阅读说明：本技术 一种水力旋流器倒圆台形状确定方法 (Method for determining shape of inverted round table of hydrocyclone ) 是由 张彦飞 孙玉梅 王晓博 安凯 武世宏 隋新 陈祥光 于 2020-03-21 设计创作，主要内容包括：本发明公开了一种通过实验数据确定倒圆台形状的方法。采用常用的水力旋流器做实验,在距离下底面<Image he="18" wi="75" file="DEST_PATH_IMAGE001.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>处的倒圆台器壁上安装截面为半圆形的超声波测速管,其中<Image he="19" wi="13" file="891628DEST_PATH_IMAGE002.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>为可安装超声波测速管的最大数目。超声波测速管内部安装超声波测速仪,超声波测速仪通过导线与旋流器外部的计算机连接,计算机控制超声波测速仪并记录测量结果。通过该实验测出倒圆台不同高度器壁处的料浆速度,并由此计算出相应高度粗颗粒的离心力；限制不同高度的粗颗粒具有相同的离心力,并由计算出器壁到倒圆台轴线的理想距离；将这些理想距离拟合成一条直线就得到了倒圆台的母线,从而确定了倒圆台的高度。(The invention discloses a method for determining the shape of an inverted round table through experimental data. The experiment is carried out by adopting a common hydrocyclone, and the bottom surface is arranged at a lower distance An ultrasonic speed measuring tube with a semicircular section is arranged on the wall of the inverted circular truncated cone device, wherein The maximum number of the ultrasonic speed measuring tubes can be installed. The ultrasonic velocimeter is arranged in the ultrasonic velocimeter tube, the ultrasonic velocimeter is connected with a computer outside the cyclone tube through a wire, and the computer controls the ultrasonic velocimeter and records the measurement result. Measuring the slurry speeds of the wall parts of the inverted circular truncated cone at different heights through the experiment, and calculating the centrifugal force of coarse particles with corresponding heights; the coarse particles limiting different heights being identicalCentrifugal force and calculating the ideal distance from the wall to the axis of the inverted circular truncated cone; fitting the ideal distances into a straight line obtains the generatrix of the rounding table, thereby determining the height of the rounding table.)

1. A method for determining the shape of an inverted round table of a hydrocyclone is characterized by comprising the following steps: the method comprises the following steps:

a. experimental hardware configuration: a common hydrocyclone is adopted, and the height of an inverted round table of the hydrocyclone is represented by H; installing ultrasonic speed measuring tubes (3) with semicircular sections on the wall of the inverted circular truncated cone at the positions H, 2H, … and nh away from the lower bottom surface, wherein H is the height difference between two adjacent ultrasonic speed measuring tubes (3), and n is a positive number satisfying that nh is less than or equal to H and less than (n +1) H, namely the maximum number of the ultrasonic speed measuring tubes (3) can be installed; an ultrasonic velocimeter is arranged inside the ultrasonic velocimeter tube (3), the ultrasonic velocimeter is connected with a computer outside the cyclone through a wire, and the computer controls the ultrasonic velocimeter and records the measurement result;

b. experimental data acquisition and b-centrifugal force calculation: after a slurry pump is started, slurry flows into the cyclone from the feed port (1), and after fine particles and water flow out of the overflow pipe (2) and settled sand is discharged from the underflow port (4), the computer controls the ultrasonic velocimeter to measure the speed and records the measurement result; r and R represent radii of the upper and lower bottom surfaces of the rounding table, respectively, v₁，v₂,…,v_nRespectively showing the measurement results of the ultrasonic velocimeters installed at the positions h, 2h, … and nh from the lower bottom surface, and the ideal distances from the coarse particles with the mass m to the axis of the rounding table are sequentially as follows in order to keep the centrifugal force consistent

c. Determination of straight line fitting and inverted frustum shape

By n points on a plane

Fitting a straight line y through the points (H, R) ═ a (x-H) + R, where a is a undetermined constant;

n points are arrangedSubstituting the linear equation y into a (x-R) + H to obtain an overdetermined equation set

Its least square solution is

In the equation y ═ a (x-H) + R, x ═ R)/a + H can be determined, where H-x ═ R/a is the determined height of the rounding table.

