CN116576929A - Ultrasonic gas meter module with low Reynolds number flow state automatic compensation function - Google Patents
Ultrasonic gas meter module with low Reynolds number flow state automatic compensation function Download PDFInfo
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/66—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters
- G01F1/662—Constructional details
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
- G01F1/66—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow by measuring frequency, phase shift or propagation time of electromagnetic or other waves, e.g. using ultrasonic flowmeters
- G01F1/667—Arrangements of transducers for ultrasonic flowmeters; Circuits for operating ultrasonic flowmeters
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F25/00—Testing or calibration of apparatus for measuring volume, volume flow or liquid level or for metering by volume
- G01F25/10—Testing or calibration of apparatus for measuring volume, volume flow or liquid level or for metering by volume of flowmeters
- G01F25/15—Testing or calibration of apparatus for measuring volume, volume flow or liquid level or for metering by volume of flowmeters specially adapted for gas meters
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Abstract
The invention discloses an ultrasonic gas meter module with low Reynolds number flow state automatic compensation, which belongs to the technical field of ultrasonic gas meters and comprises a main runner which is of a venturi-like structure, wherein a rectifier and an ultrasonic sensor are arranged at the input end and the output end of the main runner, a plurality of bypass runners are arranged at the outer side of the output end of the main runner, and the bypass runners are uniformly distributed around the axis of the main runner. The main runner adopts a venturi-like tube structure, has a larger cavity space, has a measuring section with an outline of an arc tangent line which is smoothly connected, has small pressure loss and good rectifying effect, and enlarges the upper limit of flow measurement; the separation and transition of boundary layers can be reduced and slowed down at the same time, even in a turbulent flow form, the particle exchange of each layer of fluid is less, the pollutant deposition is less, the ultrasonic sensor arranged in opposite emission can obtain enough measurement time and time difference according to the enlarged axis length of the space of the shell cavity, and the influence of acoustic energy loss caused by reflection and sound channel length change caused by dirt on the reflecting surface is avoided.
Description
Technical Field
The invention belongs to the technical field of ultrasonic gas meters, and particularly relates to an ultrasonic gas meter module with low Reynolds number flow state automatic compensation.
Background
The gas ultrasonic metering technology is widely applied to the natural gas trade metering industry, and the promulgation of relevant international and national standards and verification regulations also lays a technical foundation for the application and popularization of ultrasonic flowmeter meters. According to the related requirements of national standard GB/T39841-2021 ultrasonic gas meter, the ultrasonic gas meter measuring range of urban household and middle-small industrial and commercial users is from 0.016m 3 /h to 10m 3 The pressure loss is not more than 250Pa (with a valve), and the accuracy is not less than 1.5%; wherein the flow range of the G1.6 household gas meter is 0.016m 3 /h to 2.5m 3 And/h, the Reynolds number of the conventional flow channel design in the flow interval is 15-4000, the fluid form changes greatly, and three flow states of laminar flow, transitional flow and turbulent flow are spanned; how to effectively solve the influence of flow state change on the metering precision, control the manufacturing and application cost, and put high requirements on the design of an ultrasonic gas meter module.
The Reynolds number (Reynolds number) is a dimensionless number that can be used to characterize fluid flow. Re=ρνd/μ, where ρ, νd, μ are the density, flow rate and coefficient of viscosity of the fluid, respectively, and d is a characteristic length. The small Reynolds number means that the viscous force among the particles is dominant when the fluid flows, and the particles of the fluid regularly flow parallel to the inner wall of the pipeline and are in a laminar flow state. The large Reynolds number means that the inertia force is dominant, the fluid is in a turbulent flow state, the Reynolds number Re of the pipeline is smaller than 2000 and is in a laminar flow state, re is larger than 4000 and is in a turbulent flow state, and Re is in a transitional flow state between 2000 and 4000. Under different flowing states, the motion rule, the flow velocity distribution and the like of the fluid are different, so that the average flow velocity v and the maximum flow velocity v of the fluid in the pipeline are caused max Also, the ratio of (2) is different, as shown in FIG. 5, which shows a laminar flow pattern with a Reynolds number of less than 2000, and FIG. 6, which shows a turbulent flow pattern with a Reynolds number of greater than 4000.
