CN109341931B - Improved hydrostatic pressure testing experimental device and testing method - Google Patents
Improved hydrostatic pressure testing experimental device and testing method Download PDFInfo
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- CN109341931B CN109341931B CN201811024595.9A CN201811024595A CN109341931B CN 109341931 B CN109341931 B CN 109341931B CN 201811024595 A CN201811024595 A CN 201811024595A CN 109341931 B CN109341931 B CN 109341931B
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- 230000002706 hydrostatic effect Effects 0.000 title claims abstract description 110
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
- G01L7/00—Measuring the steady or quasi-steady pressure of a fluid or a fluent solid material by mechanical or fluid pressure-sensitive elements
- G01L7/02—Measuring the steady or quasi-steady pressure of a fluid or a fluent solid material by mechanical or fluid pressure-sensitive elements in the form of elastically-deformable gauges
- G01L7/024—Measuring the steady or quasi-steady pressure of a fluid or a fluent solid material by mechanical or fluid pressure-sensitive elements in the form of elastically-deformable gauges with mechanical transmitting or indicating means
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- G09B23/00—Models for scientific, medical, or mathematical purposes, e.g. full-sized devices for demonstration purposes
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Abstract
The invention discloses an improved hydrostatic pressure testing experimental device and a testing method. The water storage device is used for supporting the whole device and temporarily storing experimental water; the control mechanism is used for controlling water stored in the support to flow between the box body and the support; the leveling device is used for setting the box body in a horizontal state; the pressure-bearing device is used for converting hydrostatic pressure into a rotating moment of the pressure-bearing body; the measuring transmission device is used for converting the rotating moment of the pressure bearing device into the deformation of the torsion spring, the torque of the torsion spring is obtained through the deformation of the torsion spring, and then the numerical value of the hydrostatic pressure is obtained, so that the quantitative relation between the hydrostatic pressure and the water depth is obtained. The hydrostatic pressure measuring device is simple in structure and clear in principle, and by means of the technical design, the hydrostatic pressure can be accurately measured, the hydrostatic pressure rules of different water depths can be displayed, and the hydrostatic pressure action point can be determined.
Description
Technical Field
The invention relates to a hydraulics experiment teaching instrument and a test method thereof, in particular to an improved hydrostatic pressure test experimental device and a test method thereof.
Background
the existing hydrostatic pressure demonstration experimental device is rough in measurement and single in function, mainly comprises a water tank and a lever force measuring mechanism, and has the following principle: under the action of hydrostatic pressure, the pressure-bearing body deflects to push a lever connected with the pressure-bearing body to rotate, after a system is stabilized, a weight with certain mass is applied to one end of the lever, and the hydrostatic pressure is measured according to the lever balance principle.
However, the error between the hydrostatic pressure measured by the conventional device and a theoretical value is large due to systematic or random factors such as the difficulty in controlling the self weight of the lever and the precision of the weight, and the large error in the judgment of the system balance by human eyes. Considering the existing system, the inherent error and the operation error are inevitable. In summary, the conventional device can only roughly measure the hydrostatic pressure, and the measuring process is not intuitive and the principle is not obvious.
in addition, the existing hydrostatic pressure experimental device cannot reflect the relation between the hydrostatic pressure and the water depth. In the teaching process of hydraulics and hydrodynamics, hydrostatic pressure is an abstract concept, the hydrostatic pressure is in direct proportion to water depth, and a proportionality coefficient is the product of water density and gravity acceleration. For example: the original device can only measure a simple force value, and for students who contact the experiment for the first time, the experiment principle and the physical relation are abstract, so that the knowledge of the hydrostatic pressure is not deep, and certain interference is brought to the experiment teaching of hydraulics and hydrodynamics.
