Method for calculating flow based on water level and flow velocity data acquired by equipment

Abstract

The invention relates to a method for calculating flow based on water level flow velocity data acquired by equipment. The method comprises the following steps: acquiring original equipment and originally set parameters; calculating the area of each subsection surface according to the actually reported water level; according to the calculated area of each subsection surface, matching the scene flow velocity and the subsection surface area of each subsection surface, and calculating the flow of the subsection surface; and calculating the flow of the whole section according to the sectional surface flow. Meanwhile, optimization processing is carried out aiming at the special conditions that rivers are blocked by rockfall, sundries exist in the field and the like, meanwhile, a safe flow limiting mechanism and a peak elimination processing algorithm are added in the processing process, and the problems that at the present stage, data coverage of water conservancy platforms is incomplete, analysis conducted by previous equipment collecting data lacks platform computing power, and data analysis efficiency is poor are solved. And the requirement of platform calculation on the water regimen data under special conditions is met. Through the intelligent algorithm of the platform, the accuracy of data and the stability of the platform are ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of water area monitoring, and in particular to a method for calculating flow rate based on water level and flow velocity data collected by equipment. Background Art

[0002] The Smart Water Conservancy Platform is a comprehensive management system that leverages modern information technologies such as the Internet of Things, big data, cloud computing, and artificial intelligence to provide intelligent management and decision-making support for water conservancy facilities and water resources. The Smart Water Conservancy Solution provided by Shuzhineng offers comprehensive support for reservoirs, hydropower stations, rivers, irrigation areas, and more, with the following features:

[0003] 1. Data collection and integration:

[0004] Collect various types of hydrological data, meteorological data, water quality data and water conservancy project operation data.

[0005] Integrate data from different sources and formats and establish unified data standards and specifications.

[0006] There are devices on the market that can calculate flow, but if the river span is large, the corresponding equipment may be limited, making it impossible to calculate flow with a single device. Furthermore, if the terrain or cross-section changes, the device algorithm may not be able to adjust the calculation rules, thus affecting the data.

[0007] The platform mainly displays the collected data, and abnormal data is mainly discovered, processed and recovered manually.

[0008] 2. Real-time monitoring and early warning:

[0009] Real-time monitoring of important hydrological stations, water conservancy projects and water resources.

[0010] Establish an early warning mechanism to issue warnings for extreme weather, floods, droughts and other disasters.

[0011] 3. Data analysis and decision support:

[0012] Use big data analysis technology to mine historical data and predict future hydrological conditions and water resource changes.

[0013] Provide decision support tools to assist managers in formulating strategies for water resource allocation, flood control and drought relief.

[0014] 4. Resource management and optimized scheduling:

[0015] Carry out refined management of water resources and allocate and schedule them rationally.

[0016] Optimize the operation plan of water conservancy projects and improve the utilization efficiency of water resources.

[0017] 5. Visual display:

[0018] Complex data can be presented intuitively through charts, maps, etc. to facilitate user understanding and use.

[0019] Therefore, the deficiencies in the current prior art are:

[0020] 1. The data dimension is single, only monitoring basic parameters such as water level and rainfall

[0021] 2. Data processing relies on device reporting. When there are multiple devices, the platform lacks computing power.

[0022] 3. Lack of computing support for special scenarios, such as shielding part of the collected data and removing invalid area data.

[0023] 4. There may be hidden dangers in protecting against abnormal equipment configuration, that is, whether the platform stability can be guaranteed when the equipment reports high voltage.

[0024] 5. Abnormal data cannot be automatically detected and peak eliminated. Summary of the Invention

[0025] This invention aims to overcome the shortcomings of existing technologies by proposing a method for calculating flow rates based on water level and flow velocity data collected by equipment. This method addresses issues such as data coverage, computing power, and handling special scenarios in water conservancy monitoring. By integrating multi-source data and intelligent flow calculation, the method improves the comprehensiveness, accuracy, and emergency response capabilities of water conservancy monitoring, making it suitable for a variety of practical applications, including water conservancy monitoring and emergency management.

