CN113777260A - Device and method for testing liquid evaporation rate under gas circulation - Google Patents
Device and method for testing liquid evaporation rate under gas circulation Download PDFInfo
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- 238000001704 evaporation Methods 0.000 title claims abstract description 311
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- 238000012360 testing method Methods 0.000 title claims abstract description 120
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 38
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- 238000004364 calculation method Methods 0.000 claims description 8
- 238000010438 heat treatment Methods 0.000 claims description 8
- 238000001035 drying Methods 0.000 claims description 7
- 230000007613 environmental effect Effects 0.000 claims description 4
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- 238000013022 venting Methods 0.000 claims description 4
- 238000002474 experimental method Methods 0.000 claims description 3
- 238000012544 monitoring process Methods 0.000 claims description 3
- 238000010998 test method Methods 0.000 claims 1
- 239000007789 gas Substances 0.000 description 84
- 238000005303 weighing Methods 0.000 description 11
- 238000005259 measurement Methods 0.000 description 9
- 238000007605 air drying Methods 0.000 description 8
- 230000007246 mechanism Effects 0.000 description 8
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 6
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- 230000009286 beneficial effect Effects 0.000 description 2
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- 230000007547 defect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
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- 239000012267 brine Substances 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
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- HPALAKNZSZLMCH-UHFFFAOYSA-M sodium;chloride;hydrate Chemical compound O.[Na+].[Cl-] HPALAKNZSZLMCH-UHFFFAOYSA-M 0.000 description 1
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- G—PHYSICS
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N25/00—Investigating or analyzing materials by the use of thermal means
- G01N25/56—Investigating or analyzing materials by the use of thermal means by investigating moisture content
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Abstract
The invention provides a testing device and a testing method for liquid evaporation rate under gas circulation, wherein the testing device comprises an evaporation container, a liquid injection valve, a liquid level meter, a flow control unit, a constant temperature control unit, a pressure control unit, a dew point control unit and an air release valve, wherein the flow control unit is arranged at an inlet of the evaporation container so as to change the gas flow in the evaporation container; the constant temperature control unit is arranged outside the evaporation container to change the temperature of the liquid in the evaporation container; a pressure control unit disposed at an outlet of the evaporation vessel to change an internal pressure of the evaporation vessel; the dew point control unit is arranged at the inlet of the evaporation container to change the dew point of the circulating gas. The testing device and the testing method for the liquid evaporation rate under the gas circulation can measure the water evaporation rate under different dry air parameters and flow field parameters, and have the advantages of various testing conditions, short measuring time and small measuring error.
Description
Technical Field
The invention relates to the technical field of liquid evaporation rate testing devices, in particular to an evaporation rate testing device under dry air circulation and a testing method thereof.
Background
The newly-built natural gas pipeline may have hidden troubles and defects, so pressure testing is required before production. When water is used as a pressure testing medium, residual liquid water and water vapor in a pipeline after pressure testing can cause great harm to the safe operation of the pipeline, such as the pipeline conveying efficiency is reduced, hydrate is generated, parts such as a valve and a filter are blocked, the pipeline conveying natural gas is unqualified, and the residual water is difficult to remove in a simple pipeline cleaning mode, so that the pipeline must be dried.
At present, a dry air drying method is the most commonly applied method for drying a natural gas pipeline, and in order to perfect the theoretical basis and wide applicability of the dry air drying method, a water evaporation rate testing device needs to be invented to reflect the influence of the dew point, flow rate, ambient temperature and other factors of dry air on the drying effect of the dry air, so as to obtain a function model of the drying rate of the dry air and guide the relevant research work of the drying technical index of the dry air method.
However, although the indoor weighing method is mostly used for the research on the water evaporation efficiency, the weighing sensor is greatly affected by external environmental factors, and the measurement using the weighing method has a large error. And conventional measuring device does not have the function of controlling parameters such as liquid surface gas flow velocity and ambient temperature during evaporation, and the test condition is single. For example, patent document CN 204988929U, entitled weighing device for moisture evaporation rate test, published in 2016, 1, 20, describes a weighing device for moisture evaporation rate test, which includes a frame, a weighing device, an elevating mechanism and a rotating mechanism, wherein the rotating mechanism is rotatably disposed on the frame, the elevating mechanism is disposed on the frame and located below the rotating mechanism, and the weighing device is suspended on the frame and located on one side of the rotating mechanism. Although the device realizes the weighing of the moisture evaporation rate test through the coordination work of the weighing device, the lifting mechanism and the rotating mechanism, the test working condition is single, and the test conditions under different complex working conditions can not be met. A device and a method for measuring evaporation rate under multi-factor coupling action are disclosed in No. CN 110954435A, which is published in No. 4/3/2020, wherein the weighing system comprises an electronic balance, a data acquisition system, a suspender and a basket, the heating system comprises a heating furnace body, a lifting device, a thermocouple and a temperature controller, the reactor system comprises an annular cooling sampling tube and an airflow blowing three-layer reactor which are connected through a frosted opening, the electronic day is horizontally arranged on the top of a device rack, the data acquisition system is connected with a computer signal connected with the electronic balance through a data line, the basket is suspended in the reactor through the suspender, the heating furnace body is arranged on a lifting screw rod of the device rack, the annular cooling sampler is fixed at the middle upper position of the device rack through a fixing frame, the airflow blowing three-layer reactor is arranged in the central part of the heating furnace body. Although the device can measure the evaporation rate of the sample at different temperatures and wind speeds, the measuring method is a weighing method, and large measuring errors are easy to occur.
