CN218825932U - Comprehensive measuring device for liquid surface tension coefficient and liquid viscosity coefficient - Google Patents
Comprehensive measuring device for liquid surface tension coefficient and liquid viscosity coefficient Download PDFInfo
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- CN218825932U CN218825932U CN202223051708.9U CN202223051708U CN218825932U CN 218825932 U CN218825932 U CN 218825932U CN 202223051708 U CN202223051708 U CN 202223051708U CN 218825932 U CN218825932 U CN 218825932U
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Abstract
The utility model relates to a liquid surface tension coefficient and liquid viscosity coefficient integrated determination device. The utility model discloses a U type differential pressure gauge, capillary, pressure boost pressure relief device, two pressure regulating steady voltage containers. The pressure regulating and stabilizing container comprises an annular barrel body and an upper cover which are sealed through a flange, a high-level connector and a low-level connector are arranged on the side wall of the barrel body, and the low-level connector is arranged close to the bottom; the bottom of the air inlet is vertically provided with an air inlet column, and the opening position of the top end of the air inlet column is lower than the high-level connecting port; the upper cover is provided with a working hole. The high-level connectors of the two pressure-regulating and pressure-stabilizing containers are communicated through a hose. The utility model discloses improved the experiment principle, got rid of the experiment interference factor that arouses the error to reduce the experiment error through the data fitting. Through simply changing device equipment mode, can also measure the viscosity coefficient of liquid, the experimental result is ideal, has realized integrative dual-purpose.
Description
Technical Field
The utility model belongs to the technical field of teaching experiment instrument, a liquid surface tension coefficient and liquid viscosity coefficient integrated determination device is related to.
Background
The liquid contacts with air to form a surface layer, and the liquid molecules in the surface layer are attracted by the molecules in the liquid more than by the air molecules, so that the liquid has the tendency of reducing the surface area. This force that reduces the surface area of a liquid is called the surface tension of the liquid, and the surface tension coefficient is the surface tension acting on the surface of the liquid per unit length. The viscosity coefficient of a liquid is an important physical quantity that describes the nature of the friction in a liquid and is only manifested when there is relative motion in the liquid. Liquid surface tension and liquid viscosity are of great importance in many industrial sectors and in the field of scientific research.
In the course of university physics basic experiments, measuring the surface tension coefficient of liquid and measuring the viscosity coefficient of liquid are important experiments. The methods for measuring the surface tension coefficient of a liquid include a pull-off method, a capillary rise method, a liquid drop weight measurement method, and the like. The capillary rise method is one of the most accurate methods for measuring the surface tension of a liquid by utilizing the capillary action. The method for measuring the viscosity coefficient of the liquid comprises a falling ball method and a capillary tube method.
The invention patent application with the application number of CN202111108129.0 discloses a surface tension optical measuring system and a method based on capillary phenomenon, which comprises a base, a first slide block and a second slide block, wherein the first slide block and the second slide block are arranged on the base and are used for adjusting the distance between an industrial camera and a cuvette so as to acquire a required picture; and the first lifting rod and the second lifting rod are used for adjusting the fine adjustment of the horizontal height between the borne industrial camera and the cuvette. Through multiple adjustments of the vertical height and the horizontal direction, after the capillary liquid level is stabilized, the capillary liquid level is shot and processed, the picture is processed for multiple times through the image collecting and processing module, and the tension information of the liquid surface to be measured is obtained through calculation according to a formula.
The invention patent application with the application number of CN201710820168.0 discloses a method for testing the surface tension coefficient of a low-pressure liquid, and different low-pressure environments are realized through a vacuum box and a vacuum pump; and based on the capillary principle, measuring the rising height of the liquid to be measured in the capillary under low-pressure air, taking the unevenness and limited surface area correction of the liquid level into consideration, and calculating the liquid surface tension coefficient according to the liquid density, the inner and outer diameters of the capillary, the contact angle between glass and the liquid and the inner diameter of the beaker.