[0026] The present invention solves the technical problem by adopting the following technical solutions:

[0027] The method for calculating flow rate based on water level and flow rate data collected by equipment includes the following steps:

[0028] Step 1: Get the original device and the parameters of the original settings;

[0029] Step 2: Calculate the area of each segmented surface based on the actually reported water level and the parameters set in the previous step;

[0030] Step 3: According to the calculated area of each segmented surface, match the scene flow velocity and cross-sectional area of each segmented surface to calculate the segmented surface flow rate;

[0031] Step 4: Calculate the flow rate of the entire section based on the segmented surface flow rate and end.

[0032] Moreover, the specific implementation method of step 1 is: on-site technicians obtain the starting distance and the corresponding riverbed elevation, and use the starting distance and the riverbed elevation as a vertical line, and obtain the cross-section of the water area based on the obtained vertical line.

[0033] Moreover, the starting point distance is the distance between the collection point on the river and the starting point, with one side of the river channel as the starting point; the river bottom elevation is the elevation of the river bottom corresponding to the collection point.

[0034] Moreover, the specific implementation method of step 2 is: if both the left and right vertical lines are above the water level, there is no section;

[0035] If the elevation of the vertical line on one side is higher than the water level, the calculation method of the cross-sectional water area is:

[0036] [Length of water surface*(water level-low point elevation)] / 2

[0037] The calculation method of the water-passing surface length is:

[0038] |Difference in distance from starting point|*[(water level - low point elevation) / (high point elevation - low point elevation)]

[0039] If the elevation of the vertical lines on both sides is lower than or equal to the water level, the calculation method of the cross-sectional water area is:

[0040] [(water level - elevation of the left vertical line) + (water level - elevation of the right vertical line)] * \difference in distance from the starting point\ / 2.

[0041] Moreover, the specific implementation method of step 3 is:

[0042] Segmented surface flow rate = scene flow rate corresponding to the segmented surface * segmented surface area.

[0043] Moreover, the specific implementation method of step 4 is: calculating the sum of the flow rates of the segmented surfaces to be equal to the flow rate of the entire section.

[0044] Furthermore, it also includes a flow method for special scenarios, which includes the following steps:

[0045] Step 5: traverse the flow velocity data to obtain the flow velocity v0 before and after the boundary point;

[0046] Take the two flow velocities v1 and v2 at the two ends of the interval range and use the linear average method to calculate the boundary point flow velocity: let the interval between the starting point data of v1 and the starting point data of the boundary point be d1, and the interval between the starting point data of d2 and the starting point data of the boundary point be d2, then the boundary point flow velocity v0 is:

[0047]

[0048] If there is flow velocity on only one side of the boundary, the boundary flow velocity is the single-side flow velocity;

[0049] Step 6: Calculate the starting velocity value and the surface velocity value;

[0050] Step 7: Calculate the node velocity value and the surface velocity value;

[0051] Step 8: Calculate the range average flow rate;

[0052] The range average velocity is the mean of the two boundary velocity values:

[0053]

[0054] Step 9, calculate the river bottom elevation at the starting point;

[0055] Step 10, calculate the river bottom elevation of the node;

[0056] The riverbed elevation at the boundary of the range is calculated as:

[0057] Take the riverbed elevations zb1 and zb2 of the two vertical lines at both ends of the interval range, and use the linear average method to calculate the boundary vertical line elevation. Assume that the interval between vertical line 1 and the starting point of the boundary vertical line is d1, and the interval between vertical line 2 and the starting point of the boundary vertical line is d2. Then the elevation zb of the boundary vertical line is:

[0058]

[0059] If there is a vertical line on only one side of the boundary, the boundary velocity is the vertical line on that side;

[0060] Step 11: Integrate the Vo list used to calculate the cross-sectional area;

[0061] Step 12: Calculate the range area. The calculation method of the interval range area is: the sum of the cross-sectional areas of all vertical lines within the interval range;

[0062] The calculation method of the cross-sectional area is:

[0063] Both left and right vertical lines are above the water level: no section

[0064] The elevation of the vertical line on one side is higher than the water level: the triangle formula is used to calculate the area of the segmented surface.

[0065]

[0066] The elevation of the vertical lines on both sides is lower than or equal to the water level: the trapezoidal formula is used to calculate the cross-sectional area.

[0067]

[0068] Step 13: Calculate the range flow rate;

[0069] The range flow rate is calculated as:

[0070] Q=v 区间 *Sum(cross-sectional area)

[0071] Get a list of range results.

