SU425189A1 - DEVICE FOR SETTING BOUNDARY CONDITIONS FOR THIRD KIND - Google Patents

Description

one

The invention relates to computing, in particular, to electronic devices for setting boundary conditions of the third kind with time-varying coefficients and solving boundary-value problems of a narabolic type on / C-grids.

A device for setting third kind of boundary conditions with variable coefficients is known, containing a / C-grid, the boundary points of which are connected to the nerve switching blocks, the second group of switching blocks and the control unit with two outputs, one of which is connected to the inputs of the switching nerve blocks.

However, the use of this device is not advisable only when the coefficients at different boundary points are connected by a linear relationship.

The purpose of the invention is to create a device for setting boundary conditions of the third kind with variable coefficients, when the coefficients at different boundary points can differ from one another in any way, depending on the solution at this point and time-varying parameters (nanrnmer, when simulating heat transfer radiation at different temperatures at different boundary points), which has a minimum of electronic equipment and does not require any settings at each point, i.e. an extension of the class of tasks.

For this, the proposed device contains boundary resistors, a voltage driver unit and a current compensating unit, the output of which is connected to the input of a voltage driver unit connected to each of the second group switching blocks connected through the corresponding boundary resistors to the boundary points of the / C grid, and the other the output of the control unit is connected to the switching units of the nerve and the second subsoil.

The drawing shows a block diagram of the proposed device of this device.

The device contains an I-C grid, a switching unit 2, a control unit 3, a surge collector 4, a voltage supply unit 5, a boundary resistor 6.

The boundary points of the C-grid 1 through the boundary resistors 6 and the individual switching units 2 with non-earth sources of nitanns are connected to the output of the common control unit 5. The same boundary points are connected to the input of the current-matching unit 4, the output of which is connected to the input block zadayun1, his nahr. The device is equipped with blocks 3. 3. The corresponding outputs of which are connected to the control inputs of the switching blocks of each boundary point. Operating with the frequency NLCHY of the control unit 3 in turn turns on the switching units 2, referring to different boundary points. In this case, through current-compensating block 4 to the input of the block of the driving voltage 5, the voltage of this boundary point is disconnected, and a voltage arises at its output, which creates the required current through the boundary resistor 6. A sample in which the driver voltage unit 5 is made on the base of a functional converter with an amplifier of direct current is developed as the 1st ramer of the device implementation. The control unit 3 consists of a master oscillator 7, a switch dekatron 8 with an output stage 9 and a waiting multivibrator 10 at each output. Switching units consist of diode bridges 11, flip-flops 12 with ungrounded power sources and separation transformers 13. The output stages 9 and the waiting multivibrators 10 of the control unit 3 are connected to the separation transformers 13 of the switching units 2. The waiting multivibrators serve to delay the switching of the switching unit through which the boundary current flows for the duration of the transient process in the block of the driving voltage 5 that occurs when the input of the latter is switched from one boundary point and another Yu. When the diode bridge is turned on, the points with the number p and the limiting resistance Rn, the driver voltage unit must have a voltage of 6pc at the output, providing the required current limit. In the expression for the voltage f / an, in general, the voltage of the solution at a given point Un- is included. To apply the voltage (a) to the corresponding input of the driver unit, one additional switching unit is used for each boundary point. The donor-switching switching units connect the boundary points to the input of the driver unit through a common current-compensating unit in order to avoid parasitic currents. The main switching unit must be turned on when the additional switching unit of the same boundary point is turned on; With good frequency properties of the nodes, they can be triggered simultaneously. With the frequency of operation of the device v and the time the main switching unit is in the open state, the specified limit .1 and the current must be 1 - fold greater than the rated one. This scheme allows switching switching blocks at each boundary point with a frequency of 400 Hz, i.e., to simulate non-stationary processes with a time constant of a few hundredths of a second. At the same time, the change in the effective conductivity of the boundary resistor, i.e., the conductivity multiplied by the fraction of the residence time of the switching blocks in the on state, does not exceed 1% in the total operating voltage. Subject of the invention. A device for setting third kind boundary conditions, comprising an iRC grid, the boundary points of which are connected to the first group of switching units, the second group of switching units and a control unit with two outputs, one of which is connected to the inputs of the switching units of the nerve soil, characterized by that, in order to expand the class of solved tasks, it contains boundary resistors, a voltage setting block and a current-compensating block, the output of which is connected to the input of a voltage setting block, connected with each of the switching blocks of the second group, connected through the corresponding boundary resistors to the boundary points of the RC grid, and the other output of the control unit is connected to the switching blocks of the first and second soils.