Open channel flow meter for rectangular channel flow monitoring and flow measurement method thereof

Abstract

The present invention discloses an open channel flow meter for rectangular channel flow monitoring and a flow measurement method thereof, which is composed of a channel water flow form monitoring device and a flow monitoring controller arranged in the rectangular channel. The flow measurement method comprises: S1, constructing a three-section flow measurement environment of the rectangular channel; S2, a control module issues a control instruction to control the upstream and downstream pressure water level monitors to monitor the flow of the rectangular channel in a set monitoring period Δ t According to the set acquisition frequency, the water level data of the upstream monitoring section Ls and the water level data of the downstream monitoring section Lx are collected synchronously; S3, the flow rate of the monitored section Le is calculated. The present invention breaks through the traditional flow measurement method. Through the changes in the upstream and downstream water levels of the monitored section of the channel caused by the action of the channel side wall and the channel flow form monitoring device installed at the monitored section, the average flow rate of the monitored section is monitored and calculated based on the energy conservation and channel continuity equation. It has the advantages of high measurement accuracy and simple installation and flow measurement.

Description

Technical Field

[0001] The invention relates to the field of open channel flow monitoring, in particular to an open channel flow meter used for rectangular channel flow monitoring and a flow measurement method thereof. Background Art

[0002] Accurate monitoring of open channel flow is the basis of water conservation in irrigation areas. At present, the main means of monitoring and measuring open channel flow are the velocity area method, the core of which is to monitor the average velocity of the flow section. The methods of measuring flow velocity include electromagnetic method, ultrasonic (time difference method), Doppler method, and building flow measurement method. The electromagnetic method has the disadvantage of being difficult to break through the limitation of large-section flow measurement; the Doppler method is mainly used to measure strip flow velocity and has low accuracy; the multi-channel flow measurement equipment used by the ultrasonic time difference method has strict requirements for on-site installation and is very expensive. Summary of the invention

[0003] The present invention aims to provide an open channel flow meter for rectangular channel flow monitoring which has high measurement accuracy and is easy to install. Another object of the present invention is to provide a flow measurement method for the open channel flow meter.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] The open channel flow meter for rectangular channel flow monitoring of the present invention is composed of a channel water flow form monitoring device arranged in the rectangular channel and a flow monitoring controller arranged outside the rectangular channel; the channel water flow form monitoring device includes a wall-attached vertical plate used to be connected to the channel side wall, a water-facing side vertical plate and a water-receiving side vertical plate connected to the wall-attached vertical plate; the water-facing side vertical plate, the water-receiving side vertical plate and the wall-attached vertical plate constitute a vertical tube with an isosceles triangle cross section, and filter holes for eliminating water flow disturbance are opened on the plate surfaces of the water-facing side vertical plate and the water-receiving side vertical plate, and a base is arranged at the lower tube mouth of the vertical tube; the vertical tube is provided with a filter hole for eliminating water flow disturbance; the vertical tube is provided with a base; the vertical tube is provided with a filter hole for eliminating water flow disturbance ... A partition is provided to divide the inner cavity of the vertical cylinder into two right-angled triangle cross-sections of an upstream cylinder cavity and a downstream cylinder cavity; an upstream riser and a downstream riser are respectively provided in the upstream cylinder cavity and the downstream cylinder cavity; filter holes for eliminating water flow disturbance are respectively provided on the circumference of the upstream and downstream risers; an upstream pressure water level monitor and a downstream pressure water level monitor are respectively provided in the upstream and downstream risers on the base; control interfaces of the upstream and downstream pressure water level monitors are led out from the upper cylinder port of the vertical cylinder through cables, and the control interface cables are connected to the flow monitoring controller.

[0006] The flow monitoring controller comprises:

[0007] A basic parameter input control module, used to input the rectangular channel width, the vertical tube water blocking width and monitoring control parameters and store them in a memory;

[0008] A control module, used to issue control instructions to control the upstream and downstream pressure water level monitors to synchronously collect the water levels of the channel sections monitored by each of them according to the set collection frequency within the set monitoring period and calculate the average water level within the set monitoring period and the area of ​​the water-passing section of the average water level;

[0009] The instantaneous flow monitoring and calculation module is used to calculate the instantaneous average flow of the monitored section within the set monitoring period and calculate the average flow of the monitored section within the set monitoring time period.

[0010] The filter holes arranged on the surface of the water-incoming side vertical plate, the surface of the water-incoming side vertical plate and the peripheral surfaces of the upstream and downstream side vertical pipes are all rectangular vertical holes.

