CN112556610A - Method for measuring equivalent diameter of irregular hole in energy-gathered blasting - Google Patents
Method for measuring equivalent diameter of irregular hole in energy-gathered blasting Download PDFInfo
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- CN112556610A CN112556610A CN202011413954.7A CN202011413954A CN112556610A CN 112556610 A CN112556610 A CN 112556610A CN 202011413954 A CN202011413954 A CN 202011413954A CN 112556610 A CN112556610 A CN 112556610A
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B13/00—Measuring arrangements characterised by the use of fluids
- G01B13/08—Measuring arrangements characterised by the use of fluids for measuring diameters
- G01B13/10—Measuring arrangements characterised by the use of fluids for measuring diameters internal diameters
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Abstract
The invention belongs to the field of energy-gathered blasting efficiency evaluation and pore diameter measurement, and particularly relates to a method for measuring the equivalent diameter of an irregular hole in energy-gathered blasting. The invention solves the problem of measuring the equivalent diameter of the irregular hole in the energy-gathering blasting in the weapon industry, and is also suitable for measuring the equivalent diameter of the irregular hole in other industries.
Description
Technical Field
The invention belongs to the field of energy-gathered blasting efficiency evaluation and pore diameter measurement, and particularly relates to a method for measuring equivalent diameter of an irregular hole of energy-gathered blasting.
Background
The size of a broken hole caused by a jet flow or a bullet formed after the energy-gathering warhead explodes on a target plate is an important quantitative parameter for evaluating the damage efficiency of the energy-gathering warhead. Because explosion is a very rapid energy release process, huge impact load acts on the target plate to form broken holes, and the target plate is deformed, warped and torn at the same time, so that the shapes of the broken holes on the target plate are very irregular, and the accurate measurement of the diameters of the broken holes on the target plate is very difficult.
For measuring the diameter of a broken hole formed on a target plate after energy-gathered blasting, a common method comprises a graduated scale direct measurement method, an optical indirect measurement method and the like. For the direct measuring method of the graduated scale, the advantage is that the measurement is simple and convenient, direct, the disadvantage is that the measurement accuracy is not high, especially for the broken hole with distorted target plate shape and irregular appearance, it is difficult to obtain the accurate measured data directly, the measuring error is very large, basically in centimeter level; for the indirect optical measurement method, the method has the advantages of being capable of measuring the diameters of distorted and irregular holes, and has the disadvantages of high cost and easily influenced test results by post-processing methods and human factors. Moreover, these measurement methods are only the measurement of the distance between two points on the irregular hole, and a plurality of test values are obtained, and due to the extreme irregularity of the shape of the hole, it is difficult to accurately determine the equivalent diameter of the irregular hole, and thus it is difficult to perform the performance evaluation.
Disclosure of Invention
The technical problem solved by the invention is as follows: in order to measure the equivalent diameter of the irregular hole formed after the energy-gathered blasting, the method for measuring the equivalent diameter of the irregular hole is provided, and the problems that the precision of a direct measuring method of the graduated scale is not high, the cost of an optical indirect measuring method is high, and the method is easily influenced by human factors are solved.
The technical scheme of the invention is as follows: a method for measuring equivalent diameter of irregular holes of energy-gathered blasting comprises the following steps:
step 1: after the diameters of the irregular holes are preliminarily estimated, the diameters D of a plurality of standard target plate through holes are determined, wherein the irregular hole diameter value is located between a plurality of standard hole diameter values;
step 2: respectively carrying out water flow tests on a plurality of standard target plates by using the same container, wherein the initial water capacity in the container is the same before each test, carrying out a plurality of tests on the same standard target plate, averaging the flow passing through the through holes of the standard target plates after the tests, and returning the water capacity in the container to the initial capacity after each test; defining the distance between the horizontal plane in the container and the through hole of the standard target plate before the test is started as H1, and the cross-sectional area of the container is A; the volume V of the final outflow water is related to the diameter D of the through hole of the standard target plate by:
wherein V0Indicates that the liquid level is H1The volume of water, g is the gravity acceleration, t is the test time, mu represents the flow coefficient;
further obtaining: v is with respect to D4A polynomial of (D), V ═ f (D)4)；
And step 3: and (3) performing data fitting on the relation between V and D according to the average value of the plurality of standard target plates obtained in the step (2) to obtain a formula of the standard target plate 'target plate aperture-water flow':
V＝a1×D4+a2×D3+a3×D2+a4×D+a5
wherein V represents the flow rate of water and has a unit of L; d represents the aperture of the target plate and the unit is mm; a is1、a2、a3、a4、a5The coefficients obtained for the fitting;
and 4, step 4: the flow value of the water flowing through the irregular holes in the step 2 test is measured as V within the same initial water volume, the same time period and the same pressureS；
And 5: v obtained in the step 4SThe fitting formula of 'target plate aperture-water flow' of the standard target plate is substituted to obtain the equivalent diameter D of the irregular hole0。
The further technical scheme of the invention is as follows: the pore diameter interval of the upper and lower 10cm of the irregular pore diameter value is 2-3mm, and the pore diameter interval of the pore diameter of the.