Differential pressure flowmeter (resistance)A flow member), such as an orifice plate flow meter, a venturi flow meter, etc., whose outflow coefficient C varies with a change in reynolds number; such as beta value (d) 0 and/D) is 0.2, where D 0 For the smallest diameter on the primary flow channel of the flowmeter, D is the diameter of the input end of the flowmeter, and when the reynolds number is greater than 1000, the outflow coefficient C remains substantially constant, wherein the outflow coefficient C is about 0.59; beta value (d) 0 With a Reynolds number greater than 100000, the outflow coefficient C can also be kept constant, approximately 0.69; wherein the outflow coefficient C is calculated by Wherein qm is the mass flow, Δp is the differential pressure, ρ is the density of the fluid, and in most cases, the larger the β value, the larger the outflow coefficient C; however, when the Reynolds number is smaller than 600, the outflow coefficient of the large beta value is greatly reduced along with the reduction of the Reynolds number until the Reynolds number is reduced to 20, the flow is reversed, and the outflow coefficient of the large beta value is smaller than the outflow coefficient of the small beta value; as in fig. 10. The basic fluid flow change rule lays a theoretical foundation for balancing and compensating the large measured value of the micro flow of the main flow channel under the condition of low Reynolds number of the micro-pore bypass flow channel.
When measuring gas, the different flow rates of gas meter operation in-process can form laminar flow or turbulent flow to influence to measuring result, the present ultrasonic gas meter mostly adopts reflective measurement module, and its runner cross-section is rectangular structure, and cuts apart into a plurality of 2mm thin passageway with the gas flow channel through setting up the rectification grid in the runner, therefore the laminar flow state in reynolds number 2000 is all controllable to the gas flow state of single lamina, has avoided the influence of different fluid form changes to measuring accuracy. But this feature suffers from the following drawbacks;
1. the rectangular cross-section design also limits the channel length design, even with 45 ° angle mono reflection, the velocity vector in the channel direction is only the effective channel lengthResulting in small measurement time differences and limited metering accuracy.
2. The device is only suitable for clean fuel gas, and once the reflecting surface is polluted, the sound path length is changed, so that the metering accuracy is affected.
3. Each reflection will lose acoustic energy, about 3-5 dB; meanwhile, the echo signals are easy to generate distortion, and more energy resources are needed for compensation.
4. The high flow rate pressure loss is large, the applicable flow range of the module with single size is narrow, and the range ratio is not more than 200:1, the need for more modules to cover more flow measurement requirements results in increased manufacturing costs
Therefore, it is necessary to design an ultrasonic gas meter module with low Reynolds number flow regime automatic compensation to solve these problems.
Disclosure of Invention
The invention provides an ultrasonic gas meter module with wide range, low pressure loss, dirt resistance and low overall manufacturing cost and capable of automatically compensating low Reynolds number flow state.
In order to solve the technical problems, the invention adopts the following technical scheme:
the utility model provides a low Reynolds number flow state self-compensating's supersound gas table module, includes the sprue, the sprue is venturi-like structure the input and the output of sprue all are provided with rectifier and ultrasonic sensor the output outside of sprue is provided with a plurality of bypass runner, bypass runner is around sprue axis evenly distributed.
Preferably, the bypass flow channel comprises an air outlet pipe sleeved on the outer side of the output end of the main flow channel, the air outlet pipe is connected with the main flow channel through a flow limiting pore plate, a plurality of through holes are formed in the flow limiting pore plate, and the through holes are uniformly distributed around the axis of the main flow channel.
So set up, combined into the bypass runner, and the installation of the subassembly of being convenient for is fixed, can carry out the balance and the compensation of flow for the sprue through leaving a room, and the outlet duct still is connected with gas table coupling airtight, makes the air current that flows through sprue and bypass runner flow out the gas table.
Preferably, the main runner is divided into an upstream gradually-decreasing section, a throat and a downstream gradually-increasing section, the throat is the position with the smallest diameter on the main runner, the upstream gradually-decreasing section is the position between the input end of the main runner and the throat, the downstream gradually-increasing section is the position between the throat and the output end of the main runner, the diameter D of the input end on the main runner is larger than the diameter of the output end, the diameter of the output end of the main runner is larger than the diameter D of the throat, and the ratio D/D of the diameter D of the throat to the diameter D of the input end is 0.4-0.6.
The device is arranged in such a way, the stability of the flow state is realized by controlling the range of the diameter of the throat part and the diameter of the input end, and meanwhile, the influence of vortex generated after the fitting is installed on the detection result is reduced.
