Turbine flow meter

Abstract

The invention relates to the technical field of flow detection, in particular to a turbine flowmeter. The turbine flowmeter comprises a main body, a rotating shaft, a turbine and a detection assembly, an accommodating cavity for fluid to flow through is formed in the main body; the rotating shaft is located in the containing cavity and arranged in the fluid flowing direction. The rotating shaft is rotationally connected with the body. The turbine is located in the containing cavity and arranged on the rotating shaft. The detection assembly is located in the containing cavity and arranged on a blade of the turbine, and the detection assembly is used for detecting the attack angle of the fluid to the blade so that the turbine flowmeter can determine the fluid flow according to the attack angle. When the turbine flowmeter is used for detection, the influence of a correction or compensation mechanism on the detection efficiency can be eliminated, the detection cost can be reduced, and the detection precision can be improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of flow detection, in particular to a turbine flowmeter. BACKGROUND

[0002] The turbine flowmeter is a very precise volumetric flow testing technology, which calculates the volumetric flow of fluid by measuring the speed of fluid driving the turbine to rotate, and has the advantages of high precision and large measurable flow range.

[0003] In actual operation, the turbine flowmeter utilizes the driving force of fluid on the turbine blades to drive the turbine to rotate. However, there is also a problem of energy loss when the turbine rotates, for example, the viscous resistance of fluid and the friction of mechanical parts (such as bearings) will cause energy loss, which affects the accuracy of the measurement results.

[0004] In order to improve the measurement accuracy, the turbine flowmeter usually adopts a correction or compensation mechanism, such as experimental calibration, mathematical model correction or sensor signal processing, to reduce the influence of factors such as fluid viscosity and bearing friction on the test accuracy. However, these correction or compensation mechanisms are more complicated, which is not conducive to improving the detection efficiency, and will increase the detection cost. SUMMARY

[0005] The embodiments of the present application at least provide a turbine flowmeter, which can eliminate the influence of correction or compensation mechanism on detection efficiency, reduce detection cost and improve detection accuracy.

[0006] In a first aspect, the embodiments of the present application provide a turbine flowmeter, comprising:

[0007] a main body, a rotating shaft, a turbine and a detection assembly;

[0008] The main body is internally provided with a containing cavity for fluid to flow through;

[0009] The rotating shaft is located in the containing cavity and is arranged along the fluid flow direction, and the rotating shaft is rotationally connected with the main body;

[0010] The turbine is located in the containing cavity and is arranged on the rotating shaft;

[0011] The detection assembly is located in the containing cavity and is arranged on the blades of the turbine, and the detection assembly is used to detect the attack angle of the fluid on the blades, so that the turbine flowmeter determines the volumetric flow according to the attack angle.

[0012] In an optional implementation, the detection assembly comprises a plurality of pressure measurement holes, and the detection assembly obtains the attack angle through the pressure in the holes of the plurality of pressure measurement holes.

[0013] In an alternative embodiment, the detection assembly comprises a first pressure measuring hole, a second pressure measuring hole and a center pressure measuring hole, the first pressure measuring hole and the second pressure measuring hole are symmetrically distributed relative to the center pressure measuring hole, the pressure in the holes of the first pressure measuring hole, the second pressure measuring hole and the center pressure measuring hole satisfies the following formula:

[0014]

[0015] wherein C i is a constant coefficient, which can be determined by theoretical analysis and experimental calibration; α is the angle of attack of the fluid to the blade; P O is the pressure in the center pressure measuring hole; P L is the pressure in the first pressure measuring hole; and P R is the pressure in the second pressure measuring hole.

[0016] In an alternative embodiment, the volumetric flow rate satisfies the following formula:

[0017]

[0018] In the above formula, Q is the volumetric flow rate into the turbine; R is the radius of the blade from the center of rotation; A is the cross-sectional area of the fluid flowing in the containing cavity; α is the angle of attack of the fluid to the blade; β is the relative fluid velocity angle of the fluid to the axial direction; and ω is the rotational speed of the turbine.