Disclosure of Invention
The purpose of the invention is as follows: in order to overcome the defects of the prior art, an improved hydrostatic pressure testing experimental device and a testing method are provided.
the technical scheme is as follows: the utility model provides a modified hydrostatic pressure test experimental apparatus, includes water storage device, control mechanism, levelling device, pressure-bearing device and measures transmission, wherein:
the water storage device comprises a support and a water storage tank, wherein the support is internally of a hollow structure and is used for storing experimental water;
The control mechanism is used for controlling water stored in the support to flow between the box body and the support;
The leveling device is used for setting the box body in a horizontal state;
the pressure-bearing device is used for converting hydrostatic pressure into the rotating moment of the pressure-bearing body;
And the measurement transmission device is used for converting the rotating torque of the pressure-bearing device into the deformation of the torsion spring, obtaining the torque of the torsion spring through the deformation of the torsion spring, further obtaining the quantitative relation between the hydrostatic pressure and the water depth, and thus obtaining the numerical value of the hydrostatic pressure.
preferably, the control mechanism comprises a small pump and a two-way valve, the two-way valve is respectively connected with the water inlet and the water outlet through hoses, and water stored in the support is controlled by the small pump to enter the box body through the two-way valve and the water inlet, or water in the box body is controlled to enter the support through the two-way valve and the water outlet.
preferably, the leveling device comprises three leveling screws and a level gauge, the three leveling screws are used for fixing the box body on the support, the lower end of each leveling screw is fixed on the support, the upper end of each leveling screw is connected with the lower bottom plate of the box body, one end of the bottom plate of the box body extends out of a platform, the platform is provided with the level gauge, and the level gauge is observed and the height of each leveling screw is adjusted to enable the box body to be in a horizontal position.
Preferably, the pressure-bearing device comprises a first pressure-bearing body, a second pressure-bearing body and a third pressure-bearing body; the pressure-bearing bodies are coaxially arranged and are of light quarter circular structures with different radiuses, the side surface of each pressure-bearing body is provided with a cylindrical convex rod which is respectively a first convex rod, a second convex rod and a third convex rod, and the distances from the third convex rod, the second convex rod and the first convex rod to the lower rectangular surface of the pressure-bearing body are sequentially increased; the side of each pressure-bearing body departing from the convex rod is marked with scales, and the convex rod is connected with the measuring transmission device through a round cake.
preferably, the measuring transmission device comprises a slideway, a transmission wire, an instrument support, a central shaft, a triple bearing and a measuring instrument, wherein,
the slideway is arranged on a flat plate near the inner wall of one side of the box body, which is far away from the small-sized pump machine, the flat plate is fixed through a clamping groove at the bottom of the box body, the slideway comprises a first slideway, a second slideway and a third slideway, the three slideways are respectively matched with three cylindrical convex rods on three pressure-bearing bodies and connected through a round cake, the cylindrical convex rods can move along the slideways, and the movement ranges of the corresponding cylindrical convex rods are allowed to be different by each slideway;
The triple bearing is three KONKAVE bearings which are arranged in parallel and respectively comprise a first bearing, a second bearing and a third bearing;
The measuring instrument comprises an instrument panel, a pointer, a torsion spring and a thin shaft, wherein the pointer is arranged on the front side of the instrument panel, the thin shaft is arranged on the back side of the instrument panel, and the torsion spring is wound on the thin shaft; the pointer comprises a first pointer, a second pointer and a third pointer, the torsion springs comprise a first torsion spring, a second torsion spring and a third torsion spring, the thin shaft is of a three-layer sleeve structure and comprises a first sleeve, a second sleeve and a third sleeve, balls are arranged among the sleeves, each sleeve is provided with a corresponding torsion spring, and the part of each sleeve, which extends out of the front face of the instrument panel, is connected with the corresponding pointer;
the measuring instrument is fixed at one end of the central shaft close to the slideway, a groove is formed in one end of the central shaft close to the slideway and used for placing a triple bearing, the triple bearing is indirectly contacted with the central shaft through a ball, three transmission wires are provided and are rigid wires which can not generate obvious length change under the action of force, and the three transmission wires are respectively a first transmission wire, a second transmission wire and a third transmission wire; each pressure bearing body corresponds to the corresponding sleeve and the pointer of the cylindrical convex rod, the transmission wire and the thin shaft one by one.
preferably, the torsion spring is made of a material having good elasticity and rotation properties.