Preferably, the number of the through holes is 9-18, and the diameter d of the through holes b 1/15 to 1/20 of the diameter D of the input end of the main flow channel, and the diameter D of the through flow hole b ≥1.6mm。
So arranged, choking flow can be avoided.
Preferably, an outer skirt is sleeved outside the main flow passage, the outer skirt is connected with the air outlet pipe, and the length of the outer skirt is not less than the diameter d of the through flow hole b Five times more than before.
By the arrangement, the influence of external air flow can be reduced.
Preferably, the output end of the main flow channel is also fixedly provided with an inner skirt, and the length of the inner skirt is not less than the diameter d of the through flow hole b 。
So set up, separate main runner air current and bypass air current, do not influence each other.
Preferably, the length of the main runner is L, the length of the upstream convergent section is 3/4 of the length of the main runner, the downstream divergent section is 1/4 of the length of the main runner, the inner wall profiles of the upstream convergent section and the downstream divergent section are smooth arc tangent lines, and the convergent angle alpha of the inner wall of the upstream convergent section is 3-5 degrees.
By the arrangement, the pressure loss can be reduced, the fluid form of the main flow channel is stabilized, and the measurement accuracy is improved.
Preferably, the rectifier and the ultrasonic sensor comprise an air inlet rectifier, an air outlet rectifier, an air inlet ultrasonic sensor and an air outlet ultrasonic sensor, the air inlet rectifier is mounted at the input end of the main runner, the air inlet ultrasonic sensor is mounted on the air inlet rectifier, the air outlet rectifier is mounted in the air outlet pipe, the air outlet ultrasonic sensor is mounted on the air outlet rectifier, and the output end of the air inlet ultrasonic sensor is opposite to the input end of the air outlet ultrasonic sensor.
By the arrangement, vortex flowing into and out of the main runner can be reduced, and the ultrasonic sensor can be stably positioned.
Preferably, the input end of the main runner is also connected with an air inlet pipe, and the air inlet rectifier is positioned in the air inlet pipe.
So set up, the installation and the fixed of subassembly of being convenient for.
The invention has the advantages and positive effects that:
1. the main flow channel has larger cavity space, the outline of the measuring section is smoothly connected with the arc tangent line, and even in a turbulent flow form, the particle exchange of each layer of fluid is less, and the pollutant deposition is less.
2. The correlation ultrasonic sensor is arranged at two ends of the axis of the main runner, the length of the axis can be amplified according to the space of the shell cavity, and meanwhile, the sound channel direction is the fluid movement direction, so that the effective sound channel length of the design is the actual sound channel length, the measurement time and the time difference with enough length can be obtained, and the measurement accuracy is ensured.
3. The correlation channel arrangement has no acoustic energy loss caused by reflection, and the correlation channel arrangement has no influence of channel length change caused by dirt on the reflecting surface.
4. The main runner adopts a venturi-like tube structure, has small pressure loss and good rectifying effect, and can reduce and slow down the separation and transition of the boundary layer.
5. The flow balance effect of the bypass flow passage extends the lower limit of flow measurement, and the measuring range ratio can reach 1000:1, the production efficiency is improved, and the manufacturing cost is reduced.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions of the prior art, the drawings that are necessary for the description of the embodiments or the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention and that other drawings can be obtained according to these drawings without inventive faculty for a person skilled in the art.
FIG. 1 is a schematic axial view of the whole structure of an ultrasonic gas meter module with low Reynolds number flow regime automatic compensation according to the invention;
FIG. 2 is a schematic longitudinal section view of the internal structure of an ultrasonic gas meter module with low Reynolds number flow regime automatic compensation according to the invention;
FIG. 3 is a schematic diagram of a main flow path segment structure of an ultrasonic gas meter module with low Reynolds number flow regime automatic compensation according to the present invention;
FIG. 4 is a schematic diagram of the distribution structure of through holes of an ultrasonic gas meter module with low Reynolds number flow regime automatic compensation according to the invention;
FIG. 5 is a schematic diagram of a laminar flow regime with Reynolds numbers less than 2000;
FIG. 6 is a schematic representation of a turbulent flow regime for Reynolds numbers greater than 4000;
FIG. 7 is a schematic view showing the mounting structure of the measuring module in the airtight watchcase;
FIG. 8 is a schematic diagram of a CFD simulated channel region velocity profile;
FIG. 9 is a schematic diagram of CFD measurement bias, with flow m on the abscissa 3 The ordinate is the measurement deviation;
FIG. 10 is a schematic diagram of the relationship between the outflow coefficient C and the Reynolds number and D/D.