The further technical scheme of the invention is as follows: mu is the flow coefficient of the outflow from the orifice of the target plate, and the value of mu is generally between 0.58 and 0.9.
The further technical scheme of the invention is as follows: the preliminary estimation means that ruler measurement is carried out on irregular aperture, the maximum and minimum positions of the broken aperture are measured respectively, and the average value is taken.
Effects of the invention
The invention has the technical effects that: based on the reasons, the invention provides the method for measuring the equivalent diameter of the irregular hole by comparing the flow of water flowing through the circular regular through hole and the irregular hole under certain pressure within certain time, not only can measure the equivalent diameter of the irregular hole, but also can avoid the influence of human factors, and meanwhile, the measurement precision is higher and can reach 2 mm. The method is suitable for measuring the equivalent diameter of the irregular hole, is close to practical engineering application, is simple and convenient, is easy to implement and has lower cost.
Drawings
FIG. 1: schematic structural diagram of standard target plate
FIG. 2: unsteady flow schematic
Detailed Description
In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be considered as limiting the present invention.
Referring to fig. 1-2, a technical solution for an energy-gathered blasting irregular hole equivalent diameter measurement method is as follows: measuring the flow of water flowing through the standard target plate under the same initial condition, at the same pressure and in the same time period, recording the corresponding flow of water of different apertures of the standard target plate under the same condition, and obtaining a formula of 'aperture of the target plate-flow of water' through data fitting. The standard target plate is schematically structured as shown in fig. 1, and has a circular through hole in the center, which has the same material and the same thickness as the target plate to be measured (irregular hole). And then measuring the flow of water flowing through the irregular holes under the same condition, at the same pressure and in the same time period, considering that the equivalent diameter of the measured irregular holes corresponds to the diameter of the circular through hole of the standard target plate under the same flow, and substituting the flow value of the irregular holes into a formula obtained by fitting standard target plate flow data to obtain the equivalent diameter of the irregular holes.
The water flowing through the target plate is unsteady, and as shown in fig. 2, the cross-sectional area a of the container is set to be constant. It should be noted that if the container is a cylinder, it is a cylinder in cross section; if the vessel is cylindrical above and inverted conical below, this is again a cylindrical cross-section, i.e. water from H1-H2In the meantime. The container is preferably a cylinder, provided that the volume of water to be dispensed can be calculated if the container is not a cylinder. In this example, the vessel is a cylinder with a cross-section a. The area of the through hole of the target plate is a, and when the distance between the free liquid level and the center of the through hole is y, the flow Q of the through hole in the dt time period can be calculated by using a constant outflow formula: the dt is a derivative concept, and refers to any time interval from t0 to t1, the flow rate of water in the dt time interval is firstly obtained, and then the dt is integrated in the t0 to t1 time interval to obtain the flow rate of water flowing through the whole time interval.
Throughout the test, the parameter at the beginning of the test (i.e., at time t 0) has a value of H1、V0A, the parameters in the test process are mu, g, a, t, y and D, and the parameter at the end of the test (time t 1) is H2、V1，Q、V。
In the formula, μ represents a flow coefficient; g represents the gravitational acceleration.
If the liquid flow decreases by dy height during dt, the volume of liquid flowing out through the through-hole should be equal to the volume of liquid falling in the container according to the continuity equation, which is given by equation (1):
according to the formula (2):
the liquid level in the container is obtained from H by integrating the formula (3)1Down to H2The required time t is:
the relationship between the volume of the outflow water and the outflow time t is established according to equation (4), namely:
in the formula, V0Indicates that the liquid level is H1The volume of water; v1Indicates that the liquid level is H2The volume of water.
