A method for testing the range of a water cannon in an aquatic environment

Abstract

A method for testing the range of a water cannon in an aquatic environment, relating to the field of water cannons. The method includes the following steps: constructing a water cannon test platform; mounting the water cannon on the platform to spray water for testing; establishing a two-dimensional coordinate system with the intersection of the water cannon's outlet perpendicular to a preset horizontal plane as the origin; collecting the trajectory information of the water cannon's jet stream within the two-dimensional coordinate system and fitting it to establish a jet trajectory fitting equation; calculating the water cannon's range under shipboard conditions based on the jet trajectory fitting equation and the water cannon's testing requirements. This method obtains the water cannon's jet stream trajectory data, fits it to obtain the jet trajectory fitting equation, and then calculates the water cannon's range under shipboard conditions. It solves the problem that high-power water cannons cannot be tested under rated operating conditions due to limitations in land-based testing conditions, filling a gap in domestic methods for testing the free jet performance of water cannon equipment in aquatic environments.

Description

Technical Field

[0001] This application relates to the field of water cannons, specifically to a method for testing the range of a water cannon in an aquatic environment. Background Technology

[0002] Besides being used as a land-based firefighting tool and riot control weapon, water cannons are also widely used on various fireboats and government vessels. Range and flow rate are their most important performance indicators. While flow rate testing is relatively simple, range testing is more complex. The testing standards for water cannons specify the definition and testing methods for range: Range testing must be conducted in an open, flat area; under wind speed conditions of less than 2 m / s, the water cannon's elevation angle should be 30 ± 2°, the water cannon outlet height from the ground should not exceed 3 m, and the water should be sprayed in the downwind direction; once the water cannon inlet pressure reaches the rated working pressure and stabilizes, a stopwatch should be used to measure the farthest point of continuous spraying of the medium over a period of at least 10 seconds. The origin (starting point) is the intersection of the plumb line from the water cannon outlet and the ground; the horizontal distance from the farthest point to the origin is the water cannon range.

[0003] For water cannons with high flow rates and high lift, when the power of the water cannon is relatively large (e.g., 2400m), 3 Taking a water cannon with a flow rate of / h as an example (the water cannon pump power is above 1600kW), the requirements for the driving power of the water cannon pump are relatively high. Sufficient water supply and an open area with a diameter of at least 300m are needed for testing, and local environmental regulations must be met. Water cannon manufacturers generally lack the land-based testing conditions for high-power water cannons, making it impossible to conduct water cannon range tests during the factory testing phase. Furthermore, the laboratory environment and the actual shipboard operating environment are not entirely consistent. Typically, when water cannon performance testing is conducted after installation on a ship, the height of the water cannon above the water surface is generally much greater than 3m. Even when setting up targets on the water surface to test the water cannon's range, the test results will be greater than the actual range of the water cannon, affecting the research and development and use of the water cannon.

[0004] Therefore, a method for testing the range of water cannons in an aquatic environment is needed to verify the range indicators of water cannons. Summary of the Invention

[0005] The purpose of this application is to provide a method for testing the range of water cannons in aquatic environments, which solves the problem that high-power water cannons cannot be tested under rated operating conditions due to limitations in land-based testing conditions, and fills the gap in domestic methods for testing the free jet performance of water cannon equipment in aquatic environments.

[0006] This application is implemented as follows:

[0007] This application provides a method for testing the range of a water cannon in a marine environment, including the following steps:

[0008] A water cannon test platform was set up, and the water cannon was installed on the water cannon test platform to spray water for testing;

[0009] A two-dimensional coordinate system is established with the intersection of the vertical line drawn from the water cannon's outlet and the preset horizontal plane as the origin.

[0010] The motion trajectory information of the water jet from the water cannon in a two-dimensional coordinate system is collected and fitted to establish the jet trajectory fitting equation;

[0011] The range of the water cannon under ship loading conditions was calculated based on the jet trajectory fitting equation and the water cannon test requirements.

[0012] In some alternative implementations, when the water cannon is mounted on a water cannon test platform to spray water for testing, the height of the water cannon's outlet from the ground of the water cannon test platform is kept within 3 meters.

[0013] In some alternative implementations, when the water cannon is mounted on a water cannon test platform to spray water for testing, the elevation angle of the water cannon is adjusted to 15° to 45°.

[0014] In some optional implementations, when fitting the trajectory curve of the water jet in a two-dimensional coordinate system to establish the jet trajectory fitting equation, the jet trajectory fitting equation is established by fitting the coordinates of at least three points of the trajectory of the water jet in the two-dimensional coordinate system.