[0011] Notches are respectively opened on the bottom pipe walls of the upstream and downstream side risers, so that canal water can smoothly enter the upstream and downstream side risers.

[0012] The flow measurement method of the open channel flowmeter of the present invention comprises the following steps:

[0013] S1, construct the three-section flow measurement environment of the rectangular channel:

[0014] Install an open channel flow meter on the channel side wall at the designated monitored section Le in the channel, the steps are as follows:

[0015] S1.1, place the base of the vertical tube on the bottom of the channel, overlap the partition in the vertical tube with the monitored section Le, fix the wall-attached vertical plate to the channel side wall, and extend the upper tube mouth of the vertical tube above the channel;

[0016] S1.2, set the upstream side of the water-facing side plate as the upstream monitoring section Ls, set the downstream side of the water-receiving side plate as the downstream monitoring section Lx; the upstream side pressure water level monitor is used to monitor the water level of the upstream side during the set monitoring period Δ t The water level of the upstream monitoring section Ls is collected according to the set collection frequency, and the downstream pressure water level monitor is used to collect the water level of the upstream monitoring section Ls in the set monitoring period Δ t Collecting the water level of the downstream monitoring section Lx according to the set collection frequency;

[0017] S2, the control module issues a control instruction to control the upstream and downstream pressure water level monitors to monitor the water level during the set monitoring period Δ t According to the set acquisition frequency, the water level data of the upstream monitoring section Ls and the downstream monitoring section Lx are collected synchronously, and the water level data of the set monitoring period Δ tThe average water level hs data of the upstream monitoring section Ls, the average water level hx data of the downstream monitoring section Lx, and the average water flow area of ​​the monitored section Le Data, average water flow area of ​​upstream monitoring section Ls Data, average water flow area of ​​downstream monitoring section Lx Data; Among them, the average water area of ​​the monitored section Le Equal to the average water flow area of ​​the upstream monitoring section Ls Subtract the water blocking area of ​​the channel flow pattern monitoring device (vertical tube) below the average water level hs of the upstream monitoring section Ls;

[0018] S3, flow calculation of monitored section Le:

[0019] The control module will obtain the average water level hs data, average water level hx data, and average water area Data, average water area Data and average water area The data is output to the instantaneous flow monitoring calculation module, which derives the Δ based on the above parameters according to the energy conservation principle of the three sections. t The calculation method of average flow rate during a period is as follows:

[0020] According to the three-section energy conservation principle, the instantaneous average total energy E of the upstream monitoring section Ls is LS Subtract the instantaneous average total energy E of the downstream monitoring section Lx Lx Equal to the average momentum change ΔE of the monitored section Le Lx ,in:

[0021] ;

[0022] ;

[0023] At the same time, according to the channel flow continuity equation Q s =Q x =Q e have:

[0024] ;

[0025] Thus we get ;

[0026] Q s : The upstream monitoring section Ls is in Δ t Average flow rate during the time period;

[0027] Q x : Downstream monitoring section Lx in Δ t Average flow rate during the time period;

[0028] Q e : The monitored section Le is in Δ t Average flow rate during the time period;

[0029] m : Δ t The average quality of water flowing through the three sections Ls, Le, and Lx during a period of time;

[0030] V s : The upstream monitoring section Ls is in Δ t Average flow rate during the time period;

[0031] V x : Downstream monitoring section Lx in Δ t Average flow rate during the time period;

[0032] V e : The monitored section Le is in Δ t Average flow rate during the time period;

[0033] g - acceleration due to gravity.

[0034] In S2, the monitoring period Δt is set between 5 seconds and 60 seconds, the acquisition frequency is 2-3 times per second, and the average water level hs data of the upstream monitoring section Ls and the average water level hx data of the downstream monitoring section Lx are calculated once in each monitoring period Δt; when calculating the average water level hs data and the average water level hx data, the maximum value and the minimum value are removed respectively and the average value is taken.

[0035] The present invention breaks through the traditional flow measurement method. Through the changes in the upper and lower water levels of the monitored section of the channel caused by the action of the channel water flow form monitoring device installed at the monitored section and the channel side wall, the average flow of the monitored section is monitored and calculated through the energy conservation and channel continuity equation. The error caused by the energy conversion of the transducer device in the traditional flow measurement method is eliminated, and parameter calibration is not required. It has the advantages of high measurement accuracy, simple installation and flow measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 It is a structural schematic diagram of the open channel water flow pattern monitoring device of the present invention.

[0037] Figure 2 yes Figure 1 AA section enlarged structural diagram.

[0038] Figure 3 It is a schematic diagram of the structure of the upstream riser (or downstream riser) of the present invention.