in another embodiment of the present invention, an improved hydrostatic pressure testing method includes:
Opening the small pump and the two-way valve, and pumping a certain amount of water into the box body for later use;
Adjusting the volume of water in the two-way valve control box body, judging whether the water submerges the rectangular surface under all the pressure-bearing bodies, and if so, researching the rectangular distribution of hydrostatic pressure; if not, the triangular distribution of the hydrostatic pressure is researched;
After water is injected, the bearing body rotates, meanwhile, the cylindrical convex rod on the side face of the bearing body rotates, a transmission wire connected to the cylindrical convex rod bypasses a corresponding bearing in the triple bearing to generate displacement in the vertical direction, a corresponding sleeve of the thin shaft is pulled to rotate at a tangent point of the corresponding sleeve of the thin shaft, the sleeve rotates to drive a corresponding torsion spring to generate homodromous deformation, after the system is balanced, the angular displacement generated by the torsion spring is reflected on a dial plate through a pointer connected to the sleeve, and according to a quantitative relational expression, numerical values and positions of different hydrostatic pressures corresponding to the dial plate are determined, so that the quantitative relation between the water depth and the hydrostatic pressure is obtained.
furthermore, the two side surfaces of each pressure-bearing body are equal in size, the force borne by the arc-shaped surface passes through the center of the central shaft, the moment of hydrostatic pressure acting on the pressure-bearing body to the central shaft is generated only by the hydrostatic pressure acting on the rectangular plane, and different pointer angular displacements corresponding to the moments of different hydrostatic pressures to the central shaft are obtained according to a hydrostatic pressure direction rule formula (1) and space force system balance principle formulas (2) and (3) and based on a Hooke's law formula (4); the formula is as follows:
σ＝-p (1)；
∑Fi＝0 (2)；
∑Mi＝0 (3)；
wherein, sigma is the surface pressure on the surface of the pressure bearing body, p is the hydrostatic pressure at a certain point, FiFor any spatial force in the system, MiRepresents the moment of any force in the system to the central shaft, M is the moment, k is the stiffness coefficient of the torsion spring,The negative sign in formula (1) represents that the pressure of the bearing surface is along the normal direction in the surface of the bearing surface, which is the rotation angle of the thin shaft.
Further, by combining a hydrostatic pressure synthesis formula (5) and a hydrostatic pressure action point and centroid relation formula (6), the hydrostatic pressure relation at different water depth positions is obtained:
∫pds＝P (5)；
Wherein P is hydrostatic pressure, yDas coordinates of the hydrostatic pressure action point, yCIs a centroid coordinate of a rectangular surface of a pressure-bearing body, ICThe moment of inertia of the pressure-bearing body to the main shaft of the horizontal centroid, and A is the area of the rectangular surface of the pressure-bearing body.
Has the advantages that: compared with the prior art, the method is used for accurately and quantitatively measuring the hydrostatic pressure, and can also determine the hydrostatic pressure action point by setting a plurality of pressure-bearing bodies to show the hydrostatic pressure distribution rules under different water depths.
The invention is designed based on the hydrostatic basic equation, the force and moment balance principle. A torsion spring with a torsion angle in direct proportion to a couple of force is utilized to drive the pointer to deflect, and the hydrostatic pressure value is accurately measured.
The invention is an improvement on the basis of the existing experimental equipment. The existing instrument utilizes the lever principle to measure the pressure, and because the weight mass is discontinuous, the randomness exists in manual operation and other reasons, the error between the surface pressure value measured by the experiment and the theoretical value is larger. Besides the basic function of measuring the hydrostatic pressure, the invention can also intuitively and accurately illustrate the relationship between the hydrostatic pressure and the water depth.
the hydrostatic pressure measuring device is simple in structure and clear in principle, can measure hydrostatic pressure intuitively and accurately, and can determine a hydrostatic pressure action point. The device is beneficial to students to research the hydrostatic pressure distribution characteristics under the conditions of triangular pressure distribution and trapezoidal pressure distribution, and the intuitive understanding of the hydrostatic pressure action points is formed. The invention improves the determination principle and the determination method on the prior art, and provides a new experimental device for teaching of hydraulics and hydrodynamics experiments.
drawings
FIG. 1 is a schematic structural view of the present invention;
FIG. 2 is a back elevation view of the present invention;
FIG. 3 is a schematic structural view of a pressure-bearing device and a part of a measuring transmission device of the invention;
FIG. 4 is a schematic view of the slide of the present invention;
FIG. 5 is a schematic view of a portion of the measurement transmission of the present invention;
Fig. 6 is a schematic view of a thin shaft structure of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the following detailed description of the technical solutions of the present invention is made with reference to the accompanying drawings.