[0015] In some alternative implementations, when fitting the trajectory curve of the water jet in a two-dimensional coordinate system to establish the jet trajectory fitting equation, the jet trajectory fitting equation is established based on the coordinates of the water jet at the water cannon outlet, at the highest point, and at the impact buoy target.

[0016] In some alternative implementations, when fitting the trajectory curve of the water jet in a two-dimensional coordinate system to establish the jet trajectory fitting equation, the jet trajectory fitting equation is established based on the coordinates of the water jet at the water cannon outlet, the highest point, the impact buoy target, and at least one other location.

[0017] In some alternative implementations, the coordinates (x, y) of the jet water flow at its highest point are... C y C The following formula is used to calculate:

[0018]

[0019] In the formula, x C Let y be the x-coordinate of the highest point of the jet stream, m; Cdenoted as ordinate of the highest point of the jet stream, in meters; h is the height of the water cannon muzzle relative to the horizontal plane, in meters; v0 is the initial velocity of the water droplets in the jet stream, in meters per second; and the elevation angle of the water cannon muzzle is 30 degrees.

[0020] In some optional implementations, when fitting the trajectory curve of the water jet in a two-dimensional coordinate system to establish the jet trajectory fitting equation, image recognition or laser ranging is used to obtain the coordinates of the trajectory of the water jet in the two-dimensional coordinate system.

[0021] The beneficial effects of this application are as follows: The water cannon range testing method provided by this application in aquatic environment includes the following steps: setting up a water cannon aquatic test platform, installing the water cannon on the platform to spray water for testing; establishing a two-dimensional coordinate system with the intersection of the water cannon's outlet perpendicular to a preset horizontal plane as the origin; collecting the motion trajectory information of the water cannon's spray in the two-dimensional coordinate system and fitting it to establish a jet trajectory fitting equation; calculating the water cannon range under ship mounting conditions based on the jet trajectory fitting equation and the water cannon test requirements. The water cannon range testing method provided by this application in aquatic environment obtains the jet trajectory fitting equation by acquiring the water cannon's spray trajectory data and then calculates the water cannon range under ship mounting conditions. This solves the problem that high-power water cannons cannot be tested under rated operating conditions due to limitations in land-based test conditions, and fills the gap in domestic water cannon equipment free jet performance testing methods in aquatic environments. Attached Figure Description

[0022] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 A flowchart illustrating the water cannon range testing method in an aquatic environment provided in this application embodiment;

[0024] Figure 2 This is a schematic diagram of the XY two-dimensional coordinate system established by using the intersection of the water cannon outlet as the vertical line and the preset horizontal plane as the origin in the water cannon range testing method in the water environment provided in Embodiment 1 of this application.

[0025] Figure 3 This is a schematic diagram of the forces acting in the air during the rising phase of the water jet in the water cannon's range test method in an aquatic environment, as provided in Embodiment 1 of this application.

[0026] Figure 4This is a schematic diagram of the water cannon jet trajectory fitting curve in the water cannon range testing method provided in Embodiment 1 of this application. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of this application, but not all embodiments.

[0028] Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0029] The features and performance of the water cannon range testing method in the aquatic environment described in this application are further described in detail below with reference to the embodiments.

[0030] like Figure 1 As shown in the figure, this application provides a method for testing the range of a water cannon in a marine environment, including the following steps:

[0031] Step 1: Construct a water cannon test platform according to the water cannon range testing method and requirements. Install the water cannon on the test platform to spray water for testing. Place a buoy target on the water surface and direct the water cannon's spray at the buoy target. Optionally, the height of the water cannon's outlet from the ground of the test platform should be within 3 meters. Optionally, the elevation angle of the water cannon can be adjusted to 15°–45°. Optionally, the elevation angle can be adjusted to 30°. Optionally, the water cannon test platform can be constructed on a river, lake, or sea surface. The water surface refers to river water, lake water, or sea water. In this embodiment, the horizontal plane refers to the horizontal plane or sea level.

[0032] Step 2, as follows Figure 2 As shown, a two-dimensional XY coordinate system is established with the intersection of the vertical line from the water cannon's outlet and the preset horizontal plane as the origin. The direction of the water cannon's launch is the positive X-axis, and the vertical upward direction is the positive Y-axis. The water cannon launches water in the direction of the wind.

[0033] Step 3: Collect the trajectory information of the water jet in the two-dimensional coordinate system, and establish the jet trajectory fitting equation based on the coordinates of at least three points on the trajectory of the water jet in the two-dimensional coordinate system.