[0019] In an alternative embodiment, further comprising a driving assembly, the driving assembly is located in the containing cavity and is arranged on the rotating shaft, the driving assembly is used to drive the turbine to rotate according to the size of the angle of attack, so that the angle of attack is zero.

[0020] In an alternative embodiment, the driving assembly is a driving motor, the driving assembly is used to output torque to the turbine to make it rotate.

[0021] In an alternative embodiment, the rotational speed of the driving assembly is consistent with the rotational speed of the turbine, and the driving assembly has a built-in speed measuring assembly.

[0022] In an alternative embodiment, the driving assembly is located downstream of the turbine.

[0023] In an alternative embodiment, the volumetric flow rate satisfies the following formula:

[0024]

[0025] In the above formula, Q is the volumetric flow rate into the turbine; R is the radius of the blade from the center of rotation; A is the cross-sectional area of the fluid flowing within the housing; β is the relative fluid velocity angle of the fluid to the axial direction; and ω is the rotational speed of the turbine.

[0026] In an alternative embodiment, the rotating shaft is located downstream of the turbine, one end of the rotating shaft is rotationally connected to the main body, and the other end is connected to the rear end of the turbine.

[0027] The above technical solutions of the present application have the following beneficial technical effects:

[0028] Compared with the turbine flowmeter with a correction or compensation mechanism, the turbine flowmeter of the present application determines the volumetric flow rate by detecting the angle of attack of the fluid on the blade. Since the force of the fluid on the blade changes when the angle of attack changes, this reflects the energy conversion efficiency and loss within the system. Therefore, by measuring the angle of attack, the energy loss in the system can be directly evaluated, and the flow rate can be determined by the angle of attack without relying on an additional correction or compensation mechanism. This is beneficial for eliminating the influence of the correction or compensation mechanism on the detection efficiency, and can improve the detection accuracy and reduce the detection cost.

[0029] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the following preferred embodiments are described in detail below, and the accompanying drawings are described as follows. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments. The drawings herein are incorporated into the specification and form a part of the specification. These drawings show embodiments consistent with the present application, and together with the specification, serve to illustrate the technical solutions of the present application. It should be understood that the following drawings only show certain embodiments of the present application, and therefore should not be considered as limiting the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0031] Figure 1 Fig. 1 shows a structural schematic diagram of a turbine flowmeter provided by an embodiment of the present application;

[0032] Figure 2 Fig. 2 shows a structural schematic diagram of a detection assembly provided by an embodiment of the present application;

[0033] Figure 3 Fig. 3 shows a structural schematic diagram of another detection assembly provided by an embodiment of the present application;

[0034] Figure 4 Fig. 4 shows a structural schematic diagram of another turbine flowmeter provided by an embodiment of the present application;

[0035] Figure 5 Fig. 1 shows a structural schematic diagram of a turbine flowmeter provided by an embodiment of the present application;

[0036] Figure 6 Fig. 1 shows a structural schematic diagram of a turbine flowmeter provided by an embodiment of the present application;

[0037] Figure 7 Fig. 1 shows a structural schematic diagram of a turbine flowmeter provided by an embodiment of the present application; Figure 6 Fig. 1 shows a structural schematic diagram of a turbine flowmeter provided by an embodiment of the present application;

[0038] Figure 8 Fig. 1 shows a structural schematic diagram of a turbine flowmeter provided by an embodiment of the present application;

[0039] Figure 9 Fig. 1 shows a structural schematic diagram of a turbine flowmeter provided by an embodiment of the present application; Figure 8 Fig. 1 shows a structural schematic diagram of a turbine flowmeter provided by an embodiment of the present application;

[0040] In the figure, 1 is a main body; 2 is a rotating shaft; 3 is a turbine; 31 is a blade; 4 is a detection assembly; 41 is a first pressure measuring hole; 42 is a second pressure measuring hole; 43 is a central pressure measuring hole; 5 is a driving assembly. DETAILED DESCRIPTION

[0041] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. Note that the relative arrangement, numerical expressions, and numerical values of components and steps set forth in these embodiments are not limiting to the scope of the present application unless otherwise specifically stated.

