SU945873A1 - Diffusion process simulating device - Google Patents

Description

The invention relates to computing technology, and specifically to electronic devices for modeling diffusion processes and solving partial differential equations, and can be applied in the study of thermal, diffusion, electrical, optical, and other processes. A device containing white noise sources, voltage to pulse frequency converters, reversible dividers with a controllable division factor, coordinate sampling counters, a storage unit and a control and processing unit that simulates a continuous diffusion process is known. The disadvantage of this device is the impossibility of accurate modeling. the process itself scatters a diffusing particle, for example, taking into account its non-isotropy and the random nature of the mean free path. The closest to the invention according to the technical solution is devices simulating diffusion processes, representing a sequence of steps, the length of each of which corresponds to a given diffusion coefficient, and the direction is a random value, equally selected from a fixed set of directions, containing a memory block, a buffer register , subtracting counter, clock generator, summing counter, random number generator and integrators 2}. However, this device does not allow simulating diffusion processes with non-isotropic scattering of particles and free path of a random length. The purpose of the invention is to improve the accuracy of problem solving. The goal is achieved by the fact that a device for modeling diffusion processes, containing a velocity determination unit, the outputs of which are connected respectively to the information inputs of three integrators, the outputs of which are respectively connected to the coordinate 39458734

diat inputs of the fixation unit of the reg-ry is connected to the common bus, and the output

of the results associated respectively with the output of the block, the first input

the inputs of the block set boundary conditions, functional converter two

and the block setting initial conditions, triperemen {1st and second information input

the outputs of which, respectively, are connected; the 5first switch are corresponding to the control inputs of the integrators; additionally, a controlled generator of Poisson signals, a speed module module calculating unit and two blocks are introduced

The fork-guards of the ugp scatters, with the first switch, are the corresponding outputs of the integrators respectively the control inputs of the unit, and are connected to the three control inputs of the Poisson signal generator, the output of which is connected to the first control input of the speed module calculator and the inputs of the scattering angles, the outputs of which are respectively connected to the first and second information inputs of the velocity components, the third information input of which is connected to the output of the speed module computing unit connected to the fourth control input of the Poisson generator and the integrated input of the result fixation unit, and the first output of the boundary condition specifying unit connected to the input of the initial conditions specifying unit, the fourth output of which is connected to the second information input of the calculating unit, velocity module , the second control unit whose input is connected to the second output of the boundary conditions setting block, the third output of which is connected to the control input of the determining unit the compressed-speed, scattering angle forming unit contains white noise generators, keys, triggers, descrambler, and functional converter, and the outputs of the white noise generator through the keys are respectively connected to the trigger inputs, the outputs of which are respectively connected to the decoder inputs, output which is connected to the input of the function converter, the output of which is the output of the block, and the combined control inputs of the keys are inputdM of the block, the calculating unit of the velocity module contains the function a two variable converter, a memory node, a trigger and two switches; the output of the two variable function converter is connected to the first information input of the first switch, the output of which is connected to the input input of the memory node, the output of which is connected to the first information input of the second switch, the second information the entrance to which

Claims (2)

