SU1151175A1 - Versions of electromagnetic induction pump - Google Patents

Abstract

1. Electromagnetic induction pump comprising a channel, a magnetic core and a multiphase excitation winding with the number of pole pairs Pn not t. less than at least two and the phase zones of successive pairs of poles are shifted in phase, in order to increase efficiency by eliminating unstable pump operation with pronounced pressure and flow fluctuations, the phase zones of the excitation winding belonging to each phase, are located on each subsequent pair of pole divisions along the entire length of the pump with a shift by the angle P of the p. electric degrees, where m. m is the number of phases of the excitation winding, n 1 f

Description

The invention relates to the field of magnetohydrodynamic technology (MHD technology), in particular to the field of linear induction electromagnetic pumps. It can be used in pumps for pumping allic liquid coolants in the circuits of nuclear power plants with fast neutron reactors, research liquid metal circuits, in the metallurgical industry, and in other process plants. A number of induction pump designs are known, the main components of which are an inductor with a core, a channel and a multi-phase winding of the excitation. The winding creates a magnetic field that runs along the channel, when interacting with currents induced in the liquid metal, an electromagnetic force arises that ensures the movement of the liquid metal in the pump channel. It is known that the main parameter characterizing the intensity of magnetohydrodynamic processes in induction electromagnetic pumps is the electromagnetic interaction parameter Rnie R.n, S, where S is the slip; / o - (magnetic number fn (s / 2 Reynoldai bi -I, and - pole division; - conductivity of the pumped medium; Co 2ir f - circular frequency f - frequency of the supply current, In linear induction pumps with the parameters of electromagnetic interaction Rms velocity profile the conductive liquid in the channel becomes substantially inhomogeneous, as a result, when the pump becomes unstable, the flow characteristic becomes non-monotonic, low-frequency (1-2 Hz) pressure fluctuations appear in the pump, One current with an amplitude of ± 20 or more. The liquid flow of metal from an electrically conductive working heat) in the pump is pulsating and causes vibration of the pump and the circuit, which is unacceptable during pump operation, for example, in main KOHTyjpax fast neutron reactors. Also, an electromagnetic induction pump containing a channel, a magnetic core, a multiphase excitation winding with a number of pole pairs of at least two, and the phase zones of successive pairs of poles are phase-shifted, this device is eliminated and instability of operation at Rfns, the linear current load waves (6Jt - OCX + b) of successive pairs of poles are out of phase relative to each other with advance by the angle / 3 +120 electrical degrees or with a delay of / 120 electr. Such a design of the pump in a number of cases makes it possible to reduce the level of fluctuations in the output parameters of the pump, to stabilize the flow rate, the porous characteristic, but does not allow solving the task as a whole. Stabilization is achieved by increasing the current consumed by the pump, reducing its overall power and efficiency. Since the frequency and amplitude of the pump parameter fluctuations depend on its design parameters and mode of operation, it is quite natural that the angle of shift is 120 ° proposed for. reducing pulsations may not be optimal in all cases. As recently conducted experimental studies have shown, it is possible to reduce the level of pulsations and stabilize the flow pressure characteristic at angles other than jf with the same or even lower energy costs and increase the efficiency of the pump compared to a known solution. The aim of the invention is to increase efficiency by eliminating unstable pump operation with various pressure and flow fluctuations. The goal is achieved by the fact that the phase zones of the excitation winding belonging to each phase are located on each subsequent pair of pole divisions along the entire length of the pump with a shift. g on angle ft - - n electric (t degrees, where m is the number of phases of the excitation winding 5; n 1 - (2га - 1); In the second variant of the pump, the phase zones of the excitation winding belonging to each phase are located in separate pairs of pole divisions relative ny of the previous pair of pole divisions shifted by an angle L - p electrical degrees. In the third version of the pump containing an excitation winding with the number of pole pairs Pn not less than two, the phase zones of the excitation winding belonging to each phase are located on separate pairs of pole divisions relative to previous limiting a pair of pole divisions with a shift by an angle (L 1G fc -7- f electrical degrees, where q is the number of slots per pole and phase m is the number of phases of the excitation winding; 1 - (q-1). the pump cut; Fig. 2, 3,4-circuit of the excitation winding; Fig. 5 and 6 experimental curves illustrating the effect of shear angle on efficiency and speed; Fig. 1 shows a longitudinal section of an electromagnetic pump consisting of straight channel with internal magnetic core 1 and inductor 2, in the grooves of which three-phase excitation winding 3 is laid, is made of claim coils. Figure 2 shows a circuit of the excitation winding with the number of pairs of EP 3 poles and the number of slots per pole and phase q "performed according to the first variant with a shift of the phase winding zones on each subsequent pair of pole divisions 2 (relative to the previous pair of full divisions at an angle I. Gp 1 | 0. 5 300 m3. In FIG. 3, a winding circuit with the number of pairs of pole divisions Pn 3 and the number of grooves per pole and phase q 2 is shown, made according to the second variant with phase shift of the excitation winding at the last, in in this case, a pair of pole deposits at an angle. |. p - ip. 120 In figure 4 p The scheme of the winding is made according to the third variant with a phase zone shift at the winding on the last pair of poles by an angle of / 5 "I (}. ,,. 0 .4 ---- 1 30 and the wave of the Ti-q 7 3-2 current load When voltage is applied to the pump winding, linear current load 4 waves are created on each pair of pole divisions, which due to the displacement of the phase winding zones are also shifted one relative to the other by the same angle. Discharges in the linear current load of the inductor winding (see FIG. 2, 3, 4), which are formed when the phase zones are shifted, result in the appearance of additional electromagnetic fields in a moving electrically conductive medium, having the character of waves with a decreasing amplitude running from the interfaces. Their interaction with the primary magnetic field (field of the excitation winding) creates additional to the main electromagnetic forces in an electrically conductive medium. As the experiment shows, these forces align the velocity profile in azimuth and reduce flow and pressure fluctuations. This is achieved, as a rule, at the expense of additional energy costs due to additional joule power losses in an electrically conductive environment. With separate combinations of characteristic parameters, it is possible to reduce the power consumption (increased efficiency) in comparison with the classical scheme. The studies were carried out on an induction linear cylindrical pump with the following characteristic parameters: Rm 4.7; m "3; q 2, the number of pairs of poles Pp .. 3. According to the first and second embodiments of the invention | 5, y, c 60, | 1 perch, according to the third option 30. When winding with Pf with the indicated phase-angle shift of the phase zones, in all cases there was observed a decrease in varying degrees of pressure and flow fluctuations of the pump and expansion of its stable operation zone. As stated in the work, the source of oscillation of the parameters is the occurrence of a non-uniform azimuth profile of the velocity of fluid flow in the pump channel at R S 1 and the formation of eddy currents when this profile leaves the pump. Hence, the degree of attenuation of oscillations depends on the degree of alignment of the velocity profile. Fig. 5 shows the experimentally obtained distribution of the axial component CKOIJOCTH (V) in the azimuth of the cylindrical channel at its exit from the different angles of shift of the phase zones. The profiles correspond to a slip of S 0.525, the sensor numbers located along the abscissa axis are located: around the circumference of the channel. The smaller the shift angle of the phase zones, the less the velocity profile levels out, and the fluctuations in flow and pressure are less suppressed.

