CN100430729C - Pressure sensing high-concentration water flow hydrodynamometer - Google Patents

Abstract

The invention provides a pressure sensing high-concentration current meter to measure the current speed by the Pitot tube operating principle. It includes the current detector, the converter and the computer; the current detector includes the induced pressure tube and the pressure sensing cavity; the induced pressure tube is a long hollow tube and the pressure sensing cavity is divided into the water pressure sensing cavity and the air sensing cavity by the elastic girder; the water pressure sensing cavity is connected to the induced pressure tube and one side of the air pressure cavity is connected with the pressure sensing slug which generates the electric signal according to the pressure from the elastic girder; the signal is transferred to the computer through the converter and the computer computes the current speed according to the electric signal. So the current meter can measure the high concentration current speed precisely.

Description

Pressure sensing high-concentration water flow hydrodynamometer

Technical field

The present invention relates to a kind of pressure sensing high-concentration water flow hydrodynamometer, be meant a kind of a kind of pressure sensing type current meter that utilizes Pitot tube principle of work, the trickle deformation measurement high concentration of pressure-sensitive chip current flow velocity especially, belong to the measurement mechanism field.

Background technology

The flow rate of water flow situation that in hydro science research and engineering application, often needs to understand a certain waters, instrument that this just needs some corresponding current of use to test the speed.At present, normally used flow rate of water flow instrument has a lot, and this is comprising Pitot tubular type, laser type, rotary propeller type, electromagnetic type, tagging formula or the like current meter.The device of the extremely low rate of flow of fluid of a kind of measurement for example, just is provided among the Chinese invention patent ZL 02155453.6.This invention utilizes Pitot tube as the current sniffer, utilizes that the scale pressure measurement is two-tube measures current total pressure and static pressure, and by reading microscope head in the piezometric tube is read, and then by calculating the flow velocity of current.Such current speed measuring device can be good at satisfying the requirement of testing the speed to low concentration current such as clear water, and still testing the speed for the high concentration current but exists problems.

The high concentration current as a large amount of hyper-concentration flows that exist in China Huanghe valley, are a kind of certain viscous fine particles of carrying under one's arms particularly, the special current that the high concentration solid-liquid two-phase flow of the complexity that forms under certain specific waterpower and boundary condition is moving.This current have the concentration of solid particles height, grain composition is wide and visual difference etc. is unfavorable for the characteristics that current test the speed.Therefore utilize above-mentioned general flow rate of water flow instrument to be difficult to measure accurately the flow velocity of this high concentration current.At present, this current meter that can measure high concentration current flow velocity still belongs to blank, and this gives the scientific research of the movement mechanism of high concentration current, and China's flood that reasonably brings the Yellow River under control has been brought great resistance.Therefore, a kind of flow velocity instrument that can accurately measure this high concentration current flow velocity of our exigence.Believe that such high concentration current current meter can solve the existing issue that the high concentration current test the speed to a certain extent, promote scientific research, and help the scientific and effective formulation of China measure of harnessing the Yellow River high concentration current movement mechanism.

Summary of the invention

Fundamental purpose of the present invention is to provide a kind of Pitot tube principle of work, pressure sensing type method utilized accurately to measure high concentration current flow velocity, the particularly pressure sensing high-concentration water flow hydrodynamometer of hyper-concentration flow flow velocity.

Goal of the invention of the present invention is achieved by following technical solution:

A kind of pressure sensing high-concentration water flow hydrodynamometer is characterized in that: comprise water flow detector, converter;

Described water flow detector comprises pressure guiding pipe and pressure-sensitive chamber; Described pressure guiding pipe is a hollow elongated tubular; Described pressure-sensitive chamber is a cavity, and by elastic beam this cavity is divided into water-filling pressure-sensitive chamber and air pressure-sensitive chamber; Described water-filling pressure-sensitive chamber is communicated with pressure guiding pipe by the set charging pipe of wall; Described water-filling pressure-sensitive chamber also is connected with aqueduct by charging pipe, and this aqueduct is communicated to waterborne; Described air pressure-sensitive chamber is connected with wireway and is communicated with atmosphere; Air pressure-sensitive chamber one side of described elastic beam is connected with pressure-sensitive chip; Described pressure-sensitive chip produces electric signal according to the pressure that elastic beam is subjected to;

Described converter is connected with computing machine, sends described electric signal to computing machine.