Actually, the first and second information inputs of the block, the first and second inputs of the trigger, are connected respectively to the control inputs of the memory node and the output of the trigger is connected to the control input of the second switch. FIG. 1 is a block diagram of the device; Fig. 2 is a block diagram of the formation of the scattering angle; in fig. 3 is a block diagram of the speed module calculating unit; The device contains integrators 1, block 2 determining the components quickly and controlled generator 3. bullets of the signals, blocks 4 and 5 of scattering angle formation, block 6 calculating the speed module, block 7 specifying the boundary conditions , block 8 setting initial conditions, block 9 fixing the results, Each block 4 and 5 of scattering angle formation contains a functional converter Yu, triggers 11, keys 12, white noise generators 13, decipheror Block 6 calculating the velocity module contains A dual transducer 15 of two variables, memory node 1 b, trigger 17, and two switches 18 and 19. A controlled generator of 3 Poisson signals can be a set of radioactive particle counters whose average frequencies are 1: 2: 4 ... The control of such a sensor is carried out by automatically connecting the counters to the common input in different combinations. Angle shapers of angles 0-4 and 5 are designed to simulate scattering on a random Angle of a wandering particle on the atoms of the medium. In most cases, the probability of such a scattering is axially symmetrical about the direction of motion before the collision. Such a scattering can be fully described by setting the probability of the deviation of the particles by an angle from the initial direction of motion with an uniform direction, characterized by the angle ((the projection of the vector of the new velocity on the plane perpendicular to the previous direction of motion) Angle b 4 and angle 5 can from a set of triggers triggered from a noise source, the outputs of which are connected to the inputs of function converters via decoders. The resulting set of trigger sets corresponds to the random, uniformly distributed on the O + () segment, the value where U1 is the number of triggers, and after the decoder we will have random stresses O t uniformly distributed on the OQ segment - a. where and U are chosen with according to the task. the probability density of obtaining the angle 0 is P (0), then the functional converter must, having such random voltage U ,, at the input, produce a voltage corresponding to the condition R ((07dl6 1- (3U (Uc 0 in this case) , i.e. IU in and U must be established such a functional dependence, To predetermined probability ingress angle 9 at each interval in- multiple SRI equally familiarize likelihood preparing a model voltage U in the range and. - and -f -Of this condition, then II is blowing - ± Lr (o1), (0-0), ОР (0-0) - the probability of a corner in a value in the interval in-in. Denoting P (0-9 (e)), we get (| where is fuschtsi, inverse to f. It is known in advance and can be selected on a fushogonal transducer. For example, if the scattering is isotropic in the center of mass, it’s all equals anisotropic), then) i-AlCos9), because su a. i p. So QI.arccos И-1у-Ь Similarly., №s output signal of another random number sensor. The module for calculating the velocity module 6 includes a functional converter 15, which must produce a fuction of two variables Q and V, where V is the particle velocity before collision. For example, when simulating a particle with a mass of TP with stationary atoms of the medium with mass M, this function has the form -V / m-t 1Mtsv9v V (). Therefore, in this case, it must reproduce the function 1: П Шп1С05в1 (M + GT) and multiply its output signal from memory node 16, which is included in the calculating unit of the speed module 6 and contains the value V. The device works as follows. The integrators 1 simulate the broken trajectory of a moving particle, integrating the output signals of the velocity component determining unit 2, which vary at random intervals according to probability laws that correspond to the scattering mechanism of the particle. The integration time intervals, determining the mean free path between two scatterings, are generated with a controlled generator of 3 Poisson signals, the parameter of which varies according to the diffusion coefficient, which depends in general on coordinates and velocity of particles. When the generator of Poisson signals 3 is triggered, the angle forcing 4 generates the deflection angle of the particle trajectory from the previous motion altitude, and the angle forming 5 produces the direction of this deflection I / in a plane perpendicular to the previous direction of motion. Using the same generator signal of the 3 Poisson signals, the speed modulus calculation unit 6 outputs a zero signal to interrupt the work of the integrators 1 and fi x 1 of the flow 10 for the blocking time necessary to generate a new motion direction. After the value of the deviation angle at the input appears, the speed subtraction blszh 6 generates and stores the corresponding new value of modulus V velocity, which simulates the particle energy loss during scattering. At the same time, the component 2 of determining the velocity components generates and stores signals corresponding to the cosines of the angles between the 7 axes of the coordinates and the new direction of motion COS (V 2) cose COS 0-Sin in sin 9 COS, COS (V, X) r5in VOESCHSZVCH + cos6 cosM sine003 f-sin If s-fn 0sin cosi),) 5.tYiesivi4 cose + 40059 sin 4 sin eCOS fcos loginssin, where Q-vi are the angles of the previous motion pattern. Then this block generates and mines the values of the trigonometric angles of the new direction of the movement (V, l) leCOS (V, Z) COS 