[0042] Embodiments of the present application will be described in detail below, examples of which are shown in the accompanying drawings, in which the same or similar components or components having the same or similar functions are denoted by the same or similar reference numerals throughout. The embodiments described below by reference to the accompanying drawings are exemplary and are intended only for explanation of the present application and cannot be understood as limiting the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative labor are within the scope of protection of the present application.

[0043] The terms "first", "second" in the specification and claims of the present application can explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "a plurality of" is two or more, unless otherwise stated. In addition, "and / or" in the specification and claims means at least one of the connected objects, and the character " / ", generally means that the front and rear associated objects are in an "or" relationship.

[0044] In the description of the present application, it needs to be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like are based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0045] In the description of the present application, it needs to be understood that unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0046] Reference Figure 1 The embodiment of the present application provides a turbine flowmeter, which can eliminate the influence of correction or compensation mechanism on detection efficiency, and can reduce detection cost and improve detection precision.

[0047] Specifically, the turbine flowmeter comprises:

[0048] A main body 1, the inside of the main body 1 is provided with a containing cavity for fluid to flow through;

[0049] A rotating shaft 2, the rotating shaft 2 is located in the containing cavity and is arranged along the fluid flow direction, and the rotating shaft 2 is rotationally connected with the main body 1;

[0050] A turbine 3, the turbine 3 is located in the containing cavity and is arranged on the rotating shaft 2;

[0051] A detection assembly 4, the detection assembly 4 is located in the containing cavity and is arranged on the blade 31 of the turbine 3, and the detection assembly 4 is used for detecting the attack angle of the fluid to the blade 31, so that the turbine flowmeter determines the volumetric flow according to the attack angle.

[0052] In order to determine the volumetric flow, the volumetric flow satisfies the following formula:

[0053]

[0054] In the above formula, Q is the volumetric flow rate into the turbine; R is the radius of the blade from the center of rotation; A is the cross-sectional area of the fluid flowing within the housing; a is the angle of attack of the fluid to the blade; b is the relative fluid velocity angle of the fluid to the axial direction; and w is the rotational speed of the turbine.

[0055] Since b is a fixed amount, R and A are known parameters, and w can be measured in various ways, such as a conventional Hall sensor mounted outside the shell to sense the magnetism of the turbine blade, or a tachometer mounted coaxially with the turbine. Therefore, the flow rate Q can be obtained by the above formula.

[0056] It should be noted that when the fluid medium transmits driving force to the turbine blade, it must flow into the leading edge of the blade with a certain angle of attack. The greater the angle of attack, the greater the driving force generated. When the angle of attack is zero, the driving force is zero. This is well known in the fields of aerodynamics and airfoil lift theory.

[0057] Compared with the turbine flowmeter with a correction or compensation mechanism, the turbine flowmeter of the embodiment of the application determines the volumetric flow rate by detecting the angle of attack of the fluid to the blade. Since the force of the fluid to the blade changes when the angle of attack changes, this reflects the energy conversion efficiency and loss within the system. Therefore, the energy loss in the system can be directly evaluated by measuring the angle of attack, and the flow rate can be determined by the angle of attack without relying on an additional correction or compensation mechanism. This is conducive to eliminating the influence of the correction or compensation mechanism on the detection efficiency, improving the detection precision, and reducing the detection cost.

[0058] Optionally, the detection assembly 4 includes a plurality of pressure measurement holes, and the detection assembly 4 obtains the angle of attack through the pressure in the holes of the plurality of pressure measurement holes. For example, the pressure measurement holes can be three, five, or seven, etc.

[0059] Reference Figure 2 Optionally, the detection assembly 4 includes three pressure measurement holes, namely a first pressure measurement hole 41, a second pressure measurement hole 42, and a center pressure measurement hole 43. The first pressure measurement hole 41 and the second pressure measurement hole 42 are symmetrically distributed relative to the center pressure measurement hole 43. The pressures in the holes of the first pressure measurement hole 41, the second pressure measurement hole 42, and the center pressure measurement hole 43 satisfy the following formula:

[0060]

[0061] wherein C i is a constant coefficient, which can be determined by theoretical analysis and experimental calibration; a is the angle of attack of the fluid to the blade; P O is the pressure in the hole of the center pressure measurement hole; P L is the pressure in the hole of the first pressure measurement hole; and P R is the pressure in the hole of the second pressure measurement hole.