A positive effect is achieved, as experiments show, in the entire above-mentioned range of variation of the angle ft. The choice of a specific phase angle shift using known methods for calculating induction pumps is not possible. In order to determine theoretically optimally in each particular case the angle ft, it is necessary to solve the two-dimensional magnetohydrodynamic problem of the turbulent motion of a conducting medium in a traveling magnetic field. There is no such solution at this time.

The results of experimental studies allow us to make the following recommendations on the choice of the optimal shift angles of the phase zones. The greater the value of the shear angle A, the more the flow and pressure fluctuations are suppressed. On the other hand, the larger ft, the greater the cost of power and less efficiency of the pump (see Fig. 6). Fig 6: - NAROS efficiency; Q is the flow rate of the liquid metal; S - slip;

Experimental studies conducted on a series of pumps show that the choice of the optimum shear angle and the number of pairs of poles Pj on which phase shifts should be made depends on the design of the machine: its depth, the degree of asymmetry of the magnetic gap along the depth and perimeter, conditions entry and exit. For machines with asymmetric channel input and pronounced oscillations of parameters, it is necessary to take large angles and phase shifts on each pair of pole divisions, starting from the second from the entrance. For machines with moderate oscillations, it is sufficient to introduce a shift on individual pairs of pole divisions along the length of the machine. For machines with weak oscillations, it is sufficient to conduct a small phase shift along the entire length of the machine or on separate pairs of pole divisions. Since it is not possible to find one optimal shear angle to solve the whole task for each pump as a whole, one of the proposed options is used to achieve the goal depending on the level of oscillation determined by the design features of the pump and the mode of operation. The use of the proposed options will expand the area of stable operation of electromagnetic pumps. The experience of designing electromagnetic pumps shows that they, as a rule, have the maximum efficiency with the minimum weight of active materials per unit of power in the range of values 1, where the pumps operate unstably. The use of the proposed solutions eliminates the instability of pump operation in the field, selects the optimal geometrical dimensions of the channel and inductor and thereby increases the efficiency of pumps by 3-5%, and reduces the weight of active materials by 15-20%,

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Claims (4)

1. Electromagnetic induction pump comprising a channel core and a polyphase excitation winding with the number of pole pairs Pn · _not less than, at least two phase zone wherein successive pairs of poles are out of phase, characterized in that, in order to increase efficiency by eliminating the unstable operation of the pump with pronounced fluctuations in pressure and flow, the phase zones of the excitation winding belonging to each phase are located on each subsequent pair of pole divisions along the entire length of the pump with an angle shift 'ΐΓ = - η electrical degrees, where t t is the number of phases of the excitation winding, η = 1 t (2t-1). 2 2. Pump; containing channel, magnetic core and multiphase excitation winding with the number of pole pairs Pn not less than at least three and the phase zones of successive pairs of poles are shifted in phase, characterized in that in order to increase efficiency by eliminating unstable pump operation with moderate fluctuations in pressure and flow, the phase zones of the excitation winding belonging to each phase are located at individual pairs of pole divisions relative to the previous pair of pole divisions with offset Hom at angle β = - η electric ¹ and kih degrees, where t - the number of phases of the excitation winding, ^- η = 1T- (2m-1). 3. A pump containing a channel, a magnetic circuit and a multiphase excitation winding with a number of pole pairs Pn of at least two, and the phase zones of successive pairs of 'poles are shifted in phase, characterized in that, in order to increase efficiency by eliminating unstable operation of the pump with weak fluctuations in pressure and flow and increase its efficiency, the phase zones of the excitation winding belonging to each phase are located at individual pairs of pole divisions relative to the previous pair of pole divisions with a shift homo corner four? > · = + ----- ¢ - electrical degrees, - t-ς " where t is the number of phases of the excitation winding; ς is the number of grooves per pole and phase ·, I ι- (ς-ι) · 3 1151175 four