4 t coe (v, x) co5 (V, y) After the blocking time of the generator signal 3 poiss The signals of the velocity mode calculating unit 6 output the values of the velocity V, and block 2 determines the velocity components, multiplying its corresponding functions, producing the velocity components (V,) -, (v, x)., V (). The boundary condition block 7 generates the function Zpp.Z (X ,: and compares it with 2, where X ,, Z is the current coordinates of the differentiating particle. At 2 g corresponds to the particle exit to the boundary, the boundary condition block 7 outputs an integration interrupt signal to the block 6 when calculating the network speed and when solving a boundary value problem, it generates a random number from a sequence uniformly distributed on a fixed segment, according to the value of which either sends a speed inverse signal to the velocity determining unit 2, which is One changes the signs of all components after which integration 73 resumes, which corresponds to the reflection of a particle from the boundary, or causes the initial conditions block 8 to work, specifying coordinates on the entry of a new particle according to a random law, corresponding to the distribution of sources. The velocity components determine the magnitudes of the components by the new values of the angles Q and H, then the integration is performed in the usual way. When simulating diffusion, reflection from the boundary is not seen. To record the simulation results, a flux of diffusing particles is determined, equal to the total path of all particles per unit volume per unit, the time in the vicinity of the point where the solution is determined. Thus, the implementation of the device in accordance with the invention makes it possible to simulate a diffusion process taking into account a random path length of a diffusing particle, since the latter determines the time between two successive pulses of a controlled generator of Poisson s; 1 signals, and also taking into account the non-isotropy of scattering by setting the corresponding law Working out random values of angles G and H into functional transducers contained in angle sensors. This makes it possible to more accurately solve the problems of neutron diffusion in real media. Formula of the Invention A device for modeling diffusion processes, comprising a velocity component determination unit, the outputs of which are connected respectively to the information inputs of three integrators whose outputs are connected to the coordinate inputs of the result fixation unit associated respectively with the inputs of the boundary conditions setting block and the initial setting block conditions, the three outputs of which, respectively, & dinene, with the control inputs of the integrators, characterized in that, in order to improve the accuracy, In addition, a control generator of Poisson signals, a velocity module calculating unit and two scattering angle generating units are added, the integrator outputs are respectively connected to the three control inputs of the Poisson signal generator, the output of which is connected to the first control input of the velocity module calculating unit and the inputs of the scattering angle forming units, the outputs of which are respectively connected with the first and second information inputs of the velocity component determination unit, the third infop an Its input is connected to the output of the speed module computing unit, connected to the fourth control input of the Poisson signal generator and to the integral input of the results fixing unit, and the first output of the boundary condition setting unit is connected to the task unit code, initial conditions, the fourth output is connected with the second information input of the speed module computing unit, the second control input of which is connected to the second output of the boundary conditions setting unit, the third output of which is connected to the control vl5poschim input unit constituting opredeletsh speed. 2, the device according to claim 1, wherein the faint scattering angle comprises a noise generator, keys, triggers, a decoder, a functional transducer, and the outputs of the white noise generators are connected via keys respectively , dami triggers,: the outputs of which are respectively connected to the inputs of the decoder, the output of which is connected to the input of the function converter, the output of which is the output of the block, and the combined control 5th key entries in the input of the block. 3. The device according to PP. 1 and 2, that the module of calculating the speed module contains a functional converter of two variables, a memory node, a trigger AND two switches, with the output of the two variable variable converter connected to the first information input of the first switch, the output of which is connected to the information the input of the memory node whose output is connected to the first information input of the second switch, the second input {1st input of which is connected to the common bus, and the input is the output of the block, the first 1 input function The two variable transducer and the second information input of the first switch are the first and second information inputs of the block respectively, the first and second inputs of the trigger connected respectively to the control inputs of the memory node and the first switch are the corresponding HQ first and second controls unit inputs, and the trigger output is connected to the control input of the second switch. Sources of information taken into account during the examination 1. USSR author's certificate No. 377808, cl. tJOSG 7/48, 1969. 2. USSR author's certificate number 458839, cl. QO6Gi 7/48. 1973 {prototype). R 3 to Fig-e / / 7 15th / J8 7777 Phage.Z