Novel device and method for mixed measurement of liquid viscosity coefficient and solid rotational inertia

Abstract

The invention discloses a novel liquid viscosity coefficient and solid rotational inertia mixed measurement device and method, and the device comprises a supporting part, a pressure sensor, a digital voltmeter, a rope winding and unwinding device, a round rod, a cylinder, a round cup, a pedestal device for rotating the round cup, a fixed pulley, a weight, a circular ring, and a fixed rope buckle. Circular rings with different inner diameters are added into a base device of a rotary round cup and placed into round cups with different radiuses, a weight is bound to an inner groove in the side face of an upper rotary body of the base device of the rotary round cup through a rope, and the rope passes through the center of a fixed pulley to enable the weight to freely fall. The method comprises the steps of liquid viscosity coefficient measurement and solid rotational inertia measurement. Experiment steps are effectively compressed, the occupied space of a single device is small, and compared with two sets of independent equipment which are purchased respectively, the cost can be effectively saved; the non-contact method avoids the problem that the viscosity coefficient of non-transparent or low-transparent liquid is difficult to observe and measure in a falling ball method, and expands the measurement range.

Description

Technical Field

[0001] The present invention relates to the field of measurement, and in particular to a novel device and method for mixed measurement of liquid viscosity coefficient and solid rotational inertia. Background Art

[0002] Viscosity directly influences the flow properties of a liquid, indicating its ability to resist shear deformation. The moment of inertia, a physical quantity that describes the inertia of a rigid body rotating about its axis, directly influences the dynamic performance of rotating systems. In the fields of fluid mechanics and rigid-body dynamics, viscosity and moment of inertia are two crucial physical parameters, playing a key role in numerous scientific research and engineering applications. In precision instruments or industrial equipment, moment of inertia influences the dynamic response of mechanical components, while viscosity affects fluid damping and lubrication.

[0003] Currently, there are numerous methods for measuring viscosity, including the capillary tube method, the falling ball method, the rotating cylinder method, and the Ostwald viscometer method. Common methods for measuring the moment of inertia are typically used, such as the three-wire pendulum, the torsion pendulum, and the compound pendulum. However, currently used experimental instruments have limited functionality and can only measure one parameter, either the moment of inertia or the viscosity, separately. If both the moment of inertia and the viscosity are to be measured simultaneously, different experimental instruments must be used, resulting in low measurement efficiency. Therefore, it is necessary to propose a novel device and method for the combined measurement of liquid viscosity and solid moment of inertia. Summary of the Invention

[0004] Purpose of the invention: The purpose of the present invention is to provide a novel device and method for mixed measurement of liquid viscosity coefficient and solid rotational inertia.

[0005] Technical solution: The novel device for hybrid measurement of liquid viscosity coefficient and solid rotational inertia described in the present invention includes a support part, a pressure sensor, a digital voltmeter, a rope retraction device, a round rod, a cylinder, a round cup, a base device for rotating the round cup, a fixed pulley, a weight, a ring and a fixed rope buckle; the pressure sensor is fixed to the support part by the fixed rope buckle and can move up and down, and the digital voltmeter displays the electrical signal of the pressure sensor; the rope retraction device is symmetrically embedded in the round rod of the straight plate, the upper part of which is fixedly connected to the end of the rope and the lower part is screwed to the cylinder; an internal threaded hole is provided on the upper part of the cylinder; the upper part of the base device of the rotating round cup is provided with a concave inside the rotating body to clamp the round cup, a groove is provided on the side, and the lower part is provided with a speed adjustment knob and a display screen and button for storing the rotation cycle function of the rotating body; the base device of the rotating round cup is added with round rings of different inner diameters, and the round rings of different inner diameters are placed in round cups of different radius sizes; the weight is tied to the inner groove on the side of the rotating body of the upper rotating cup base device by a rope, and the rope passes through the center of the fixed pulley to allow the weight to fall freely.