[0062] That is, the detection assembly 4 is actually a three-hole angle measurement structure. The three-hole angle measurement does not require direct contact with the airflow, has high measurement accuracy, and has less interference with the airflow, so it can more truly reflect the characteristics of the airflow. Moreover, the three-hole angle measurement can achieve real-time attack angle monitoring by quickly collecting and processing pressure data, which is particularly important for systems that need to be dynamically adjusted. In addition, the design of the pressure measurement holes is relatively simple, the manufacturing cost is low, and it is easy to integrate into existing systems.

[0063] Reference Figures 1 to 2 Optionally, the detection assembly 4 is arranged at the leading edge of the blade 31 of the turbine 3. In this way, the sensitivity and accuracy of the measurement can be improved. Specifically, the change of the attack angle is usually most significant when the fluid reaches the leading edge of the blade 31, so arranging the detection assembly 4 at the leading edge of the blade 31 of the turbine 3 can capture the subtle changes in the direction of the fluid, thereby improving the sensitivity and accuracy of the measurement. In addition, the leading edge of the blade 31 of the turbine 3 is the first part contacted by the fluid, so arranging the attack angle detection assembly 4 at this position can more directly and accurately reflect the attack angle of the airflow relative to the blade 31.

[0064] Optionally, it also includes a driving assembly 5 located in the accommodating cavity and arranged on the rotating shaft 2, the driving assembly 5 is used to drive the turbine 3 to rotate according to the size of the attack angle, so that the attack angle is zero. In this way, the measurement of the attack angle can be replaced by the measurement of the turbine speed, which is less affected by the environment (temperature, pressure, etc.) than the detection of the attack angle, has higher accuracy, and thus is conducive to improving the measurement accuracy of the turbine flowmeter.

[0065] Correspondingly, the volumetric flow rate satisfies the following formula:

[0066]

[0067] In the above formula, Q is the volumetric flow rate entering the turbine; R is the radius of the blade from the center of rotation; A is the cross-sectional area of the fluid flowing in the accommodating cavity; β is the relative flow velocity angle of the fluid to the axial direction; and ω is the rotational speed of the turbine.

[0068] In specific implementation, whether the attack angle is zero can be determined by the pressure in the first pressure measurement hole 41 and the second pressure measurement hole 42. Specifically, when the pressure in the first pressure measurement hole 41 and the second pressure measurement hole 42 is equal, the attack angle of the fluid to the blade 31 is zero. Correspondingly, in specific arrangement, the detection assembly 4 can cancel the pressure measurement hole 43, as shown in FIG. 4B, which can reduce the design difficulty and cost. Figure 3

[0069] ​Optionally, the driving assembly 5 is a driving motor, and the driving assembly 5 is configured to output torque to the turbine 3 to drive the turbine 3 to rotate. Of course, the driving assembly 5 can also be other types of structures, such as a compressed air driving structure, a steam driving structure, etc.

[0070] Optionally, the rotating speed of the driving assembly 5 is consistent with the rotating speed of the turbine 3. That is, the rotating speed of the turbine 3 can be determined by measuring the rotating speed of the driving motor.

[0071] Optionally, the driving assembly 5 is provided with an internal speed measuring assembly. That is, the driving assembly 5 can detect its rotating speed through the internal speed measuring assembly, so as to obtain the rotating speed of the turbine 3. Compared with an external speed measuring assembly, the internal speed measuring assembly can provide more accurate speed feedback, which is helpful to improve the control accuracy of the system.

[0072] Reference Figure 1 Optionally, the driving assembly 5 is located downstream of the turbine 3, so as to avoid occupying the space upstream of the turbine 3 by the motor, thereby reducing the pressure loss and flow interference of the fluid when passing through, and avoiding affecting the detection accuracy of the detection assembly 4.

