Search results for "Thermomagnetic convection"

Thermomagnetic Materials: Thermomagnetic Properties Improved by Self-Organized Flower-Like Phase Separation of Ferromagnetic Co2Dy0.5Mn0.5Sn (Adv. Fu…

2012

Thermomagnetic Properties Improved by Self-Organized Flower-Like Phase Separation of Ferromagnetic Co2Dy0.5Mn0.5Sn

2012

A thermodynamically stable phase separation of Co2Dy0.5Mn0.5Sn into the Heusler compound Co2MnSn and Co8Dy3Sn4 is induced by rapid cooling from the liquid phase. The phase separation forms an ordered flower-like structure on the microscale. The increased scattering of phonons at the phase boundaries reduces the thermal conductivity and thus improves thermoelectric and spincaloric properties.

Numerical investigation of thermomagnetic convection in a heated cylinder under the magnetic field of a solenoid

2011

The main objective of this paper is the numerical investigation of the process of thermomagnetic convection of a special temperature sensitive ferrofluid. The fluid is studied in a cylindrical domain, with constant temperatures on the top and bottom ends and adiabatic boundary conditions on the sidewalls. The thermomagnetic convection is generated by a non-uniform constant magnetic field of a solenoid, which is placed in a hollow area inside the domain. It has been found that the efficiency of convective heat transfer in such a set-up can be increased up to sevenfold by magnetic field within the studied range of parameters.

Heat and mass transfer phenomena in magnetic fluids

2007

In this article the influence of a magnetic field on heat and mass transport phenomena in magnetic fluids (ferrofluids) will be discussed. The first section is dealing with a magnetically driven convection, the so called thermomagnetic convection while in the second section the influence of a temperature gradient on the mass transport, the Soret effect in ferrofluids, is reviewed. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

Design and Experimental Test of a Thermomagnetic Motor

2012

Abstract This paper presents a Thermomagnetic Motor. The design of the motor is based on a thermal-magnetic coupled dynamic model, which is obtained by assuming the use of a ferromagnetic material working at temperatures near the curie point. The motor is modeled in terms of both its magnetic as well thermal properties (magnetic permeability and thermal conductivity) and the thermal processes are supposed to be influenced by the thermal conductivity, the convection and the advection. An analytical expression of the generated torque, which links this quantity to the magnetic, thermal and geometrical parameters of the generated torque is given. A design of a machine, based on this theory is p…

Design and Test of a Thermomagnetic Motor Using a Gadolinium Rotor

2013

This paper presents a Thermomagnetic Motor, whose design of the motor is based on a thermal-magnetic coupled dynamic model, which models its magnetic as well thermal properties (magnetic permeability and thermal conductivity). The thermal processes are supposed to be influenced by the thermal conductivity, the convection and the advection. An analytical expression of the generated torque, which links this quantity to the magnetic, thermal and geometrical parameters of the generated torque is given. A design of a machine, based on this theory is proposed and the related performances are numerically simulated. An experimental verification of the performances is reported.

A dq axis theory of the magnetic, thermal, and mechanical properties of Curie motor

2011

A dq axis theory of a thermomagnetic Curie motor is presented. This theory allows one to estimate the performances of a Curie motor from its geometrical, magnetic, and thermal properties. The proposed approach shows that the thermomagnetic Curie motor is equivalent from a magnetic point of view to a dc electric machine. The physical meaning of the parameters used in the dq theory of Curie motor is explicated. The theory is validated by using experimental data.

D-Q axis theory of thermomagnetic Curie motor

2010

This paper presents a the d-q axis theory of a thermomagnetic Curie motor. From this theory a maximization procedure of the performances of Curie motor has been developed. The proposed approach has shown that the thermomagnetic Curie motor is equivalent from a magnetic point of view to a d.c. electric machine. Consequently, a design of a Curie motor has been proposed and the calculated performances show a significant improvement in comparison to the performances reported in literature.

A reversible hydrogen‐bond isomerization triggered by an abrupt spin crossover near room temperature.

2020

The spin crossover salt [Fe(bpp) 2 ](isonicNO) 2 ·2.4H 2 O ( 1 ·2.4H 2 O) (bpp = 2,6‐bis(pyrazol‐3‐yl)pyridine; isonicNO = isonicotinate N‐oxide anion) exhibits a very abrupt spin crossover at T 1 /2 = 274.4 K. This triggers a supramolecular linkage (H‐bond) isomerization that responds reversibly towards light irradiation or temperature change. Isotopic effects in the thermomagnetic behaviour reveal the importance of hydrogen bonds in defining the magnetic state. Further, the title compound can be reversibly dehydrated to afford 1 , a material that also exhibits spin crossover coupled to H‐bond isomerization, leading to strong kinetic effects in the thermomagnetic properties.

Magnetic characteristics of industrial dust from different sources of emission: A case study of Poland

2015

Abstract Dust emission and deposition in topsoil have negative effect on individual components of the ecosystem. In addition to routine geochemical analyses, magnetic measurements may provide useful complementary information related to the type, concentration and grain-size distribution of the technogenic magnetic particles (TMPs) and thus the degree of contamination of the environment. The aim of this contribution is to use magnetic parameters in distinguishing dust from a wide range of sources of air pollution (power industry, cement, coke, ceramic industries and biomass combustion). We measured magnetic susceptibility, hysteresis parameters and thermomagnetic curves. Our results suggest …