[0006] Furthermore, an adjustable speed motor and a speed control module are arranged inside the base device of the rotating circular cup, magnets are placed on the edges of the symmetrical blades fixed to the adjustable speed motor, and a Hall switch sensor is installed below the magnet and connected to a single-chip microcomputer timer.

[0007] Furthermore, the rope retracting and releasing device is used to change the height of the cylinder immersed in the liquid, and to change the constant speed of the motor by rotating the speed regulating knob of the base device of the round cup.

[0008] Furthermore, the base device of the rotating circular cup can replace cylinders of different radius sizes by screw connection.

[0009] The novel method for hybrid measurement of liquid viscosity coefficient and solid rotational inertia of the present invention includes liquid viscosity coefficient measurement and solid rotational inertia measurement.

[0010] Furthermore, the liquid viscosity coefficient measurement includes the following steps:

[0011] (1.1) Pour the liquid to be tested into a circular cup with a radius of r2, so that the liquid to be tested submerges the cylinder with a radius of r1 and a height of H, and the distance between the bottom of the cylinder and the bottom of the cup is δ;

[0012] (1.2) Connect the power supply to the base of the rotating cup and rotate the speed knob to rotate the cup at an angular velocity ω. This causes the cylinder to generate a torque M, which in turn generates a pressure F on the pressure sensor through a rod symmetrically embedded in the straight plate, at a distance r from the center of the rod.

[0013] (1.3) Substituting the radius r2, r1, distance δ, height H, and angular velocity ω into the solution formula, the torque on the side of the cylinder is solved as follows:

[0014]

[0015] Among them, μ is the viscosity coefficient of the liquid to be measured, and M1 is the torque on the side of the cylinder.

[0016] Furthermore, the torque on the cylinder side is integrated and solved as follows:

[0017]

[0018] Among them, M2 is the torque magnitude of the cylinder bottom surface;

[0019] The viscosity coefficient calculation formula is as follows:

[0020]

[0021] The system is kept stationary by the pressure sensor. The resultant torque theorem shows that the resultant torque in the horizontal direction is 0. The force F on the pressure sensor and the distance r between its force center and the axis of the circular rod are substituted into the formula to replace the unknowns M1 and M2 to obtain the final formula for the viscosity coefficient calculation method:

[0022]

[0023] Among them, F is the force applied to the pressure sensor, and its magnitude can be obtained based on the corresponding relationship between the voltage change of the digital voltmeter and the force; r is the distance between the force center and the axis of the circular rod, M1 is the magnitude of the torque on the side of the cylinder, and M2 is the magnitude of the torque on the side of the cylinder.

[0024] Furthermore, the solid moment of inertia measurement comprises the following steps:

[0025] (2.1) Power is supplied to the base of the rotating cup, and the rotating body is moved so that it rotates idly and then joins the ring. A series of rotation periods T (t1, t2, t3, t4, ...) and T1 (t1, t2, t3, t4, ...) of the rotating body are recorded by a single-chip microcomputer timer.

[0026] (2.2) Connect the power supply to the base device of the rotating circular cup, tie the weight to the rope, and tie the other end of the rope to the inner groove on the side of the upper rotating body of the rotating circular cup base device. Pass the rope through the center of the fixed pulley to allow the weight to rotate freely and join the ring to rotate. Use the single-chip microcomputer timer to record a series of rotation periods T2 (t1, t2, t3, t4, ...) and T3 (t1, t2, t3, t4, ...) of the rotating body;

[0027] (2.3) A simple force analysis of the above process shows that formulas (1), (2), and (3) correspond to the force state caused by the uniform acceleration motion under the action of the weight pulling, while formula (4) corresponds to the force state when the rotating body is only subjected to the friction force and moves in a uniform deceleration until it stops:

[0028]

[0029] Among them, T represents the tension of the rope under the falling weight, M f represents the torque generated by the friction force only, a represents the acceleration of the weight when it falls, J0 represents the moment of inertia of the idling rotating body, β1 and β2 represent the angular acceleration of the rigid body under two force states when idling;

[0030] (2.4) The solution formula for the moment of inertia is as follows:

[0031]

[0032] Among them, J1 and J2 represent the rotational inertia of the rotating body when idling and when the ring is added, m is the mass of the weight, and β3 and β4 represent the angular acceleration of the rigid body under the two force states when the ring is added.