Deducing the volume V of the inflow water at the time t through the formula (5) as follows:
substituting the diameter D of the through hole of the target plate into the formula (6) to obtain the relation between the volume V of the outflow water and the diameter D of the through hole of the target plate as follows:
as can be seen from equation (7), V is with respect to D4I.e.:
V＝f(D4) (8)
the following describes a method for measuring the equivalent diameter of an irregular hole of energy-gathered blasting in detail by combining specific embodiments.
The invention can be achieved by the following steps:
the method comprises the following steps: on the premise of roughly measuring the diameter of the irregular hole, the diameters of a series of standard target plate circular through holes are determined, the diameter range from small to large needs to cover the roughly measured diameter of the irregular hole, the larger the number of target plates is, the closer the test value is to the true value, but if the number of target plates is too large, the test cost is greatly increased under the condition that the test precision is not obviously improved. Therefore, the aperture interval around the rough diameter is preferably 2-3mm, the rest is preferably 5mm, and the minimum aperture is preferably 40mm, which can be adjusted according to the actual engineering. In this example, the diameter of the rough-measured irregular hole is about phi mm, and the standard target plate is determined to have the hole diameters of (phi-20) mm, (phi-15) mm, (phi-10) mm, (phi-5) mm, (phi-2) mm, phi mm, (phi +2) mm, (phi +5) mm, (phi +10) mm, (phi +15) mm and (phi +20) mm, respectively.
Step two: the flow of water flowing through the standard target plate with different apertures under the same initial condition, under the same pressure and in the same time period is measured, the average value can be measured for multiple times, the flow of the water flowing through the through hole under the same condition of the different apertures of the standard target plate is recorded, and the pressure value can be determined according to the actual application of engineering. In this embodiment, the standard target plate determined in step one is used, the flow value of water flowing through the standard target plate within time t is recorded, the average value is obtained by measuring 3 times, the pressure value is one atmosphere, and the test data is shown in table 1.
TABLE 1 flow recording chart of water corresponding to different apertures of standard target plate
| Serial number | Target plate aperture D (mm) | Flow rate V (L) | Remarks for |
| 1 | Φ-20 | |
|
| 2 | Φ-15 | V02 | |
| 3 | Φ-10 | V03 | |
| 4 | Φ-5 | V04 | |
| 5 | Φ-2 | V05 | |
| 6 | Φ | V06 | |
| 7 | Φ+2 | V07 | |
| 8 | Φ+5 | V08 | |
| 9 | Φ+10 | V09 | |
| 10 | Φ+15 | V10 | |
| 11 | Φ+20 | V11 |
Step three: and (3) fitting the data according to the relation between V and D in the formula (8) by using the data in the table 1 to obtain a formula of the standard target plate 'target plate aperture-water flow'. In this embodiment, the relation of "target plate aperture-water flow" of the standard target plate obtained by data fitting is:
V＝a1×D4+a2×D3+a3×D2+a4×D+a5 (9)
wherein V represents the flow rate of water and has a unit of L; d represents the aperture of the target plate and the unit is mm; a is1、a2、a3、a4、a5Obtained by fittingAnd (4) the coefficient. The parameters can be arbitrarily given, for example, the fitting formula is V10 × D4+20×D3+30×D2+40 XD +50, V measured in step fourSD is 2.465mm by substituting 1000L into the formula.