[0039] Figure 4It is a plan view of the channel water flow pattern monitoring device of the present invention arranged in a rectangular channel.

[0040] Figure 5 It is a schematic elevation view of the channel water flow pattern monitoring device of the present invention arranged in a rectangular channel.

[0041] Figure 6 It is a block diagram of the circuit control system of the present invention.

[0042] Figure 7 It is a flow chart of the flow measurement method of the present invention. DETAILED DESCRIPTION

[0043] The following is a detailed description of an embodiment of the present invention in conjunction with the accompanying drawings. This embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation method and a specific operation process are given, but the protection scope of the present invention is not limited to the following embodiment.

[0044] like Figure 1-6 As shown, the open channel flowmeter for rectangular channel flow monitoring of the present invention is composed of a channel water flow form monitoring device arranged in the rectangular channel and a flow monitoring controller arranged outside the rectangular channel.

[0045] The channel water flow form monitoring device comprises a wall-attached vertical plate 2 connected to the channel side wall 1, a water-facing side vertical plate 3 and a water-receiving side vertical plate 4 connected to the wall-attached vertical plate 2; the water-facing side vertical plate 3, the water-receiving side vertical plate 4 and the wall-attached vertical plate 2 form a vertical tube with an isosceles triangle cross section, such as Figure 2 shown.

[0046] Filter holes 5.1 for eliminating water flow disturbance are evenly distributed on the plate surface of the water-facing side plate 3 and the water-receiving side plate 4. The filter holes 5.1 are rectangular vertical hole structures, which are easier to eliminate water flow disturbance. A base 6 is provided at the lower tube mouth of the vertical tube; a partition 7 is provided in the vertical tube to divide the inner cavity of the vertical tube into two upstream tube cavities 8 and downstream tube cavities 9 with right-angled triangle cross sections. The upstream tube cavity 8 and the downstream tube cavity 9 are respectively provided with upstream side risers 10 and downstream side risers 11. Filter holes 5.2 for eliminating water flow disturbance are respectively provided on the circumference of the upstream and downstream side risers 10 and 11. The filter holes 5.2 are rectangular vertical hole structures, which are easier to eliminate water flow disturbance; notches 12 are respectively provided on the bottom tube walls of the upstream and downstream side risers 10 and 11, so that the canal water can smoothly enter the upstream and downstream side risers 10 and 11.

[0047] An upstream side pressure water level monitor 13 and a downstream side pressure water level monitor 14 are respectively arranged in the upstream and downstream side risers 10 and 11 on the base 6. The control interfaces and power interfaces of the upstream and downstream side pressure water level monitors 13 and 14 are respectively led out from the upper tube mouth of the riser through cables, and the control interface cables are connected to the flow monitoring controller.

[0048] like Figure 6 As shown, the flow monitoring controller includes: a basic parameter input control module, which is used to input the rectangular channel width, the vertical tube water blocking width and the monitoring control parameters (monitoring period, collection frequency) and store them in the memory; a control module, which is used to issue control instructions to control the upstream and downstream side pressure water level monitors 13 and 14 to synchronously collect the water levels of the channel sections they monitor within the set monitoring period according to the set collection frequency and calculate the average water level within the set monitoring period and the area of ​​the water-passing section under the average water level; an instantaneous flow monitoring calculation module, which is used to calculate the average flow of the monitored section within the set monitoring period.

[0049] like Figure 1-7 As shown, the flow measurement method of the open channel flowmeter of the present invention comprises the following steps:

[0050] S1, construct the three-section flow measurement environment of the rectangular channel:

[0051] An open channel flow meter is installed on the channel sidewall 1 at the designated monitored section Le in the channel 15, the steps are as follows:

[0052] S1.1, place the base 6 of the vertical tube on the bottom of the channel, make the partition 7 in the vertical tube overlap with the monitored section Le, fix the wall-attached vertical plate 2 to the channel side wall, and extend the upper tube mouth of the vertical tube above the channel 15;

[0053] S1.2, set the section where the upstream side vertical edge 16 of the water-facing side vertical plate 3 is located as the upstream monitoring section Ls, and set the section where the downstream side vertical edge 17 of the water-receiving side vertical plate 4 is located as the downstream monitoring section Lx; the upstream side pressure water level monitor 13 is used to monitor the water level during the set monitoring period Δ t The water level of the upstream monitoring section Ls is collected according to the set collection frequency, and the downstream pressure water level monitor 14 is used to collect the water level of the upstream monitoring section Ls in the set monitoring period Δ t The water level of the downstream monitoring section Lx is collected according to the set collection frequency;