Described elastic beam is one deck barrier film; Described elastic beam can produce deformation according to suffered pressure.

The barrier film of described elastic beam for making by phosphor-copper.

The pressure that electric signal that described pressure-sensitive chip produced and elastic beam are subjected to is linear.

Described pressure guiding pipe is the curved long tube of a hollow; The nozzle diameter scope of pressure guiding pipe is between 2-3mm; Pipe range is between 8-12cm.

Between described pressure-sensitive chip and converter, also be in series with amplification system, be used to compensate, amplify the electric signal that described pressure-sensitive chip produces.

A kind of method of measuring high concentration current flow velocity, this method realizes that by the described pressure sensing high-concentration water flow hydrodynamometer of claim 1 its concrete steps are:

(1) measures high concentration water's current density to be measured;

(2) in water-filling pressure-sensitive chamber, charge into clear water by charging pipe, with the charging pipe sealing, make and form a closed system that is full of clear water in charging pipe, water-filling pressure-sensitive chamber, the pressure guiding pipe after waiting to be full of;

(3) water flow detector vertically is positioned in the high concentration current to be measured, and measures the measuring point depth of water that water flow detector institute location is put;

(4) in the flow velocity calculation procedure that survey high concentration water current density and measuring point depth of water parameter input computing machine is deposited;

(5) open converter, make computing machine receive the pressure-sensitive electric signal that records by pressure-sensitive chip, and calculate the flow velocity of the current of surveying by computing machine by the flow velocity calculation procedure.

Flow velocity calculation procedure in the described step (4) is determined by following step:

(1) measures the flow rate of water flow of somewhere clear water by having current meter now;

(2) connecting pipe with pressure sensing high-concentration water flow hydrodynamometer is fixed in above-mentioned measuring point place, measures the electric signal that pressure-sensitive chip produced;

(3) water velocity of measuring by existing current meter, and the computing formula of current dynamic pressure, the electric signal that the match pressure-sensitive chip produces and the funtcional relationship of current dynamic pressure;

(4) electric signal that produces of the pressure-sensitive chip that obtains by step (3) and the funtcional relationship and the flow rate of water flow computing formula of current dynamic pressure are determined the flow velocity calculation procedure.

The invention has the beneficial effects as follows: by ingenious structural design of the present invention, overcome concentration of solid particles height in the high concentration current, grain composition is wide and visual difference etc. is unfavorable for the characteristics that current test the speed, provide a kind of and can make things convenient for the pressure sensing high-concentration water flow hydrodynamometer of accurately measuring high concentration current flow velocity.

Description of drawings

Fig. 1 is a Pitot tube principle of work synoptic diagram;

Fig. 2 is the structural representation of high concentration current current meter;

Fig. 3 is a pressure-sensitive chamber cross-sectional view.

Embodiment

Below in conjunction with drawings and Examples the present invention is further described.

Pressure sensing high-concentration water flow hydrodynamometer involved in the present invention is that a kind of employing Pitot tube principle of work is at the specially designed flow rate of water flow instrument of high concentration current characteristics.

Pitot tube is a kind of measurement mechanism of relatively using always in fluid tests the speed at present.Fig. 1 is a Pitot tube principle of work synoptic diagram.The pressure that fluid is produced in flow process can be divided into two kinds: dynamic pressure and static pressure.Dynamic pressure is meant because the energy that macroscopic motion produced of fluid.Static pressure is meant the formed inherent energy of molecular thermalmotion owing to fluid itself, and the existence of static pressure only is decided by the thermal motion of molecule, and whether it doesn't matter with macroscopic motion.And the concentrated expression of the macroscopic motion of fluid and molecular thermalmotion own, i.e. dynamic pressure and static pressure sum are called total head.As shown in Figure 1, Pitot tube measures simultaneously that fluid is met the pressure of the flow direction and perpendicular to the pressure that flows to when measuring rate of flow of fluid.The pressure of meeting the flow direction is above-mentioned fluid total head, is above-mentioned hydrostatic pressure perpendicular to the pressure that flows to.Can obtain the dynamic pressure of fluid by the two difference.And the dynamic pressure of fluid is a parameter that is closely connected with rate of flow of fluid, just can obtain flow rate of fluid by calculating.