Therefore, the invention needs to invent a water evaporation rate testing device and a testing method, overcomes the defects of large measurement error and single testing working condition in the prior art, can realize high-precision measurement in a short time, and meets the testing conditions of different working conditions.
Disclosure of Invention
The present invention aims to address at least one of the above-mentioned deficiencies of the prior art. For example, it is an object of the present invention to provide a device and a method for testing the evaporation rate of a liquid under gas flow, which can satisfy the test conditions of different working conditions.
In order to achieve the above object, the present invention provides a device for testing a liquid evaporation rate under gas circulation, the device for testing a liquid evaporation rate under gas circulation comprising an evaporation container, a liquid filling valve, a liquid level meter, a flow control unit, a thermostatic control unit, a pressure control unit, a dew point control unit and an air release valve, wherein the evaporation container comprises an inlet pipe section, an evaporation main body pipe section and an outlet pipe section which are arranged from left to right in sequence, the tops of the inlet pipe section, the evaporation main body pipe section and the outlet pipe section are all located on the same horizontal plane, the inner diameter of the evaporation main body pipe section is larger than that of the outlet pipe section so as to prevent a liquid to be tested from being blown into the outlet pipe section, and the aspect ratio of the inlet pipe section is larger than or equal to 12.5 so that gas can sufficiently flow before entering the evaporation main body pipe section; the lower part of the evaporation main body pipe section is provided with a liquid injection valve so as to inject or discharge liquid to be tested into the evaporation container; the liquid level meter is arranged on one side of the evaporation main body pipe section to measure the liquid level change in the evaporation container within preset time; the flow control unit is arranged in the inlet pipe section and can change the gas flow at the inlet of the evaporation container so as to test the liquid evaporation rate at different gas flow rates; the constant temperature control unit is arranged outside the evaporation main body pipe section and can control the temperature of liquid to be tested in the evaporation main body pipe section to be constant at a preset temperature so as to test the evaporation rate of the liquid at different environmental temperatures; the pressure control unit is arranged in the outlet pipe section and can change the pressure inside the evaporation container so as to test the evaporation rate of the liquid under different container pressures; the dew point control unit is connected with the inlet pipe section and can provide flowing gas with different dew points for the evaporation container so as to test the evaporation rate of liquid at different gas dew points; the vent valve is disposed in the outlet tube section and is capable of venting the gas within the vaporization container after the test is completed.
In one exemplary embodiment of the apparatus for testing the evaporation rate of a liquid under gas circulation of the present invention, the cross-section of the evaporation vessel may be circular or square, and the inner diameter of the evaporation body pipe section is larger than that of the inlet pipe section, the inner diameter of the inlet pipe section may be larger than that of the outlet pipe section, the liquid to be tested may be water, and the gas may be dry air.
In an exemplary embodiment of the apparatus for testing the evaporation rate of a liquid under gas circulation of the present invention, the liquid level meter may be a magnetostrictive liquid level meter, and the magnetostrictive liquid level meter is communicated with the evaporation main body pipe section through a liquid level valve.
In an exemplary embodiment of the device for testing the evaporation rate of a liquid under gas circulation of the present invention, the flow control unit may include a throttle valve capable of controlling the gas flow rate at the inlet of the evaporation container by changing the opening degree of the throttle valve, and a flow meter capable of monitoring the gas flow rate at the inlet of the evaporation container.
In an exemplary embodiment of the apparatus for testing the liquid evaporation rate under gas circulation according to the present invention, the constant temperature control unit may include a heat exchanger, a circulation pipe, and a constant temperature circulation control system, the heat exchanger is disposed outside the evaporation main pipe section and connected to the constant temperature circulation control system through the circulation pipe to maintain the temperature of the liquid to be tested in the evaporation main pipe section equal to the temperature of the heat exchange medium, the constant temperature circulation control system includes a heating part, a cooling part, and a circulation pump therein, and is capable of controlling the temperature of the circulating heat exchange medium to be constant at a predetermined temperature; the device for testing the liquid evaporation rate can also comprise a temperature sensor, wherein the temperature sensor is arranged at the lower part of the evaporation main body pipe section and can monitor the temperature of the liquid to be tested in the evaporation main body pipe section.
In an exemplary embodiment of the apparatus for testing a liquid evaporation rate under gas circulation of the present invention, the pressure control unit may include a back pressure valve provided in the outlet pipe section and capable of controlling the amount of pressure inside the evaporation vessel; the testing device further comprises a pressure gauge, wherein the pressure gauge is installed on the upper portion of the evaporation main body pipe section and can monitor the internal pressure in the evaporation main body pipe section.
