SU1560800A1 - Method and apparatus for determining inlet impedance of blade pump - Google Patents

Abstract

The invention relates to engineering hydraulics and improves the performance of a vane pump test to determine its input impedance by reducing the time required to process measurement results. Input and pressure lines 1 and 2 are connected respectively to input 3 and output 4 of the test pump 5. Piston pulsator (П) 6 with drive 7 is installed in line 1 at input 3. The second П 9 is installed before П 6 along the flow and connected the pressure sensor connected to it, through the piston stroke control unit 10 - with the drive 7. The unit 10 is connected with the aid of the phase shift control unit 11 to the P6. Harmonic flow pulsations with a given frequency are created in one of the sections of line 1 and the required operating mode of the pump 5 is set. The pressure and flow pulsations are measured and recorded and the input impedance is determined. Pulsations are created in another section with the same frequency. After the pump 5 comes to the mode, the amplitude of the flow pulsations is changed in one section. In this case, in another section, the phase of the pulsations is changed until a zero amplitude of pressure pulsations is obtained in a section more distant from the pump 5. Then, the ratio of the amplitudes of the flow rate pulsations and the phase shift between the pulsations are measured. According to the test results, it is possible to construct the dependence of the modulus and the argument of the input impedance on the frequency of forced oscillations. 2 s. And 2 z. P. f-ly, 3 ill.

Description

The invention relates to engineering hydraulics and can be used in determining the dynamic characteristics, in particular the impedance of various hydraulic devices, such as vane pumps.

The purpose of the invention is to increase the productivity of tests by reducing the time spent on processing measurement results.

Figure 1 is a diagram of an apparatus for carrying out a method for determining the input impedance of a vane pump; in fig. 2 is a diagram of the input line with pulsator connection nodes; FIG. 3 is a diagram of the recording of pressure sensor signals.

The method for determining the input impedance of a vane pump is to create harmonic flow pulsations with a given frequency in one of the sections of the input line at the pump inlet and set the required operating mode of the pump, measure and record the pressure and flow pulsations, after which the input impedance, while additionally creating harmonic flow pulsations in another section of the pump inlet line with the same frequency; after the pump has reached the mode, the amplitude of the pulsations ode one input pipe section and the other section is varied until the phase of pulsations producing a zero amplitude pulsation pressure in the more remote from the pump section, and then measured

the ratio of the amplitudes of the flow pulsations and the phase shift between the pulsations, and the input impedance value are determined according to the following expression:

(ABOUT

7 -IR + iWI)

Ј. k ™ ,.

1 + Јg e H A,

where Z is the input impedance of the pump,

s / cm;

R, t are the coefficients of the hydraulic and inertial resistances of the section of the pump inlet line, between the cross sections with the sources of flow rate pulsations, s / cm;

W - the angular velocity of rotation of the drive of the sources of pulsations of the flow rate (i; 2Y); Ai

d - the ratio of the amplitudes of the pulse - 1 flow rate in the near to

pump and remote section, respectively;

i t / is the phase shift of the flow rate pulsations in two sections.

A device for carrying out the method comprises inlet and pressure lines 1 and 2, connected respectively to input 3 and output A of the test pump 5, a piston pulsator 6 with a drive 7 installed in the input line 1 at the input 3 to pump 5, pressure sensor 8, This device is equipped with a second pulsator 9, a pulsator piston stroke control unit 10 and a pulsation phase shift control unit 11 for pulsators B and 9, a second pulsator 9 is installed in front of the first flow 5