As shown in fig. 1 to 6, an improved hydrostatic pressure testing experimental device mainly comprises a water storage device 1, a control mechanism 2, a leveling device 3, a pressure-bearing device 4 and a measuring transmission device 5, wherein the water storage device comprises a support 11 and a water storage tank, and the water storage tank comprises a tank body 12, a water inlet 13 and a water outlet 14; the control mechanism comprises a small pump 21 and a two-way valve 22; the leveling device comprises a level gauge 31 and a leveling screw 32, and the pressure-bearing device comprises a first pressure-bearing body 41, a second pressure-bearing body 42 and a third pressure-bearing body 43; the measuring transmission device comprises a slideway 51, a transmission wire 52, an instrument support 53, a central shaft 54, a triple bearing 55 and a measuring instrument 56, wherein the triple bearing is three KONKAVE bearings which are arranged in parallel and respectively comprises a first bearing, a second bearing and a third bearing; the measuring instrument comprises a gauge panel 561, a pointer, a torsion spring 562 and a thin shaft 563; the pointer comprises a first pointer, a second pointer and a third pointer, the torsion springs comprise a first torsion spring, a second torsion spring and a third torsion spring, the thin shaft comprises a first sleeve, a second sleeve and a third sleeve, and the sleeves are directly connected through balls; the first torsion spring is sleeved on the first sleeve, and the first sleeve is connected with the first pointer; the second torsion spring is sleeved on a second sleeve, and the second sleeve is connected with a second pointer; the third torsion spring is sleeved on the third sleeve, and the third sleeve is connected with the third pointer.
the support is a rectangular support, four support legs are arranged below the support, the interior of the support is of a hollow structure, water can be temporarily stored in the support when an experiment is not performed, and the support can play a role in storing experiment water and supporting and stabilizing an experimental instrument; the box body is made of transparent materials and used for temporarily storing experimental water and serving as a supporting structure of an upper measuring instrument, the box body is fixed on the support through three leveling screws, the lower end of each leveling screw is fixed on the support, the upper end of each leveling screw is connected with a lower bottom plate of the box body, one end of a bottom plate of the box body extends out of a platform (the platform and the bottom plate of the box body are in an integrated structure), a level gauge is arranged on the platform, the level gauge is observed, the height of each leveling screw is adjusted, and the box body can be in a; the small pump is arranged on the edge of a ridge on the support, is positioned on one side of the box body, and forms a control mechanism for controlling the volume of water in the box body together with the two-way valve; before the experiment formally begins, water stored in the support is input into the box body through a small pump.
As shown in fig. 3, the first pressure-bearing body, the second pressure-bearing body and the third pressure-bearing body are light quarter ring-shaped structures with different radiuses, can be made of light materials but not limited to high-density polymers, and are coaxially arranged to have different radiuses and ring widths, and the three sections of rings can be approximately regarded as being cut by quarter circles; a cylindrical convex rod 44 is arranged on the side surface of each pressure bearing body close to the slide way, namely a first convex rod, a second convex rod and a third convex rod, and the distances from the third convex rod, the second convex rod and the first convex rod to the lower rectangular surface of the pressure bearing body are sequentially increased so as to ensure that a third driving wire is positioned above the second convex rod and a second driving wire is positioned above the first convex rod; the free end of the convex rod is movably connected with a round cake 45 with a radius slightly larger than that of the convex rod, and scales are engraved on the side surfaces of the pressure-bearing bodies far away from the convex rod for measuring the depth of water injection; the convex rod of each pressure-bearing body passes through the corresponding slideway and then is connected with the round cake, and the round cake is fixed at the free end of the convex rod through threads; the round cake is arranged to prevent the convex rod of the pressure-bearing body from separating from the slideway; the convex rod moves along with the slide way, so that the pressure-bearing body can only rotate around the space of the central shaft in the corresponding space area.
a right-angle fan-shaped flat plate parallel to the side wall is arranged near the inner wall of one side of the box body, which is far away from the small pump, a hole is arranged near the right-angle part of the flat plate, a central shaft just passes through the hole to fix the flat plate, and in addition, a clamping groove is arranged near the projection of the lower sharp corner of the slideway on the lower surface of the inner part of the box body to further fix the flat plate; the flat plate is arranged in parallel with the side wall of the box body, and as shown in fig. 4, three slide ways, namely a first slide way, a second slide way and a third slide way, are arranged on the flat plate; the three slideways are coaxially arranged in a quarter-ring shape with different radiuses and correspond to the first pressure-bearing body, the second pressure-bearing body and the third pressure-bearing body respectively; each slide cooperates with corresponding cylindrical nose bar, and cylindrical nose bar can follow the slide and remove, and each slide allows corresponding cylindrical nose bar motion range diverse to it is suitable that the pressure-bearing body is located horizontal position slightly off-centre under the messenger does not fill water the condition, and each pressure-bearing body does not contact bottom half when not filling water promptly.