In an exemplary embodiment of the apparatus for testing a liquid evaporation rate under gas circulation of the present invention, the dew point control unit may include a gas supply device provided at an inlet side of the evaporation vessel, connected to the inlet pipe section to supply the evaporation vessel with circulation gas of different dew points; the test device also includes a dew point meter mounted in the outlet pipe section and capable of monitoring the gas dew point in the evaporation body pipe section.
In an exemplary embodiment of the device for testing the evaporation rate of a liquid under gas circulation, the device may further include a transparent window disposed on a side wall of the evaporation main body pipe section, and the transparent window may be capable of observing the liquid level change of the liquid to be tested during the experiment.
The invention also provides a method for testing the liquid evaporation rate under gas circulation, wherein the liquid evaporation rate is obtained by measuring with the testing device, and the method comprises the following steps:
s1, building a device for testing the liquid evaporation rate under the gas circulation, connecting an external gas supply pipeline with an evaporation container, and connecting an external liquid injection pipeline with a liquid injection valve;
s2, after the liquid to be tested with the testing dosage is injected into the evaporation container, the liquid injection valve is closed, and the first liquid level of the liquid level meter before the liquid is evaporated is recorded;
s3, starting a constant temperature control unit, setting a test temperature, starting a dew point control unit, introducing gas with a preset dew point into an evaporation container, controlling the gas flow and the container pressure through a flow control unit and a pressure control unit, and recording the liquid temperature, the gas dew point, the gas flow and the container pressure in the liquid evaporation process;
s4, stopping supplying air after a preset time, opening an emptying valve, and recording a second liquid level of the liquid level meter after the liquid is evaporated after the pressure in the evaporation container is restored to the atmospheric pressure;
s5, calculating the evaporation rate of the liquid to be tested under the specified liquid temperature, gas dew point, gas flow and container pressure according to the calculation formula of the evaporation rate, wherein the calculation formula of the evaporation rate is as follows:
wherein w is the evaporation rate per unit area of the liquid to be tested, g/(cm)2.s)；ρwIs the density, g/cm, of the liquid to be tested under experimental conditions3；S1Is the internal cross-sectional area of the liquid level meter, cm2；S2Is the bottom area, cm, of the evaporation container2；H1Is a first liquid level, cm, before the liquid to be tested evaporates; h2The second liquid level, cm, of the liquid to be tested after evaporation; t is the test time, s.
In one exemplary embodiment of the method for testing the evaporation rate of a liquid under gas circulation of the present invention, the method may further comprise:
s6, repeating the steps S2 to S5, and respectively testing the liquid evaporation rate at different liquid temperatures, the liquid evaporation rate at different gas dew points, the liquid evaporation rate at different gas flow rates and the liquid evaporation rate at different container pressures to obtain a function model of the drying rate of the liquid to be tested under gas circulation.
Compared with the prior art, the beneficial effects of the invention comprise at least one of the following:
(1) the testing device for the liquid evaporation rate under gas circulation provided by the invention can realize the measurement of the water evaporation rate under different dry air parameters and flow field parameters, and has the advantages of various testing conditions, short testing time, high precision and small error;
(2) the method for testing the liquid evaporation rate under gas circulation can reflect the influence of the dew point, flow rate, environment temperature and other factors of dry air on the dry air drying effect, thereby obtaining a function model of the dry air drying rate to guide the related research work of the dry air drying technical indexes;
(3) the device and the method for testing the liquid evaporation rate under gas circulation provided by the invention are also suitable for the research on the evaporation rate in other fields, have various working conditions and have wide application prospects.
Drawings
The above and other objects and/or features of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings, in which:
fig. 1 shows a schematic configuration diagram of a test device for water evaporation rate in dry air circulation of an exemplary embodiment of the test device for liquid evaporation rate in gas circulation of the present invention.
Description of reference numerals:
1-a throttle valve, 2-a flowmeter, 3-a magnetostrictive liquid level meter, 4-a first liquid level valve, 5-a second liquid level valve, 6-a circulating water pipe, 7-a thermostatic circulation control system, 8-an evaporation container, 9-a pressure gauge, 10-a double-pipe heat exchanger, 11-a dew point instrument, 12-an emptying valve, 13-a back pressure valve, 14-a transparent window, 15-a temperature sensor and 16-a water injection and discharge valve.
Detailed Description
Hereinafter, the apparatus for testing the evaporation rate of a liquid under gas flow-through and the method for testing the same according to the present invention will be described in detail with reference to the exemplary embodiments.
It should be noted that "first", "second", "third", "fourth", etc. are merely for convenience of description and for convenience of distinction, and are not to be construed as indicating or implying relative importance. "left", "right", "front", "back", "upper" and "lower" are merely for convenience of description and to constitute relative orientations or positional relationships, and do not indicate or imply that the components referred to must have that particular orientation or position. For those of ordinary skill in the art, the term "pressure" in part herein corresponds to pressure.