[0073] Reference Figure 4 Optionally, the rotating shaft 2 is located downstream of the turbine 3, and one end of the rotating shaft 2 is rotationally connected to the main body 1, and the other end is connected to the rear end of the turbine 3. That is, the guide and support structure at the inlet of the accommodating cavity can be cancelled, so as to reduce the turbulence at the inlet position, thereby eliminating the influence of the inlet turbulence on the attack angle measurement.

[0074] Optionally, the turbine flowmeter further comprises a flow guide, and the flow guide is located in the accommodating cavity and is located upstream of the turbine 3. That is, the flow guide can be installed as an independent flow control device upstream of the turbine 3, so as to not only meet the requirement of inlet flow guide, but also reduce the turbulence at the inlet position, thereby eliminating the influence of the inlet turbulence on the attack angle measurement.

[0075] Reference Figure 5 Optionally, the blades 31 of the turbine 3 can be a cylinder or an elliptical cylinder, etc. In this way, the structure design of the blades 31 of the turbine 3 can be more flexible. Specifically, since the turbine 3 is driven by the driving assembly 5, the blades 31 of the turbine 3 are no longer required to convert energy between the turbine 3 and the fluid, so the structure design of the blades 31 of the turbine 3 can be more flexible, which is helpful to reduce the design difficulty of the blades 31.

[0076] Optionally, the number of blades 31 of the turbine 3 is two, and the two blades 31 are arranged symmetrically relative to the axis of the turbine 3, which is enough to keep the turbine 3 rotationally balanced. In this way, the cost can be reduced. Specifically, since the turbine 3 is driven by the drive assembly 5, the blades 31 are no longer needed to convert energy between the turbine 3 and the fluid, so the number of turbine 3 blades 31 can be reduced, which helps to reduce costs.

[0077] For the sake of understanding, we will analyze the central idea of the present application in detail below.

[0078] Reference Figure 6 and Figure 7 , Figure 6 shows the cross section of a single rotor turbine flowmeter, Figure 7 shows a velocity triangle of a single rotor turbine flowmeter. In general, we use the following notes in the description of the velocity triangle:

[0079] ω: turbine rotational speed;

[0080] R: radius of the blade from the center of rotation;

[0081] T: torque exerted by the fluid medium on the turbine cascade;

[0082] work done by the turbine on the fluid flow per unit mass flow rate;

[0083] V: fluid velocity in the absolute coordinate system;

[0084] V x : axial component of V, using subscript x;

[0085] V t : tangential component of V, using subscript t;

[0086] W: flow velocity relative to the turbine cascade;

[0087] U: tangential wheel speed, equal to radius R times rotational speed w;

[0088] α: absolute fluid velocity angle of the fluid with the axis;

[0089] β: relative fluid velocity angle of the fluid with the axis;

[0090] 1: represents the flow station at the inlet of the single or first turbine cascade;

[0091] 2: represents the flow station at the outlet of the single or first turbine cascade.

[0092] A well-known theorem in turbomachinery, the "Euler turbine" equation, is used to describe the energy exerted by the turbine on the fluid medium passing through it:

[0093]

[0094] Under the current model assumption that the turbine cross-sectional radius is constant, R, the turbine inlet and outlet tangential velocities are the same, then:

[0095] U1 = U2 = ωR (2)

[0096] In the current analysis, the fluid enters the turbine cascade in the axial direction, and the tangential component of the absolute velocity at station 1 is zero. Therefore,

[0097] V 1t = 0 (3)

[0098] Or,

[0099]

[0100] In the above formula, Q is the volumetric flow rate entering the turbine; A is the cross-sectional area of the fluid flowing in the containment cavity.