The reference numerals are explained as follows:
1. an air inlet pipe; 2. a main flow passage; 21. an upstream tapered section; 22. a throat; 23. a downstream diverging section; 3. an air outlet pipe; 4. a flow restricting orifice plate; 5. an intake rectifier; 6. an air inlet guide sleeve; 7. an air inlet ultrasonic sensor; 8. a through-flow hole; 9. an air outlet rectifier; 10. an air outlet ultrasonic sensor; 11. an outer skirt; 12. an inner skirt.
Detailed Description
In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first", "a second", etc. may explicitly or implicitly include one or more such feature. In the description of the present invention, unless otherwise indicated, the meaning of "a plurality" is two or more.
In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art in a specific case.
The invention is further described below with reference to the accompanying drawings:
example 1: as shown in fig. 1-10, an ultrasonic gas meter module with low reynolds number flow state automatic compensation comprises a main runner 2, wherein the main runner 2 is of a venturi-like structure, a rectifier and an ultrasonic sensor are arranged at the input end and the output end of the main runner 2, a plurality of bypass runners are arranged at the outer side of the output end of the main runner 2, and the bypass runners are uniformly distributed around the axis of the main runner 2.
Specifically, the bypass runner includes the outlet duct 3 of suit in the sprue 2 output outside, and outlet duct 3 links to each other through restriction orifice plate 4 with sprue 2, has offered a plurality of through holes 8 on restriction orifice plate 4, and a plurality of through holes 8 are around sprue 2 axis evenly distributed, set up like this and have combined into the bypass runner, and the installation of being convenient for the subassembly is fixed, can carry out balance and the compensation of flow for sprue 2 through leaving the sky, and the outlet duct still is connected with gas table coupling airtight, makes the air current that flows through sprue and bypass runner flow out the gas table.
Further, the main flow channel 2 is divided into an upstream tapering section 21, a throat section 22 and a downstream diverging section 23, the throat section 22 is the position with the smallest diameter on the main flow channel 2, the upstream tapering section 21 is the position between the input end of the main flow channel 2 and the throat section 22, the downstream diverging section 23 is the position between the throat section 22 and the output end of the main flow channel 2, the diameter D of the input end on the main flow channel 2 is larger than the diameter of the output end, the diameter of the output end of the main flow channel 2 is larger than the diameter D of the throat section 22, and the ratio D/D of the diameter D of the throat section to the diameter D of the input end is 0.4-0.6, namely, the beta of the device is 0.4-0.6, so that the stability of the flow state is realized by controlling the range of the diameter of the throat section 22 and the diameter of the input end, and the influence of vortex generated after the fitting is installed on the detection result is reduced.
Further, the number of the through holes 8 is 9-18, and the diameter d of the through holes 8 b Is 1/15 to 1/20 of the diameter D of the input end of the main flow channel 2, and the diameter D of the through hole 8 b Is more than or equal to 1.6mm, so that choking flow can be avoided.
Further, an outer protecting skirt 11 is sleeved outside the main flow passage 2, the outer protecting skirt 11 is connected with the air outlet pipe 3, and the length of the outer protecting skirt 11 is not less than the diameter d of the through flow hole 8 b By five times, the influence of external air flow can be reduced.
Furthermore, the output end of the main runner 2 is also fixedly provided with an inner apron 12, and the length of the inner apron 12 is not less than the diameter d of the through hole 8 b The separation main runner 2 air flow and the bypass air flow are arranged in this way, and do not affect each other.
Specifically, the length of the main runner 2 is L, the length of the upstream convergent section 21 is 3/4 of the length of the main runner 2, the downstream divergent section 23 is 1/4 of the length of the main runner 2, the inner wall profiles of the upstream convergent section 21 and the downstream divergent section 23 are smooth arc tangents, and the convergent angle α of the inner wall of the upstream convergent section 21 is 3 ° to 5 °, so that the pressure loss can be reduced, the fluid form of the main runner is stabilized, and the measurement accuracy is improved.
