A secondary water supply pipeline with spiral rifling and its flow velocity calculation method

Abstract

The present invention belongs to the technical field of fluid transportation water supply pipelines, and particularly relates to a secondary water supply pipeline provided with spiral male rifling and a flow velocity calculation method thereof. The flow velocity calculation method includes: obtaining the gradually changing cross-sectional area of the spiral male rifling through an equivalent cycloid and an arc; obtaining the effective cross-sectional area of the conical pipeline; and then using the Bernoulli equation and the continuity equation to obtain the flow velocity at any point in the conical pipeline, and accurately calculating the flow rate of the entire cross-section of the conical pipeline through integration. The calculation method of the present invention improves the accuracy and precision of the calculation results, so as to more clearly and accurately calculate and analyze the flow rate and flow velocity values generated by the secondary water supply pipeline provided with spiral male rifling, and can provide a reference for the design of the secondary water supply system.

Description

Technical Field

[0001] The present invention belongs to the technical field of fluid transportation water supply pipelines, and particularly relates to a secondary water supply pipeline provided with spiral male rifling and a flow velocity calculation method thereof. Background Art

[0002] Water pipes are essential equipment for water supply. According to the material of the water pipes, they can be divided into: metal pipes, plastic-coated metal pipes, and plastic pipes. Among them, the most commonly used water pipes in daily life are stainless steel pipes in metal pipes and PPR pipes in plastic pipes. Stainless steel is safe, hygienic, healthy, and durable, eliminating the problem of plastic pipe pollution, and the price is also much more economical than copper pipes, which is the preferred water pipe material. As a new type of water pipe, PPR pipes can be used as both cold pipes and hot pipes, and they are non-toxic, lightweight, pressure-resistant, and corrosion-resistant. However, regardless of the type of pipe used, under the same initial conditions, the water flow velocity and head in the pipeline are almost the same, and there is still room for improvement in energy conservation and water conservation of existing water supply pipelines.

[0003] The invention patent with the publication number CN 107906086 A provides a sleeve-type spiral flow generating device. The design of the spiral fins will affect the flow uniformity of the fluid in the pipeline. If the fluid flow is not uniform, it may lead to too high or too low local pressure, thereby affecting the efficiency and stability of the entire system. And because the space between the spiral fins and the inner pipe is small, and the design of the spiral fins is relatively complex, it will cause difficulties in cleaning and maintenance, increase the workload of the operators, and affect the long-term operation efficiency of the device.

[0004] The invention patent with the publication number CN 118623102 A provides a water supply pipeline for a new type of secondary water supply equipment. Since the water supply pipeline provided with spiral rifling is a straight pipeline, the effect of improving the flow velocity is limited. Summary of the Invention

[0005] In view of the above technical problems, the present invention provides a secondary water supply pipeline provided with spiral male rifling and a flow velocity calculation method thereof, which reduces energy consumption, saves water use costs, and achieves the same water supply effect under the drive of a low-grade power motor. To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0006] A secondary water supply pipeline with spiral male rifling, comprising a straight pipeline, a conical pipeline, spiral male rifling, square connecting flanges, O-ring sealing grooves and straight groove bolt through holes. One end of the straight pipeline is connected to the large end of the conical pipeline. The conical pipeline is provided with spiral male rifling. There are two square connecting flanges. One square connecting flange is connected to the other end of the straight pipeline, and the other square connecting flange is connected to the small end of the conical pipeline. The square connecting flange at the other end of the straight pipeline is connected to the outlet of the water pump through the straight groove bolt through hole. The square connecting flange at the small end of the conical pipeline is connected to the network pipeline through the straight groove bolt through hole. O-ring sealing grooves are arranged in both square connecting flanges.

[0007] The straight pipeline and the conical pipeline are made of galvanized steel pipe, stainless steel pipe or cast iron pipe.

[0008] A method for calculating the flow rate of a secondary water supply pipeline with spiral male rifling, comprising the following steps:

[0009] S1. Equivalent the cross-sectional area of the spiral male rifling into the area enclosed by a cycloid and an arc, and calculate the cross-sectional area of the spiral male rifling.

[0010] S2. According to the cross-sectional area of the spiral male rifling calculated in S1, calculate the effective cross-sectional area of the conical pipeline.

[0011] S3. According to the effective cross-sectional area of the conical pipeline calculated in S2, calculate the flow velocity at any point in the conical pipeline through the Bernoulli equation.

[0012] S4. According to the flow velocity at any point in the conical pipeline calculated in S3, calculate the flow rate of the entire cross-section of the conical pipeline.

[0013] The method for calculating the cross-sectional area of the spiral male rifling obtained in S1 is as follows:

[0014] Equivalent the cross-sectional area of the spiral male rifling into the area enclosed by a cycloid and an arc according to the cutting method.