[0054] S2, the control module issues a control instruction to control the upstream and downstream pressure water level monitors 13 and 14 to monitor the water level during the set monitoring period Δ t According to the set acquisition frequency, the water level data of the upstream monitoring section Ls and the downstream monitoring section Lx are collected synchronously, and the water level data of the set monitoring period Δ t The average water level hs data of the upstream monitoring section Ls, the average water level hx data of the downstream monitoring section Lx, and the average water flow area of ​​the monitored section Le Data, average water flow area of ​​upstream monitoring section Ls Data, average water flow area of ​​downstream monitoring section Lx Data; Among them, the average water area of ​​the monitored section Le Equal to the average water flow area of ​​the upstream monitoring section Ls Subtract the water blocking area of ​​the vertical tube below the average water level hs of the monitoring section Ls on the upstream side (water blocking area of ​​the vertical tube: the projection area of ​​the vertical plate 3 on the water-upstream side below the average water level hs of the monitoring section Ls, perpendicular to the channel axis);

[0055] S3, flow calculation of monitored section Le:

[0056] The control module will obtain the average water level hs data, average water level hx data, and average water area Data, average water area Data and average water area The data is output to the instantaneous flow monitoring calculation module, which derives the Δ based on the above parameters according to the energy conservation principle of the three sections. t The calculation method of average flow rate during a period is as follows:

[0057] According to the three-section energy conservation principle, the instantaneous average total energy E of the upstream monitoring section Ls is LS Subtract the instantaneous average total energy E of the downstream monitoring section Lx Lx Equal to the average momentum change ΔE of the monitored section Le Lx ,in:

[0058] ;

[0059] ;

[0060] At the same time, according to the channel flow continuity equation Q s =Q x =Q e have:

[0061] ;

[0062] Thus we get ;

[0063] Q s : The upstream monitoring section Ls is in Δ t Average flow rate during the time period;

[0064] Q x : Downstream monitoring section Lx in Δ t Average flow rate during the time period;

[0065] Q e : The monitored section Le is in Δ tAverage flow rate during the time period;

[0066] m : Δ t The average quality of water flowing through the three sections Ls, Le, and Lx during a period of time;

[0067] V s : The upstream monitoring section Ls is in Δ t Average flow rate during the time period;

[0068] V x : Downstream monitoring section Lx in Δ t Average flow rate during the time period;

[0069] V e : The monitored section Le is in Δ t Average flow rate during the time period;

[0070] g - acceleration due to gravity.

[0071] In S2, the monitoring period ∆t is set between 5 seconds and 60 seconds, and the collection frequency is 2-3 times per second. The average water level hs data of the upstream monitoring section Ls and the average water level hx data of the downstream monitoring section Lx are calculated once in each monitoring period ∆t. When calculating the average water level hs data and the average water level hx data, the maximum value and the minimum value are removed respectively and the average value is taken.

Claims

1. An open channel flow meter for rectangular channel flow monitoring, characterized in that: The invention comprises a channel water flow form monitoring device arranged in a rectangular channel and a flow monitoring controller arranged outside the rectangular channel; the channel water flow form monitoring device comprises a wall-attached vertical plate used to be connected to the channel side wall, a water-facing side vertical plate and a water-receiving side vertical plate connected to the wall-attached vertical plate; the water-facing side vertical plate, the water-receiving side vertical plate and the wall-attached vertical plate constitute a vertical tube with an isosceles triangle cross section, and filter holes for eliminating water flow disturbance are opened on the plate surfaces of the water-facing side vertical plate and the water-receiving side vertical plate, and a base is arranged at the lower tube mouth of the vertical tube; a partition is arranged in the vertical tube to separate the inner cavity of the vertical tube It is an upstream cylinder cavity and a downstream cylinder cavity with two right-angled triangle cross-sections, wherein an upstream riser and a downstream riser are respectively arranged in the upstream cylinder cavity and the downstream cylinder cavity, and filter holes for eliminating water flow disturbance are respectively opened on the circumference of the upstream and downstream risers; an upstream pressure water level monitor and a downstream pressure water level monitor are respectively arranged in the upstream and downstream risers on the base, and the control interfaces of the upstream and downstream pressure water level monitors are led out from the upper cylinder port of the riser through cables, and the control interface cables are connected to the flow monitoring controller.