A height measuring instrument is needed in the traditional capillary tube rising method in the experimental process, the measuring operation difficulty is high, and the operation steps are complex. Meanwhile, the liquid column is greatly influenced by the friction of the inner wall of the capillary and the friction among liquid layers in the ascending process in the capillary, and the liquid column cannot reach the ideal height. In addition, before the experiment, if the capillary removes the infiltration improper operation, the capillary inner wall hangs the drop of water, and the liquid column rises the process and can have the slip phenomenon, leads to the measurement of liquid column height to have the error.
Disclosure of Invention
An object of the utility model is to provide a liquid surface tension coefficient and liquid viscosity coefficient integrated determination device to prior art not enough.
The utility model discloses a two pressure regulating steady voltage containers, a U type differential pressure gauge, a capillary that has the scale, a pressure boost pressure relief device to and rubber buffer and coupling hose. Furthermore, the pressurizing and pressure reducing device comprises a cylinder, a built-in piston and an external handle, wherein the handle is connected with the piston and manually controls the piston to move up and down in the cylinder.
The two pressure regulating and stabilizing containers have the same structure and comprise a barrel body and an upper cover; the top surface of the barrel body is open, the barrel body is transparent, the side wall of the barrel body is provided with a high-level connector and a low-level connector, and the low-level connector is arranged close to the bottom; the bottom of the barrel body is vertically provided with a ventilation column, one end of the ventilation column is opened at the bottom of the barrel body, and the opening position of the other end of the ventilation column is lower than the high-level connecting port; the edge of the upper part of the barrel body is outwards turned to form a flange ring structure, and the upper cover and the barrel body are fixed and sealed through fastening nuts; the upper cover is provided with a working hole; before assembly, the container cavity is communicated with the outside through the ventilation column, the working hole, the high-level connector and the low-level connector; the high-level connectors of the two pressure-regulating and pressure-stabilizing containers are communicated through a hose.
The utility model discloses use the measurement accuracy who improves the interior liquid column of capillary as the core, designed one set of liquid surface tension coefficient and liquid viscosity coefficient comprehensive measurement device, the device changes the height of the interior liquid column of capillary through the pressure of adjusting in the airtight container, reduces the mode of liquid level through the decompression and gets rid of the influence that friction and liquid column slided and bring. The utility model discloses improved the experiment principle, got rid of the experiment interference factor that arouses the error to reduce the experiment error through the data fitting. Experimental results show that the improved device improves the measurement precision of the surface tension coefficient of the liquid and reduces relative errors. The utility model discloses change device equipment mode simply, can also measure the viscosity coefficient of liquid, the experimental result ideal to an organic whole is dual-purpose has been realized. The device is simple and convenient to operate, high in efficiency, easy to disassemble and assemble and convenient to popularize and apply in teaching and production practice.
Drawings
FIG. 1 is a schematic view of the present invention;
fig. 2 is a schematic diagram of the pressure regulating and stabilizing vessel in fig. 1.
Detailed Description
As shown in figure 1, the comprehensive measuring device for the surface tension coefficient and the liquid viscosity coefficient of the liquid comprises two pressure-regulating and pressure-stabilizing containers 1 and 2, a U-shaped differential pressure gauge 3, a graduated capillary tube 4, a pressure-boosting and pressure-reducing device 5, a rubber plug and a connecting hose. The capillary tube 4 is a thickened capillary tube with scales, the inner diameter is 1mm, the outer diameter is 4mm, the length is 350mm, and the scale is marked on the outer wall every 0.5 mm. The pressure boosting and reducing device 5 comprises a cylinder, a built-in piston and an external handle, wherein the handle is connected with the piston, and the piston is manually controlled to move up and down in the cylinder.
As shown in FIG. 2, the two pressure-regulating and pressure-stabilizing vessels have the same structure and comprise a barrel body 11 and an upper cover 12. The top surface of the barrel body 11 is open, the barrel body is transparent, a high-level connector 13 and a low-level connector 14 are arranged on the side wall of the barrel body 11, and the low-level connector 14 is arranged close to the bottom. The bottom is vertically provided with a ventilation column 15, one end of the ventilation column 15 is opened at the bottom of the barrel body 11, and the opening position of the other end is lower than the high-level connecting port 13. The upper edge of the barrel body 11 is turned outwards to form a flange ring structure, and the upper cover 12 and the barrel body 11 are fixed and sealed through a fastening nut 16. The upper cover 12 is provided with a working hole 17. Before assembly, the cavity of the container is communicated with the outside through the ventilation column 15, the working hole 17, the high-level connector 13 and the low-level connector 14. The high-level connectors of the two pressure-regulating and pressure-stabilizing containers are communicated through a hose.
