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Performance sampling verification method for propeller current meter

A current meter and propeller technology, which is applied in the field of sampling verification of the performance of the propeller current meter in river hydrological testing, can solve the problems of lack of technical index monitoring means, high labor intensity, and car collision accidents, and achieve scientific process operation, low labor intensity, The effect of high test accuracy

Inactive Publication Date: 2012-09-12
JIANGSU NANSHUI TECH
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  • Abstract
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  • Claims
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AI Technical Summary

Problems solved by technology

[0007] 2. Problems existing in mass production verification of current flow meters
According to Newton's third law: the action force and the reaction force are generated at the same time and are interdependent; when the waves aroused by the instrument hit the surrounding tank walls, they will be reflected and act on the instrument. After repeated superposition, the situation is very complicated and does not conform to the flow velocity Therefore, the verification system does not have the national measurement legal accuracy, that is, the verification accuracy of the flow meter cannot be guaranteed, and there are the following problems:
There is no way to count the error and quantity of type b) and type c) false detections, and they have been found in the inspection and verification;
[0011] (3) Assignment deviation: There are certain differences in the assignment of verification results between different tanks and the same tank at different times, which is unfavorable for flood control, irrigation, national economic water resource utilization, and hydrological flow reorganization;
[0012] (4) Labor intensity: Batch production inspections require overtime and overtime work. Workers are exhausted. In order to complete the production quota on time, workers have short rest time and even have to eat on the inspection car. Working overtime late at night is mentally exhausted, driving at high speed, and mental stress , the labor intensity is high, and there have been crashes;
[0013] (5) Production efficiency: The verification speed is 0.04-4m / s, with a total of 16 measuring points. After the high-speed verification is completed, the low-speed verification must be performed after the "water body is calm", and the production efficiency is low;
[0014] (6) Working conditions: "Calm water body" is only a personal feeling, lacking strict technical indicators and corresponding monitoring means;
[0015] (7) Power consumption: The weight of the verified vehicle group is 0.3 to 11 tons, and the power is 4 to 364 kilowatts, which consumes a lot of energy;
[0031] (3) Sampling method: The American verification flow meter adopts random sampling. Due to the above-mentioned problems of individual accuracy, its overall accuracy is poor
[0032] (4) Flume verification: determined by the international standard ISO 2537, the verification of the flow meter is a random measurement, and there are random errors and systematic errors
According to the above individual accuracy and the problems existing in mass production verification of flow meters, the current simple random sampling method cannot ensure individual and overall accuracy

Method used

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  • Performance sampling verification method for propeller current meter
  • Performance sampling verification method for propeller current meter
  • Performance sampling verification method for propeller current meter

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Embodiment Construction

[0068] The following is an explanation of the theory of this case, a block-by-block description of the preferred scheme of this case, and a verification result combined with specific examples.

[0069] Related Explanation of Theory

[0070] 1. Hydraulic pitch K of the propeller current meter

[0071] Assuming that the instrument has no internal friction resistance, the main parameters of the motion equation of the propeller current meter are deduced by the theory of fluid mechanics:

[0072] K={[C Y / (C X -C Y )tan 2 α]+[C X / (C Y -C X )]}πDtanα (2)

[0073] In the formula: C X is the propeller surface resistance coefficient; C Y is the resistance coefficient of the propeller airfoil structure; tanα is the propeller tangent of the measured cross-section of the propeller; the big scratch is the propeller drag coefficient, represented by B; πDtanα is the geometric pitch of the propeller, represented by H; so the above formula is simplified as:

[0074] K=BH (3)

[00...

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Abstract

The invention discloses a performance sampling verification method for a propeller current meter. According to the method, a relation of propeller helical angles alpha, an inner friction moment M of a rotary supporting component and the verification performance of a propeller current meter is established, and aiming at mass production, the values of the alpha and the M are precisely determined; the alpha values are finely grouped, and according to a method of non-random quota sampling for the totality, random sampling for groups and weighted statistics for a result, a sample machine is precisely verified under a still water condition; meanwhile, theoretical calculating values are supplemented in verification for analysis and reference for correcting errors in time; through the measures, the total precision of the sample machine is guaranteed to be high; meanwhile, medium high and low speed standard linear formulas are used to ensure that the use of a hydrological testing current meter is precise and convenient; in production, the defects of the traditional mass production are overcome, and the workloads of verification works, labor intensity, power consumption, equipment overhaul and maintenance, and the like are reduced by 2 / 3; and the operation of verification procedures is scientific and normative and conforms to a modern production mode and a national standardized technical policy, so that the method has the advantages of better scientific, social and economic benefits.

Description

technical field [0001] The invention relates to a method for sampling and verifying the performance of a propeller current meter for hydrological testing of rivers. Background technique [0002] 1. Performance verification of flow meter [0003] The current meter is used to measure the speed of river water flow, and its performance verification is based on the principle of relative motion of objects: assuming that the river flow is a static water body, when measuring the flow, the current meter fixed on the measuring point is a moving body. The verification equipment designed according to this is a straight open channel with long water tanks, and tracks are laid on both sides of the bank. T run, and at the same time detect the corresponding speed n output by the current meter, assuming the speed of the test vehicle V T is the standard input quantity V, that is, V T =V, through the verification of the flow meter verification tank, determine the medium and high speed perfor...

Claims

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Application Information

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IPC IPC(8): G01P21/02
Inventor 杨汉塘周冬生杨立丽王为朴
Owner JIANGSU NANSHUI TECH
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