The instrument support has two, fixes respectively at box and is close to a lateral wall of slide and another lateral wall edge relative, and center pin one end is fixed on an instrument support, and the other end passes the flat board that the slide is located and fixes on another instrument support, and the epaxial one end that is close to the slide of center pin has a recess for place the trigeminy bearing, and the trigeminy bearing passes through ball indirect contact with the center pin, can also apply appropriate amount lubricating oil if necessary to ensure that frictional force is minimum as far as possible, reduce experimental error, guarantee to measure the accuracy. As shown in fig. 5, the transmission threads are rigid threads which do not have an obvious extension or shortening phenomenon under the action of force, and there are three transmission threads, namely a first transmission thread, a second transmission thread and a third transmission thread, the first transmission thread is led out from the first protruding rod, wound on the first bearing, and converted into vertical movement after passing through the first bearing, and vertically connected to a tangent point of one side of the first sleeve of the thin shaft in the vertical direction, so that the first sleeve of the thin shaft is driven to rotate, and the first transmission thread is used for transmitting the rotation angle of the first pressure-bearing body around the shaft to the corresponding sleeve of the thin shaft; in the same way, the second and third transmission wires are respectively used for transmitting the rotation angle of the second and third pressure-bearing bodies around the shaft to the corresponding sleeves of the shaft. Torsion springs are wound on the sleeves of the thin shaft and used for measuring the rotating torque of the sleeves of the thin shaft, and the rotation of the pressure-bearing body can cause the deformation of the torsion springs so as to generate balanced torque with the torsion springs and obtain a quantitative relation; the torsion spring should be a high-elastic spring with strong restoring capability to ensure that the proportional relation of the spring is not changed under the long-term experimental condition and the corresponding relation between the scales carved on the dial and the pressure intensity is ensured.
The balls have the functions of reducing the friction resistance and reducing the system error; the torsion spring is preferably made of quartz wire, but is not limited to quartz wire, and other materials with good elasticity and rotation performance can be used.
The thin shaft is of a three-layer sleeve structure, balls are arranged between the sleeves, each sleeve is connected with a corresponding transmission wire, and the side of the sleeve, close to the instrument panel, is connected with a pointer; as shown in fig. 6, if the transmission thread drives the thin shaft to rotate counterclockwise, the torsion spring deforms in the same direction, and further generates a moment in the opposite direction to the balance direction, and the index of the pointer is obtained after the system is balanced; it is worth noting that the convex rods corresponding to the three bearing bodies, the driving wires, the corresponding sleeves of the thin shafts and the pointers are strictly corresponding, and the sequence of the convex rods, the driving wires, the corresponding sleeves of the thin shafts and the pointers is not required to be changed.
The invention relates to an improvement of an existing teaching instrument for hydraulics experiments in higher schools, in particular to the field of hydrostatics, and the teaching instrument is used for measuring hydrostatic pressure in the teaching of the hydraulics experiments and exploring hydrostatic pressure laws of different water depths.
The scientific basis of the invention is as follows:
Hydrostatic fundamental equation (1) and hydrostatic pressure characteristics (2);
and involves some mechanical knowledge (3) - (7), the main formula is as follows:
σ＝-p (2)；
∫pds＝P (3)；
The invention relates to some theoretical mechanics knowledge, which mainly comprises force system balance and couple balance, and the formula is as follows:
∑Fi＝0 (6)；
∑Mi＝0 (7)；
Wherein z is water depth, p is hydrostatic pressure at a certain point, rho is water density, g is gravitational acceleration, and C is a constant; sigma is the surface pressure borne by the surface of the pressure bearing body; p is hydrostatic pressure; m is moment, k is the stiffness coefficient of the torsion spring,Is the angle of rotation of the thin axis, yDacting by hydrostatic pressureCoordinates of points, yCis a centroid coordinate of a rectangular surface of a pressure-bearing body, ICThe moment of inertia of the pressure-bearing body to the main shaft of the horizontal centroid, and A is the area of the rectangular surface of the pressure-bearing body. The negative sign in the formula (2) indicates that the surface pressure applied to the pressure bearing surface is along the direction of the normal line in the surface.
