SU1561044A1 - Method of determining parameters of the process of mixing in flow of liquid - Google Patents

Abstract

The invention relates to the field of measurement technology and can be used to determine the parameters of the mixing of fluid flows. The aim of the invention is to increase the informativity of the method by determining the parameters of the mixing process at the same time throughout the entire flow cross section studied. In the cuvette, several layers of liquid with different concentrations of the photochromic substance (PCF) are created, or several streams with different concentrations of PCV are fed at the channel entrance. The investigated flow cross section is irradiated with a pulsed photoinductive beam. Then, after 10 ^-12 -10 ^-6 s, the cross-section of the flow is also irradiated with a pulsed dejectivating laser beam. Moreover, the width of the deactivating laser beam is chosen greater than the width of the inducing laser beam, and the duration of the pulses is chosen equal. The intensity ratio J _on / J _{about the} deactivating and photoinductive laser beams is set from the ratio J _on / J _о = 1-EXP (-K ₁ H) / 1-EXP (-K ₂ H), where K ₁ , K ₂ are the absorption coefficients photoinductive and deactivating laser beams, and H is the width of the investigated cross section. In the flow of fluid there are areas with different color intensity. The recording of the movement of the color marks obtained allows you to determine the mixing time, intensive mixing area and stagnant zones.

Description

one

(21) 4453253 / 24-10

(22) 06.30.88

(46) 04.30.90. Bul E- 16

(/ 1) Institute for Problems in Mechanics of the Academy of Sciences

the USSR

(72) V.N. Yurechko and P.V. Martynov

(53) 532.574 (088.8) (56) USSR Autographic Certificate Nte 1285376, cl. G 01 P 5/18, 1985.

(54) METHOD FOR DETERMINING THE PARAMETERS OF THE MIXING PROCESS IN A FLOW OF LIQUID

(57) The invention relates to a measurement technique and can be used to determine mixing parameters for fluid flows. The aim of the invention is to increase the informativity of the method by determining the parameters of the mixing process at the same time throughout the entire flow cross section studied. In the cuvette, several layers of liquid with different concentrations of the Photochromic substance (PCB) are created or several streams with different concentrations of PCB are fed at the channel entrance. A pulsed beam-inducing beam and the flow section being studied are transmitted. Then, the same cross section of the stream is irradiated through - with a pulsed deactivating laser beam. Moreover, the width of the deactivating laser beam is chosen greater than the width of the inducing laser beam, and the duration of the pulses is chosen equal. The intensity ratio 1OV / 10 of deactivating and self-induced laser beams is set from

t / t 1 exp (-KJi)., ... Wlo - (b) Where K K is the absorption coefficients of the Photo-inducing and deactivating laser beams, ah is the width of the cross section under study. In the flow of fluid there are areas with different color intensity. The recording of the movement of the color marks obtained allows you to determine the mixing time, intensive mixing area and stagnant zones.

I

(L

l

)

& Ј

The inventor relates to measurement techniques and can be used to study mixing processes in a liquid.

The aim of the invention is to increase the informativity of the method by determining the parameters of the mixing process at the same time throughout the entire flow cross section studied.

The method is carried out as follows.

In the cuvette, several layers of liquid with different concentrations of chromo-chromic substance (PCF) are created, or several streams with different concentrations of PCF are fed at the channel inlet. Include the laser, which creates a laser beam, causing photochemical reactions in the liquid. The beam passes through a quartz cylindrical lens and then enters the liquid, staining the entire cross section under study. Through

ten

- P.

- with the second laser feeds

the beam of deactivating radiation to the cylindrical lens and then the radiation passes through the cross section under study.

In the flow of fluid there are areas with different color intensity. Recording the movement of color marks allows you to determine the mixing time, the area and their size of the intensive mixing process and, conversely, stagnant zones.

Example 1. In a cuvette 25 cm wide and 30 cm long inside which there is a sbér, 3 layers are created with a concentration of PCF in the upper layer

l-e

mol / l, on average 5

four

ten

-4 mole

/ l

ten

and in the lower 10 mol / l. In quality FHW, intsolin spiropyrans were chosen, plates with different values were attached to the lateral surfaces of the cuvette (temperatures. Due to the temperature gradient in the cuvette, circulation currents rupture, leading to layer mixing. By a laser beam with a wavelength of 347 them The flow of liquid is processed through a cylindrical lens, and the laser beams pass through the entire flow cross section under study, oriented perpendicular to the optical detection system, at a distance of 12 cm from the other side and another 12 The mark is 1 cm wide. Through this cross section, the deactivating laser radiation is processed, the intensity of which is less than the photoinductive radiation intensity, with a wavelength of 530 nm. The change in the movement of color marks is recorded using a speed camera. intensive mixing areas and areas in which mixing is extremely slow are defined. Since the width of the laser deactivating beam along the optical axis of the registration system exceeds the width of the laser yutoinduziruyuschego beam, then through the entire color mark (all color mark will be covered) will pass deactivating laser radiation. In addition, the energy distribution of laser radiation across the width of the beam along the optical axis of the registration system should be created the same.