The venturi tube structure is fast contraction, the main runner 2 of the device adopts a tapered venturi tube-like structure and is restrained by the size, the venturi tube-like structure is used as a main runner, and the central axis flow velocity is measured to obtain the average flow velocity. When the Reynolds number is larger than 4000, as shown in FIG. 6, the fluid form is stable and reliable, and the good measurement precision can be maintained without any correction; in the case that the Reynolds number is smaller than 2000, as shown in FIG. 5, the axial center area of the fluid state is gradually pointed, and the flow velocity measured by the central axis is gradually increased compared with the average flow velocity; after the Reynolds number is less than 30, the central axis flow rate increases by approximately 50% from the average flow rate. The bypass flow passage disclosed by the invention can balance and compensate the defect of large flow metering of the low-Reynolds number venturi flow passage.
Specifically, rectifier and ultrasonic sensor include the rectifier that admits air 5, the rectifier that gives vent to anger 9, the ultrasonic sensor that admits air 7 and the ultrasonic sensor that gives vent to anger 10, the rectifier that admits air 5 installs the input at sprue 2, the ultrasonic sensor that admits air 7 installs on admitting air rectifier 5, still install the air guide cover 6 on admitting air rectifier 5, the rectifier that gives vent to anger 9 is installed in outlet duct 3, the ultrasonic sensor that gives vent to anger 10 is installed on the rectifier that gives vent to anger 9, and the transmitting end of the ultrasonic sensor that admits air 7 is relative with the receiving end of the ultrasonic sensor that gives vent to anger 10, so set up the vortex that can reduce business turn over sprue 2, also can play the effect of stable location to the ultrasonic sensor.
The input end of the main runner 2 is also connected with an air inlet pipe 1, an air inlet rectifier 5 is positioned in the air inlet pipe 1, the assembly is convenient to install and fix, and meanwhile, an air inlet guide cover is also installed on the air inlet rectifier, and air flow flowing to the back of the air inlet ultrasonic sensor can be smoothly guided to the periphery through the air inlet guide cover, so that the air flows into the main runner through the air inlet rectifier.
The working procedure of this embodiment is:
the invention focuses on the measurement of small flow and micro flow, which is needed to be installed in a closed meter shell, the gas outlet pipe 3 is connected with the output end of the closed meter shell, in operation, the fuel gas enters the main flow channel 2 through the gas inlet rectifier 5 and then exits the main flow channel 2 through the gas outlet rectifier 9, in the process, the fuel gas is compressed when flowing from the input end with larger diameter to the throat part 22 with smaller diameter, so that the flow speed is increased, and the volume is expanded after passing through the throat part 22, and the flow speed is reduced.
The beta value of the flow channel type venturi tube can be referenced as 0.8 under the conventional condition; the beta value of the microporous bypass flow passage can be designed to be 0.2. Referring to FIG. 10, when the Reynolds number is not less than 2000, the corresponding flow rate is not less than 1.4m 3 /h; the outflow coefficient of the bypass flow passage is about 0.6; the venturi-like outflow coefficient C is about 1.24; at a Reynolds number of 60, the corresponding flow rate is about 0.04m 3 And/h, the venturi-like outflow coefficient is about 0.94, and the bypass flow passage outflow coefficient is about 0.68. Meaning that the flow rate decreases and the flow rate ratio of the bypass flow passage out increases; when the Reynolds number is less than or equal to 24, the corresponding flow is 0.016m 3 The venturi-like flow coefficient will be 0.66 and the bypass flow coefficient will also be 0.66, meaning that the flow rate ratio of the bypass flow will increase by approximately 50% at this time, as compared to a high Reynolds number. The increased flow of the bypass flow passage reduces the flow of the main flow passage, and practically compensates the defect of increased measurement deviation caused by measuring a high flow speed area of the central axis when the main flow passage venturi tube has a low Reynolds number, as shown in figure 5.
Based on the relevant national standard, in Q min ～Q t The measurement accuracy is better than +/-3 percent
The minimum value Q is set in the present embodiment min Is 0.016m 3 /h, critical node Q t Is 1m 3 Taking this flow range as an example, the present embodiment is described in a theoretical calculation manner:
1. ensuring that the uncertainty of time measurement is better than +/-2%;
a) And calculating the throat diameter d of the main flow channel 2:
the flow range is 0.016-10 m 3 And/h, the Reynolds number is 15-15000, and the maximum flow velocity of the throat diameter of the main flow channel 2 is not more than 25m/s.