the experimental process comprises the following steps:
the experimental device is correctly installed, the instrument is fixed on a horizontal desktop, whether all parts are tightly connected or not and whether the connecting hose leaks water or not are checked, the level gauge is observed, and the leveling screws are adjusted to ensure the level of the device.
During the interval of the experiment, enough water can be stored in the hollow structure of the bottom support. Before the experiment, the small pump and the two-way valve are opened, and a proper amount of water is pumped into the box body for standby application according to the needs.
at the beginning of the experiment, the volume of water in the control box body of the two-way valve is adjusted, and it is worth noting that: when water does not completely submerge the lower rectangular surface of the pressure-bearing body, the triangular distribution of hydrostatic pressure can be researched, and when water just submerges the lower rectangular surface of the pressure-bearing body, the rectangular distribution of hydrostatic pressure can be researched; the following description will be given by taking as an example that water just submerges all rectangular surfaces under the pressure-bearing body (this embodiment is an implementation process of a hydrostatic pressure rectangular pressure distribution study):
Under the effect of hydrostatic pressure, the position change of different degrees will take place for the pressure-bearing body, according to formula (1), there is the direct ratio between hydrostatic pressure and the depth of water, consequently, the depth of water is the deeper, and hydrostatic pressure is big more, and water is also big more to the effort of pressure-bearing body.
According to the formulas (6) and (7) and the hydrostatic pressure calculation principle, acting forces of the hydrostatic pressure on the arc part of the pressure-bearing body pass through the central shaft, so that no moment is applied to the central shaft; in addition, the hydrostatic pressure intensity actions on the two sides of the pressure-bearing body are equal in magnitude and opposite in direction, and are completely offset.
thus, only the hydrostatic pressure to which the rectangular section below the pressure-bearing body is subjected can have the effect of varying its position. According to the formula (1), the three pressure-bearing bodies are subjected to different hydrostatic pressures and different moments on the central shaft, and as a result, the angular displacement of the three pressure-bearing bodies rotating around the shaft is different.
After water is injected into the box body, the pressure bearing body rotates, meanwhile, the cylindrical convex rod fixedly connected to the surface of the pressure bearing body rotates, the transmission wire connected to the convex rod generates displacement in the vertical direction by bypassing the triple bearing, and the corresponding sleeve of the thin shaft is pulled to rotate at the tangent point of the corresponding sleeve of the thin shaft.
Each sleeve of the thin shaft is wound with a torsion spring, the torsion spring has a moment effect on the corresponding sleeve of the thin shaft, the sleeve rotates to drive the torsion spring to deform at a certain angle in the same direction, and the torsion spring is characterized in that the torsion spring per seThe torsion spring generates torque in the opposite direction balanced with the rotation torque of the sleeve, and when the torque is balanced with the torque borne by the pressure bearing body, the whole system reaches a balanced state.
The angular displacement generated by the torsion spring is reflected on the dial plate through a pointer connected to the sleeve, and the couple of hydrostatic pressure on different pressure-bearing bodies to the central shaft can be known according to a formula (6); according to a formula (5), by combining the vertical distance from the central shaft to the centroid of each pressure bearing body, the hydrostatic pressure borne by each pressure bearing body and the action point thereof can be known; according to the formula (3), the hydrostatic pressure of the rectangular surface centroid of each pressure-bearing body can be obtained by combining the known rectangular surface area of each pressure-bearing body, and accordingly, the quantitative relation between the water depth and the hydrostatic pressure can be obtained. The values and positions of different hydrostatic pressures on the dial can be determined. The measurement principle belongs to the prior art and is not described herein.
according to the principle and the method, the hydrostatic pressure borne by different positions of the pressure bearing bodies can be measured, and the hydrostatic pressure of different water depths can be further obtained. Because the pressure-bearing bodies corresponding to different pointers are different, the position relation between the hydrostatic pressure and the water depth can be visually observed according to the difference of numerical values pointed by the pointers.
