage. The proposed solution is based on a bootstrap reservoir which is charged by the lowest cylinder chamber pressure. This strategy is feasible for the class of ECDs that is capable of controlling the lowest cylinder chamber pressure alongside the cylinder motion. An ECD consisting of two electric prime movers is considered as a case study. It is shown how the gasless reservoir may be integrated into the system, and an analysis of how this affects the operating range and the dynamic couplings of the system is presented. This leads to the derivation of a control strategy for the Multi-Input-Multi-Output (MIMO) system based on state decoupling, by defining virtual inputs to control virtual outputs. A numerical study suggests that the reservoir volume may be reduced by approximately 50% for the given system dimensions. The proposed control strategy shows good position tracking performance while also being able to control the reservoir pressure within the pre-defined limits of 1 to 3 bar.

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