[0033] Furthermore, the moment of inertia can be obtained by calculating the angular acceleration of the rigid body. The formula for solving the angular acceleration is as follows:

[0034]

[0035] Among them, the difference of the rotation period T2 (t1, t2, t3, t4, ...) is substituted. In this experiment, the average value is calculated multiple times as the angular acceleration β, and k2 and k1 represent the number of the period.

[0036] Furthermore, the expression of the moment of inertia of the ring is:

[0037] J3=J2-J1 (8)

[0038] Among them, J1 represents the moment of inertia of the rotating body when idling, J2 represents the moment of inertia of the added ring, and J3 represents the moment of inertia of the ring.

[0039] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0040] (1) The present invention adopts a rotating mixing measurement scheme, which effectively compresses the experimental steps. The single device takes up less space and can effectively save costs compared to purchasing two independent sets of equipment.

[0041] (2) The liquid viscosity coefficient measurement proposed in the present invention is a non-contact method, which avoids the problem of difficulty in observing and measuring the viscosity coefficient of opaque or low-transparency liquids in the falling ball method. At the same time, by adjusting the rotation speed, it can be achieved for low-viscosity liquids, thus expanding the measurement range;

[0042] (3) An adjustable speed motor and a speed control module are provided inside the base device of the rotating circular cup of the present invention. A magnet is placed on the edge of the symmetrical blades fixed to the motor. A Hall switch sensor is installed 10 to 15 mm below the magnet and is connected to a single-chip microcomputer timer. The two parts can work independently, and the design is reasonable. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 This is a structural diagram of the overall device of the present invention;

[0044] Figure 2 This is a diagram showing the internal structure of the rotating base of the present invention;

[0045] Figure 3 This is a force analysis diagram of the liquid viscosity coefficient measurement method of the present invention;

[0046] Figure 4This is a force analysis diagram of the solid moment of inertia measurement method of the present invention. DETAILED DESCRIPTION

[0047] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0048] like Figure 1 As shown, the novel device for hybrid measurement of liquid viscosity coefficient and solid rotational inertia of the present invention includes a support part 1, a pressure sensor 2, a digital voltmeter 3, a rope retracting device 4, a round rod 5, a cylinder 6, a round cup 7, a base device 8 for rotating the round cup, a fixed pulley 9, a weight 10, a ring 11, and a fixed rope buckle 12; the pressure sensor 2 is fixed to the support part 1 by the fixed rope buckle 12 and can move up and down, and the digital voltmeter 3 displays the electrical signal of the pressure sensor; the rope retracting device 4 is symmetrically embedded in the straight round rod 5, and its upper part is connected to the end of the rope It is fixedly connected, with the lower part being screwed to the cylinder; an internal threaded hole is provided on the upper part of the cylinder 6; the upper part of the base device 8 of the rotating circular cup is provided with an inner concave of the rotating body to clamp the circular cup 7, a groove is provided on the side, and a speed adjustment knob and a display screen and button for storing the rotation cycle function of the rotating body are provided on the lower part. The base device 8 of the rotating circular cup is added with rings 11 of different inner diameters, and the rings 11 of different inner diameters are placed in the circular cups 7 of different radius sizes. The weights 10 are tied to the inner groove on the side of the upper rotating body of the base device 8 of the rotating circular cup by a rope, and the rope passes through the center of the fixed pulley 9 to make the weights fall freely.

[0049] like Figure 2 As shown, the rotating cup base assembly 8 houses an adjustable-speed motor and a speed control module. Magnets are placed on the edges of the symmetrical blades attached to the adjustable-speed motor. Below the magnets, a Hall effect sensor is installed and connected to a single-chip microcomputer timer. The rope retraction and release device 4 is used to adjust the cylinder's immersion height in the liquid, and the motor's constant speed is adjusted by rotating the cup base assembly 8 with a speed control knob. The rotating cup base assembly 8 allows for interchangeable cylinders 6 of varying radii via threaded connections.