[0034] Because the water jet launched by the water cannon is prone to divergence in the latter half of its trajectory, i.e., the water column breaks up, making its trajectory simulation very difficult, this study only analyzes the trajectory characteristics of the water jet in the rising stage. The water micro-particles in the water jet launched by the water cannon are taken as the research object to analyze their forces and motion, and a fitting equation for the jet trajectory in the rising stage of the water jet is established.

[0035] Optionally, the water cannon jet trajectory curve is a parabola-like curve, fitted using a quadratic polynomial curve. The trajectory starts at the water cannon muzzle and ends at the buoy target position. Combining this with the position information of typical points in the middle of the water cannon jet, such as the highest point, the jet trajectory fitting equation is established using ORIGIN software. Optionally, the jet trajectory fitting equation is established by fitting the coordinates of the jet at the water cannon outlet, the highest point, and the point of impact on the buoy target. Optionally, the jet trajectory fitting equation is established by fitting the coordinates of the jet at the water cannon outlet, the highest point, the point of impact on the buoy target, and at least one other position.

[0036] Among them, when the elevation angle of the water cannon muzzle is 30°, the coordinates (x, y) of the highest point of the jet water flow are... C y C The following formula is used to calculate:

[0037]

[0038] In the formula, x C Let y be the x-coordinate of the highest point of the jet stream, m; C denoted as ordinate of the highest point of the jet stream, in meters; h is the height of the water cannon muzzle relative to the horizontal plane, in meters; v0 is the initial velocity of the water droplets in the jet stream, in meters per second.

[0039] Optionally, when fitting the trajectory curve of the water jet in the two-dimensional coordinate system to establish the jet trajectory fitting equation, image recognition or laser ranging can be used to obtain the coordinates of the trajectory of the water jet in the two-dimensional coordinate system.

[0040] Step 4: Calculate the water cannon range under ship loading conditions based on the jet trajectory fitting equation and water cannon test requirements. Based on the water cannon range test requirements and the Y coordinate information of the water cannon test platform, the X coordinate information of the corresponding point can be obtained, which is the water cannon range.

[0041] The water cannon range testing method provided in this application involves setting up a water cannon test platform and installing the water cannon on the platform to spray water. After obtaining the position information of several points on the water cannon jet trajectory, the jet trajectory curve is fitted to establish a jet trajectory fitting equation. Based on the actual ship test results, the actual range of the water cannon can be calculated according to the jet trajectory fitting equation. This method meets the range testing requirements of water cannons installed on actual ships in a water environment, solves the problem that high-power water cannons cannot be tested under rated operating conditions due to limitations in land-based test conditions, and fills the gap in domestic water cannon equipment free jet performance testing methods in a water environment.

[0042] Example 1

[0043] like Figure 1 As shown in the figure, this application provides a method for testing the range of a water cannon in a marine environment, including the following steps:

[0044] Step 1: Referring to the requirements for water cannon range testing in GB19156-2003 General Technical Conditions for Fire Monitors, build a water cannon test platform, install the water cannon on the water cannon test platform to spray water flow for testing, and set up a buoy target on the water surface so that the water flow sprayed by the water cannon hits the buoy target.

[0045] Step 2, as follows Figure 2 As shown, a two-dimensional XY coordinate system is established with the intersection of the vertical line from the water cannon outlet and the horizontal plane as the origin. The direction of the water cannon's ejection is defined as the positive X-axis, and vertically upward is defined as the positive Y-axis. The forces and motion of water particles in the water jet during the rising phase are analyzed. The aerial motion and forces of the water particles are shown in the figure. Figure 3 As shown.

[0046] Step 3: Collect the trajectory information of the water jet in the two-dimensional coordinate system, and establish the jet trajectory fitting equation based on the coordinates of four points on the trajectory of the water jet in the two-dimensional coordinate system.

[0047] Neglecting wind speed, the water jet particle is only affected by gravity and air resistance (ignoring buoyancy and Coriolis force); when the object's velocity is much lower than that of a low-velocity projectile, the air resistance can be approximated as proportional to the velocity. According to Newton's second law, the equations of motion for a unit mass of water jet particle in the x and y directions are as follows:

[0048]

[0049] In the formula, k is the air resistance coefficient, which is taken as 0.02 according to relevant literature. Assume the muzzle height of the water cannon is h, the initial velocity of the water particle is v0, the elevation angle is 30°, and g = 9.8m. 2Solving the above system of differential equations, we get:

[0050] x = 43.30v0(1-e -0.02t );

[0051] y = (24500 + 25v0)(1 - e -0.02t -490t+h;

[0052] v x =0.866v0e -0.02t ;

[0053] v y =(490+0.5v0)e -0.02t -490;

[0054] When the water particle rises to its highest point C, v y =0, the coordinates of point C can be obtained as follows:

[0055]

[0056] Using point O, the intersection of the perpendicular line drawn from the water cannon outlet and the horizontal plane, as the origin of the coordinate system, the coordinates of point A (water cannon outlet) and point E (buoy target) are (0, h) and (L1, h1) respectively, and the coordinates of point D are (L, h0), where L is the range of the water cannon. Based on the coordinate information of the points along the water cannon jet trajectory, a fitting curve equation for the water cannon jet trajectory is established, and the coordinates of point D are calculated to obtain the water cannon range.

