SU1733728A1 - Method of creating pressure resonance oscillations - Google Patents

Abstract

Summary of the Invention: Gas is introduced into the working fluid of the hydromechanical oscillatory system to form a gas volume. The parameters of the gas volume are chosen according to the ratio f VK S / Q, where f is the oscillation frequency, K is constant for this system; S is the cross-sectional area, Q is the gas volume. The system is tuned to resonant oscillations by changing the gas supply to the gas-filled element. 1 il.

Description

The invention relates to a vibration technique and relates to the creation of fluctuations in fluid pressure in a measuring and pulsating apparatus.

A known method for producing resonant fluctuations in fluid pressure, based on the interaction of mechanical and electrical signals of an electroosmotic micropump-sensor system, according to which the signal from the sensor is amplified and changed in phase until a stable self-oscillatory process occurs. The frequency of the oscillations changes the mass of the fluid in the cavity between the micropump and the sensor to chop the frequency of the oscillations produced.

The disadvantages of this method are the complexity of its instrumentation, the low intensity of the resulting fluctuations in the pressure of the fluid and greater energy efficiency.

The closest to the present invention is a method for obtaining resonant pressure oscillations, which means that the hydromechanical oscillatory system is influenced by an oscillation generator and, having changed the mass of the fluid in the system, it is tuned to the resonant mode. The mass change is produced according to the harmonic law and regulates the amplitude and frequency of the mass change before the appearance of stable parametric oscillations.

According to this method, the hydromechanical oscillatory system is formed by a sealed cavity and the volume of liquid filling it, and the mass change of the liquid in the system is due to the elastic deformation of the sealed cavity communicated with another liquid cavity, in which an oscillator creates an alternating (hydrodynamic) pressure. In this case, the fluid inside the cavity formed by a cylinder with flexible membranes at the ends is an inertial element of the nonlinear oscillatory system and the cavity itself is an elastic element.

(L

WITH

x |

CJ

with

Xi

Yu

00

However, this system has a low quality factor (sensitivity), since the greater rigidity of the cylinder causes a low elasticity of the elastic element during system oscillations, and the presence of flexible membranes increases its compliance, but significantly reduces the restoring force. This causes a low gain when the resonant oscillations of the system are excited and does not allow (despite large power inputs) to obtain high values of the amplitude of fluctuations of the fluid pressure.

In addition, the malleability of the fluid cavity is low, limiting the possibility of changing the mass of fluid in it, reduces the possibility of tuning the oscillatory system to the resonant mode.

The purpose of the invention is to increase the amplitude of the resonant oscillations of the fluid pressure.

This goal is achieved by the fact that according to the method of obtaining resonant pressure oscillations in a hydromechanical oscillatory system, by changing the parameters of its elements, the working fluid of the oscillating system introduces gas to form a gas volume, the parameters of which are chosen by the ratio

housing 1, is connected to the system 11 of the pressurization and gas drainage. The gap between the grill 7 and the bottom 3 of the housing is significantly larger than the diameter of the gas-filled element 8. Outside the housing 1 is fixed a nozzle 12 mounted at the level of the gas-filled element 8. The separator is connected to the nozzle 12, including a disk housing 13 with two central nozzles, divided into two sealed membrane cavities 14.

The method is carried out as follows.

In the initial position, the cylindrical body 1 is filled with liquid at 80-85% of height (the rest of it is filled with air), while the gas-filled element 8 containing a volume of gas O is kept in the liquid at a predetermined level using a grid 7. In this case a non-linear inside the body 1 is formed an oscillatory system in which the fluid is an inertial element and the gas volume contained in it is an elastic element. The dynamic contact between these elements of the liquid-gas oscillatory system is made through an elastic film 9. The natural frequency of oscillations of such an oscillatory system, which characterizes the frequency range of resonant oscillations, is related to the parameters of the elastic-inertial properties of the system

where f is the resonant frequency of oscillations of the system, Hz;

K is a constant value for a given oscillatory system;

S is the cross-sectional area of the gas volume, cm2;