[0050] The novel method for hybrid measurement of liquid viscosity coefficient and solid rotational inertia comprises measurement of liquid viscosity coefficient and measurement of solid rotational inertia.

[0051] Liquid viscosity coefficient measurement method force analysis diagram as shown Figure 3 As shown, the novel method for hybrid measurement of liquid viscosity coefficient and solid rotational inertia, the liquid viscosity coefficient measurement includes the following steps:

[0052] (1.1) Pour the liquid to be tested into a circular cup with a radius of r2, so that the liquid to be tested submerges the cylinder with a radius of r1 and a height of H, and the distance between the bottom of the cylinder and the bottom of the cup is δ;

[0053] (1.2) Connect the power supply to the base of the rotating cup and rotate the speed knob to rotate the cup at an angular velocity ω. This causes the cylinder to generate a torque M, which in turn generates a pressure F on the pressure sensor through a rod symmetrically embedded in the straight plate, at a distance r from the center of the rod.

[0054] (1.3) Substituting the radius r2, r1, distance δ, height H, and angular velocity ω into the solution formula, the torque on the side of the cylinder is solved as follows:

[0055]

[0056] Among them, μ is the viscosity coefficient of the liquid to be measured, and M1 is the torque on the side of the cylinder.

[0057] The torque on the side of the cylinder is integrated and solved as follows:

[0058]

[0059] Among them, M2 is the torque magnitude of the cylinder bottom surface;

[0060] The viscosity coefficient calculation formula is as follows:

[0061]

[0062] The system is kept stationary by the pressure sensor. The resultant torque theorem shows that the resultant torque in the horizontal direction is 0. The force F on the pressure sensor and the distance r between its force center and the axis of the circular rod are substituted into the formula to replace the unknowns M1 and M2 to obtain the final formula for the viscosity coefficient calculation method:

[0063]

[0064] Among them, F is the force applied to the pressure sensor, and its magnitude can be obtained based on the corresponding relationship between the voltage change of the digital voltmeter and the force; r is the distance between the force center and the axis of the circular rod, M1 is the magnitude of the torque on the side of the cylinder, and M2 is the magnitude of the torque on the side of the cylinder.

[0065] Solid moment of inertia measurement method force analysis diagram as shown Figure 4 As shown, the solid moment of inertia measurement includes the following steps:

[0066] (2.1) Power is supplied to the base of the rotating cup, and the rotating body is moved so that it rotates idly and then joins the ring. A series of rotation periods T (t1, t2, t3, t4, ...) and T1 (t1, t2, t3, t4, ...) of the rotating body are recorded by a single-chip microcomputer timer.

[0067] (2.2) Connect the power supply to the base device of the rotating circular cup, tie the weight to the rope, and tie the other end of the rope to the inner groove on the side of the upper rotating body of the rotating circular cup base device. Pass the rope through the center of the fixed pulley to allow the weight to rotate freely and join the ring to rotate. Use the single-chip microcomputer timer to record a series of rotation periods T2 (t1, t2, t3, t4, ...) and T3 (t1, t2, t3, t4, ...) of the rotating body;

[0068] (2.3) A simple force analysis of the above process shows that formulas (1), (2), and (3) correspond to the force state caused by the uniform acceleration motion under the action of the weight pulling, while formula (4) corresponds to the force state when the rotating body is only subjected to the friction force and moves in a uniform deceleration until it stops:

[0069]

[0070] Among them, T represents the tension of the rope under the falling weight, M f represents the torque generated by the friction force only, a represents the acceleration of the weight when it falls, J0 represents the moment of inertia of the idling rotating body, β1 and β2 represent the angular acceleration of the rigid body under two force states when idling;

[0071] (2.4) The solution formula for the moment of inertia is as follows:

[0072]

[0073] Among them, J1 and J2 represent the rotational inertia of the rotating body when idling and when the ring is added, m is the mass of the weight, and β3 and β4 represent the angular acceleration of the rigid body under the two force states when the ring is added.