[0057] With a flow rate of 2400m 3 Taking a water cannon with a flow rate of / h as an example, the cannon nozzle diameter is 125mm. Referring to the water cannon range test requirements in GB19156-2003 "General Technical Conditions for Fire Monitors", a marine environmental test platform for the water cannon range was constructed: the height of the water cannon outlet from the horizontal plane of the water cannon base was 2.5m, the water cannon elevation angle was adjusted to 30°, and the height of the horizontal plane of the water cannon base from the horizontal plane was h0 = 10m; a buoy target was set on the sea surface at a height h1 of 1m, and the horizontal distance from the farthest buoy target hit by the water cannon to the water cannon nozzle was 240m; a flow meter and pressure gauge were installed at the water cannon inlet, and after the water cannon reached the rated pressure, the water cannon flow rate was measured to be 2410m³ / h. 3 The calculated water flow velocity at the water cannon outlet is v0 = 54.55 m / s.

[0058] Based on the above conditions, the coordinates of points A, B, and E are A(0, 12.5), C(124.55, 49.10), and E(240, 1), respectively. To improve the accuracy of the trajectory fitting curve, the coordinates of point B (46.77, 34.64) at the water jet's travel time t = 1s are added as an auxiliary point for the fitting curve. Based on the coordinate information of the above four points, the ORIGIN software is used to establish the water jet trajectory fitting curve, as follows. Figure 4 As shown, the fitting equation for the water cannon jet trajectory is y = -0.003x. 2 +0.656x+11.782. According to y c =h0=10m, so the actual range of the water cannon is L=xc=226m.

[0059] It should be noted that the coordinates of points B and C are calculated and contain a certain degree of error. The actual coordinates of other water cannon trajectory points can be obtained using technologies such as image recognition or laser ranging. The actual measurement results should be used for water cannon trajectory curve fitting.

[0060] The embodiments described above are some, but not all, of the embodiments of this application. The detailed description of the embodiments of this application is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

Claims

1. A method for testing the range of a water cannon in a water environment, characterized in that, Includes the following steps: A water cannon test platform is set up, and the water cannon is installed on the water cannon test platform to spray water for testing; when the water cannon is installed on the water cannon test platform to spray water for testing, the height of the water cannon outlet from the ground of the water cannon test platform is within 3m. A two-dimensional coordinate system is established with the intersection of the perpendicular line drawn from the outlet of the water cannon and the preset horizontal plane as the origin. The motion trajectory information of the water jet from the water cannon in the two-dimensional coordinate system is collected and fitted to establish a jet trajectory fitting equation; When fitting the trajectory curve of the water jet in the two-dimensional coordinate system to establish the jet trajectory fitting equation, the jet trajectory fitting equation is established based on the coordinates of the water jet at the water cannon outlet, the highest point, the impact buoy target and at least one other position. The range of the water cannon in the ship-mounted state is calculated based on the jet trajectory fitting equation and the water cannon test requirements.

2. The method for testing the range of a water cannon in a water environment according to claim 1, characterized in that, When testing the water cannon by installing it on the water cannon test platform, the elevation angle of the water cannon should be adjusted to 15°~45°.

3. The method for testing the range of a water cannon in an aquatic environment according to claim 1, characterized in that, The coordinates (x) of the highest point of the jet stream C y C The following formula is used to calculate: ； ； In the formula, x C Let y be the x-coordinate of the jet of water at its highest point, m; C denoted as ordinate of the highest point of the jet water flow, in meters; h is the height of the water cannon muzzle relative to the horizontal plane, in meters; v0 is the initial velocity of the water droplets in the jet water flow, in meters per second; and the elevation angle of the water cannon muzzle is 30°.

4. The method for testing the range of a water cannon in a water environment according to claim 1, characterized in that, When fitting the trajectory curve of the water jet in the two-dimensional coordinate system to establish the jet trajectory fitting equation, image recognition or laser ranging is used to obtain the coordinates of the trajectory of the water jet in the two-dimensional coordinate system.

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