Q is the volume of gas in a liquid, see

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

The device comprises a vertical cylindrical body 1 with an airtight lid 2 and a bottom 3, partially filled with liquid. To the bottom 3 of the housing 1 is connected installed concentrically to him a cylinder 4 of smaller diameter with a bottom 5, in which is located the generator 6 oscillations. A horizontal grid 7 is placed in the lower part of the housing 1. Fixed on the inner wall of the housing, under which is located the gas-filled element 8, made in the form of an airtight cavity made of an elastic, elastic (for example, rubber) film 9. The internal cavity of the 1-element 8 is flexible eg rubber tube 10 sealed tightly in a cylindrical wall

35

| p - p 5 Q h p

Hz

0

five

0

five

where n is the adiabatic coefficient;

p is the pressure above the free surface of the liquid, dyne / cm;

S is the area of the horizontal section of the gas-filled element, cm;

Q is the volume of gas in a liquid, cm

h is the height of the liquid column above the gas volume, cm;

t

p is the density of the liquid, g / cm.

The resulting oscillating liquid-gas system with free placement of the gas volume at a given level in a liquid is characterized by very high sensitivity, which is due to the high elastic properties of the gas contained in the liquid and the large specific surface of its dynamic contact with the liquid.

Since the parameters p, p, p for any particular liquid-gas oscillatory system are constant, with a constant value of h, relation (1) can be converted;

f S

 - - -Q

(2)

n p where K-F is a constant value for

This fluid-gas oscillatory system.

When the oscillator b is switched on, the oscillations of pressure in the cylinder 4 are excited, which are transmitted to the liquid in the housing 1 and through the elastic film 9 to the gas volume contained in it. In a fluid, a dynamic pressure is excited, the value of which depends on the amplitude of the external vibration component (vibration acceleration) and on the degree of coordination of the frequency of vibration action with the natural frequency fc of the system.

By tuning the generator frequency to the frequency fc, a resonant mode of oscillations of the liquid-gas system is obtained, characterized by an increase in the intensity of the oscillations and a sharp increase (4-6 times) in the amplitude of the dynamic pressure waves in the liquid. In this case, the liquid is instantly turbulized, captures the gas in the upper part of the body, and turns into a homogeneous hydrosol filling the entire body cavity. The presence of gas in the liquid volume additionally increases the sensitivity of the oscillating system liquid-gas, which causes an increase in the amplitude of the dynamic pressure waves in the liquid, increases the intensity of the resonant oscillations of the system.

The pressure pulsations of the gas-liquid medium inside the housing 1 are transmitted through the nozzle 12 to the consumer, which is connected to the outlet nozzle of the separator 13. The frequency of the pressure pulsations transmitted to the consumer is changed by changing the natural frequency of the oscillations of the liquid-gas system, for which the system 11 is modified (increased or reduce) the amount of gas inside the elastic shell 9 in

according to dependence (2) and adjust the oscillator frequency.

The adjustment of the parameters of the resonant pulsations of the liquid-gas system (frequencies, hydrodynamic pressure) can also be carried out by changing the magnitude of the vibration acceleration with a change in the amplitude of the vibration action.

The proposed method allows to significantly increase the intensity of the excited resonant pressure oscillations in the hydromechanical oscillatory system. This is achieved by increasing the sensitivity of the oscillating system by placing a hermetic gas volume in a liquid and using the elastic properties of the gas when it dynamically interacts with the liquid under the condition of vibration in the system. Increasing the sensitivity (Q) of the oscillatory system allows a significant increase in the amplitude of the obtained resonant pressure oscillations. Wherein

It also makes it easier to set up the system for a resonant mode, reducing energy consumption for obtaining resonant pressure oscillations.

Claims (1)

Invention Formula The method of obtaining resonant pressure oscillations in a hydromechanical oscillatory system by changing the parameters of its elements, characterized in that, in order to increase the amplitude resonant oscillations; a gas is introduced into the working fluid of the oscillating system with the formation of a gas volume; its parameters are chosen according to the ratio 40 f 1 Q where f is the resonant frequency of oscillations of the system, Hz; K is a constant value for a given oscillatory system; S is the cross-sectional area of the gas volume cm 50 Q is the volume of gas in a liquid, see /four