a pulsator 6 and connected with a pressure sensor 8 connected to it, as well as through a piston stroke control unit 10 - with a drive 7 simultaneously connected by means of a phase shift control unit 11 to the first pulsator 6, the pulsator 9 piston stroke control unit 10 in the form of a platform 12 with the possibility of its horizontal movement relative to the fixed base 13 with two coupling halves 16 and 17 installed in its racks 14 and 15, connected by a jumper 18 located at an angle to the axis of rotation (not shown) of the half dome 16 and 17, as well as by means of a self-aligning bearing 19, which interacts with the bridge 18, with the second pulsator 9, one of the coupling halves 17 using two shafts 20 and 21 connected by a halite coupling 22, is connected to the actuator 7, the adjustment unit 11 The phase shift of the flow pulsations is made in the form of a carrier 23 supported on a threaded coupling 24 connected by one shaft 25 with a drive 7 and the other shaft 26 with a pulsator 6 at the inlet 3 to the pump 5 with the possibility of horizontal movement of the carrier 23 relative to the fixed base 27 together with clutch 24 o onstruktivno connection pulsator 6 and 9 to the inlet line 1 is performed via manifolds 28 and 29 respectively. The pressure sensor 8 is connected to the pulsator 9 through the collector 29 and connected through the filter 30 to a secondary device in the form of a voltmeter 31. The piston stroke control unit 10 and the phase shift control unit 11 for measuring the displacements have reference bars 32 and 33 mounted on fixed bases 13 and 27, respectively, and the movement of nodes 10 and 11 itself is carried out with the help of actuators in the form of handwheels 34 and 35 by means of screw-nut gears, respectively.

In the screw-phase adjustment unit 11, the threads on the shafts 25 and 26, as well as the coupling 24, are designed in such a way that the tangent of the lifting angle of the thread is greater than the friction angle, so that axial displacements of the coupling 24 will cause the shafts 25 and 26 to roll

608006

The larger turning of the shafts 25 and 26 with a smaller axial displacement - the coupling 24 of the direction of threads on the shafts 25 and 26 and in the corresponding sections (not shown) of the coupling 24 are opposite.

A device for implementing the method works as follows.

10 After the device input line 1 is filled with the working fluid, the pump 5 under test is turned on, after which it is brought to a predetermined pressure mode of operation at the input

) 5 mavistrali 1 and flow in the pressure line 2 at the outlet 4 of the pump 5, include the drive 7 and by means of shafts 20,21 and 25,26 using the couplings 22 and 24 put pulsators in motion

20 9 and 6, respectively, and then begin to change the amplitude of the flow pulsations obtained by the operation of the pulsator 9 using the piston stroke control unit 10, and at the pump inlet 3

25 5 change the flow ripple phase

with the help of the phase shift control unit 11 associated with the pulsator 6 installed here. It is preferable to initially carry out a change

The 30 pulsation phases of the flow created by both pulsators 6 and 9. To do this, rotate the handwheel 35 and move the screw-nut 37 driven through the pair 23 together with the threaded coupling 24. Depending on the direction of displacement of the coupling 24, the shafts 25 and 26 will rotate relative to the middle position by the angle + c or -c, which is fixed by means of a ruler 33 mounted on a fixed base 27. The direction of rotation of the screw-nut pair 37 is carried out in one direction or the other so as to ensure a minimum of readings on the secondary instrument in the form of a voltmeter and 31, which converts the signal coming after the filter 30 from the pressure sensor 8. Then, using the piston stroke adjustment unit 10, the amplitude of the TUDU of pulsation flow rate pulsator is changed, 9. To do this, rotate the handwheel and shift the screw-nut 36 to shift the platform 12 to one side or the other, together with the struts 14 and 15 and the opposing coupling half 16 and 17 and a jumper 18, which moves freely within the self-aligning bearing 19, thanks to its installation at an angle to the axis of rotation of the semi-35

40

Clutches 16 and 17, and provided that the pulsator 9 moves only in one plane, allows the stroke of the porgan to be changed, and, consequently, the amplitude of the pulsations. According to the indications taken from the fixed on the base 13 of the ruler 32 in the case of its graduation in the divisions of the ratio A2 / A, directly fix the current value of the ratio A / A. The direction and movement of the platform 12 is adjusted until the reading of the voltmeter 31 becomes zero. The value of the ratio recorded here at the indications of the ruler 32, as well as the phase angle I /, taken at the indications of the ruler 33, is used to determine the input impedance of the pump 5,

