RU1772650C - Method and bench for hydrodynamic tests - Google Patents

Description

1

(21) 4796925/29 (22) 02.27.90 (46) 10.30.92. Bull. Number 40

(71) Special Design and Technology Bureau of the Institute of Technical Mechanics, Academy of Sciences of the Ukrainian SSR

(72) I.K.Manko, V.P. Severin and N.L. Tomchakov

(56) USSR Copyright Certificate Ms 1620703, cl. G 01 M 10/00, 1989

(54) METHOD FOR HYDRODYNAMIC TESTS AND STAND FOR ITS IMPLEMENTATION

(57) The invention relates to stands for hydrodynamic testing of components and

 hydraulic units. The aim of the invention is to expand the functionality by obtaining the frequency characteristics of the studied nodes. The method of hydrodynamic testing consists in supplying a working fluid under pressure to the inlet of the test unit, changing the pressure behind it by using the energy of the flowing fluid, setting a disturbance in pressure and fluid flow in the control pressure line and recording flow parameters. The stand for the implementation of the method comprises a supply tank, pressure and drain lines, a pump, a test unit, a device for controlling the flow parameters behind the test site, a shut-off valve, a drain valve, a fluid oscillation generator and a control valve 2 sf, 1 silt

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with

The invention relates to mechanical engineering hydraulics, and in particular to methods and test benches for hydrodynamic testing of units and hydraulic units

The aim of the invention is to expand the functionality by obtaining the frequency characteristics of the studied nodes.

The drawing shows a stand for hydrodynamic testing.

The stand for hydrodynamic tests contains a supply tank (not shown), a serially connected pump 1, an inlet choke 2, a separation unit 3, a pressure line 4, a test unit 5, a drain line 6, a tank 7, a device 8 for controlling the flow of working fluid in the main line 6

Behind the test node 5, the control cavity of the device 8 is connected through the shut-off valve W to the outlet of pump 1 and through the drain valve Bz to the atmosphere. In parallel with valve E $ 2, a pressure oscillation generator 9 and control valve Vz are installed. The bench also contains sensors of a flow measurement system.

The method is implemented as follows.

In the initial position, the shut-off valve Bt is closed, the drain valves Ba and the control Valve are open, while the flow control device 8 is open. The working medium from the pump 1 under pressure, established by the inlet choke 2, after degassing in the separation tank 3 along the pressure line 4

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is fed to the input of the investigated unit of the hydraulic unit 5 Since the control device 8 is normally open, there is no pressure behind the studied unit 5. The shut-off valve EI opens, part of the flow of the working medium from the pump outlet is fed into the control cavity of the control device 8 and then to the drainage in two parallel lines: through the drain valve B2 and through the pressure oscillator with the control valve Vz. A pressure oscillation generator is put into operation, which can be made, for example, in the form of a spool of a certain geometry (defining the law of pressure measurement), periodically, with a certain frequency f, overlapping a partially or completely passage section of the drainage line. Valves B2 and Bz are closed (that is, their passage area is reduced), while the pressure in the control cavity of control device 8 increases to the value specified in the test program, and therefore in the outlet pipe of hydraulic unit 5. The amplitude of pressure fluctuations is controlled by changing the ratio flow rates through the valves Vg and Vz.

The flow parameters are recorded: flow rate, static and dynamic pressure components before and after the test unit at this disturbance frequency f specified by the oscillation generator. Similar measurements are made at other values of the oscillation frequency, and thus the amplitude-frequency characteristics of the test nodes are determined.

Hydraulic lines, pumps and other elements of complex technical systems can be tested on this bench.

Claims (2)

1. A method of hydrodynamic testing, which includes supplying a working medium under pressure to the inlet of the test unit, changing the pressure behind it by using the energy of the flowing fluid by taking part of the flow rate of the working medium under pressure from the list of the unit, and feeding it to the control devices with the flow rate of the working medium at the outlet of the unit, as well as recording flow parameters, characterized in that, in order to expand the functionality by obtaining the frequency characteristics of the units under study, pressure and flow perturbations are set in the control pressure line. 2. A stand for hydrodynamic tests, including a supply tank, pressure and drain lines, a pump, an investigated unit, a device for controlling the flow parameters behind the studied unit, made in the form of a cylindrical body with holes for diverting the flow fluid flowing into the drain manifold, while the spool is movably mounted inside the housing, made in the form of a glass with unloading holes, rigidly connected to a bellows located between the end surface of the spool and the housing cover, and the bellows cavity is connected through a shut-off valve to the entrance of the test site and through the drainage valve with the atmosphere, a system for registering flow parameters, characterized in that in the control pressure line of the device for regulating flow parameters behind the test node, parallel to the drain valve a fluid oscillation generator and a control valve are connected in series.