The invention provides a device for testing the evaporation rate of liquid under gas circulation. In an exemplary embodiment of the present invention, the liquid evaporation rate test device under gas flow may include an evaporation vessel, a liquid filling valve, a liquid level meter, a flow control unit, a thermostatic control unit, a pressure control unit, a dew point control unit, and an air release valve.
Specifically, the evaporation vessel has an inlet pipe section, an evaporation body pipe section, and an outlet pipe section arranged in this order from left to right. Here, "left" means a side close to the inlet of the evaporation vessel, "right" means a side close to the outlet of the evaporation vessel, and left to right means a direction in which the ventilation gas flows from the inlet of the evaporation vessel to the outlet of the evaporation vessel. Wherein the top of the inlet pipe section, the top of the evaporation main body pipe section and the top of the outlet pipe section are all positioned on the same horizontal plane, and the inner diameter of the evaporation main body pipe section is larger than that of the outlet pipe section (namely D)Outlet pipe section<DEvaporation main body pipe section) To prevent the liquid to be tested from being blown into the outlet pipe section. The length-width ratio of the inlet pipe section is greater than or equal to 12.5, namely, the length of the inlet pipe section is at least 12.5 times of the pipe diameter of the inlet pipe section, so that the gas can flow fully before entering the evaporation main body pipe section, and the full development of a flow field is ensured. Preferably, the optimal length of the actual inlet pipe section is 40 inlet pipe section diameters. The cross section of the evaporation container can be round or square, for example, the evaporation container can be a square pipe, and the evaporation main pipe section of the evaporation container is a cuboid flow channel; the evaporation container can also be a round pipe, and the evaporation main body pipe section of the evaporation container is a cylindrical flow channel.
Further, the inner diameter of the evaporation body section may be greater than the inner diameter of the inlet section, and the inner diameter of the inlet section may be greater than the inner diameter of the outlet section (i.e., D)Outlet pipe section<DInlet pipe section<DEvaporation main body pipe section) So that the liquid to be tested can be stored in the evaporation main body pipe section in a concentrated manner, and the flow field in the inlet pipe section can be ensuredWith sufficient development, it is also possible to make the central position at the inlet of the evaporation vessel higher than the outlet, so that it is possible to prevent the liquid to be tested from being blown out of the evaporation vessel, thereby causing testing errors.
The liquid to be tested injected into the evaporation main body pipe section of the evaporation container can be water, and can also be other evaporation liquids, such as brine, petrochemical liquid and the like; the gas flowing through the inlet line section of the evaporator vessel can be dry air or else another gas flowing through, for example CO2、N2And the like.
The lower part of the evaporation main body pipe section is provided with a liquid injection valve so as to inject or discharge liquid to be tested into the evaporation container. For example, a liquid injection valve may be disposed at the bottom of the evaporation main body pipe section of the evaporation container, and externally connected to a pipe for the liquid to be tested, for injecting or discharging the liquid to be tested into the evaporation container.
The liquid level meter is installed at one side of the evaporation main body pipe section to measure the liquid level change in the evaporation vessel for a predetermined time, thereby calculating the liquid evaporation rate. The liquid level meter can be arranged at the inlet side of the evaporation main body pipe section, and can also be arranged at the outlet side of the evaporation main body pipe section. A liquid level valve can be arranged between the liquid level meter and the evaporation main body pipe section so as to cut off the communication between the liquid level meter and the liquid level in the evaporation main body pipe section at any time, thereby accurately measuring the liquid level change in the evaporation container within a certain time. For example, the level gauge may be a magnetostrictive level gauge with a measurement accuracy of ± 0.5 mm. The magnetostrictive liquid level meter can be installed on the inlet side of the evaporation main body pipe section of the evaporation container, and is provided with a first liquid level valve and a second liquid level valve for controlling the communication between the magnetostrictive liquid level meter and the evaporation container.
The flow control unit is disposed in the inlet tubing section and is capable of varying the gas flow at the inlet of the vaporization vessel to test the rate of liquid vaporization at different gas flow rates. For example, the flow control unit may include a throttle valve and a flow meter, the throttle valve may be disposed at the front end of the inlet pipe section, and a flow meter may be connected behind the throttle valve, the throttle valve may control the gas flow at the inlet of the evaporation container by changing the opening degree of the throttle valve, and the flow meter may measure the gas flow at the inlet of the evaporation container. Preferably, the flowmeter can be a high-precision and high-reliability waist wheel flowmeter.
The constant temperature control unit is arranged outside the evaporation main body pipe section and can control the temperature of liquid to be tested in the evaporation main body pipe section to be constant at a preset temperature so as to test the evaporation rate of the liquid at different environmental temperatures. For example, the thermostatic control unit may include a heat exchanger, a circulation tube, and a thermostatic circulation control system. The heat exchanger is arranged outside the evaporation main body pipe section and is connected with the constant-temperature circulation control system through the circulating pipe so as to maintain the temperature of the liquid to be tested in the evaporation main body pipe section to be equal to the temperature of the heat exchange medium in the constant-temperature circulation control system. The constant-temperature circulation control system can internally comprise a heating part, a refrigerating part and a circulating pump, and can control the temperature of a circulating heat exchange medium to be constant at a preset temperature. The liquid evaporation rate testing device can further comprise a temperature sensor which is arranged at the lower part of the evaporation main body pipe section and can measure the temperature of the liquid to be tested in the evaporation main body pipe section.