[0101] For simplicity, without loss of the general applicability of the current analysis, we will assume that the cross-sectional area A of the flow entering and leaving the turbine cascade is the same. Then, the axial component of the absolute fluid velocity at the turbine machine outlet should be equal to the axial component at the turbine machine inlet, then:

[0102]

[0103] We consider the ideal case of zero loss and assume that the flow angle at the turbine machine blade outlet is the same as the turbine machine blade outlet metal flow angle, then, 2x , V 2t , ω, R and β form the following relationship:

[0104]

[0105] Combining equations (1) to (6), then:

[0106]

[0107] Or,

[0108]

[0109] Equation (8) is a well-known linear relationship between volumetric flow rate and turbine rotational speed.

[0110] If there are system losses in the turbine flow meter, including blade viscous losses and bearing friction losses, the accuracy of the linear relationship in formula (8) will be affected. That is, under steady conditions, the power transferred from the fluid medium to the turbine is equal to the losses associated with the turbine rotation.

[0111] In order for the fluid medium to transmit driving force to the turbine blades, it must flow into the leading edge of the blades at a certain angle of attack. This is well known in fields such as aerodynamics and airfoil lift theory. Figure 8 As shown. Furthermore, the larger the angle of attack, the greater the driving force generated; when the angle of attack is zero, the driving force is zero.

[0112] according to Figure 8 It can draw the velocity triangle upstream of the turbine blade cascade, such as Figure 9 As shown.

[0113] according to Figure 9 The following formula can be derived:

[0114] β1=β-α1 (9)

[0115] U1=ωR=V 1x tanβ1=V 1x tan(β-α) (10)

[0116]

[0117] In formula (12), the blade angle β is a fixed quantity, R and A are known parameters, and ω can be obtained by measurement. Therefore, if the fluid angle of attack α is measured, the volumetric flow rate QQ can be obtained by formula (12).

[0118] In this application, the fluid angle of attack can be obtained using a three-hole angle measurement method. The concept of three-hole angle measurement is embodied in the leading edge of a turbine blade, where the leading edge of the turbine blade has three pressure measurement holes, such as... Figure 2 As shown.

[0119] Figure 2 The diagram shows a first pressure measuring hole, a second pressure measuring hole, and a central pressure measuring hole. The first and second pressure measuring holes are symmetrically distributed relative to the central pressure measuring hole. The pressure inside the first, second, and central pressure measuring holes satisfies the following formula:

[0120]

[0121] Among them, C i It is a constant coefficient, which can be determined through theoretical analysis and experimental calibration; P O It is the pressure inside the central pressure measuring hole; P L It is the pressure inside the first pressure measuring hole; PR is the pressure inside the second pressure measurement hole.

[0122] It is further contemplated that if the driving motor is used to drive the rotation of the turbine, and the rotational speed of the motor (i.e. the rotational speed of the turbine) is controlled such that the measured angle of attack is zero, then the equation for calculating the flow rate is reduced to equation (8). In this state, the rotation of the turbine is driven by the fluid and the motor. This means that the relationship between the rotational speed of the turbine flow meter and the flow rate is no longer affected by any system losses. Because these losses require energy, which is offset by the driving motor.

[0123] It is further contemplated that because the rotational speed of the driving motor is related to the rotational speed of the turbine, in a specific implementation, a driving motor with a built-in speed sensor can be used. The built-in speed sensor of the driving motor can be used to measure the rotational speed of the driving motor, and thus the rotational speed of the turbine. In this way, there is no need to add an additional speed measurement component, which helps to reduce the cost and structural complexity.

[0124] It is further contemplated that because the purpose of controlling the rotational speed of the driving motor is to make the angle of attack zero, in a specific implementation, when the angle of attack is zero, the pressure inside the first pressure measurement hole 41 and the pressure inside the second pressure measurement hole 42 are equal. Therefore, the detection component 4 can cancel the pressure measurement hole 43 to reduce the design difficulty and cost.

[0125] It is further contemplated that if the guide and / or support structure of the inlet is removed, the turbine rotor is supported by the downstream structure alone, as shown in Figure 4 This design eliminates the influence of turbulence in the turbine rotor inlet on the measurement of the angle of attack, further improving the flow conditions into the turbine, so that the angle of attack measurement and motor control can be more accurate and undisturbed. Of course, if the inlet guide is still needed, the guide can be installed as a separate flow control device upstream of the turbine rotor.

