Development of a hardware-software system for the experimental study of the ferromagnetic groove carrying conductor surface
The paper presents the results of an experimental study of the ferromagnetic groove electromagnetic field based on a developed laboratory bench equipped with a hardware — software measuring system. A technique for determining the current density in the conductor cross-section by measuring the magnetic field induction when immersing two types of sensors (frameless fine measuring coil and Hall sensor of a digital millislotometer) has been implemented for various depths inside the groove. The use of a measuring coil as a sensor makes it possible to obtain the current density distribution over the conductor height through the procedure of integrating the voltage proportional to the EMF induced in the measuring coil using a LabVIEW environment-built in a digital integrator. Measurement of magnetic field induction by the Hall digital sensor at a laboratory bench provides the measuring coil verification and the reliability of the experimental study results determination. With the help of the hardware-software complex, a distribution of the current density and magnetic induction along the conductor height in the ferromagnetic groove is obtained at a laboratory bench. The results of an experimental investigation of the surface effect are compared with the results of calculating the alternating magnetic field of a conductor with a current in a ferromagnetic groove in the Elcut 5.6 program complex. The active and the inductive conductor resistance at the industrial frequency are determined.
The measuriment of ferromagnets magnetic characteristics using Labview software
The digital method of measurement and registration of dynamic loops hysteresis family of magneto-soft materials where, along with known analogues from electro-technical steel, magnetic materials with considerably smaller specific magnetic losses such as amorphous alloys on the basis of iron, is offered. Tests of magnetic properties of materials are carried out on the base of the hardware-software measuring complex in which along with the standard established electric equipment and USB oscillograph for realization of a digital method, the software for the personal computer developed in the environment of visual programming of Borland Delphi 7.0, connected through the ActieveX technology with the Labview 7.0 environment, is applied. The software allows carrying out input of basic data concerning geometry of prototypes of cores from magnetic materials and numbers of rounds of the magnetizing and measuring windings located on their surface. Experimental data on voltage at measuring winding terminals are processed by means of the virtual integrator in a Labview package. The developed software provides the possibility of saving the obtained hysteresis loop in the form of a text file, and creation of the hysteresis loops family on the virtual oscillograph screen.
Evaluation of CuAl2O4 as an Oxygen Carrier in Chemical-Looping Combustion
The chemical-looping combustion (CLC) process is a novel solution for efficient combustion with intrinsic separation of carbon dioxide. The process uses a metal oxide as an oxygen carrier to transfer oxygen from an air to a fuel reactor where the fuel, or gasification products of the fuel, reacts with the solid oxygen carrier. In this work, copper(II) aluminate (CuAl2O4) was assessed as a potential oxygen carrier using methane as fuel. The carrier particles were produced by freeze–granulation and calcined at 1050 °C for a duration of 6 h. The chemical-looping characteristics were evaluated in a laboratory-scale fluidized-bed reactor in the temperature range of 900–950 °C during 45 alternating redox cycles. The oxygen carrier exhibited reproducible and stable reactivity behavior in this temperature range. Neither agglomeration nor defluidization was noticed in any of the cycles carried out at 900–925 °C. However, after reactivity tests at 950 °C, soft agglomeration and particle fragmentation were observed. Systematic phase analysis of the Cu–Al–O system during the redox cycle was carried out as a function of duration of reduction and oxygen concentration during the oxidation period. It was found that the CuAl2O4 is reduced to copper(I) aluminate (CuAlO2; delafossite), Cu2O, and elemental Cu. The CuAlO2 phase is characterized by slow kinetics for oxidation into CuO and CuAl2O4. Despite this kinetic limitation, complete conversion of methane with reproducible reactivity of the oxygen carrier is achieved. Thus, CuAl2O4 could be a potential oxygen carrier for chemical-looping combustion.