Calculating to obtain a throat diameter d not smaller than 11.9mm; considering that the outer diameter of the transmitting and receiving ports of the ultrasonic sensor is 14mm, the throat diameter of the main runner 2 is designed to be 16mm.
b) Channel length L calculation:
the natural gas sound velocity at 20 ℃ is about 427.7m/s, the length of a sound channel is 70mm, and the time difference is about 7.65ns when the minimum metering flow rate is 0.01m/s according to the atmospheric pressure of 1; the time measurement accuracy of + -2% is + -0.15 ns, which is about + -2%. The time resolution of the existing ultrasonic chip is 30ps, the measurement precision is considered according to three times of resolution, and the time measurement precision can be better than 100ps, namely +/-0.1 ns; therefore, the correlation type sound channel arrangement, the sound channel length of 70mm and the time measurement precision of +/-0.15 ns can meet the requirement of +/-2% of the uncertainty of time measurement.
c) Inlet and outlet diameter D of main channel 2:
according to the actual cross-sectional area (pi D of the inlet and outlet of the main flow channel 2 2 Subtracting the cross-sectional area of the sensor and the sleeve and the cross-sectional area of the deflector of the rectifier from 4), about 32-36 mm.
2. Throat diameter position of main runner 2
The throat diameter position of the main runner 2 can be controlled to be 3/4 of the sound channel, namely, the sound channel starts to 52-53 mm.
3. Main runner 2 profile
The throat diameter of the main runner 2 is a parallel point, and the upstream arc tangent line is smoothly connected with the outer end of the diameter D of the inlet position; the downstream circular arc tangent line is smoothly connected to the outlet orifice plate inner ring.
4. Pore diameter and number of restriction orifice plates 4
The beta value of the reference ministry standard HG/T20570-95 technical Provisions of engineering design of process systems is less than 0.2. The existing industrial die processing and die drawing precision requirements can select 1.6-2.4 mm as the aperture d of the through-flow hole 8 on the initial prototype current-limiting orifice plate 4 b The number of through holes 8 on the orifice plate 4 can be selected to be 8-12 in the initial stage according to the 10-15% of the throat 22 cross section area as the total cross section area of the orifice plate 4.
5. CFD flow regime simulation
After primary structural parameters of an ultrasonic gas meter module are selected preliminarily, CFD flow state simulation is carried outSoftware for performing wide-range flow simulation, such as 0.016-16 m 3 /h; observing the speed distribution and streamline development, as shown in figure-08; detecting the streamline speed of the sound channel area; an average flow rate is obtained.
Screening according to the following performance priority level requirements, adjusting related structural parameters, grouping and combining simulation tests, and determining flow state development and change trend caused by parameter change and influence on measurement accuracy, wherein the flow state development and change trend and influence on measurement accuracy are used for guiding fine adjustment of related parameters of a 3D printing module:
a) The flow state in the measuring flow channel is stable, and the flow line is not crossed;
b) The measured flow deviation is within the expected range, the large flow (more than 1.6m 3 The ratio of the water to the water is better than +/-1 percent, and the small flow (0.1 to 1.6 m) 3 /h) is better than + -3%; micro flow (less than 0.1 m) 3 /h) is better than + -6%;
c) The pressure loss is small, and the national standard requirement is met;
6. CFD flow state simulation and module parameter setting
Performing CFD flow state simulation iterative calculation according to the calculation parameters; the main module parameters include: the diameter D of the input end of the main runner 2, the diameter D of the output end of the main runner 2, the diameter D of the throat 22, the position of the throat 22 on the main runner 2, and the aperture D of the through-flow hole 8 b And the number, length of the outer skirt 11 and the inner skirt 12, etc. When the deviation of the simulated measurement flow meets the expected requirement and the pressure loss meets the national standard requirement, the flow state simulation module parameter setting can be used.
The foregoing describes one embodiment of the present invention in detail, but the description is only a preferred embodiment of the present invention and should not be construed as limiting the scope of the invention. All equivalent changes and modifications within the scope of the present invention are intended to be covered by the present invention.
Claims (9)
1. The utility model provides a low Reynolds number flow state self-compensating's supersound gas table module, includes sprue (2), sprue (2) are venturi-like structure the input and the output of sprue (2) all are provided with rectifier and ultrasonic sensor, its characterized in that: a plurality of bypass flow channels are arranged outside the output end of the main flow channel (2), and the bypass flow channels are uniformly distributed around the axis of the main flow channel (2).
