CN102830049A - Ultrasound array micronano detection method of particle sizes multiphase fluid particles - Google Patents

Abstract

The invention aims at providing an ultrasound array micronano detection method of particle sizes of multiphase fluid particles. The ultrasound array micronano detection method is used for detecting the particle sizes and the like of particles in suspension liquid. The ultrasound array micronano detection method of the particle sizes of the multiphase fluid particles comprises the following steps of: demarcating multiphase fluid with particles in different sizes and determining a relation between a multiphase fluid attenuation coefficient and the particle sizes. Ultrasound beams are vertically irradiated in the multiphase fluid to be detected, and an ultrasound transducer array receives reflection or transmission ultrasonic waves form the inside of the multiphase fluid. The average particle size is determined according to the relation between the attenuation coefficient and the particle sizes of the suspension liquid particles.

Description

Heterogeneous fluid grain graininess supersonic array micro-nano detection method

One, technical field

The invention belongs to technical field of nondestructive testing, be specifically related to polyphasic flow suspending liquid and ultrasound examination, is that a kind of use supersonic array detects methods such as heterogeneous fluid grain graininess.

Two, background technology

Heterogeneous fluid grain graininess supersonic array micro-nano detection method is a kind of Dynamic Non-Destruction Measurement that uses supersonic array to detect the heterogeneous fluid grain graininess; It utilizes high-frequency ultrasonic and tested heterogeneous fluid particle to interact; Obtain grain graininess parameter in the heterogeneous fluid, all be widely used in the field in many ways in Aero-Space, industrial machinery and biomedicine etc.

The grain graininess of heterogeneous fluid plays main effect in many industries; Water, gas content in the granularity of mud particle and concentration and the profit gas three-phase flow body during like petroleum drilling; The content of river load; The concentration of ore pulp and coal slurry when ore dressing and coal washing, therefore the detection to the polyphasic flow characteristic has important practical significance.

Heterogeneous fluid grain graininess supersonic array micro-nano detection method is used the ultrasound wave of frequency range as 0.1MHz-100MHz, uses supersonic array to measure polyphasic flow grain graininess etc.Because frequency of ultrasonic is high more, resolution is high more, but penetration capacity is just poor more, and it is also just serious more to inject the scattering effect that causes behind the object, causes receiving signal weakening thus, needs the transducer of choose reasonable corresponding frequencies when therefore detecting.Incide change of sound field in the tested heterogeneous fluid through calculating each frequency transducer ultrasonic waves transmitted, effectively adjust the relative position of transducer array, obtain the acoustic attenuation coefficient of heterogeneous fluid, thereby obtain grain graininess size in the heterogeneous fluid.

U.S. Epstein and professor Carhart derive the influence of thermal loss to acoustic attenuation, and Allegra and Hawley have developed this model, have taken all factors into consideration the influence of various acoustic attenuation factors, have set up the ECAH model.Domestic Shanghai University of Science and Technology particle and the Cai Xiaoshu of multiphase flow measurement technical institute professor, associate professor Su Mingxu etc. have been developed the ECAH model, adopt Single-Input Single-Output to measure the relation between acoustic attenuation coefficient and the grain graininess.Not retrieving related patent U.S. Patent No. or document at present as yet uses supersonic array to detect the heterogeneous fluid grain graininess.

Three, summary of the invention

The object of the invention provides a kind of heterogeneous fluid grain graininess supersonic array micro-nano detection method, is used to detect the heterogeneous fluid grain graininess.

Heterogeneous fluid grain graininess supersonic array detection method of the present invention comprises: the heterogeneous fluid to the variable grain granularity is demarcated, and confirms the relation between heterogeneous fluid acoustic attenuation coefficient and the grain graininess.Ultrasonic beam is impinged perpendicularly in the heterogeneous fluid to be measured, and ultrasound transducer array receives and comes from polyphasic flow inner reflection or transmission ultrasonic signal.According to the relation between attenuation coefficient and the suspension particle particle diameter, confirm the average grain granule size.

Four, description of drawings

Fig. 1 heterogeneous fluid supersonic array pick-up unit synoptic diagram.

Fig. 2 heterogeneous fluid ultrasound transducer array synoptic diagram.