Technical Field

The invention relates to a method for determining the shape of an inverted round table of a hydrocyclone, belonging to the technical field of solid-liquid separation.

Background

The hydraulic cyclone is a device which utilizes fluid pressure to generate rotary motion so as to realize solid-liquid separation, and is widely used in the industries of ore dressing, metallurgy, environmental protection, chemical industry, light industry, coal, electric power and the like. The upper end of the hydraulic cyclone is cylindrical, and the lower end of the hydraulic cyclone is in an inverted truncated cone shape. After slurry is injected from the feed inlet at a certain speed along the tangential direction of the cylinder, the slurry is forced to make a rotary motion when meeting the blockage of the wall of the cyclone. The ore pulp rotates at a high speed, so that the centrifugal force on coarse solid particles, fine solid particles and water is different, the centrifugal force on the coarse solid particles in the ore pulp is high, the coarse solid particles can move towards the wall of the ore pulp by overcoming hydraulic resistance and spirally move downwards along the wall of the ore pulp under the combined action of the gravity of the coarse solid particles, and the fine particles and most of the water do rotary motion along the ore pulp when the fine particles and most of the water are not close to the wall of the ore pulp because the centrifugal force is small. Under the push of the subsequent slurry, the coarse particles continue to be concentrated to the periphery, while the fine particles and water stay in the central area. After slurry flows from the cylindrical part of the cyclone to the inverted round table part, the flowing section is smaller and smaller, and under the contraction and compression of outer layer slurry, inner layer slurry containing a large number of fine particles has to change the surface direction and moves upwards to form an inner cyclone which is discharged from the overflow pipe to become overflow; and the coarse particles continue to spirally move downwards along the wall of the device to form an outer rotational flow, and finally are discharged from the bottom flow port to become settled sand.

Because the friction between slurry entering the cyclone and the wall of the cyclone is caused, the linear velocity of the movement of coarse particles near the wall of the cyclone is continuously reduced along with the sinking of the slurry, so that the centrifugal force is also continuously reduced, and the lower half part of the cyclone is designed into the shape of the inverted truncated cone so as to ensure that the coarse particles have enough centrifugal force to concentrate to the periphery. Under the condition that the inner diameters of the cylinder and the underflow opening are constant, the shape of the inverted round table is determined to be only the included angle between the generatrix and the bottom surface. With the increase of the included angle, the rounding table is gradually close to the cylinder, which is not beneficial to the concentration of coarse particles to the periphery. On the contrary, the side surface of the inverted circular truncated cone is gradually gentle along with the reduction of the included angle, the centrifugal force of the coarse particles positioned below the inverted circular truncated cone is gradually increased, and the coarse particles start to move upwards when the centrifugal force exceeds the centrifugal force above the inverted circular truncated cone, so that the solid-liquid separation is not facilitated. Therefore, the hydrocyclone can be ensured to have the best solid-liquid separation effect only if the included angle between the inverted circular truncated cone generatrix and the bottom surface is properly selected.

Disclosure of Invention

The invention discloses a method for determining the shape of an inverted round table through experimental data, in view of the fact that the solid-liquid separation effect of a hydrocyclone is closely related to the included angle between a bus of the inverted round table and the bottom surface.

The radius R of the upper bottom surface of the inverted truncated cone is the same as that of the cylinder, and the radius R of the lower bottom surface is the radius of the underflow port 4, so that the determination of the shape of the inverted truncated cone is the determination of the height of the inverted truncated cone. In order to ensure that the hydrocyclone has the best solid-liquid separation effect, the coarse particles close to the wall of the inverted circular truncated cone have the same centrifugal force no matter how high the coarse particles are in the inverted circular truncated cone. The invention adopts a common hydrocyclone for experiment, and an ultrasonic speed measuring tube with a semicircular section is arranged on the wall of an inverted circular truncated cone at the position h, 2h, … and nh away from the lower bottom surface, wherein h is the height difference between two adjacent ultrasonic speed measuring tubes, and n is the maximum number of the ultrasonic speed measuring tubes which can be arranged. The ultrasonic velocimeter is arranged in the ultrasonic velocimeter tube, the ultrasonic velocimeter is connected with a computer outside the cyclone tube through a wire, and the computer controls the ultrasonic velocimeter and records the measurement result. Measuring the slurry speeds of the wall parts of the inverted circular truncated cone at different heights through the experiment, and calculating the centrifugal force of coarse particles with corresponding heights; limiting coarse particles with different heights to have the same centrifugal force, and calculating the ideal distance from the wall to the axis of the rounding table; fitting the ideal distances into a straight line obtains the generatrix of the rounding table, thereby determining the height of the rounding table.