The invention relates to the field of teaching instruments for hydraulics experiments in higher schools, in particular to an experiment demonstration instrument capable of accurately measuring hydrostatic pressure. The existing instrument utilizes the lever principle to measure the surface pressure, and because the weight mass is discontinuous and the randomness exists in manual operation, the error between the surface pressure value measured by the experiment and the theoretical value is larger. Besides the basic function of measuring the hydrostatic pressure, the invention can intuitively and accurately explain the related knowledge of the relation between the hydrostatic pressure and the water depth. The invention aims to provide an accurate and intuitive experimental apparatus for measuring and demonstrating hydrostatic pressure.
Claims (7)
1. the utility model provides a modified hydrostatic pressure tests experimental apparatus which characterized in that: including water storage device, control mechanism, levelling device, pressure-bearing device and measurement transmission, wherein:
The water storage device comprises a support and a water storage tank, wherein the support is internally of a hollow structure and is used for storing experimental water;
the control mechanism is used for controlling water stored in the support to flow between the box body and the support;
the leveling device is used for setting the box body in a horizontal state;
The pressure-bearing device is used for converting hydrostatic pressure into the rotating moment of the pressure-bearing body; the pressure-bearing device comprises a first pressure-bearing body, a second pressure-bearing body and a third pressure-bearing body; the pressure-bearing bodies are coaxially arranged and are of light quarter circular structures with different radiuses, the side surface of each pressure-bearing body is provided with a cylindrical convex rod which is respectively a first convex rod, a second convex rod and a third convex rod, and the distances from the third convex rod, the second convex rod and the first convex rod to the lower rectangular surface of the pressure-bearing body are sequentially increased; scales are carved on the side surface of each pressure-bearing body, which is far away from the convex rod, and the convex rod is connected with a measuring transmission device through a round cake;
The measuring transmission device is used for converting the rotating torque of the pressure-bearing device into the deformation of the torsion spring, obtaining the torque of the torsion spring through the deformation of the torsion spring, further obtaining the quantitative relation between the hydrostatic pressure and the water depth, and thus obtaining the numerical value of the hydrostatic pressure;
The measuring transmission device comprises a slideway, a transmission wire, an instrument support, a central shaft, a triple bearing and a measuring instrument, wherein,
The slideway is arranged on a flat plate near the inner wall of one side of the box body, which is far away from the small-sized pump machine, the flat plate is fixed through a clamping groove at the bottom of the box body, the slideway comprises a first slideway, a second slideway and a third slideway, the three slideways are respectively matched with three cylindrical convex rods on three pressure-bearing bodies and connected through a round cake, the cylindrical convex rods can move along the slideways, and the movement ranges of the corresponding cylindrical convex rods are allowed to be different by each slideway;
The triple bearing is three KONKAVE bearings which are arranged in parallel and respectively comprise a first bearing, a second bearing and a third bearing;
the measuring instrument comprises an instrument panel, a pointer, a torsion spring and a thin shaft, wherein the pointer is arranged on the front side of the instrument panel, the thin shaft is arranged on the back side of the instrument panel, and the torsion spring is wound on the thin shaft; the pointer comprises a first pointer, a second pointer and a third pointer, the torsion springs comprise a first torsion spring, a second torsion spring and a third torsion spring, the thin shaft is of a three-layer sleeve structure and comprises a first sleeve, a second sleeve and a third sleeve, balls are arranged among the sleeves, each sleeve is provided with a corresponding torsion spring, and the part of each sleeve, which extends out of the front face of the instrument panel, is connected with the corresponding pointer;
the measuring instrument is fixed at one end of the central shaft close to the slideway, a groove is formed in one end of the central shaft close to the slideway and used for placing a triple bearing, the triple bearing is indirectly contacted with the central shaft through a ball, three transmission wires are provided and are rigid wires which can not generate obvious length change under the action of force, and the three transmission wires are respectively a first transmission wire, a second transmission wire and a third transmission wire; each pressure bearing body corresponds to the corresponding sleeve and the pointer of the cylindrical convex rod, the transmission wire and the thin shaft one by one.
