SU1250954A1 - Device for visualizing current pattern on surface of model - Google Patents

Description

2, The device according to claim 1, which is the fact that in order to make the device more economical and to have reliable results when tested in cold and non-stationary flows, it is equipped with additional electrodes placed on the surface of the housing downstream behind the ring electrodes, and filled in in a vvde bands, set flush with the outer over

one

The invention relates to hydrodynamic tests and can be used in the study of the pattern of flow around a model with flows of liquid or gas.

The aim of the invention is to expand the field of application by visualizing the streamlines on the model surface, as well as improving the accuracy of reproduction of the pattern of the flow on the model surface.

Fig. 1 shows the general scheme of the device implementation; 2 is its electrical circuit. .

The device comprises a body 1 of the test object (model), which is either made entirely of electrically insulating material or coated with electrically insulating material on its outer surface. With the help of k; analov 2, the outer surface of the housing 1 is communicated in an internal capacitance 3, made of heat insulating material. Internal capacity 3 is divided into three chambers. The anterior chamber 4 is filled with an imaging composition and separated from the rest of the tank by a piston 5. On the inner end surfaces of the chamber 4 with an imaging composition and a piston paneshen are layers of high-resistance material 6 forming heating elements to ensure the heating of the imaging composition. Inside the chamber 4 there is an annular shell 7 which can

perform the role of additional OMI-.

heating element (when using visualizing

corpus and oriented in the meridional direction, and the visualizing composition contains an electropanes filler.

3. Device PB of claim 1, about tl and - that the end walls of the control chamber and the control piston are provided with electrically conductive plates electrically connected to the control unit.

substances that are completely non-electroplating, on the contrary, with high electrical conductivity).

Channels 2, jointly chamber 4 with the outer surface of the housing 1, are made in the form of heat and electrical insulating cylindrical tubes 8, on the end surface of which are flush with the outer surface of the case I there are layers in the form of washers made of electrically conductive material forming annular electrodes 9. Number and the location of the tubes 8 with annular electrodes 9 may vary depending on the task of visualizing specific surface areas of the object being perceived. Below along the surface in the direction of the supposed surface current lines, when the object is placed in the flow with the working medium, layers of electrically conductive material are placed flush with the surface, forming strip electrodes 10.

By means of fastening elements 11, the body of the test object (an element of the ship's control body, an apparatus or their full model, etc.) is mounted on a rack (holder) for placing it in the flow of the working medium. The separating piston 5 by means of the rod 12 is rigidly connected with the control piston 13, with which the control chamber 14 is formed at the inlet of the tank 3, into which the electropneumatic valve 15 installed in the main 16 is supplied to

control gas or liquid pressure. Between the pistons 5 and 13, an interportae chamber 17 is formed, communicated by means of an adjustable valve 18 with the environment. This makes it possible to reliably seal the chamber 4 with the imaging composition, eliminate leaks through the gap between the piston 5 and the insert 7, and also ensure a predetermined (constant) pressure drop across the control slug 13 as it moves and thereby changes the volume of the chamber 17 The piston 13 is made larger than the piston 5. They form a pressure multiplicator, which allows a given control force to be obtained to displace the imaging composition from chamber 4 using a low operating pressure (for example, on line process air).

The heating elements 6 and 7, the electrodes 9 and 10 and the electropneumatic valve 15 are connected to the power source via electrical circuits - a communication line 19 to the control unit 20 that switches the switching on of Elements 6 or 7 (it is possible to work together electric pneumatic valve and turning off the heaters when the circuit is closed between electrodes 9 and 10. Capacity 3 is made in the form of a cylindrical cup made of heat and electrical insulation material fixed inside the housing 1 using fastening elements 21 and 22 and provided in the front with a hole with a plug 23 for providing the camera 4 with an imaging composition. To simplify the operation of the camera 4, the nose 24 of the housing is removable.

To control the temperature of the imaging composition during heating, a temperature sensor 25 is connected in chamber 4 and connected to a control unit 23 by one of the lines 19, which maintains the required heating temperature by alternately turning on and off the heating elements 6, 7 or power supplied from an electrical source ( not shown).

On the end surfaces of the control chamber 14 and the control piston 13, plates of electrically conductive material are installed, which form a co-capacitor 26, which is also connected to the control unit 20 of the communication lines 19.