If the pressure difference between the lowest point of the liquid level in the capillary and the atmospheric pressure is delta P 0 Then according to the equilibrium relationship, there is Δ P 0 πR 2 =2 π R γ cos θ; wherein R is the capillary radius, theta is the contact angle, and gamma is the surface tension coefficient.
Assuming that the liquid rises in the capillary at atmospheric pressure to a height h 0 ，ρ Liquid for treating urinary tract infection The density of the liquid to be measured is defined as ρ Liquid for treating urinary tract infection gh 0 πR 2 =2 π R γ cos θ, i.e.
For immersion liquids (e.g., clean glass and pure water), the contact angle θ is approximately 0,cos θ =1, and thus the above equation can be simplified to
When in measurement, the height from the lowest point of the liquid level of the concave liquid in the capillary to the liquid level outside the capillary is h 0 Above this level, there is also a small volume of liquid around the concave surface, the volume of which should be equal to
I.e. equal to a high in the tube>
Of the liquid column of (a), thus, h in the above discussion 0 Shall be increased>
The correction term value of (1). Then, it is combined with>
If the pressure in the container is increased, the liquid level in the capillary will continue to rise and satisfy the formula rho Liquid for treating urinary tract infection gh 1 ＝P Applying pressure ，h 1 Is at the initial liquid column height h 0 The height of the liquid column which is continuously increased is measured by a U-shaped differential pressure gauge Applying pressure 。
Clean water is added into a U-shaped pipe of the U-shaped differential pressure gauge, so that P is Applying pressure ＝ρ Water (W) gh Difference (D) ，h Difference (D) Is the height difference of liquid column in U-shaped differential pressure meter tube, rho Water (I) Is the density of the water in the differential pressure gauge. Thus ρ Liquid for treating urinary tract infection gh 1 ＝ρ Water (W) gh Difference (D) Obtaining:
because of h 0 +h 1 ＝h Measuring ，h Measuring The method is a measurement value of the height of a liquid column in the experimental process, namely the height from a horizontal plane to the lowest point of a concave liquid surface in a capillary tube, and the formula is shifted and deformed to obtain:
simply shift the item and deform to get->
If the liquid to be measured is pure water, the formula is simpler, that is
Thus, only obtain h Side survey And h Difference (D) The intercept is obtained according to the linear relation between the two, and the surface tension coefficient gamma of the liquid can be measured.
Measurement principle of liquid viscosity coefficient experiment:
in the fluid, the interface of different flow velocity layers has tangential interaction force, and the layer with high flow velocity is subjected to opposite force and velocity directions, namely, the layer is decelerated; the layer with a small flow velocity is subjected to the same force and velocity direction, i.e. accelerated. As a result of this interaction, the relative movement is slowed down. This property of a fluid is viscosity, and this pair of forces is called internal friction.
As can be seen from experiments, the internal friction force F is in direct proportion to the contact area S between the two layers and the velocity gradient at the position
In direct proportion, namely: />
The proportionality coefficient eta is called the viscosity of the fluid and has the unit of Pa.s or N.s.m -2 。
When the fluid with viscosity eta performs laminar flow motion in a thin pipe with uniform inner diameter, the volume of the fluid flowing at the time t is
Wherein R is the capillary radius, L is the capillary length, p 1 、p 2 This equation is called Poiseup's equation, and the above equation is rewritten as: />
All the quantities on the right side of the above formula can be measured, and therefore, the viscosity of the liquid can be obtained.