As shown in Figure 2, high concentration current current meter of the present invention comprises: water flow detector 1, converter 2.Water flow detector 1 is used for deeply sample water flow data under water.Water flow detector 1 connects converter 2, and the water flow data simulating signal that sampling is obtained sends converter 2 to.Converter 2 is that digital signal sends to computing machine 3 with the water flow data analog signal conversion that obtains.Computing machine 3 calculates flow rate of water flow according to water flow data by predetermined calculation procedure.

This water flow detector 1 integral body is the long tube of a hollow, and the required various devices of test are equipped with in its inside, during detection water flow detector 1 is vertically goed deep under water.Inner each device of detector can be divided into impulse system, pressure-sensitive system, measuring staff, four parts of amplification system.The impulse system is positioned at water flow detector 1 bottom, is the curved pressure guiding pipe 4 of a hollow.Pressure guiding pipe 4 front-end probes stretch out outside the detector, should pop one's head in face of water (flow) direction when surveying.Be terminated at the pressure-sensitive chamber 5 of pressure-sensitive system behind the pressure guiding pipe 4.Pressure-sensitive chamber 5 is used to measure the pressure of current, converts this pressure to electric signal, and by measuring staff the electric signal that records is sent to amplification system.The electric signal that is sent to amplification system is sent to converter 2 after circuit compensation, amplification.In addition, also be provided with clearing device 14, be used for before measurement, regulating the drift of instrument in water flow detector 1 outside.

Because the object of measuring is the current of high concentration, the length of pressure guiding pipe 4 and internal diameter size become the key of decision measurement data accuracy.According to flow field boundary layer theory and numerical simulation result in the fluid mechanics, under the condition of the equal uniform flow of fluid, make in the water 4 pairs of current of pressure guiding pipe not form additional turbulent flow and disturbance flow field, the point diameter of pressure guiding pipe 4 generally can not surpass 2-3mm, pipe thickness is no more than 0.5mm, and the determining of this numerical value guaranteed the current meter distortionless prerequisite of sampling.In addition, the length of pressure guiding pipe 4 also is a factor of left and right sides measurement accuracy.The present invention is based on the experiment of flow field analysis and repeated multiple times, determine that finally the length of pressure guiding pipe 4 should remain between the 8-12cm, the data that record are more satisfactory.

As shown in Figure 3, be the cross-sectional view in pressure-sensitive chamber 5.The pressure-sensitive chamber 5 outer bullet shaped that form are a cavity in the middle of it.As figure, on one side pressure-sensitive chamber 5 tips are upstream face, this face straight down when surveying.The cavity in pressure-sensitive chamber 5 is divided into two cavitys by elastic beam 6, and the cavity of upstream face direction is water-filling pressure-sensitive chamber 7, and the cavity of an other end is air pressure-sensitive chamber 8.Offer charging pipe 9 on the upstream face, be communicated with water-filling pressure-sensitive chamber 7.Charging pipe 9 other ends are communicated with the aqueduct 10 in pressure guiding pipe 4 and the measuring staff.Aqueduct 10 is a flexible pipe, charges into clear water in aqueduct 10 and clamp when measuring, and making becomes a closed system that is full of clear water in the aqueduct 10, promptly keep the static pressure state of water in this closed system.8 one sides offer snorkel 11 in the air pressure-sensitive chamber in pressure-sensitive chamber, are used for being communicated with the wireway 13 in air pressure-sensitive chamber 8 and the measuring staff.Described aqueduct 10 and wireway 13 all are communicated to waterborne through measuring staff.

Elastic beam 6 is easy to the barrier film of deformation for one deck, and its can be according to the different and corresponding generation deformation of the pressure of both sides cavity.On the sidewall of the air pressure-sensitive chamber of elastic beam 68 one sides, be stained with pressure-sensitive chip 12.Pressure-sensitive chip 12 can change the generation electric signal according to the deformation of elastic beam 6.The suffered pressure of this electric signal and elastic beam 6 is linear.This electric signal is sent to the amplification system on water flow detector 1 top through snorkel 11, wireway 13.Elastic beam 6 and pressure-sensitive chip 12 are the core pressure-sensitive parts of current meter of the present invention, and its sensitivity directly has influence on the accuracy that finally records data.For guarantee to record data accurately, the elastic beam 6 in the present embodiment is that the phosphor-copper material that adopts thickness to be no more than 0.5mm is made, and pressure-sensitive chip 12 chip that also to be the monocrystalline silicon that adopts thickness to be no more than 0.5mm make.Because the outstanding resilient characteristic of phosphor-copper material itself, and the ultra-thin design of elastic beam 6 and pressure-sensitive chip 12, this strengthens the accuracy of current meter measurement greatly.