A pressure control unit is disposed in the outlet tube section and is capable of varying the pressure inside the vaporization vessel to test the rate of vaporization of the liquid at different vessel pressures. For example, the pressure control unit may include a back pressure valve provided at a rear end of the outlet pipe section and capable of controlling the amount of pressure in the evaporation vessel, and a pressure gauge. The device for testing the evaporation rate of the liquid can further comprise a pressure gauge, wherein the pressure gauge is arranged at the upper part of the evaporation main body pipe section and can monitor the internal pressure in the evaporation main body pipe section.
The dew point control unit is connected with the inlet pipe section of the evaporation container and can provide flowing gas with different dew points to the evaporation container so as to test the evaporation rate of liquid at the dew points of different gases. For example, the dew point control unit may comprise a gas supply device arranged at the inlet side of the evaporation vessel, connected to the inlet pipe section to supply circulating gas of different dew points to the evaporation vessel. The liquid evaporation rate testing device can also comprise a dew point meter which is arranged in the outlet pipe section and can monitor the dew point of the gas in the evaporation main pipe section.
The vent valve is disposed in the outlet tube section and is capable of venting the gas within the vaporization container after the test is completed. For example, a blow valve may be provided at the rear end of the outlet pipe section and installed before the back pressure valve.
Furthermore, the testing device for the liquid evaporation rate can also comprise a transparent window arranged on the side wall of the evaporation main body pipe section, and the transparent window can observe the liquid level change condition and the liquid level change condition of the liquid to be tested in the experimental process.
The device for testing the liquid evaporation rate under the gas circulation in the embodiment can realize the measurement of the water evaporation rate under different dry air parameters and flow field parameters, is suitable for various working conditions, and has short measurement time, high precision and small error. For example, a throttle valve and a flowmeter are arranged in front of an inlet of the evaporation container, and a back pressure valve is arranged at an outlet of the evaporation container, so that the flow rate and the pressure of gas in the evaporation container can be controlled; a heat exchanger and a constant-temperature circulation control system are arranged outside the evaporation container, so that the water temperature in the evaporation container can be controlled; the inlet of the evaporation container is connected with an external air supply device, so that the dew point of the gas flowing into the evaporation container can be controlled.
The length, the size and the like of each part of the testing device in the embodiment are simulated by the flow field, so that the full development of the flow field can be ensured; the pipe diameter of the outlet section of the evaporation container is smaller than that of the inlet section, and the central position of the outlet section of the evaporation container is higher than that of the inlet section, so that water can be prevented from being blown out; a transparent window is arranged on the side wall of the outlet end of the evaporation container, so that the liquid level change condition in the evaporation container can be observed.
The invention also provides a method for testing the liquid evaporation rate under gas circulation. In an exemplary embodiment of the present invention, the liquid evaporation rate is measured by using the testing apparatus as described above, and the method for testing the liquid evaporation rate under gas flow may include the steps of:
s1, building a testing device for liquid evaporation rate under gas circulation, connecting an external gas supply pipeline with the evaporation container, and connecting an external liquid injection pipeline with the liquid injection valve.
And S2, after the liquid to be tested with the testing dosage is injected into the evaporation container, closing the liquid injection valve, and recording the first liquid level of the liquid level meter before the liquid is evaporated.
And S3, starting the constant temperature control unit, setting the test temperature, starting the dew point control unit, introducing gas with a preset dew point into the evaporation container, controlling the gas flow and the container pressure through the flow control unit and the pressure control unit, and recording the liquid temperature, the gas dew point, the gas flow and the container pressure in the liquid evaporation process.
And S4, stopping supplying air after a preset time, opening an emptying valve, and recording a second liquid level of the liquid level meter after the liquid is evaporated after the pressure in the evaporation container is restored to the atmospheric pressure.
S5, calculating the evaporation rate of the liquid to be tested under the specified liquid temperature, gas dew point, gas flow and container pressure according to the calculation formula of the evaporation rate, wherein the calculation formula of the evaporation rate is as follows:
wherein w is the evaporation rate per unit area of the liquid to be tested, g/(cm)2.s)；ρwIs the density, g/cm, of the liquid to be tested under experimental conditions3；S1Is the internal cross-sectional area of the liquid level meter, cm2；S2Is the bottom area, cm, of the evaporation container2；H1Is a first liquid level, cm, before the liquid to be tested evaporates; h2The second liquid level, cm, of the liquid to be tested after evaporation; t is the test time, s.