e

1561044

Example 2. The method is carried out in the same way as in example 1, only the ratio of the intensity of the photoinductive

i. to deactivation

rudder 1OV support equal to: (1 - exp (-Kah) / 1 - - exp (-FMh),

V1.

where 1C ,, KЈ are the co-actives of absorption of photoinductive and deactivating radiation by the liquid; fluid section width

h

20

25

30 45 and the time of radiation exposure on the speed of both radiations is chosen equal to the pulse duration. In this case, the degree of exposure of laser radiation to any point of the cross section is the same. So, with the passage of laser radiation, its absorption occurs according to the Lambert-Baer law, i.e. the intensity of transmitted photoinductive and deactivating light decreases according to the following degrees:

I,

Io exp -K, x);

Ti Ioe

In order for the intensity of the inducing light in the return section to be the same, at each point of the section it is necessary that the treatment intensity, which is the difference of the photoinductive and deactivating light passing through the given point, at the starting point of the light entering and at the ending point of the section .

06

 I0 expC-K h) - - IaR exp (-K.h).

about

From here

In / I

OB

 1 - exp (-Kzh) / l - - exp (-K, h).

In this case, the intensity of the color marks will be the same for each point of the section and the distortion of the results due to the processing of the results is reduced to zero.

p 3. The method is carried out; as in example 1, the method also applies

After deactivating radiation covering the entire cross section in a narrow part of a given section, penetrating the entire width of the section is subjected to additional processing of photoinductive radiation, while the intensity of the additional botoinductive radiation exceeds 1.7 times the intensity of the initial photoinductive radiation. Since the intensity of the resulting mark is Bleer, this mark is clearly visible against the background of more pale marks, moreover, this mark has some thickening at the point of entry of the laser beam, which also makes it possible to distinguish it from other marks. By moving this mark, the velocity field of the fluid and the cross section under study is determined.

In order for the label to be clearly visible, it is necessary that the intensity of the additional photoinductive radiation be greater than the intensity of the initial Aeroinductive radiation by 1.5-2 times, and the concentration of spiropyran be in the range of 10 ff - 1 SGGE g / l. The coefficients K (, K Ј for yochochromic liquids, n of which indolinic spiropyrans are dissolved with a concentration of 10–4 g / l, are equal to K 0.21 / cm,

Ka 0.12 VCM.

Thus, in the method it is possible to measure the parameters of the mixing process in the selected section, while the fluid layers, both close to the recording system and further from the recording system than the section under study, do not distort the results. In addition, simultaneously with the mixing parameters, it is possible to measure the velocity field.

Claims (1)

Invention Formula The method for determining the parameters of the mixing process in a fluid flow, Included in the creation of layers with different concentrations of the chromic substance in the liquid shit, the impact of the pulsed laser photoinduced radiation on the section of the liquid flow under study and the intensity of the radiation intensity and movement of the resulting color marks About the studied flow parameters, characterized in that, in order to increase accuracy and inormativity, after affecting the studied flow cross section by means of pulsed laser Photoinductive radiation on the same flow section, the same direction is impacted by pulsed laser deactivating radiation, while the width laser deactivating beam is greater than the width of the laser photoinductive beam, the ratio of the intensities of the deactivating and Lottoinductive laser radiations is determined from the ratio 1о6 1 1 ЁХЕ 1кл1}) 10 1 - exp (-К2п) where 1OB, 10 are the intensities of deactivating and Aeroinductive laser radiation, respectively; K ,,, K2 are the absorption coefficients of photoinductive and deactivating laser radiation, respectively; h - the width of the investigated fluid flow sections and the time of radiation effect on the fluid flow is chosen equal, and after irradiation of the flow with pulsed laser deactivating radiation, the studied flow section is additionally affected by localized laser light (photoinductive radiation) and the velocity profile in the flow section being examined is determined by a narrow color strip.