In the present embodiment, the flow velocity computing formula of computing machine 3 flow rate of water flow calculation procedures draws by the test of clear water calibration.So-called clear water calibration test is to make current meter obtain the electric signal that pressure-sensitive chip 12 produced and the match relation function of actual flow rate of water flow by measuring the clear water flow velocity.Because such funtcional relationship is to determine that by elastic beam 6 and material, the structure of pressure-sensitive chip 12 not because of the survey current are that clear water or high concentration water change, resulting relation function gets final product in the computing formula of substitution high concentration current flow velocity.

When measuring current, total external pressure that current meter pressure guiding pipe 4 is subjected to is

$P=A{\mathrm{\γ}}_m(y+\frac{u^2}{2g})---\left(1\right)$

In the formula: y, u are respectively the measuring point depth of water and flow velocity; Pressure guiding pipe 4 compression areas $A=\frac{1}{4}{\mathrm{\&pi;<figure-callout\; id="2"\; label="r"\; filenames="C20061016528700111.png"\; state="\{\{state\}\}">r</figure-callout>}}^2,$ R is the internal diameter of pressure guiding pipe 4; γ _mUnit weight for the high concentration current.

According to pressure-sensitive chip 12 principle of work of current meter, pressure guiding pipe 4 total external pressure P should be linear with output voltage V, promptly

$P=A{\mathrm{\&gamma;}}_m(y+\frac{u^2}{2g})=a_{1}V+b_1---\left(2\right)$

So the resultant action head that pressure guiding pipe 4 is subjected in the high concentration current also can be expressed as

$Y=y+\frac{u^2}{2g}=\frac{1}{{\mathrm{\&rho;}}_m}(\mathrm{aV}+b)---\left(3\right)$

The flow rate of water flow that can draw pressure guiding pipe 4 probe measuring point places thus is

$u=\sqrt{2g[\frac{1}{{\mathrm{\&rho;}}_m}(\mathrm{aV}+b)-y]}---\left(4\right)$

ρ in the formula _mDensity for the high concentration current.

Wherein, coefficient $a=\frac{a_1}{\mathrm{Ag}},$ $b=\frac{b_1}{\mathrm{Ag}}$ All determined by the actual measurement of calibration instrument by the clear water test.

In the present embodiment, adopt ripe current meter to measure in the clear water fluid the fixedly flow velocity of measuring point, and by calculating the resultant action head that current meter measuring point of the present invention place is subjected in the clear water, and set up the linear relationship of itself and pressure-sensitive chip 12 output voltages.By fitting method, obtain fit equation:

$Y=y+\frac{u^2}{2g}=\mathrm{mV}+n---\left(5\right)$

Formula (5) and formula (3) are compared, obtain coefficient $\frac{1}{\mathrm{\&rho;}}a=m,$ $\frac{1}{\mathrm{\&rho;}}b=n,$ Substitution formula again (4) can draw the velocity formula of high concentration current current-meter rating:

$u=\sqrt{2g[\frac{\mathrm{\&rho;}}{{\mathrm{\&rho;}}_m}(\mathrm{mV}+n)-y]}---\left(6\right)$

In the formula: V is the current meter output voltage; ρ, ρ _mBe respectively the density of clear water and high concentration current.From formula (6), need only high concentration water's current density ρ of given measured place as can be seen _mCan obtain calculating the water velocity at measuring point place by the accurate parameter of measuring of existing method with these two of measuring point depth of water y according to pressure-sensitive chip 12 output voltages.

Because material, the structure of elastic beam 6 and pressure-sensitive chip 12 are not quite similar, and test resulting physical relationship function by calibration and also are not quite similar.So protection scope of the present invention should not only be confined to the computing formula of formula (6).And it is all by adopting above-mentioned clear water calibration test to determine to be considered as the method for velocity formula within protection scope of the present invention.