The above formula should be changed to suit the actual situation of the measurement. In this experiment, the above formula should be changed slightly: in the case of multiple measurements, it is not possible to make the outflow times t, and thus V, the same for each measurement, but the volume of outflow per unit time for each measurement differs
The same is true. The volume is not easy to measure, instead the mass of the outflowing water is measured, and if the mass of the outflowing liquid in unit time is Q, then->
Therefore, the formula is rewritten as->
In the device, pressure difference exists at two ends of the capillary tube, and atmospheric pressure P is at one end 0 The other end is the internal pressure P of the liquid Measuring (i.e., the pressure to be measured) and therefore
The liquid viscosity coefficient eta can be obtained from the equation.
1. The assembling mode and the experimental process of the experiment for measuring the surface tension coefficient of the liquid are as follows:
1. assembly of the experimental set-up (container 1 on the right and container 2 on the left):
(1) In the experimental process, the liquid to be tested is distilled water.
(2) Two pressure-regulating and pressure-stabilizing containers 1 and 2 are placed on a horizontal table top.
(3) The tops of the vent posts of the containers 1 and 2 were plugged with rubber stoppers.
(4) The lower connection port of the container 2 is closed with a rubber stopper.
(5) And injecting water into the U-shaped glass tube of the U-shaped differential pressure gauge to reach half height of the U-shaped tube. The low-level connection port of the container 1 and one end of the U-shaped differential pressure gauge are connected by rubber, and the other end of the U-shaped differential pressure gauge is communicated with the atmosphere.
(6) The connecting hose is connected with the high-level through holes of the two containers.
(7) Water is added to the vessel 2 until the water level is level with the top of the vent column.
(8) The container 1 and the container 2 are closed by the upper cover, fixed and sealed by the fastening nut.
(9) The capillary is inserted into the working hole of the container 2, the lower end of the capillary extends into the liquid level, and the joint of the working hole and the capillary is sealed.
(10) The working hole of the container 1 is connected with a pressurizing and depressurizing device.
2. The measurement process comprises the following steps:
(1) The control handle pushes in the piston to increase the internal pressure of the whole container until the height of the liquid column in the capillary is slightly lower than the opening of the capillary.
(2) The control handle withdraws from the piston, the pressure intensity in the container is slowly reduced, and the piston is pushed out to enable the liquid level in the capillary tube to descend by 8-10 mm.
(3) When the U-shaped differential pressure gauge and the liquid level in the capillary tube are still, the height h of the lowest level of the concave liquid level of the liquid level in the capillary tube at the moment is read out from the scale of the capillary tube Measuring Simultaneously reading out the height difference h of the liquid column from the U-shaped differential pressure gauge Difference (D) And recording.
(4) And (4) continuing to slowly push out the piston by using the control handle, and repeating the steps 2 and 3 for a plurality of times (at least more than 10 times).
(5) And (4) taking out the capillary tube, measuring the radius R in the capillary tube by using a moving microscope, measuring for multiple times, and averaging and recording.
(6) Obtaining h by using least square method according to experimental data Measuring About h Difference (D) The intercept of the function is obtained, and the surface tension coefficient of water is calculated.
2. The assembling mode and the experimental process of the experiment for measuring the liquid viscosity coefficient are as follows:
1. assembly of the experimental set-up (container 1 on the right and container 2 on the left):
(1) The barrel body of the container 2 is placed on an iron stand.
(2) The top of the ventilating column of the container 1 is tightly sealed by a rubber plug.
(3) The low-level connection port of the container 1 is horizontally inserted into the capillary tube, and the connection port and the capillary tube are sealed. (after the connection, a liquid collecting box can be arranged below the capillary orifice, and the capillary orifice can be bound with a cotton thread for drainage).
(4) The high-level connection port of the container 1 and the low-level connection port of the container 2 are connected by a connection hose.
(5) The container 1 is closed by the upper cover, fixed and sealed by the fastening nut.
(6) The working hole of the upper cover of the container 1 is connected with one end of a U-shaped differential pressure gauge.
(7) The length of the rubber tube inserted into the working hole of the container 1 is adjusted to ensure that the tail end of the rubber tube and the capillary opening in the container are positioned on the same horizontal plane.