[0072] The advantages and positive effects of the present invention are:

[0073] The present invention obtains the original equipment and the parameters of the original settings; calculates the area of each segmented surface according to the actually reported water level; matches the scene flow velocity and cross-sectional area of each segmented surface according to the calculated area of each segmented surface, calculates the flow of the segmented surface; and calculates the flow of the entire section based on the flow of the segmented surface. At the same time, the present invention optimizes and processes special situations such as fallen rocks blocking the river and the presence of debris on site. At the same time, a safety flow limiting mechanism and a peak elimination processing algorithm are added during the processing process, solving the problems of incomplete data coverage of various water conservancy platforms at this stage, the lack of platform computing power for data collection and analysis by previous equipment, and the requirement for platform computing of water situation data under special circumstances. The present invention ensures the accuracy of data and the stability of the platform through the platform's intelligent algorithm. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] Figure 1 This is a system structure diagram used in the present invention;

[0075] Figure 2 This is a software architecture diagram of the present invention;

[0076] Figure 3 This is a schematic diagram showing the calculation of platform flow rate according to an embodiment of the present invention;

[0077] Figure 4 This is a schematic diagram of the actual cross-section situation configured on site by on-site technicians in the present invention;

[0078] Figure 5 Calculate the area of each cross-section for the present invention;

[0079] Figure 6 Schematic diagram of the flow calculation method under a special scenario of the present invention;

[0080] Figure 7 This is a flow chart of the flow calculation method under special scenarios of the present invention. DETAILED DESCRIPTION

[0081] The present invention is further described below in conjunction with the accompanying drawings.

[0082] The flow calculation method based on the water level and flow rate data collected by the equipment is applied to Figure 1 The traffic calculation system structure shown in the figure includes users, communication networks, water conservancy equipment, a higher-level domain platform, and lower-level domain platforms. The platform is deployed in a secure network environment and is accessible to both internal and external networks. If deployed in an external network, a bastion host and firewall are typically used to ensure platform security. The platform also supports both upstream and downstream platforms. For example, if the platform is deployed at the district, county, provincial, or municipal level, the higher-level platform can pull configurations from lower-level platforms and synchronize real-time data with them.

[0083] like Figure 2 Shown is the software architecture of the present invention application

[0084] 1. Perception layer: multi-source sensor device network

[0085] Combine Figure 1 It can be seen that the platform's perception of data mainly comes from water conservancy equipment, water conservancy sensors, third-party equipment and platforms. The flow calculation algorithm mainly solves the situation where the flow equipment used on site cannot calculate the flow data according to the actual scenario and requires platform intervention for calculation.

[0086] 2. Transport layer: internal and external network data communication, software and hardware protocol docking

[0087] To address data input from multiple device networks, the platform has a dedicated docking layer for access processing. This layer supports parsing device protocols, standard water conservancy protocols (such as 206 / 651), mainstream docking protocols like HTTP and MQTT, and FTP file and image protocols. It also uses NIFI to perform data diversion, verification, and cleaning, parsing multiple data sources into a unified data stream format.

[0088] 3. Platform layer: business middle platform of microservice architecture

[0089] The core part is mainly water conservancy data collection services and basic information management services

[0090] The basic information management service mainly provides basic configuration. For this invention, it mainly provides river section configuration and effective range settings for special terrain.

[0091] The water conservancy data collection service processes and stores all access data. This invention mainly provides the ability to calculate flow, combining the configuration of basic information management services with water level and scene flow rate data to calculate flow.

[0092] 4. Application layer: Web / mobile / large-screen multi-terminal applications

[0093] Figure 2 The platform primarily features UI presentation (a single water conservancy map and a large screen displaying comprehensive water conservancy data), as well as live command presentations that combine real-time video and data. In addition to the presentations shown in the diagram, the platform can also be accessed through the app.

[0094] The flow calculation method includes the following steps:

[0095] Step 1: Get the original device and the parameters of the original settings.

[0096] The specific implementation method of step 1 is: obtain the starting distance and river bottom elevation through on-site technicians, and use the starting distance and river bottom elevation as a vertical line to obtain the cross section of the water area based on the obtained starting distance and river bottom elevation. The starting distance is the distance from the collection point on the river to the starting point, with one side of the river as the starting point; the river bottom elevation is the elevation of the river bottom corresponding to the collection point. According to the configuration, the following cross sections can be obtained Figure 4 The device collects scene flow rate data, and the scene flow rate reports a flow rate data for each section (the area between two vertical lines).

