SU1642112A1 - Method for determining effective passage area through pneudraulic resistor - Google Patents

Abstract

The invention relates to engineering hydraulics and can be used in testing pneumohydraulic resistors. The purpose of the invention is to reduce the labor intensity and improve the accuracy of determining the value of the effective passage area of the pneumohydraulic resistances. The stand implementing the method contains hermetic adjacent containers 1 and 2, between which a rigid body 3 is movably located with an indicator 4 longitudinal displacements, a drain line 6 from tank 1 with valve 7 and test pneumo-hydro resistance 8, while valve 7 is provided with control electric line with an electric stop watch 10, the pressure line 12 from the pneumohydro source 13 with the supply of the working fluid in the tank 1 and 2 through the valves 14 and 15. The working fluid can be air or gas. Due to the introduction of solid 3 into the container 1, gradually during its emptying, the pressure of the working medium in the container 1 is maintained at a supercritical pressure drop across the test fluid resistance 8 and the measured area is determined from the measured parameters. 1 and. (Ls

Description

The invention relates to engineering hydraulics and can be used in testing pneumohydraulic resistance.

The purpose of the invention is to reduce the labor intensity and improve the accuracy of determining the effective passage area of the pneumohydraulic resistance,

The drawing shows a schematic diagram of the stand that implements the proposed method.

The proposed stand contains a sealed container 1 of limited volume and an additional sealed container 2, which have one common wall and between which there is a movable solid

the body 3 with the indicator 4 longitudinal displacements, the pressure gauges 5 installed in the containers 1 and 2, the drain line 6 from the tank 1 containing the normally closed valve 7 in series and the pneumo-resistance under test 8. The valve 7 is provided with control electroline 9 with the electric stopwatch 10 and switch 11. The stand contains a pressure line 12 from the pneumohydraulic source 13 with a parallel flow of the working fluid in the tank 1 and 2 through the valves 14 and 15, respectively. A thermometer 16 is connected to the tank 1. The working medium can be air or gas.

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The method is carried out as follows.

With valves 14 and 15 open from a pneumatic source 13, tanks 1 and 2 are refilled to a predetermined working pressure P0, which is monitored by pressure gauges 5. After charging, valves 14 and 15 are closed and, using indicator 4, the initial volume of the solid 3 is fixed, located in the tank 1. In this thermometer 16, the temperature of the working fluid T0 in the tank 1 is recorded. Turning on the switch 11, a signal is given to open the valve 7 and turn on the electrosecond 10. At the same time, the working fluid outflows from the tank 1 to drain through line 6 through test pneumatic resistance 8 at supercritical pressure drop. Since in the cavity

2, the working fluid pressure is also PO, then the solid body 3 begins to move into the cavity 1 under the action of this pressure at the moment of opening the valve 7. From the equilibrium condition of the solid body 3 when the pressure P0 is applied from two sides of the containers 1 and 2, its displacements will be such that pressure

3cavity 1 remains constant and equal to P0. In this case, the condition for maintaining pressure P0 in tank 2 can be ensured by the condition of equality of the inserted volume of indicator 4 into container 2 of the sliding volume of solid 3 into container 1. The condition of constant pressure P0 in tank 1 is satisfied until the moment when the solid body 3 reaches its extreme shifted position, corresponding to the abutment of the body 3 in the wall of the tank 1, after which the pressure in the tank 1 decreases. By monitoring the pressure constant PO on the pressure gauge 5, the time t is measured, during which the pressure in cavity 1 does not change. At the time the pressure changes first, switch 11 opens the electrolines 9, when

This switches off the electric seconds 10 and closes the valve 7. The expiration time g is fixed using the electric seconds 10 and the volume of the solid body VT according to the indicator 4. The effective area of the test hydropneumatic resistance 8 S is determined by calculation from the expression for the flow rate of the working fluid (gas) during supercritical pressure drop

t a ro

Where

A- fldrir)

k -i 1 k - 1

y is the specific weight of the working fluid;

R is gas constant;

k is the adiabatic index;

g - free fall acceleration.

Thus, an increase in the efficiency of testing pneumo-resistances is achieved while reducing energy consumption, labor-intensiveness, and time-consuming, as well as improved measurement accuracy and safety of operation.

Claims (1)

Claims of Invention A method for determining the effective passage area of pneumohydraulic resistances, including emptying a volume-limited capacity at supercritical pressure drop, measuring pressure and temperature of the working fluid. in the tank and the time of its emptying followed by the placement of a solid body in it, characterized in that, in order to reduce labor intensity and increase accuracy, a solid body is introduced into the container gradually during its emptying, ensuring that the pressure of the working fluid in the container remains unchanged.  2