(8) Water is added to the vessel 2 and enters the vessel 1 through the connecting tube. And stopping adding water until the water level in the container 2 is flush with the top of the ventilating column.
(9) And observing the height difference of the liquid levels at the two ends of the U-shaped differential pressure gauge, and if the height difference of the liquid levels at the two ends of the U-shaped pipe is more than 20cm and is as small as 40cm at the moment, properly assembling. If the difference in liquid level height is too large or too small, the height of the iron stand needs to be adjusted.
(10) The whole device is kept still. And (5) stabilizing the liquid in the whole device. (Note: the water cannot be shaken or disturbed greatly, the surface of the water needs to be calm).
2. Measurement process (the indoor temperature needs to be kept stable during measurement process to keep the water temperature stable):
(1) Weighing the mass m of an empty beaker with an electronic scale 0 。
(2) The beaker is quickly moved to the capillary mouth for water receiving, and a stopwatch is pressed for timing while the water receiving is started.
(3) The time is timed for 60 seconds. The beaker was removed quickly at 60 seconds time one.
(4) Weigh mass m of beaker and water 1 And recording.
(5) The beaker was drained and the beaker was wiped dry with absorbent paper. (Note: during operation, water is added to the vessel 2 from time to ensure that the liquid level in the vessel 2 is always level with the top of the column).
(6) Repeat steps 1-6 and measure 4 groups.
(7) The time interval in step 4 was changed to 30 seconds and 45 seconds, and steps 1-7 were repeated.
(8) Reading the atmospheric pressure P in the chamber by a pressure sensor (or mercury differential pressure gauge) 0 (ii) a Measuring the radius R of the capillary tube by using a moving microscope; reading P from U-type differential pressure gauge Measuring (ii) a Measuring the length L of the capillary tube by using a ruler; the liquid temperature T is measured with a thermometer.
(9) The liquid viscosity coefficient at T ℃ and its standard uncertainty were calculated.
Finally, it should be noted that: it will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; although the invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that any reference signs in the claims shall not be construed as limiting the claim concerned.
Claims (2)
1. The device for comprehensively measuring the surface tension coefficient and the viscosity coefficient of the liquid is characterized in that: comprises two pressure regulating and stabilizing containers, a U-shaped differential pressure gauge, a capillary tube with scales, a pressure boosting and reducing device, a rubber plug and a connecting hose;
the two pressure regulating and stabilizing containers have the same structure and comprise a barrel body and an upper cover; the top surface of the barrel body is open, the barrel body is transparent, the side wall of the barrel body is provided with a high-level connector and a low-level connector, and the low-level connector is arranged close to the bottom; the bottom of the barrel body is vertically provided with a ventilation column, one end of the ventilation column is opened at the bottom of the barrel body, and the opening position of the other end of the ventilation column is lower than the high-level connecting port; the edge of the upper part of the barrel body is turned outwards to form a flange ring structure, and the upper cover and the barrel body are fixed and sealed through fastening nuts; the upper cover is provided with a working hole; before assembly, the container cavity is communicated with the outside through the ventilation column, the working hole, the high-level connector and the low-level connector; the high-level connectors of the two pressure-regulating and pressure-stabilizing containers are communicated through a hose.
2. The apparatus for comprehensively measuring the surface tension coefficient and the viscosity coefficient of a liquid according to claim 1, wherein: the pressurizing and depressurizing device comprises a cylinder, a built-in piston and an external handle, wherein the handle is connected with the piston, and the piston is manually controlled to move up and down in the cylinder.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202223051708.9U CN218825932U (en) | 2022-11-16 | 2022-11-16 | Comprehensive measuring device for liquid surface tension coefficient and liquid viscosity coefficient |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202223051708.9U CN218825932U (en) | 2022-11-16 | 2022-11-16 | Comprehensive measuring device for liquid surface tension coefficient and liquid viscosity coefficient |
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| CN218825932U true CN218825932U (en) | 2023-04-07 |
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| CN202223051708.9U Active CN218825932U (en) | 2022-11-16 | 2022-11-16 | Comprehensive measuring device for liquid surface tension coefficient and liquid viscosity coefficient |
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