[0097] Step 2: Figure 5 As shown in the figure, the area of each segmented surface is calculated based on the actual reported water level.

[0098] The specific implementation method of step 2 is: if both the left and right vertical lines are above the water level, there is no section;

[0099] If the elevation of the vertical line on one side is higher than the water level, the calculation method of the cross-sectional water area is:

[0100] [Length of water surface*(water level-low point elevation)] / 2

[0101] The calculation method of the water-passing surface length is:

[0102] |Difference in distance from starting point|*[(water level - low point elevation) / (high point elevation - low point elevation)]

[0103] If the elevation of the vertical lines on both sides is lower than or equal to the water level, the calculation method of the cross-sectional water area is:

[0104] [(water level - elevation of the left vertical line) + (water level - elevation of the right vertical line)] * \difference in distance from the starting point\ / 2.

[0105] Step 3: Based on the calculated area of each segmented surface, match the scene flow velocity and cross-sectional area of each segmented surface to calculate the segmented surface flow.

[0106] The specific implementation method of step 3 is:

[0107] Segmented surface flow rate = scene flow rate corresponding to the segmented surface * segmented surface area.

[0108] Step 4: Calculate the flow rate of the entire section based on the segmented surface flow rate.

[0109] The specific implementation method of step 4 is: calculate the sum of the flow rates of the segmented surfaces to be equal to the flow rate of the entire section.

[0110] Considering some special situations that may occur on site, such as fallen rocks blocking the river, the presence of debris on site, etc. These situations will lead to the need to demarcate the river as an area for data processing, such as Figure 5As shown, five areas are identified, and the data in these five areas are used for traffic calculation. Therefore, the traffic calculation method for special scenarios is as follows:

[0111] Step 5: traverse the flow velocity data to obtain the flow velocity v0 before and after the boundary point (the surface flow velocity is the same as the scene flow velocity);

[0112] Take the two flow velocities v1 and v2 at the two ends of the interval range and use the linear average method to calculate the boundary point flow velocity: let the interval between the starting point data of v1 and the starting point data of the boundary point be d1, and the interval between the starting point data of d2 and the starting point data of the boundary point be d2, then the boundary point flow velocity v0 is:

[0113]

[0114] If there is flow velocity on only one side of the boundary, the boundary flow velocity is the single-side flow velocity;

[0115] Calculate the starting point velocity value and surface velocity value;

[0116] Calculate node velocity values and surface velocity values;

[0117] Calculate the range average flow rate;

[0118] The range average velocity is the mean of the two boundary velocity values:

[0119]

[0120] Calculate the river bottom elevation at the starting point;

[0121] Calculate the river bottom elevation of the node;

[0122] The riverbed elevation at the boundary of the range is calculated as:

[0123] Take the riverbed elevations zb1 and zb2 of the two vertical lines at both ends of the interval range, and use the linear average method to calculate the boundary vertical line elevation. Assume that the interval between vertical line 1 and the starting point of the boundary vertical line is d1, and the interval between vertical line 2 and the starting point of the boundary vertical line is d2. Then the elevation zb of the boundary vertical line is:

[0124]

[0125] If there is a vertical line on only one side of the boundary, the boundary velocity is the vertical line on that side;

[0126] Integrate the Vo list used to calculate the cross-sectional area;

[0127] Calculate the range area;

[0128] The calculation method of the interval range area is: the sum of the cross-sectional areas of all vertical lines within the interval range;

[0129] The calculation method of the cross-sectional area is:

[0130] Both left and right vertical lines are above the water level: no section

[0131] The elevation of the vertical line on one side is higher than the water level: the triangle formula is used to calculate the area of the segmented surface.

[0132]

[0133] The elevation of the vertical lines on both sides is lower than or equal to the water level: the trapezoidal formula is used to calculate the cross-sectional area.

[0134]

[0135] Calculate range flow;

[0136] The range flow rate is calculated as:

[0137] Q=v 区间 *Sum(cross-sectional area)

[0138] Get a list of range results.