The concrete steps of using pressure sensing type current meter of the present invention to measure high concentration current flow velocity are:

1. measure high concentration water's current density ρ to be measured _m

2. charge into clear water by aqueduct 10 for 7 kinds to water-filling pressure-sensitive chamber, after waiting to be full of aqueduct 10 is clamped, make in aqueduct 10, water-filling pressure-sensitive chamber 7, charging pipe 9 and the pressure guiding pipe 4 and form a closed system that is full of clear water;

3. regulate the drift of current meter by clearing device 14;

4. water flow detector 1 vertically is positioned in the water to be measured, and measures the measuring point depth of water y that 1 location of water flow detector is put;

5. institute is surveyed high concentration water's current density ρ _mIn the flow velocity calculation procedure of being deposited with measuring point depth of water y parameter input computing machine 3;

6. open converter 2, make computing machine 3 receive the pressure-sensitive electric signal that records by pressure-sensitive chip 12, and calculate the flow velocity of the current of surveying by computing machine 3 by the flow velocity calculation procedure.

Claims (8)

1. a pressure sensing high-concentration water flow hydrodynamometer is characterized in that: comprise water flow detector, converter;

Described water flow detector comprises pressure guiding pipe and pressure-sensitive chamber; Described pressure guiding pipe is a hollow elongated tubular; Described pressure-sensitive chamber is a cavity, and by elastic beam this cavity is divided into water-filling pressure-sensitive chamber and air pressure-sensitive chamber; Described water-filling pressure-sensitive chamber is communicated with pressure guiding pipe by the set charging pipe of wall; Described water-filling pressure-sensitive chamber also is connected with aqueduct by charging pipe, and this aqueduct is communicated to waterborne; Described air pressure-sensitive chamber is connected with wireway and is communicated with atmosphere; Air pressure-sensitive chamber one side of described elastic beam is connected with pressure-sensitive chip; Described pressure-sensitive chip produces electric signal according to the pressure that elastic beam is subjected to;

Described converter is connected with computing machine, sends described electric signal to computing machine.

2. pressure sensing high-concentration water flow hydrodynamometer according to claim 1, it is characterized in that: described elastic beam is one deck barrier film; Described elastic beam can produce deformation according to suffered pressure.

3. as pressure sensing high-concentration water flow hydrodynamometer as described in the claim 2, it is characterized in that: the barrier film of described elastic beam for making by phosphor-copper.

4. pressure sensing high-concentration water flow hydrodynamometer as claimed in claim 1 or 2, it is characterized in that: the pressure that electric signal that described pressure-sensitive chip produced and elastic beam are subjected to is linear.

5. pressure sensing high-concentration water flow hydrodynamometer according to claim 1, it is characterized in that: described pressure guiding pipe is the curved long tube of a hollow; The nozzle diameter scope of pressure guiding pipe is between 2-3mm; Pipe range is between 8-12cm.

6. pressure sensing high-concentration water flow hydrodynamometer according to claim 1 is characterized in that: also be in series with amplification system between described pressure-sensitive chip and converter, be used to compensate, amplify the electric signal that described pressure-sensitive chip produces.

7. method of measuring high concentration current flow velocity, this method realizes that by the described pressure sensing high-concentration water flow hydrodynamometer of claim 1 its concrete steps are:

(1) measures high concentration water's current density to be measured;

(2) in water-filling pressure-sensitive chamber, charge into clear water by charging pipe, with the charging pipe sealing, make and form a closed system that is full of clear water in charging pipe, water-filling pressure-sensitive chamber, the pressure guiding pipe after waiting to be full of;

(3) water flow detector vertically is positioned in the high concentration current to be measured, and measures the measuring point depth of water that water flow detector institute location is put;

(4) in the flow velocity calculation procedure that survey high concentration water current density and measuring point depth of water parameter input computing machine is deposited;

(5) open converter, make computing machine receive the pressure-sensitive electric signal that records by pressure-sensitive chip, and calculate the flow velocity of the current of surveying by computing machine by the flow velocity calculation procedure.

8. the method for measurement high concentration current flow velocity as claimed in claim 7 is characterized in that: the flow velocity calculation procedure in the described step (4) is determined by following step:

(1) measures the flow rate of water flow of somewhere clear water by having current meter now;

(2) pressure guiding pipe of pressure sensing high-concentration water flow hydrodynamometer is fixed in the measuring point place of flow rate of water flow that above-mentioned existing current meter is surveyed, measures the electric signal that pressure-sensitive chip produced;

(3) water velocity of measuring by existing current meter, and the computing formula of current dynamic pressure, the electric signal that the match pressure-sensitive chip produces and the funtcional relationship of current dynamic pressure;

(4) electric signal that produces of the pressure-sensitive chip that obtains by step (3) and the funtcional relationship and the flow rate of water flow computing formula of current dynamic pressure are determined the flow velocity calculation procedure.

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