Step four: and (3) measuring the flow rate of the water flowing through the irregular holes under the same condition, wherein the measuring method is the same as the step two, and the initial condition, the pressure and the water flowing time are the same. In this example, the flow rate of water flowing through the irregular holes at one atmospheric pressure over time t was measured as VS。
Step five: and substituting the flow value of the irregular hole obtained in the fourth step into a fitting formula of 'target plate aperture-water flow' of the standard target plate to obtain the equivalent diameter of the irregular hole. In this example, V isSSubstituting into formula (9) to obtain the equivalent diameter of the irregular hole as D0。
In summary, the above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (4)
1. A method for measuring equivalent diameter of irregular holes of energy-gathered blasting is characterized by comprising the following steps:
step 1: after the diameters of the irregular holes are preliminarily estimated, the diameters D of a plurality of standard target plate through holes are determined, wherein the irregular hole diameter value is located between a plurality of standard hole diameter values;
step 2: respectively carrying out water flow tests on a plurality of standard target plates by using the same container, wherein the initial water capacity in the container is the same before each test, carrying out a plurality of tests on the same standard target plate, averaging the flow passing through the through holes of the standard target plates after the tests, and returning the water capacity in the container to the initial capacity after each test; defining the distance between the horizontal plane in the container and the through hole of the standard target plate before the test is started as H1, and the cross-sectional area of the container is A; the volume V of the final outflow water is related to the diameter D of the through hole of the standard target plate by:
wherein V0Indicates that the liquid level is H1The volume of water, g is the gravity acceleration, t is the test time, mu represents the flow coefficient;
further obtaining: v is with respect to D4A polynomial of (D), V ═ f (D)4)；
And step 3: and (3) performing data fitting on the relation between V and D according to the average value of the plurality of standard target plates obtained in the step (2) to obtain a formula of the standard target plate 'target plate aperture-water flow':
V＝a1×D4+a2×D3+a3×D2+a4×D+a5
wherein V represents the flow rate of water and has a unit of L; d represents the aperture of the target plate and the unit is mm; a is1、a2、a3、a4、a5The coefficients obtained for the fitting;
and 4, step 4: the flow value of the water flowing through the irregular holes in the step 2 test is measured as V within the same initial water volume, the same time period and the same pressureS；
And 5: v obtained in the step 4SThe fitting formula of 'target plate aperture-water flow' of the standard target plate is substituted to obtain the equivalent diameter D of the irregular hole0。
2. The method for measuring the equivalent diameter of an irregular hole for energy-gathered blasting according to claim 2, wherein the interval of the diameters of the irregular hole within the upper and lower 10cm is 2-3mm, and the interval of the diameters of the irregular hole outside the 10cm is 5 mm.
3. The method for measuring the equivalent diameter of the irregular hole for shaped blasting according to claim 1, wherein μ is a flow coefficient of outflow from the orifice of the target plate, and is generally 0.58-0.9.
4. The method for measuring the equivalent diameter of the irregular hole of the energy-gathered blasting according to claim 1, wherein the preliminary estimation is that the ruler measurement is carried out on the irregular hole diameter, the maximum and minimum positions of the hole-breaking diameter are respectively measured, and the average value is taken.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110986838A (en) * | 2019-11-19 | 2020-04-10 | 中国船舶重工集团公司第七0五研究所 | Device and method for measuring equivalent diameter of explosion hole |
| CN113175902A (en) * | 2021-04-19 | 2021-07-27 | 西安交通大学 | Pneumatic measuring device and method for micro-aperture |
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| CN108280268A (en) * | 2017-12-29 | 2018-07-13 | 中国人民解放军陆军工程大学 | Pressure vessel Parameters design for examining underwater demolition equipment performance |
| CN110986838A (en) * | 2019-11-19 | 2020-04-10 | 中国船舶重工集团公司第七0五研究所 | Device and method for measuring equivalent diameter of explosion hole |
| CN111488683A (en) * | 2020-04-09 | 2020-08-04 | 西安工业大学 | Fragment flying parameter determination method based on image processing technology |
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2020
- 2020-12-04 CN CN202011413954.7A patent/CN112556610A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| US20050257603A1 (en) * | 2004-01-09 | 2005-11-24 | Fujikin Incorporated And Tadahiro Ohmi | Small hole diameter automatic measuring apparatus, small hole diameter measurement method, and shower plate manufacturing method |
| CN105805559A (en) * | 2016-05-31 | 2016-07-27 | 中国石油大学(华东) | Liquid-phase pipe leakage irregular hole equivalent round hole experimental device and experimental method |
| CN108280268A (en) * | 2017-12-29 | 2018-07-13 | 中国人民解放军陆军工程大学 | Pressure vessel Parameters design for examining underwater demolition equipment performance |
| CN110986838A (en) * | 2019-11-19 | 2020-04-10 | 中国船舶重工集团公司第七0五研究所 | Device and method for measuring equivalent diameter of explosion hole |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN110986838A (en) * | 2019-11-19 | 2020-04-10 | 中国船舶重工集团公司第七0五研究所 | Device and method for measuring equivalent diameter of explosion hole |
| CN113175902A (en) * | 2021-04-19 | 2021-07-27 | 西安交通大学 | Pneumatic measuring device and method for micro-aperture |
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