The setting of the speed of movement of port 13, which is unambiguously determined and controlled by the change in the capacitance of the capacitor 26, determines the flow rate of the imaging substance through the channels 2 and the intensity of the imaging

streams on the surface of the object. In addition, using, for example, preliminary calibrations or control tests, it is possible to generate an additional control signal according to the value of the final capacitance capacitance 26 for turning off the supply system (and heating) of the visualizing substance and pressure relief from the control chamber 14 using an electropneumatic valve 15. Such an embodiment of the dispenser allows the device to be used in some cases even without electrodes 9 and 10 (for example, if the imaging composition is not

contains electrically conductive filler) ..

The device works as follows.

After filling the chamber 4 with an imaging composition including an electrically conductive filler, installing a detachable nose and connecting the communication lines 19 to the control unit 20

carry out control (calibration-HbieJ tests of the device, during which the heating mode and the law of flow rate change are determined. Then the object is placed into the working fluid flow of a liquid or gas. By a signal from the sensor, for example, the position of the object in the stream or the sensor controlling the process establishment wrapping around its working medium (not shown), the control unit 20 generates a signal to turn on the heater 6 and then the electropneumatic valve 15 to supply control pressure to the chamber 14. The piston 13 moves to the left and

with the help of the piston 5 displaces through the channels 2 the visualizing composition onto the surface of the housing 1.

When pistons 5 and 1.3 move to the left and because of a decrease in the volume of the chamber 17

the pressure in it increases due to the leakage of the visualizing composition through the gap between the piston 5 and the insert 7. The valve 18 supports the set

No. 1 pressure drop in chambers A and 17.

The necessary flow rate of the imaging composition is maintained both by controlling the pressure in the control chamber 14 using the electropneumatic valve 15, and by changing its viscosity by changing the heating temperature. The visualized composition displaced from the channels spreads over the surface, carried along by the external flow along the direction of the local streamlines, and when the electrode IO is reached, the circuit Between it and electrode 9 closes. The control unit 20 in this case generates a signal for depressurizing the chamber 14 through the electropneumatic valve 15 and turning off the heater.

When tested in a cold environment, when the visual composition of the vehicle may become highly viscous due to cooling as it spreads to the surface, the pattern of the flow lines obtained will be distorted due to the mismatch of the directions of the less viscous working medium and the resulting streams of the imaging substance. To eliminate this error at closure

Editor .M.Kelemesh

 put.Z

Compiled by Y. Vlasov Tehred I. Gaidosh

Order 4403/39 Circulation 778 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., d. / 5

Production and printing company, Uzhgorod, st. Project, 4

o

five

Electrodes 9 and 10 are trickled with the visualizing composition by means of control unit 20 and are fed to them by a pulse of electric current, due to which 5 the trickles are heated,

their viscosity decreases and they are oriented in the direction of external flow. Cooling (it is desirable to hardening), the streams of the visualizing substance reliably preserve the structure of the directions of the streamlines on the surface of the object under study. This is important for the nonstationary character of the flow around, since it is possible to fix instantaneous patterns of flow on the surface. It is also possible to heat the substance in channels 2 by setting the potential difference between the insert 7 and the ring electrodes 9.

When using an imaging substance non-conductive (without a filler), the dosing of its supply is carried out by controlling the change in capacitance of the capacitor 26. The heating of the composition is carried out, for example, with a cylindrical insert 7. It is also possible to use elements 6 with each of them switched on independently.

0

Corrector I. Muska

Claims (3)

1. DEVICE FOR VISUALIZING THE FLOW PICTURE ON THE SURFACE OF THE MODEL, comprising a housing with a container in which there are separation and control pistons connected by a rod, forming three chambers, one of which is filled with a visualizing compound and communicates with the model surface by a channel, the guy - the control - is informed drus with insulating inserts with ring electrodes placed flush with the outer surface of the housing concentrically around the ascent holes of the channels, while the control chamber is equipped with an electropneumatic a valve, electrically connected to the introduced control unit, is also connected in parallel to the heater and the ring electrodes. SU 1250954 A1 2, The device according to π.1, characterized in that, in order to increase the efficiency of the device and the reliability of the results when tested in cold and non-stationary flows, it is equipped with additional electrodes located on the surface of the housing downstream of the ring electrodes, and made in the form of strips mounted flush with the outer surface of the body and oriented in the meridional direction, and the visualizing composition contains an electrically conductive filler. 3. The device πό π.1, characterized in that the end walls of the control chamber and the control piston are equipped with electrically conductive plates that are electrically connected to the control unit.