Further, the method for testing the evaporation rate of the liquid under gas circulation can further comprise the following steps:
s6, repeating the steps S2 to S5, respectively testing the liquid evaporation rate at different liquid temperatures (for example, the liquid temperature ranges from minus 20 ℃ to 80 ℃), the liquid evaporation rate at different gas dew points (for example, the dew point ranges from minus 60 ℃ to 25 ℃), the liquid evaporation rate at different gas flow rates (for example, the gas flow rate ranges from 2 m/S to 10m/S), and the liquid evaporation rate at different container pressures (for example, the container pressure ranges from 0.1MPa to 2MPa), and obtaining a function model of the drying rate of the liquid to be tested under the gas circulation.
For a better understanding of the above-described exemplary embodiments of the present invention, reference is made to the following description taken in conjunction with the accompanying drawings and specific examples.
Taking the measurement of the water evaporation rate under dry air circulation as an example, fig. 1 is a schematic structural diagram of a test device for measuring the water evaporation rate under dry air circulation according to the present invention.
As shown in fig. 1, the device for testing the evaporation rate of liquid may include a throttle valve 1, a flow meter 2, a magnetostrictive liquid level meter 3, a first liquid level valve 4, a second liquid level valve 5, a circulating water pipe 6, a thermostatic circulation control system 7, an evaporation container 8, a pressure gauge 9, a double pipe heat exchanger 10, a dew point meter 11, an air release valve 12, a back pressure valve 13, a transparent window 14, a temperature sensor 15 and a water filling and discharging valve 16.
Specifically, the evaporation vessel 8 includes an inlet pipe section, an evaporation body pipe section, and an outlet pipe section, which are arranged in this order from left to right. In order to ensure that the gas flow field is fully developed, the inlet pipe section needs to have a certain length, and through flow field simulation, the pipe diameter of the inlet pipe section in the example is DN80 (namely the outer diameter is 89mm), and the length is 1000 mm; the evaporation main body pipe section is a rectangular channel, the section size of the evaporation main body pipe section is 100mm multiplied by 100mm, the length of the evaporation main body pipe section is 1000mm, and the water injection depth is 20 mm; the outlet pipe section has a pipe diameter DN40 (i.e. an outer diameter of 45mm or 48mm) and an outlet pipe section length of 500 mm.
The bottom of the evaporation main body pipe section of the evaporation container 8 is provided with a water injection and drainage valve 16 which is externally connected with a water pipeline and used for injecting water into the evaporation container 8 or discharging residual water.
The side wall of the outlet end of the evaporation main body pipe section of the evaporation container 8 is provided with a transparent window 14 for observing the liquid level change condition in the evaporation container 8.
The throttle valve 1 is arranged at the front end of an inlet pipe section of the evaporation container 8, and a flow meter 2 is connected behind the throttle valve to control the inlet gas flow of the evaporation container 8. Preferentially, the flowmeter is a waist wheel flowmeter with high precision and good reliability.
The magnetostrictive liquid level meter 3 is installed on the inlet side of the evaporation main body pipe section of the evaporation container 8, and can accurately measure the liquid level change in the evaporation container 8 within a certain time, thereby calculating the evaporation rate. The magnetostrictive liquid level meter 3 is provided with a first liquid level valve 4 and a second liquid level valve 5 for controlling the communication of the magnetostrictive liquid level meter 3 with the evaporation vessel 8.
A pressure gauge 9 is installed at an upper portion of the evaporation body pipe section of the evaporation vessel 8 to measure the internal pressure of the evaporation vessel 8. A back pressure valve 13 is provided at the rear end of the outlet pipe section of the evaporation vessel 8 to control the pressure inside the evaporation vessel 8.
The double-pipe heat exchanger 10 is arranged outside an evaporation main body pipe section of the evaporation container 8 and is connected with the constant-temperature circulation control system 7 through the circulating water pipe 6, and the constant-temperature water temperature inside the evaporation container 8 is kept constant at a test temperature through constant-temperature water circulation heat exchange. The constant temperature circulation control system 7 includes a heating component, a refrigeration system and a circulating water pump inside, and can control the temperature of the circulating heat exchange medium to be constant at a certain value.
The temperature sensor 15 is installed at the lower part of the evaporation body pipe section of the evaporation vessel 8 for measuring the temperature of the liquid to be tested in the evaporation body pipe section.
A dew point meter 11 is mounted in the outlet pipe section of the evaporation vessel 8 to measure the dry air dew point inside the evaporation vessel 8. An external air supply is connected to the inlet pipe section of the evaporation vessel 8 to supply dry air of different dew points to the evaporation vessel 8.
A vent valve 12 is mounted in the outlet section of the vaporization vessel 8 for venting the gas in the vaporization vessel 8 during the experiment.
In practical application of the test device of the present example, a method for testing the water evaporation rate of dry air circulation includes the following steps:
first, the test device is connected to an air supply pipe of an external dry air supply apparatus, and the water filling and discharging valve 16 is connected to an external water pipe.
Then, the first liquid level valve 4 and the second liquid level valve 5 are opened, the water injection and drainage valve 16 is closed after the water with the testing dosage is injected into the evaporation container 8, and the first liquid level of the magnetostrictive liquid level meter 3 is recorded as H1。
Then, starting the constant temperature circulation control system 7, setting the constant temperature circulation control system at a test temperature, wherein the flow direction of the heat exchange medium is opposite to the circulation direction of the dry air; and closing the first liquid level valve 4 and the second liquid level valve 5, opening the external dry air supply equipment after setting a dry air output dew point of the external dry air supply equipment, controlling the air flow through the throttle valve 1, and realizing pressure control through the back pressure valve 13.