[0139] The present invention also adds a safety current limiting mechanism and a peak elimination processing algorithm. The main current limiting data of the safety current limiting mechanism are water level, scene flow velocity and flow rate:

[0140] The flow rate of water level and flow data is limited by the collection interval. In theory, a single data item is reported in a single collection interval. The data limit for a single collection interval can be configured. For example, a maximum of 5 data items can be received. If the frequency is exceeded during data processing, the data in the current interval will be discarded. The flow rate data in the scene is a group of data, which is more complex to process. The main logic is as follows:

[0141] (1) Each set of scene flow rate data contains a group number as the group identifier.

[0142] (2) Obtain the number of data groups within the current time interval and limit the flow if it exceeds the threshold.

[0143] (3) Two issues are explained regarding the current limiting algorithm:

[0144] (4) The flow limiting mechanism does not simply rely on unit time or unit measurement station, but rather limits the flow of data within the collection interval. The platform supports resuming transmission after network disconnection. The data reporting rate during resuming transmission will be very high and will not be restricted by the flow limiting mechanism.

[0145] (5) The calculation of this mechanism, especially the flow rate part, is relatively time-consuming. In order not to affect the data reception speed, asynchronous concurrent processing is performed, which can intercept abnormal reports without affecting the current data reception.

[0146] The specific implementation method of the peak elimination processing algorithm is as follows:

[0147] (1) First, the platform will configure a fluctuation value. This fluctuation value is not compared with the previous data, but with the difference between the previous two data, that is, whether the increase or decrease rate of the data is within the standard range.

[0148] (2) Another value that needs to be configured is the peak elimination recovery accuracy. If the configured accuracy is 5, the result value after peak elimination is calculated based on the five data before the current data and the fluctuation value. The specific calculation algorithm is as follows:

[0149] Growth is greater than the fluctuation threshold: Repair peak = [sum of the previous n data items + (previous 1 data item + fluctuation threshold)] / (n+1)

[0150] The drop is greater than the fluctuation threshold: Repair peak value = [sum of the previous n data items + (previous data item - fluctuation threshold)] / (n+1)

[0151] Technical implementation: Record nearly n pieces of data (which can be water level, flow rate, flow rate and other dimensions) through a cache queue (first-in-first-out) and perform rolling maintenance.

[0152] (3) If peak elimination is triggered, a peak alarm will be triggered. The operation and maintenance personnel can further check whether the equipment has any abnormal data collection based on the peak alarm.

[0153] According to the above method for calculating flow rate based on water level and flow velocity data collected by equipment, the effect of the present invention has been illustrated through on-site analysis of two typical basins of the Yellow River.

[0154] River Basin A scenario: The river channel is wide and a single velocity ball cannot cover and further calculate the flow.

[0155] The calculation process of the present invention involves configuring one water level ball and 13 flow velocity balls to report water level and flow velocity, configuring basic river information on the platform, and calculating flow rate based on the algorithm of the present invention. The resulting flow rate is then compared with historical data and other algorithms to ensure accurate results. This solves the problem of equipment limitations.

[0156] Scenario B in River Basin: Due to the influence of the mountain, a huge rock is blocking the river channel, making the flow velocity data in a certain area of reference less meaningful, and the area needs to be re-divided for calculation.

[0157] The calculation process of the present invention is as follows: effective area division is configured on the platform, and flow calculation is performed according to the above algorithm, eliminating the interference of abnormal area data, so that the calculated flow is basically consistent with normal data.

[0158] In addition, multiple sites including the Yellow River site have been put into use. Even when the equipment reports abnormal data, the platform can ensure accurate and smooth field data based on the peak clipping algorithm described in the present invention.

[0159] There have been cases of abnormal human configuration on site. The reporting interval was not configured, resulting in multiple devices continuously reporting. The platform can ensure that the platform itself is not affected by current limiting.

[0160] It should be emphasized that the embodiments described in the present invention are illustrative rather than restrictive. Therefore, the present invention includes but is not limited to the embodiments described in the specific embodiments. Any other embodiments derived by those skilled in the art based on the technical solutions of the present invention also fall within the scope of protection of the present invention.

Claims

1. A method for calculating flow rate based on water level and flow rate data collected by equipment, characterized in that: The following steps are involved: Step 1: Get the original device and the parameters of the original settings; Step 2: Calculate the area of each segmented surface based on the actual reported water level and the parameters set in step 1; Step 3: According to the calculated area of each segmented surface, match the scene flow velocity and cross-sectional area of each segmented surface to calculate the segmented surface flow rate; Step 4: Calculate the flow rate of the entire section based on the segmented surface flow rate and end.