[0126] It is further contemplated that because the driving motor is introduced, there is no longer an energy conversion between the fluid and the turbine, and the number of turbine blades can be reduced. For example, the number of turbine blades can be reduced to two, which maintains the dynamic balance of rotation. Of course, the number of turbine blades can also be other numbers.

[0127] It is further contemplated that because the turbine is no longer a tool for exchanging energy with the fluid, the streamlining of the blade shape becomes unimportant. For example, each blade is a cylinder or an ellipse, as shown in Figure 5 Of course, the blades can also adopt other shapes that are easy to process.

[0128] It is intended that all such additional substitutions, modifications and variations be included within the scope of the application, the general principles and specific embodiments described herein are intended to be illustrative only and not restrictive. Accordingly, all such modifications, equivalents and alternatives are intended to be included within the scope of the application.

[0129] The above description is only specific embodiments of the present application, but the protection scope of the present application is not limited thereto, any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A turbine flow meter, characterized in that, include: Main body, rotating shaft, turbine, and detection components; The main body has an internal cavity for the flow of fluid. The rotating shaft is located within the receiving cavity and is arranged along the fluid flow direction; the rotating shaft is rotatably connected to the main body. The turbine is located within the receiving cavity and is disposed on the rotating shaft; The detection component is located within the receiving cavity and disposed on the turbine blades. The detection component is used to detect the angle of attack of the fluid on the blades so that the turbine flow meter can determine the volumetric flow rate based on the angle of attack.

2. The turbine flow meter according to claim 1, characterized in that, The detection component includes multiple pressure measuring holes, and the detection component obtains the angle of attack by measuring the pressure inside the multiple pressure measuring holes.

3. The turbine flow meter according to claim 2, characterized in that, The detection component includes a first pressure measuring hole, a second pressure measuring hole, and a central pressure measuring hole. The first and second pressure measuring holes are symmetrically distributed relative to the central pressure measuring hole. The pressures inside the first, second, and central pressure measuring holes satisfy the following formula: Among them, C i It is a constant coefficient that can be determined through theoretical analysis and experimental calibration; α is the angle of attack of the fluid on the blade; P O It is the pressure inside the central pressure measuring hole; P L It is the pressure inside the first pressure measuring hole; P R It is the pressure inside the second pressure measuring hole.

4. The turbine flow meter according to claim 2, characterized in that, Volumetric flow rate satisfies the following formula: In the above formula, Q is the volumetric flow rate entering the turbine; R is the radius of the blade measured from the center of rotation; A is the cross-sectional area of ​​the fluid flowing in the containment cavity; α is the angle of attack of the fluid on the blade; β is the relative fluid velocity angle between the fluid and the axial direction; and ω is the turbine rotational speed.

5. The turbine flow meter according to claim 1, characterized in that, Also includes: A drive assembly is located within the receiving cavity and disposed on the rotating shaft. The drive assembly is used to drive the turbine to rotate according to the size of the angle of attack, so that the angle of attack is zero.

6. The turbine flow meter according to claim 5, characterized in that, The drive component is a drive motor, which is used to output torque to the turbine to make it rotate.

7. The turbine flow meter according to claim 6, characterized in that, The rotational speed of the drive assembly is the same as that of the turbine, and the drive assembly has a built-in speed measuring component.

8. The turbine flow meter according to claim 5, characterized in that, The drive assembly is located downstream of the turbine.

9. The turbine flow meter according to claim 5, characterized in that, Volumetric flow rate satisfies the following formula: In the above formula, Q is the volumetric flow rate entering the turbine; R is the radius of the blade measured from the center of rotation; A is the cross-sectional area of ​​the fluid flowing in the containment cavity; β is the relative fluid velocity angle between the fluid and the axial direction; and ω is the turbine rotational speed.

10. The turbine flow meter according to claim 1, characterized in that, The rotating shaft is located downstream of the turbine, with one end rotatably connected to the main body and the other end connected to the rear end of the turbine.

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