Here, the values of R and I are taken into account, which are predetermined by the following Formulas:

2LR 1

R

G

and I

gF

(2)

where R is the hydraulic resistance coefficient of the section of the input line between the two pulsators; AR = pressure drop across the inlet line between two pulsators; G is the pump's weight flow rate

stationary mode; I - inertial coefficient

resistance of the section of the input line between the two pulsators;

1 - the length of the input line between the two pulsators; F is the cross-sectional area

input line; g is the acceleration of the force of gravity. To determine the input impedance Z, formula (1) is used, from which the real part of the impedance RgZ and the imaginary ImZ are found, by which the character of the input impedance of the pump is judged.

In a similar way, the magnitude of the impedance is determined for other modes of pump operation and for other frequencies of operation of the pulsators. Based on the test results, it is possible to construct the dependence of the modulus and argument of the pump input impedance on the frequency of forced oscillations.

Formula-invention

1. A method for determining the input impedance of a vane pump, which consists in creating in one of the sections of the input line at the pump inlet harmonic flow pulsations with a given frequency and setting the required mode of operation of the pump, measure and record the pressure and flow pulsations, after processing which are determined input impedance, characterized in that, in order to increase the test performance by reducing the time for processing the measurement results, harmonic pulsations are additionally created Yes

in the other section of the pump inlet line with the same frequency, after the pump enters the mode, the amplitude of the flow pulsations is changed in one section of the input line, while the pulsation phase is changed in the other cross section until the pressure pulses are zero in the section more distant from the pump, then the ratio of the amplitudes of the flow pulsations and the phase shift between the pulsations is measured, and the value of the pump input impedance is determined by the following expression:

z -ilK-i-i l-,

Claims (2)

1 +, e A1 where Z is the input impedance of the pump, s / cm; R, I are the coefficients of the hydraulic and inertial resistances of the section of the pump inlet line between the cross sections with the sources of flow pulsations, s / cm; angular rotational speed of the drive of the pulsation sources of flow; A - r - is the ratio of the amplitudes of the flow pulsations in the closest to the pump and the remote sections, respectively; If is the phase shift of the flow rate pulsations in two sections. 2. A device for determining the input impedance of a vane pump, containing the input and pressure pipes connected respectively to the inlet and outlet of the pump under test, a piston pulsator with a drive installed in the inlet line at the pump inlet, a pressure pulsation sensor, different in order to improve test performance by reducing the time for processing the results measurements, the device is equipped with a second pulse - torus, piston stroke adjustment unit. the pulsator and the phase shift regulating unit of the pulsator flow rate pulsator; the second pulsator is installed before the first pulsator along the flow path and connected with the pressure sensor connected to it, as well as through the drive unit of the piston stroke control unit simultaneously connected with the phase shift control unit .to the first pulsator. .h 3, The device according to claim 2, about tl and - and with the fact that the knot is adjustable 800 ten ten 15 The pulsator piston stroke is made in the form of a platform with the possibility of its horizontal movement relative to the fixed base with two coupling halves installed in its racks, connected by a jumper at an angle to the axis of rotation of the coupling halves, and also by means of a self-aligning bearing interacting with the bridge. the second pulsator, wherein one of the coupling halves is connected to the actuator by means of two shafts connected by a splined coupling, 4. the device according to claim 2, of which Hovhan pulsators shear flow pulsation phase is in the form vo 20 Dylan opirayuschegos the threaded sleeve, one shaft associated with the drive, and the other - with the pulsator at the pump inlet with the possibility of horizontal movement of the carrier relative to the stationary base, together with a clutch. 25 FIG. 2 29 four eight but Editor Y. Sereda Compiled by L.Gosteva Tehred M. Didyk Proofreader Ooziplje Order 964 Circulation 496 VNIIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 113035, Moscow, Zh-35, Raushsk nab. 4/5 Production and Publishing Combine Patent, Uzhgorod, st. Gagarin, 101 four thirty Fig.d Subscription