[0074] The moment of inertia can be obtained by calculating the angular acceleration of the rigid body. The formula for solving the angular acceleration is as follows:

[0075]

[0076] Among them, the difference of the rotation period T2 (t1, t2, t3, t4, ...) is substituted. In this experiment, the average value is calculated multiple times as the angular acceleration β, and k2 and k1 represent the number of the period.

[0077] The expression for the moment of inertia of the ring is:

[0078] J3=J2-J1 (8)

[0079] Among them, J1 represents the moment of inertia of the rotating body when idling, J2 represents the moment of inertia of the added ring, and J3 represents the moment of inertia of the ring.

Claims

1. A novel device for mixed measurement of liquid viscosity coefficient and solid moment of inertia, characterized in that: The invention comprises a support part (1), a pressure sensor (2), a digital voltmeter (3), a rope retracting device (4), a round rod (5), a cylinder (6), a round cup (7), a base device (8) for rotating the round cup, a fixed pulley (9), a weight (10), a ring (11) and a fixed rope buckle (12); the pressure sensor (2) is fixed to the support part (1) by the fixed rope buckle (12) and can move up and down; the digital voltmeter (3) displays the electrical signal of the pressure sensor; the rope retracting device (4) is symmetrically embedded in the round rod (5) of the straight plate, the upper part of which is fixedly connected to the end of the rope, and the lower part is fixedly connected to the round rod (5). The cylinder (6) is screwed; an internal threaded hole is provided on the upper part of the base device (8) of the rotating circular cup; a concave inner portion of the rotating body is provided on the upper part of the base device (8) of the rotating circular cup to clamp the circular cup (7), a groove is provided on the side, and a knob for adjusting the speed and a display screen and a button for storing the rotation cycle function of the rotating body are provided on the lower part; the base device (8) of the rotating circular cup is added with circular rings (11) of different inner diameters, and the circular rings (11) of different inner diameters are placed in the circular cups (7) of different radius sizes; a weight (10) is tied to the inner groove on the side of the upper rotating body of the base device (8) of the rotating circular cup by a rope, and the rope passes through the center of the fixed pulley (9) to make the weight fall freely.

2. The novel device for hybrid measurement of liquid viscosity coefficient and solid moment of inertia according to claim 1 is characterized in that: A speed-adjustable motor and a speed control module are arranged inside the base device (8) of the rotating circular cup. Magnets are placed on the edges of the symmetrical blades fixed to the speed-adjustable motor. A Hall switch sensor is installed below the magnet and connected to a single-chip microcomputer timer.

3. The novel device for hybrid measurement of liquid viscosity coefficient and solid moment of inertia according to claim 1 is characterized in that: The rope retracting and releasing device (4) is used to change the height of the cylinder immersed in the liquid, and to change the constant speed of the motor by rotating the speed regulating knob of the base device (8) of the round cup.

4. The novel device for hybrid measurement of liquid viscosity coefficient and solid moment of inertia according to claim 1 is characterized in that: The base device (8) of the rotating circular cup is capable of replacing cylinders (6) of different radius sizes by screw connection.

5. A novel method for hybrid measurement of liquid viscosity and solid moment of inertia, characterized in that: Including liquid viscosity measurement and solid moment of inertia measurement.