2. The method for calculating flow rate based on water level and flow rate data collected by equipment according to claim 1, characterized in that: The specific implementation method of step 1 is: on-site technicians obtain the starting distance and the corresponding river bottom elevation, and use the starting distance and the river bottom elevation as a vertical line to obtain the cross-section of the water area based on the obtained vertical line.

3. The method for calculating flow rate based on water level and flow rate data collected by equipment according to claim 2, characterized in that: The starting point distance is the distance between the collection point on the river and the starting point, with one side of the river channel as the starting point; the riverbed elevation is the elevation of the riverbed corresponding to the collection point.

4. The method for calculating flow rate based on water level and flow rate data collected by equipment according to claim 1, characterized in that: The specific implementation method of step 2 is: if both the left and right vertical lines are above the water level, there is no section; If the elevation of the vertical line on one side is higher than the water level, the calculation method of the cross-sectional water area is: [Length of water surface*(water level-low point elevation)] / 2 The calculation method of the water-passing surface length is: |Difference in distance from starting point|*[(water level - low point elevation) / (high point elevation - low point elevation)] If the elevation of the vertical lines on both sides is lower than or equal to the water level, the calculation method of the cross-sectional water area is: [(water level - elevation of the left vertical line) + (water level - elevation of the right vertical line)] * \difference in distance from the starting point\ / 2 Among them, the high point elevation is the elevation above the water level value at the base elevation, and the low point elevation is the elevation below the water level value.

5. The method for calculating flow rate based on water level and flow rate data collected by equipment according to claim 1, characterized in that: The specific implementation method of step 3 is: Segmented surface flow rate = scene flow rate corresponding to the segmented surface * segmented surface area.

6. The method for calculating flow rate based on water level and flow rate data collected by equipment according to claim 1, characterized in that: The specific implementation method of step 4 is: calculating the sum of the flow rates of the segmented surfaces to be equal to the flow rate of the entire section.

7. The method for calculating flow rate based on water level and flow rate data collected by equipment according to claim 1, characterized in that: It also includes a flow method for special scenarios, which includes the following steps: Step 5: traverse the flow velocity data to obtain the flow velocity v0 before and after the boundary point; Take the two flow velocities v1 and v2 at the two ends of the interval range and use the linear average method to calculate the boundary point flow velocity: let the interval between the starting point data of v1 and the starting point data of the boundary point be d1, and the interval between the starting point data of d2 and the starting point data of the boundary point be d2, then the boundary point flow velocity v0 is: If there is flow velocity on only one side of the boundary, the boundary flow velocity is the single-side flow velocity; Step 6: Calculate the starting velocity value and the surface velocity value; Step 7: Calculate the node velocity value and the surface velocity value; Step 8: Calculate the range average flow rate; The range average velocity is the mean of the two boundary velocity values: Step 9, calculate the river bottom elevation at the starting point; Step 10, calculate the river bottom elevation of the node; The riverbed elevation at the boundary of the range is calculated as: Take the riverbed elevations zb1 and zb2 of the two vertical lines at both ends of the interval range, and use the linear average method to calculate the boundary vertical line elevation. Assume that the interval between vertical line 1 and the starting point of the boundary vertical line is d1, and the interval between vertical line 2 and the starting point of the boundary vertical line is d2. Then the elevation zb of the boundary vertical line is: If there is a vertical line on only one side of the boundary, the boundary velocity is the vertical line on that side; Step 11: Integrate the Vo list used to calculate the cross-sectional area; Step 12: Calculate the range area. The calculation method of the interval range area is: the sum of the cross-sectional areas of all vertical lines within the interval range; The calculation method of the cross-sectional area is: Both left and right vertical lines are above the water level: no section The elevation of the vertical line on one side is higher than the water level: the triangle formula is used to calculate the area of the segmented surface. The elevation of the vertical lines on both sides is lower than or equal to the water level: the trapezoidal formula is used to calculate the cross-sectional area. Step 13: Calculate the range flow rate; The range flow rate is calculated as: Q=v 区间 *Sum(cross-sectional area) Get a list of range results.

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