Five, embodiment

Select corresponding ultrasonic transducer according to polyphasic flow grain graininess parameter, transducer is installed on the heterogeneous fluid supersonic array pick-up unit, all ultrasonic transducers that can be used for changing are the immersion type transducer.Heterogeneous fluid is positioned at sample cell.Fig. 1 is the pick-up unit synoptic diagram, and each several part is: sample cell, high-frequency ultrasonic transducer, high frequency ultrasound card feeding-discharging, data processing equipment etc.Fig. 2 is a heterogeneous fluid ultrasound transducer array synoptic diagram.

When sound wave is propagated in medium, the phenomenon that its intensity weakens with the increase of propagation distance gradually.According to the different reasons that cause sound intensity decay, can be divided into three kinds of main types to SATT: attenuation by absorption, scatter attenuation and diffusive attenuation.The characteristic of medium is depended in preceding two types of decay, and then one type is then caused by the characteristic of sound source.

Acoustic theory proves that attenuation by absorption and scatter attenuation are all deferred to exponential damping law.As far as the plane wave of propagating along the x direction, owing to need not take into account diffusive attenuation, then acoustic pressure is expressed from the next with the variation apart from x:

P＝P ₀e ^-αx （1）

In the formula: α---acoustic attenuation coefficient, unit are Np/m; The machine-processed more complicated of x---propagation distance attenuation by absorption relates to glutinousness, heat conduction and the various relaxation process of medium.

The comparatively general expression formula of acoustic attenuation coefficient in the single-phase medium is:

$\mathrm{\α}=\frac{{\mathrm{\ω}}^2}{2\mathrm{\ρ}{c}^3}[\frac{4}{3}{\mathrm{\η}}^{\′}+\mathrm{\τ}(\frac{1}{c_v}-\frac{1}{c_p})+\underset{i=1}{\overset{n}{\mathrm{\Σ}}}\frac{{\mathrm{\η}}_i^n}{1+{\mathrm{\ω}}^2{t}_i^2}]---\left(2\right)$

In the formula: ρ---fluid density;

The speed that c---sound wave is propagated in fluid;

ω---circular frequency;

The shear viscosity coefficient of η '---medium;

τ---coefficient of heat conductivity;

c _v---specific heat at constant volume;

c _p---specific heat at constant pressure;

---the caused low frequency of i kind relaxation process holds the stagnant coefficient that becomes sticky;

t _i---the relaxation time of i kind relaxation process.

Claims (6)

1. a heterogeneous fluid grain graininess supersonic array micro-nano detection method is characterized in that: this method use supersonic array detection heterogeneous fluid grain graininess size.Use pick-up unit to demarcate the relation between ultrasonic attenuation coefficient and the grain graininess, ultrasound wave is hung down incide in the tested heterogeneous fluid, receive ultrasonic signal through heterogeneous fluid transmission or reflection by supersonic array.

2. heterogeneous fluid granularity supersonic array micro-nano detection method according to claim 1; It is characterized in that: supersonic array is formed annular array by 16 high-frequency transducers; One of them transducers transmit ultrasonic waves signal; All the other 15 transducers form receiving array, and high-frequency ultrasonic transducer's frequency is 0.1MHz-100MHz.

3. heterogeneous fluid grain graininess supersonic array detection method according to claim 1; It is characterized in that: ultrasound wave weakens along with the increase of propagation distance gradually, causes that the reason of heterogeneous fluid SATT has factors such as wave beam diffusion, crystal grain scattering, medium absorption, stickiness loss and thermal loss.

4. polyphasic flow grain graininess supersonic array detection method according to claim 1; It is characterized in that: the ultrasonic attenuation coefficient of different frequency is different with the grain graininess Changing Pattern in the sonic propagation process, utilizes to concern the count particles granularity between attenuation coefficient and the grain graininess.

5. the detection method of attenuation coefficient in the heterogeneous fluid according to claim 4; It is characterized in that: a transducers transmit ultrasonic waves signal; All the other 15 transducers form a receiving array; Receive transmission or reflection ultrasonic signal,, obtain corresponding attenuation coefficient through to signal amplitude that each transducer is surveyed test through heterogeneous fluid.

6. the used transducer frequency of supersonic array according to claim 2, it is characterized in that: this method can detect the grain diameter that equates with the wave length of sound order of magnitude, and the average grain particle diameter of minimum detectable is 50nm.

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