Recording the dew point value of dry air, the temperature of water, the flow rate of dry air and the pressure of a pipeline after stabilization, stopping air supply after a certain time, opening an emptying valve 12, opening a first liquid level valve 4 and a second liquid level valve 5 after the pressure in an evaporation container 8 is restored to the atmospheric pressure, and recording the second liquid level of a magnetostrictive liquid level meter 3 as H2。
Calculating the evaporation rate of the liquid to be tested under the specified liquid temperature, gas dew point, gas flow and container pressure according to the calculation formula of the evaporation rate, wherein the calculation formula of the evaporation rate is as follows:
wherein w is the evaporation rate per unit area of the liquid to be tested, g/(cm)2.s)；ρwIs the density, g/cm, of the liquid to be tested under experimental conditions3；S1Is the internal cross-sectional area of the liquid level meter, cm2；S2Is the bottom area, cm, of the evaporation container2；H1Is a first liquid level, cm, before the liquid to be tested evaporates; h2The second liquid level, cm, of the liquid to be tested after evaporation; t is the test time, s.
In summary, the beneficial effects of the invention include at least one of the following:
(1) the testing device for the liquid evaporation rate under gas circulation provided by the invention can realize the measurement of the water evaporation rate under different dry air parameters and flow field parameters, and has the advantages of various testing conditions, short testing time, high precision and small error;
(2) the method for testing the liquid evaporation rate under gas circulation can reflect the influence of the dew point, flow rate, environment temperature and other factors of dry air on the dry air drying effect, thereby obtaining a function model of the dry air drying rate to guide the related research work of the dry air drying technical indexes;
(3) the device and the method for testing the liquid evaporation rate under gas circulation provided by the invention are also suitable for the research on the evaporation rate in other fields, have various working conditions and have wide application prospects.
Although the present invention has been described above in connection with the exemplary embodiments and the accompanying drawings, it will be apparent to those of ordinary skill in the art that various modifications may be made to the above-described embodiments without departing from the spirit and scope of the claims.
Claims (10)
1. A device for testing the evaporation rate of liquid under gas circulation is characterized by comprising an evaporation container, a liquid injection valve, a liquid level meter, a flow control unit, a constant temperature control unit, a pressure control unit, a dew point control unit and an emptying valve,
the evaporation container is provided with an inlet pipe section, an evaporation main body pipe section and an outlet pipe section which are sequentially arranged from left to right, the tops of the inlet pipe section, the tops of the evaporation main body pipe section and the tops of the outlet pipe sections are all positioned on the same horizontal plane, the inner diameter of the evaporation main body pipe section is larger than that of the outlet pipe section so as to prevent liquid to be tested from being blown into the outlet pipe section, and the length-width ratio of the inlet pipe section is larger than or equal to 12.5 so that gas can fully flow before entering the evaporation main body pipe section;
the lower part of the evaporation main body pipe section is provided with a liquid injection valve so as to inject or discharge liquid to be tested into the evaporation container;
the liquid level meter is arranged on one side of the evaporation main body pipe section to measure the liquid level change in the evaporation container within preset time;
the flow control unit is arranged in the inlet pipe section and can change the gas flow at the inlet of the evaporation container so as to test the liquid evaporation rate at different gas flow rates;
the constant temperature control unit is arranged outside the evaporation main body pipe section and can control the temperature of liquid to be tested in the evaporation main body pipe section to be constant at a preset temperature so as to test the evaporation rate of the liquid at different environmental temperatures;
the pressure control unit is arranged in the outlet pipe section and can change the pressure inside the evaporation container so as to test the evaporation rate of the liquid under different container pressures;
the dew point control unit is connected with the inlet pipe section and can provide flowing gas with different dew points for the evaporation container so as to test the evaporation rate of liquid at different gas dew points;
the vent valve is disposed in the outlet tube section and is capable of venting the gas within the vaporization container after the test is completed.
2. The apparatus for testing the evaporation rate of a liquid under gas flow according to claim 1, wherein the cross-section of the evaporation vessel is circular or square, and the inner diameter of the evaporation body pipe section is larger than that of the inlet pipe section, the inner diameter of the inlet pipe section is larger than that of the outlet pipe section, the liquid to be tested is water, and the gas is dry air.
3. The apparatus for testing the evaporation rate of a liquid under gas flow according to claim 2, wherein said liquid level meter is a magnetostrictive liquid level meter, and the magnetostrictive liquid level meter is communicated with the evaporation main pipe section through a liquid level valve.
4. The apparatus for testing the evaporation rate of a liquid under gas circulation according to claim 3, wherein the flow control unit comprises a throttle valve and a flow meter, the throttle valve can control the gas flow at the inlet of the evaporation container by changing the opening degree of the throttle valve, and the flow meter can monitor the gas flow at the inlet of the evaporation container.