Drawings

Fig. 1 is a schematic view of the installation of an ultrasonic tachometer tube in a hydrocyclone.

Description of the reference symbols

1 feed inlet, 2 overflow pipes, 3 ultrasonic speed measuring pipes and 4 underflow ports

Detailed Description

The radius R of the upper bottom surface of the inverted truncated cone is the same as that of the cylinder, and the radius R of the lower bottom surface is the radius of the underflow port 4, so that the determination of the shape of the inverted truncated cone is the determination of the height of the inverted truncated cone. In order to ensure that the hydrocyclone has the best solid-liquid separation effect, the coarse particles close to the wall of the inverted circular truncated cone have the same centrifugal force no matter how high the coarse particles are in the inverted circular truncated cone. When coarse particles with mass m rotate around the axis of the inverted circular table at a linear velocity v, the generated centrifugal force is mv²/(2r₀) Wherein r is₀The distance of the coarse particles from the axis of the rounding table. The common hydrocyclone is adopted for experiments, and if the slurry speeds of the wall parts of the inverted circular truncated cone with different heights can be measured, the centrifugal force of coarse particles with corresponding heights can be calculated; by limiting the same centrifugal force for coarse particles of different heights, the ideal distance of the wall from the axis of the rounding table can be calculated. Fitting the ideal distances into a straight line obtains the generatrix of the rounding table, thereby determining the height of the rounding table. The height of the rounding table is determined by the following steps:

1. experimental hardware configuration

A common hydrocyclone is adopted, and the height of an inverted round table of the hydrocyclone is indicated by H. As shown in fig. 1, the ultrasonic tachometer tube 3 with a semicircular cross section is installed on the wall of the inverted circular truncated cone at a distance of H, 2H, …, nh from the lower bottom surface, where H is the height difference between two adjacent ultrasonic tachometer tubes 3, and n is a positive number satisfying nh ≦ H < (n +1) H, that is, the maximum number of ultrasonic tachometer tubes 3 can be installed. The ultrasonic velocimeter is installed inside the ultrasonic velocimeter tube 3, the ultrasonic velocimeter is connected with a computer outside the cyclone through a wire, and the computer controls the ultrasonic velocimeter and records the measurement result.

2. Experimental data acquisition and centrifugal force calculation

Starting upSlurry flows into the swirler from the feed inlet 1 after the slurry pump, and after fine particles and water flow out of the overflow pipe 2 and settled sand is discharged from the underflow port 4, the computer controls the ultrasonic velocimeter to measure the speed and record the measurement result. R and R represent radii of the upper and lower bottom surfaces of the rounding table, respectively, v₁，v₂,…,v_nRespectively showing the measurement results of the ultrasonic velocimeters installed at the positions h, 2h, … and nh from the lower bottom surface, and the ideal distances from the coarse particles with the mass m to the axis of the rounding table are sequentially as follows in order to keep the centrifugal force consistent

3. Determination of straight line fitting and inverted frustum shape

Usually, it is not possible for an inverted circular truncated cone to have a radius of exactly h, 2h, …, nh from the lower base surfaceFor this purpose, n points on the plane are used

A straight line y passing through the point (H, R) is fitted to a (x-H) + R, where a is a undetermined constant.

N points are arrangedSubstituting the linear equation y into a (x-R) + H to obtain an overdetermined equation set

Its least square solution is

Given the equation y ═ R in a (x-H) + R

At this timeIs the determined height of the rounding off.