6. The novel method for hybrid measurement of liquid viscosity coefficient and solid moment of inertia according to claim 5 is characterized in that: The liquid viscosity coefficient measurement comprises the following steps: (1.1) Pour the liquid to be tested into a circular cup with a radius of r2, so that the liquid to be tested submerges the cylinder with a radius of r1 and a height of H, and the distance between the bottom of the cylinder and the bottom of the cup is δ; (1.2) Connect the power supply to the base of the rotating cup and rotate the speed knob to rotate the cup at an angular velocity ω. This causes the cylinder to generate a torque M, which in turn generates a pressure F on the pressure sensor through a rod symmetrically embedded in the straight plate, at a distance r from the center of the rod. (1.3) Substituting the radius r2, r1, distance δ, height H, and angular velocity ω into the solution formula, the torque on the side of the cylinder is solved as follows: Among them, μ is the viscosity coefficient of the liquid to be measured, and M1 is the torque on the side of the cylinder.

7. The novel method for hybrid measurement of liquid viscosity coefficient and solid moment of inertia according to claim 6 is characterized in that: The torque on the side of the cylinder is integrated and solved as follows: Among them, M2 is the torque magnitude of the cylinder bottom surface; The viscosity coefficient calculation formula is as follows: The system is kept stationary by the pressure sensor. The resultant torque theorem shows that the resultant torque in the horizontal direction is 0. The force F on the pressure sensor and the distance r between its force center and the axis of the circular rod are substituted into the formula to replace the unknowns M1 and M2 to obtain the final formula for the viscosity coefficient calculation method: Among them, F is the force applied to the pressure sensor, and its magnitude can be obtained based on the corresponding relationship between the voltage change of the digital voltmeter and the force; r is the distance between the force center and the axis of the circular rod, M1 is the magnitude of the torque on the side of the cylinder, and M2 is the magnitude of the torque on the side of the cylinder.

8. The novel method for hybrid measurement of liquid viscosity coefficient and solid moment of inertia according to claim 6 is characterized in that: The solid moment of inertia measurement comprises the following steps: (2.1) Power is supplied to the base of the rotating cup, and the rotating body is moved so that it rotates idly and then joins the ring. A series of rotation periods T (t1, t2, t3, t4, ...) and T1 (t1, t2, t3, t4, ...) of the rotating body are recorded by a single-chip microcomputer timer. (2.2) Connect the power supply to the base device of the rotating circular cup, tie the weight to the rope, and tie the other end of the rope to the inner groove on the side of the upper rotating body of the rotating circular cup base device. Pass the rope through the center of the fixed pulley to allow the weight to rotate freely and join the ring to rotate. Use the single-chip microcomputer timer to record a series of rotation periods T2 (t1, t2, T3, t4, ...) and T3 (t1, t2, t3, t4, ...) of the rotating body; (2.3) A simple force analysis of the above process shows that formulas (1), (2), and (3) correspond to the force state caused by the uniform acceleration motion under the action of the weight pulling, while formula (4) corresponds to the force state when the rotating body is only subjected to the friction force and moves in a uniform deceleration until it stops: Among them, T represents the tension of the rope under the falling weight, M f represents the torque generated by the friction force only, a represents the acceleration of the weight when it falls, J0 represents the moment of inertia of the idling rotating body, β1 and β2 represent the angular acceleration of the rigid body under two force states when idling; (2.4) The solution formula for the moment of inertia is as follows: Among them, J1 and J2 represent the rotational inertia of the rotating body when idling and when the ring is added, m is the mass of the weight, and β3 and β4 represent the angular acceleration of the rigid body under the two force states when the ring is added.

9. The novel method for hybrid measurement of liquid viscosity coefficient and solid moment of inertia according to claim 8, characterized in that: The moment of inertia can be obtained by calculating the angular acceleration of the rigid body. The formula for solving the angular acceleration is as follows: Among them, the difference of the rotation period T2 (t1, t2, t3, t4, ...) is substituted. In this experiment, the average value is calculated multiple times as the angular acceleration β, and k2 and k1 represent the number of the period.

10. The novel method for hybrid measurement of liquid viscosity coefficient and solid moment of inertia according to claim 8, characterized in that: The expression for the moment of inertia of the ring is: J3=J2-J1 (8) Among them, J1 represents the moment of inertia of the rotating body when idling, J2 represents the moment of inertia of the added ring, and J3 represents the moment of inertia of the ring.

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