5. The device for testing the liquid evaporation rate under the condition of gas circulation according to claim 4, wherein the constant temperature control unit comprises a heat exchanger, a circulating pipe and a constant temperature circulation control system, the heat exchanger is arranged outside the evaporation main body pipe section and is connected with the constant temperature circulation control system through the circulating pipe so as to maintain the temperature of the liquid to be tested in the evaporation main body pipe section to be equal to the temperature of a heat exchange medium, and the constant temperature circulation control system internally comprises a heating part, a refrigerating part and a circulating pump and can control the temperature of the circulating heat exchange medium to be constant at a preset temperature; the testing device also comprises a temperature sensor which is arranged at the lower part of the evaporation main body pipe section and can monitor the temperature of the liquid to be tested in the evaporation main body pipe section.
6. The apparatus for testing the evaporation rate of a liquid under gas flow according to claim 5, wherein the pressure control unit comprises a backpressure valve, the backpressure valve being disposed in the outlet pipe section and capable of controlling the pressure level in the evaporation vessel; the testing device further comprises a pressure gauge, wherein the pressure gauge is installed on the upper portion of the evaporation main body pipe section and can monitor the internal pressure in the evaporation main body pipe section.
7. The apparatus for testing the evaporation rate of a liquid under gas flow-through of claim 6, wherein the dew point control unit comprises a gas supply device disposed on the inlet side of the evaporation vessel and connected to the inlet pipe section to supply the evaporation vessel with circulating gas at different dew points; the test device also includes a dew point meter mounted in the outlet pipe section and capable of monitoring the gas dew point in the evaporation body pipe section.
8. The apparatus for testing the evaporation rate of a liquid under gas flow of claim 1, further comprising a transparent window disposed on the side wall of the evaporation main body tube section, wherein the transparent window is capable of observing the liquid level change of the liquid to be tested during the experiment.
9. A method for measuring the evaporation rate of a liquid in a gas flow, wherein the evaporation rate of the liquid is measured using the test device according to any one of claims 1 to 8, the method comprising the steps of:
s1, building a device for testing the liquid evaporation rate under the gas circulation, connecting an external gas supply pipeline with an evaporation container, and connecting an external liquid injection pipeline with a liquid injection valve;
s2, after the liquid to be tested with the testing dosage is injected into the evaporation container, the liquid injection valve is closed, and the first liquid level of the liquid level meter before the liquid is evaporated is recorded;
s3, starting a constant temperature control unit, setting a test temperature, starting a dew point control unit, introducing gas with a preset dew point into an evaporation container, controlling the gas flow and the container pressure through a flow control unit and a pressure control unit, and recording the liquid temperature, the gas dew point, the gas flow and the container pressure in the liquid evaporation process;
s4, stopping supplying air after a preset time, opening an emptying valve, and recording a second liquid level of the liquid level meter after the liquid is evaporated after the pressure in the evaporation container is restored to the atmospheric pressure;
s5, calculating the evaporation rate of the liquid to be tested under the specified liquid temperature, gas dew point, gas flow and container pressure according to the calculation formula of the evaporation rate, wherein the calculation formula of the evaporation rate is as follows:
wherein w is the evaporation rate per unit area of the liquid to be tested, g/(cm)2.s)；ρwIs the density, g/cm, of the liquid to be tested under experimental conditions3；S1Is the internal cross-sectional area of the liquid level meter, cm2；S2Is the bottom area, cm, of the evaporation container2；H1Is a first liquid level, cm, before the liquid to be tested evaporates; h2The second liquid level, cm, of the liquid to be tested after evaporation; t is the test time, s.
10. The method of testing the evaporation rate of a liquid under gas flow according to claim 9, further comprising:
s6, repeating the steps S2 to S5, and respectively testing the liquid evaporation rate at different liquid temperatures, the liquid evaporation rate at different gas dew points, the liquid evaporation rate at different gas flow rates and the liquid evaporation rate at different container pressures to obtain a function model of the drying rate of the liquid to be tested under gas circulation.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114264572A (en) * | 2021-11-16 | 2022-04-01 | 成都科瑞尔低温设备有限公司 | Static evaporation rate testing device for low-temperature liquid container |
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| US20130174913A1 (en) * | 2012-01-10 | 2013-07-11 | Munters Corporation | Method and apparatus for controlling total dissolved solids in a liquid circulation system |
| CN203895548U (en) * | 2013-12-11 | 2014-10-22 | 同济大学 | Humidifying system of high-power fuel cell |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20130174913A1 (en) * | 2012-01-10 | 2013-07-11 | Munters Corporation | Method and apparatus for controlling total dissolved solids in a liquid circulation system |
| CN203895548U (en) * | 2013-12-11 | 2014-10-22 | 同济大学 | Humidifying system of high-power fuel cell |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN114264572A (en) * | 2021-11-16 | 2022-04-01 | 成都科瑞尔低温设备有限公司 | Static evaporation rate testing device for low-temperature liquid container |
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