2. The open channel flowmeter for rectangular channel flow monitoring according to claim 1, characterized in that: The flow monitoring controller comprises: A basic parameter input control module, used to input the rectangular channel width, the vertical tube water blocking width and monitoring control parameters and store them in a memory; A control module, used to issue control instructions to control the upstream and downstream pressure water level monitors to synchronously collect the water levels of the channel sections monitored by each of them according to the set collection frequency within the set monitoring period and calculate the average water level within the set monitoring period and the area of ​​the water-passing section of the average water level; The instantaneous flow monitoring and calculation module is used to calculate the instantaneous average flow of the monitored section within the set monitoring period and calculate the average flow of the monitored section within the set monitoring time period.

3. The open channel flow meter for rectangular channel flow monitoring according to claim 1 or 2, characterized in that: The filter holes arranged on the surface of the water-incoming side vertical plate, the surface of the water-incoming side vertical plate and the peripheral surfaces of the upstream and downstream side vertical pipes are all rectangular vertical holes.

4. The open channel flow meter for rectangular channel flow monitoring according to claim 1 or 2, characterized in that: Notches are respectively opened on the bottom pipe walls of the upstream and downstream side risers, so that canal water can smoothly enter the upstream and downstream side risers.

5. The flow measurement method of the open channel flowmeter according to claim 1, characterized in that: The steps include: S1, construct the three-section flow measurement environment of the rectangular channel: A channel flow pattern monitoring device is installed on the channel side wall at the designated monitored section Le in the channel, and the steps are as follows: S1.1, place the base of the vertical tube on the bottom of the channel, overlap the partition in the vertical tube with the monitored section Le, fix the wall-attached vertical plate to the channel side wall, and extend the upper tube mouth of the vertical tube above the channel; S1.2, set the upstream side of the water-facing side plate as the upstream monitoring section Ls, set the downstream side of the water-receiving side plate as the downstream monitoring section Lx; the upstream side pressure water level monitor is used to monitor the water level during the set monitoring period Δ t The water level of the upstream monitoring section Ls is collected according to the set collection frequency, and the downstream pressure water level monitor is used to collect the water level of the upstream monitoring section Ls in the set monitoring period Δ t The water level of the downstream monitoring section Lx is collected according to the set collection frequency; S2, the control module issues a control instruction to control the upstream and downstream pressure water level monitors to monitor the water level during the set monitoring period Δ t According to the set acquisition frequency, the water level data of the upstream monitoring section Ls and the downstream monitoring section Lx are collected synchronously, and the water level data of the set monitoring period Δ t The average water level hs data of the upstream monitoring section Ls, the average water level hx data of the downstream monitoring section Lx, and the average water flow area of ​​the monitored section Le Data, average water flow area of ​​upstream monitoring section Ls Data, average water flow area of ​​downstream monitoring section Lx Data; Among them, the average water area of ​​the monitored section Le Equal to the average water flow area of ​​the upstream monitoring section Ls Subtract the water blocking area of ​​the channel flow pattern monitoring device below the average water level hs of the upstream monitoring section Ls; S3, flow calculation of monitored section Le: The control module will obtain the average water level hs data, average water level hx data, and average water area Data, average water area Data and average water area The data is output to the instantaneous flow monitoring calculation module, which derives the Δ based on the above parameters according to the energy conservation principle of the three sections. t The calculation method of average flow rate during a period is as follows: According to the three-section energy conservation principle, the instantaneous average total energy E of the upstream monitoring section Ls is LS Subtract the instantaneous average total energy E of the downstream monitoring section Lx Lx Equal to the average momentum change ΔE of the monitored section Le Lx ,in: ； ； ； ； At the same time, according to the channel flow continuity equation Q s =Q x =Q e have: ； Thus we get ； Q s : The upstream monitoring section Ls is in Δ t Average flow rate during the time period; Q x : Downstream monitoring section Lx in Δ t Average flow rate during the time period; Q e : The monitored section Le is in Δ t Average flow rate during the time period; m : Δ t The average quality of water flowing through the three sections Ls, Le and Lx during a period of time; V s : The upstream monitoring section Ls is in Δ t Average flow rate during the time period; V x : Downstream monitoring section Lx in Δ t Average flow rate during the time period; V e : The monitored section Le is in Δ t Average flow rate during the time period; g - acceleration due to gravity.

6. The monitoring method of the open channel flowmeter according to claim 5, characterized in that: In S2, the monitoring period Δt is set between 5 seconds and 60 seconds, the acquisition frequency is 2-3 times per second, and the average water level hs data of the upstream monitoring section Ls and the average water level hx data of the downstream monitoring section Lx are calculated once in each monitoring period Δt; when calculating the average water level hs data and the average water level hx data, the maximum value and the minimum value are removed respectively and the average value is taken.

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