2. An improved hydrostatic pressure test experimental facility, according to claim 1, wherein: the control mechanism comprises a small-sized pump and a two-way valve, the two-way valve is respectively connected with the water inlet and the water outlet through hoses, and water stored in the support is controlled by the small-sized pump to enter the box body through the two-way valve and the water inlet or water in the box body is controlled to enter the support through the two-way valve and the water outlet.
3. An improved hydrostatic pressure test experimental facility, according to claim 1, wherein: the leveling device comprises three leveling screws and leveling instruments, the three leveling screws are used for fixing the box body on the support, the lower ends of the leveling screws are fixed on the support, the upper ends of the leveling screws are connected with a lower bottom plate of the box body, one end of a bottom plate of the box body extends out of a platform, the platform is provided with the leveling instruments, and the leveling instruments are observed and the heights of the leveling screws are adjusted to enable the box body to be in a horizontal position.
4. An improved hydrostatic pressure test experimental facility, according to claim 1, wherein: the torsion spring is made of a material having good elasticity and turning performance.
5. a hydrostatic pressure testing method for the improved hydrostatic pressure testing experimental facility of any one of claims 1 to 4, comprising:
Opening the small pump and the two-way valve, and pumping a certain amount of water into the box body for later use;
adjusting the volume of water in the two-way valve control box body, judging whether the water submerges the rectangular surface under all the pressure-bearing bodies, and if so, researching the rectangular distribution of hydrostatic pressure; if not, the method is used for researching the triangular distribution of the hydrostatic pressure;
after water is injected, the bearing body rotates, meanwhile, the cylindrical convex rod on the side face of the bearing body rotates, a transmission wire connected to the cylindrical convex rod bypasses a corresponding bearing in the triple bearing to generate displacement in the vertical direction, a corresponding sleeve of the thin shaft is pulled to rotate at a tangent point of the corresponding sleeve of the thin shaft, the sleeve rotates to drive a corresponding torsion spring to generate homodromous deformation, after the system is balanced, the angular displacement generated by the torsion spring is reflected on a dial plate through a pointer connected to the sleeve, and according to a quantitative relational expression, numerical values and positions of different hydrostatic pressures corresponding to the dial plate are determined, so that the quantitative relation between the water depth and the hydrostatic pressure is obtained.
6. A hydrostatic pressure testing method according to claim 5, characterized in that the two side faces of each pressure-bearing body are equal in size, the forces exerted on the arc-shaped faces pass through the center of the central shaft, the moment of hydrostatic pressure acting on the pressure-bearing body to the central shaft is generated only by the hydrostatic pressure acting on the rectangular plane, and different pointer angular displacements corresponding to the moments of different hydrostatic pressures to the central shaft are obtained based on the hooke's law equation (4) according to the hydrostatic pressure direction rule equation (1) and the space force system balance principle equations (2) and (3); the formula is as follows:
σ＝-p (1)；
∑Fi＝0 (2)；
∑Mi＝0 (3)；
wherein, sigma is the surface pressure on the surface of the pressure bearing body, p is the hydrostatic pressure at a certain point, Fifor any spatial force in the system, MiRepresents the moment of any force in the system to the central shaft, M is the moment, k is the stiffness coefficient of the torsion spring,The negative sign in formula (1) represents that the pressure of the bearing surface is along the normal direction in the surface of the bearing surface, which is the rotation angle of the thin shaft.
7. A hydrostatic pressure testing method according to claim 5, wherein: and (3) calculating the hydrostatic pressure relation at different water depth positions by combining a hydrostatic pressure synthesis formula (5) and a hydrostatic pressure action point and centroid relation formula (6):
∫pds＝P (5)；
wherein P is hydrostatic pressure, yDAs coordinates of the hydrostatic pressure action point, yCIs a centroid coordinate of a rectangular surface of a pressure-bearing body, ICThe moment of inertia of the pressure-bearing body to the main shaft of the horizontal centroid, and A is the area of the rectangular surface of the pressure-bearing body.
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| CN201273849Y (en) * | 2008-09-12 | 2009-07-15 | 河海大学 | Curved surface total hydrostatic pressure experiment instrument |
| CN101673484B (en) * | 2009-09-30 | 2012-07-18 | 浙江大学 | Self-circulating electrical-testing total hydrostatic pressure tester |
| CN205228593U (en) * | 2015-12-25 | 2016-05-11 | 陈春锦 | Water level monitoring device |
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