[0015] The equivalent curve expression of the cycloid is:

[0016] ; The value range of is [0 - 2π];

[0017] Differentiate it to get:

[0018] ;

[0019] Then the area composed of the cycloid is:

[0020] ;

[0021] The equivalent curve expression of the arc is:

[0022] ;

[0023] Differentiating it gives:

[0024] ;

[0025] Then the area formed by the arc is:

[0026] ;

[0027] Then the cross-sectional area of the spiral rifling is:

[0028] ;

[0029] Where: is the cross-sectional area of the spiral rifling; is the area formed by the cycloid; is the area formed by the arc; is the rolling angle, and the value range is [0 - 2π]; is the radian; a is the height of the spiral rifling; b is the width of the spiral rifling; R is the gradually changing radius of the conical pipe, , is the radius of the small end of the conical pipe, is the radius of the large end of the conical pipe, .

[0030] The method for calculating the effective cross-sectional area of the conical pipe obtained in S2 is:

[0031] ;

[0032] Where: A 2 is the effective cross-sectional area of the conical pipe; n is the number of spiral rifling; R is the gradually changing radius of the conical pipe, .

[0033] The method for calculating the flow velocity at any point in the conical pipe obtained in S3 is: Ignoring the head loss, the Bernoulli equation is listed as follows:

[0034] ;

[0035] Then from the continuity equation ;

[0036] We get ;

[0037] Thus, the flow velocity at any point in the conical pipe is obtained:

[0038] ;

[0039] Wherein: is the flow velocity in the straight pipeline; is the flow velocity at any point in the conical pipeline; ρ is the density of water in the conical pipeline; is the pressure in the straight pipeline; is the pressure at any point in the conical pipeline; is the acceleration due to gravity; is the cross-sectional area of the straight pipeline; is the effective cross-sectional area of the conical pipeline.

[0040] The method for calculating the flow rate of the entire cross-section of the conical pipeline obtained in S4 is:

[0041] ;

[0042] Wherein: Q is the flow rate of the entire cross-section of the conical pipeline.

[0043] Compared with the prior art, the beneficial effects of the present invention are:

[0044] The present invention provides a method for calculating the flow velocity of a secondary water supply pipeline provided with spiral rifling. By equating the cross-section of the spiral rifling to the area enclosed by a cycloid and an arc, the cross-sectional area of the spiral rifling is obtained, and then the effective cross-sectional area of the conical pipeline is obtained. Then, using Bernoulli's equation and the flow velocity and pressure at a known point, the flow velocity at any point in the conical pipeline is obtained, and the flow rate of the entire cross-section of the conical pipeline is accurately calculated by integration. The calculation method of the present invention improves the accuracy and precision of the calculation results, so as to more clearly and accurately calculate and analyze the flow rate and flow velocity values generated by the secondary water supply pipeline provided with spiral rifling, and can provide a reference for the design of the secondary water supply system. Description of the Drawings

[0045] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only exemplary, and for those of ordinary skill in the art, other implementation drawings can be obtained by extending according to the provided drawings without creative efforts.

[0046] The structures, proportions, sizes, etc. shown in this specification are only used to match the content disclosed in the specification for those familiar with this technology to understand and read, and are not used to limit the implementation conditions of the present invention. Therefore, they do not have substantial technical significance. Any modification of the structure, change in the proportional relationship, or adjustment of the size, without affecting the efficacy that the present invention can produce and the purpose that can be achieved, should still fall within the scope covered by the technical content disclosed in the present invention.

[0047] Figure 1 is a schematic structural diagram of the present invention;

[0048] Figure 2 is a cross-sectional view of the water supply pipeline of the present invention;

[0049] Figure 3 is a front view of the present invention;

[0050] Figure 4 is a schematic diagram of the equivalent curve of the arc of the present invention.

[0051] Wherein: 1 is a straight pipeline, 2 is a conical pipeline, 3 is a spiral rifling, 4 is a square connecting flange, 5 is an O-shaped sealing groove, and 6 is a straight groove bolt through-hole. Specific Embodiments

[0052] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. These descriptions are only for further explaining the features and advantages of the present invention, rather than limiting the claims of the present invention; based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present application.

[0053] The following will further describe in detail the specific embodiments of the present invention in conjunction with the drawings and embodiments. The following embodiments are used to illustrate the present invention, but are not used to limit the scope of the present invention.

[0054] In the description of the present application, it should be noted that unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to specific situations.

[0055] A secondary water supply pipeline provided with spiral rifling, such as Figure 1 、 Figure 2As shown in the figure, it includes a straight pipe 1, a conical pipe 2, a spiral rifling 3, a square connecting flange 4, an O-ring seal groove 5 and a straight groove bolt through-hole 6. One end of the straight pipe 1 is connected to the large end of the conical pipe 2. A spiral rifling 3 is arranged inside the conical pipe 2. There are two square connecting flanges 4. One square connecting flange 4 is connected to the other end of the straight pipe 1, and the other square connecting flange 4 is connected to the small end of the conical pipe 2. The square connecting flange 4 at the other end of the straight pipe 1 is connected to the outlet of the water pump through the straight groove bolt through-hole 6, and the square connecting flange 4 at the small end of the conical pipe 2 is connected to the pipe network pipeline through the straight groove bolt through-hole 6. O-ring seal grooves 5 are arranged inside both square connecting flanges 4, and O-ring seals are arranged inside the O-ring seal grooves 5. Under the action of the spiral rifling 3, when the water flow passes through the conical pipe 2 at high speed, the collision flow field becomes a rotating flow field. