CN204787885U - Electrical coil luo rotating magnetic field chang device - Google Patents

Abstract

The utility model relates to an electrified coil spiral magnetic field device, comprising: a first group of coils, including six first windings, two first windings at the opposite end are connected in series to form a one-phase coil to form a first three-phase coil, the first three-phase coil The ends of the same name are connected to form a star point; the core of the first three-phase coil forms a rotating magnetic field; the second group of coils includes the second winding, and every six second windings in the longitudinal direction is a group, and every two second windings are separated by two Two second windings are connected in series to form a one-phase coil to form a second three-phase coil, and the core of the second three-phase coil forms a traveling wave magnetic field; the rotating magnetic field and the traveling wave magnetic field are coaxially superimposed to form a helical magnetic field. The utility model energized coil spiral magnetic field device can effectively reduce various defects of solidification, and can be used to increase the uniformity of temperature, promote the redistribution process of melt, and improve the metal solidification process. Suitable for different metal melt shapes.

Description

Energized coil helical magnetic field device

technical field

The utility model relates to a helical magnetic field device with an energized coil, in particular to a method for driving a metal melt to periodically flow based on the helical magnetic field of an energized coil, and belongs to the technical field of the metallurgical industry.

Background technique

Using electromagnetic methods to control the flow of molten metal is an important research direction of electromagnetic metallurgy, such as electromagnetic stirring, electromagnetic braking and other technologies.

At present, three-phase alternating current coils can realize magnetic field motion forms such as traveling waves, rotations, and spiral magnetic fields, among which the spiral magnetic field can be realized by the superposition of traveling waves and rotating magnetic fields. The principle of the above-mentioned magnetic field driving the molten metal is the same: the molten metal generates an induced current inside itself in the moving magnetic field, and the induced current interacts with the magnetic field to generate an electromagnetic body force—Lorentz force. Lorentz force is widely used in metal solidification due to its advantages of non-direct contact between electromagnetic equipment and conductive fluid, performance of volume force, certain penetration depth in conductive fluid, high force density, and less environmental pollution. Tissue control, metal fluid transport, significant heat and mass transfer to conductive fluids.

Electromagnetic stirring has an obvious effect on improving the microsegregation of the metal solidification process, which has been confirmed by a large number of laboratory experiments and industrial practices, such as grain refinement technology. But the research on concentration segregation (or component segregation) is not very deep. Generally speaking, due to the application of traveling wave magnetic field, rotating magnetic field or helical magnetic field, the movement form of electromagnetic force acting on the metal solidification front is fixed, and the melt precipitation process will proceed in a fixed mode, so that the precipitation process of the solidification front melts with time. The change is small, and the melt precipitates in a relatively fixed form. The application of a magnetic field not only fails to improve the concentration segregation, but also tends to increase the concentration segregation.

Utility model content

The purpose of this utility model is to aim at the defect of prior art, provide a kind of energized coil helical magnetic field device, with the helical magnetic field of the mode parameter of periodic change, specific motion form drives, stirs or disperses metal melt and its second phase, with To achieve the purpose of controlling various defects in the metal solidification process and improving the metal solidification process.

In order to achieve the above object, the utility model provides a energized coil helical magnetic field device, and the energized coil helical magnetic field device comprises:

The first group of coils includes six first windings, the six first windings are evenly spaced around, and the two first windings at the opposite end are connected in series to form a one-phase coil to form a first three-phase coil, and the first three-phase The ends of the same name of the coil are connected to form a star point, the first three-phase coil is connected to the first three-phase positive alternating current with the first frequency, and the first winding is sleeved on the iron core; the first three-phase coil The core forms a rotating magnetic field;

The second group of coils is horizontally embedded in the core tooth slots of the iron core, and is coaxially arranged with the first group of coils, including second windings, and every six second windings in the longitudinal direction is a group, and every interval The two second windings of the two second windings are connected in series to form a one-phase coil to form a second three-phase coil, and the ends of the same name of the second three-phase coil are connected to form a star point, so that the switching frequency of the second three-phase coil is A second three-phase positive alternating current with a second frequency; the core of the second three-phase coil forms a traveling wave magnetic field;

The rotating magnetic field and the traveling wave magnetic field are coaxially superimposed to form a helical magnetic field, and the metal melt is placed in the cavity of the energized coil helical magnetic field device, and the energized coil helical magnetic field device rotates at a first angular velocity, and the direction of rotation is set at The first period alternates, driving the metal melt to form a three-dimensional periodic spiral flow.

Therefore, the energized coil helical magnetic field device of the utility model can effectively reduce various defects of solidification, and can be used to increase temperature uniformity, promote the redistribution process of melt, and improve the metal solidification process. Suitable for different metal melt shapes.

Description of drawings

Fig. 1 is the schematic diagram of the utility model energized coil helical magnetic field device;

Fig. 2 is the top view of the utility model energized coil helical magnetic field device;

Fig. 3 is the schematic diagram of the basic principle of the helical magnetic field moving direction commutation for the energized coil helical magnetic field device of the present invention;

Fig. 4 is the waveform schematic diagram of the applied mode function of the helical magnetic field device of the utility model energized coil helical magnetic field;

5A is one of the schematic diagrams of the periodic three-dimensional flow of the metal melt when the helical magnetic field body of the utility model energized coil helical magnetic field device applies a driving force with a periodically changing direction;

Fig. 5B is the second schematic diagram of the periodic three-dimensional flow of the metal melt when the spiral magnetic field body of the utility model energized coil spiral magnetic field device applies a driving force with a periodically changing direction;

Fig. 6 is a comparative schematic diagram of numerical simulation of improving the concentration segregation of Pb-10%Sn alloy by the energized coil helical magnetic field device of the present invention.

Detailed ways

The technical solutions of the present utility model will be further described in detail through the drawings and embodiments below.

Fig. 1 and Fig. 2 are schematic diagrams and top views of the energized coil helical magnetic field device of the present invention. As shown in the figures, the present invention includes: a first group of coils 1 and a second group of coils 2 .

The first group of coils 1 includes six first windings 10, the six first windings 10 are evenly spaced around, and the two first windings at the opposite end are connected in series to form a one-phase coil to form a first three-phase coil. The same-named ends of a three-phase coil are connected to form a star point, the first three-phase coil is connected to the first three-phase positive alternating current with the first frequency, the first winding is sleeved on the iron core; the first three The core of the phase coil forms a rotating magnetic field.

Specifically, the first group of coils 1 and the second group of coils 2 are coaxially stacked and assembled in space. The first group of coils 1 is vertically placed on the iron core. The first group of coils includes the first windings A, B, C, D, E and F, where the windings A and D are connected in series to form a phase coil, and B and E are connected in series to form a phase. Coils, C and F are connected in series to form a one-phase coil, and the same-named ends of the three-phase coils are connected to form a star point, so that the three-phase coils are connected to three-phase positive alternating currents, and the frequency of the three-phase positive alternating currents is f _R . The heart forms a rotating magnetic field

The second group of coils 2 is horizontally embedded in the core slots of the iron core, and is coaxially arranged with the first group of coils 1, including second windings 20, and every six second windings in the longitudinal direction is a group , two second windings at intervals of two second windings are connected in series to form a second three-phase coil. A second three-phase positive alternating current with a second frequency; the core of the second three-phase coil forms a traveling wave magnetic field.

Specifically, the second group of coils 2 are horizontally wound and embedded in the core slots of the iron core. The second group of coils includes the second windings a, b, c, d, e and f, wherein the windings a and d are connected in series to form a phase Coils, b and e are connected in series to form a one-phase coil, c and f are connected in series to form a one-phase coil, and the terminals of the same name of the three-phase coil are connected to form a star point, so that the three-phase coil is connected to a three-phase positive alternating current, and the frequency of the three-phase positive alternating current is f _T , a traveling magnetic field is formed at the core of the second three-phase coil, and the rotating magnetic field and the traveling magnetic field are coaxially superimposed in space to form a helical magnetic field.

The rotating magnetic field and the traveling wave magnetic field are coaxially superimposed to form a helical magnetic field, and the metal melt is placed in the cavity of the energized coil helical magnetic field device, and the energized coil helical magnetic field device rotates at an angular velocity ω, and the rotation direction is set at the first A period alternates, driving the metal melt to form a three-dimensional periodic spiral flow.

Specifically, the metal melt 3 is placed in the cavity of the energized coil helical magnetic field device, and the energized coil helical magnetic field device is rotated at an angular velocity ω, and the direction of rotation is alternately changed with a period p (=1/f _m ), driving the metal The melt forms a three-dimensional periodic spiral flow.

The rotating magnetic field is formed by passing the three-phase alternating current through the first group of coils; the traveling wave magnetic field is formed by passing the three-phase alternating current through the second group of coils, and the multi-phase coils are arranged along the cylindrical surface, and the rotating magnetic field and the traveling wave magnetic field are coaxially superimposed in space Form a helical magnetic field; make the metal melt in the cavity of the energized coil helical magnetic field device, so that the traveling wave and the rotating magnetic field that form the helical magnetic field work at the same frequency. The same principle of inversion control is realized, and any two phases in the phase sequence of the traveling magnetic field and the rotating magnetic field can be adjusted at the same time. Usually the V phase is unchanged, and the U phase and W phase are adjusted. As a result of such implementation, the direction of motion of the helical magnetic field is adjusted to the opposite.

Fig. 3 is the schematic diagram of the basic principle of the reversing of the helical magnetic field movement direction of the energized coil helical magnetic field device of the present invention. As shown in the figure, in the reversing process, A represents the magnetic vector potential of the helical magnetic field, and the phase shift of π can be implemented. Realize the opposite operation of the magnetic field movement direction. The above-mentioned commutation operation of the helical magnetic field can be periodicized through the existing electrical technology, that is, the direction of movement of the helical magnetic field alternates with a period P (=1/f _m ), where f _m is the commutation frequency. Usually, the forward and reverse times in each cycle of the above-mentioned periodic change are the same, as shown in FIG. 4 , the waveform schematic diagram of the mode function applied by the energized coil helical magnetic field device of the present invention to the helical magnetic field. Under the action of such a magnetic field, the driven metal melt forms a three-dimensional periodic spiral flow. When the spiral magnetic field body of the utility model energized coil spiral magnetic field device as shown in Figure 5A and Figure 5B applies a driving force with a periodically changing direction Schematic illustration of the periodic three-dimensional flow of a metal melt. As shown, if the first half of each cycle is represented as FIG. 5A or 5B, the second half of the cycle may be represented as FIG. 5B or 5A. The above function (rectangular wave) representing the periodic change of direction can be expressed as:

$\mathrm{<span\; class="notranslate">\; m</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 4</span>}}{\mathrm{<span\; class="notranslate">\; \&pi;</span>}}\underset{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; \&infin;</span>}}{<span\; class="notranslate">\; \&Sigma;</span>}}\frac{\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; \&lsqb;</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; \&pi;</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; \&CenterDot;</span>{\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; m</span>}}<span\; class="notranslate">\; \&CenterDot;</span>\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; \&rsqb;</span>}{\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; ,</span>$

Among them: t is time, n is a natural number. And the commutation frequency f _m and f _R , f _T satisfy the following relationship:

f _m << f _R , f _m << f _T

That is, relative to f _R and f _T , it should be at least one order of magnitude smaller.

Combined with the practice of electromagnetic metallurgy, in order to enable the electromagnetic force to effectively intervene in the three-transfer process (heat transfer, mass transfer and momentum transfer) of alloy solidification, the setting of the frequency is related to the time scale of the convection and precipitation of the molten metal at the front of the solid-liquid interface . When the frequency-driven forced convection period is close to the solidification interval characteristic time of melt precipitation, the periodic flow driven by the helical magnetic field can effectively disperse the melt precipitated from the liquid phase, thereby more effectively improving the concentration of the metal during solidification Segregation. According to the above, the selection range of the frequency f _m can be between 0.02 Hz and 1 Hz.

Fig. 6 is a numerical simulation effect diagram of improving the alloy concentration segregation by the helical magnetic field of the energized coil of the utility model. Compared with the natural convection without applying the electromagnetic force, the periodic electromagnetic force well homogenizes the radial solute concentration distribution of the sample. When the period P=32s, the solute concentration distribution in the radial direction of the sample is the most uniform. According to the above, the periodic electromagnetic force can effectively improve the concentration segregation in the process of metal solidification, and the effect of improving the concentration segregation is particularly obvious when the period of the electromagnetic force is selected properly.

The utility model energized coil spiral magnetic field device has the following advantages:

(1) The formed helical magnetic field changes the distribution of the magnetic field in space and time, effectively strengthens and improves the melt redistribution process of the metal melt during solidification, and makes the solid-liquid solidification interface and the distant melt The mass is effectively convected, so that the melt is fully mixed. At an appropriate commutation frequency, it can especially improve the concentration segregation that cannot be improved or even aggravated by a single form of traveling wave, rotating or helical magnetic field, including tunnel segregation.

(2) While the macro and micro segregation of the metal melt solidification can be obtained, the microstructure of the metal can also be comprehensively improved.

(3) The heat transfer of the metal melt is effectively enhanced, and the periodic and spatially varying forced convection can make the temperature distribution in the area where the magnetic field acts more uniform.

The utility model energized coil spiral magnetic field device can effectively reduce various defects of solidification, and can be used to increase the uniformity of temperature, promote the redistribution process of melt, and improve the metal solidification process. Suitable for different metal melt shapes.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the utility model without limitation. Although the utility model has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the utility model can be The new technical solution shall be modified or equivalently replaced without departing from the spirit and scope of the technical solution of the present utility model.

Claims (1)

1. a hot-wire coil helical magnetic field device, is characterized in that, described hot-wire coil helical magnetic field device comprises:

First group of coil, comprise six the first windings, described six the first windings are evenly at equal intervals around setting, two the first windings in series of opposite end are that a phase coil forms the first three-phase coil, the Same Name of Ends of described first three-phase coil is linked to be asterism, described first three-phase coil connects the positive alternating current of the first three-phase that frequency is first frequency, and described first winding is enclosed within iron core; The heart portion of described first three-phase coil forms rotating excitation field;

Second group of coil, alternate horizontal circle is embedded in the core teeth groove of described iron core, and coaxially arrange with described first group of coil, comprise the second winding, longitudinally every six the second windings are one group, two the second windings in series at interval of two the second windings are that a phase coil forms the second three-phase coil, and the Same Name of Ends of described second three-phase coil is linked to be asterism, make described second three-phase coil connect the positive alternating current of the second three-phase that frequency is second frequency; The heart portion of described second three-phase coil forms travelling-magnetic-field;

Described rotating excitation field and described travelling-magnetic-field Coaxial Superimposed form helical magnetic field, metal bath is placed in the cavity of hot-wire coil helical magnetic field device, described hot-wire coil helical magnetic field device rotates with the first angular speed, and make direction of rotation with period 1 alternately change, drive metal bath to form three-dimensional periodic helical flow.