2. The ultrasonic gas meter module for automatic low Reynolds number flow state compensation of claim 1, wherein: the bypass runner is in including suit outlet duct (3) in the main runner (2) output outside, outlet duct (3) with main runner (2) are continuous through restriction orifice plate (4) a plurality of through holes (8) have been seted up on restriction orifice plate (4), a plurality of through holes (8) are around main runner (2) axis evenly distributed.
3. The ultrasonic gas meter module for automatic low-reynolds number flow state compensation according to claim 2, wherein: the main flow channel (2) is divided into an upstream gradually-reducing section (21), a throat (22) and a downstream gradually-expanding section (23), the throat (22) is the position with the smallest diameter on the main flow channel (2), the upstream gradually-reducing section (21) is the position between the input end of the main flow channel (2) and the throat (22), the downstream gradually-expanding section (23) is the position from the throat (22) to the output end of the main flow channel (2), the diameter D of the input end on the main flow channel (2) is larger than the diameter D of the output end of the main flow channel (2), the diameter D of the output end of the main flow channel (2) is larger than the diameter D of the throat (22), and the ratio D/D of the diameter D of the throat (22) to the diameter D of the input end is 0.4-0.6.
4. The ultrasonic gas meter module for automatic low Reynolds number flow state compensation of claim 3, wherein: the number of the through holes (8) is 9-18, and the diameter d of the through holes (8) b Is 1/15 to 1/20 of the diameter D of the input end of the main flow channel (2), and the diameter D of the through flow hole (8) b ≥1.6mm。
5. The ultrasonic gas meter module for automatic low Reynolds number flow state compensation of claim 4, wherein: an outer apron (11) is sleeved outside the main flow channel (2), the outer apron (11) is connected with the air outlet pipe (3), and the length of the outer apron (11) is not less than that of the through flowDiameter d of hole (8) b Five times more than before.
6. The ultrasonic gas meter module for automatic low Reynolds number flow state compensation of claim 4, wherein: an inner apron (12) is fixedly arranged at the output end of the main flow channel (2), and the length of the inner apron (12) is not less than the diameter d of the through flow hole (8) b 。
7. The ultrasonic gas meter module for automatic low Reynolds number flow state compensation of claim 3, wherein: the length of the main runner (2) is L, the length of the upstream convergent section (21) is 3/4 of the length of the main runner (2), the downstream divergent section (23) is 1/4 of the length of the main runner (2), the inner wall profiles of the upstream convergent section (21) and the downstream divergent section (23) are smooth arc tangent lines, and the convergent angle alpha of the inner wall of the upstream convergent section (21) is 3-5 degrees.
8. The ultrasonic gas meter module for automatic low-reynolds number flow state compensation according to claim 2, wherein: the rectifier with ultrasonic sensor includes gas inlet rectifier (5), gas outlet rectifier (9), gas inlet ultrasonic sensor (7) and gas outlet ultrasonic sensor (10), gas inlet rectifier (5) are installed the input of sprue (2), gas inlet ultrasonic sensor (7) are installed on gas inlet rectifier (5), gas outlet rectifier (9) are installed in outlet duct (3), gas outlet ultrasonic sensor (10) are installed on gas outlet rectifier (9), just the output of gas inlet ultrasonic sensor (7) with the input of gas outlet ultrasonic sensor (10) is relative.
9. The ultrasonic gas meter module for automatic low Reynolds number flow state compensation of claim 1, wherein: the output end of the main runner (2) is also connected with an air inlet pipe (1), and the air inlet rectifier (5) is positioned in the air inlet pipe (1).
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310469501.3A CN116576929A (en) | 2023-04-27 | 2023-04-27 | Ultrasonic gas meter module with low Reynolds number flow state automatic compensation function |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202310469501.3A CN116576929A (en) | 2023-04-27 | 2023-04-27 | Ultrasonic gas meter module with low Reynolds number flow state automatic compensation function |
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| CN202310469501.3A Pending CN116576929A (en) | 2023-04-27 | 2023-04-27 | Ultrasonic gas meter module with low Reynolds number flow state automatic compensation function |
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| Country | Link |
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| CN (1) | CN116576929A (en) |
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- 2023-04-27 CN CN202310469501.3A patent/CN116576929A/en active Pending
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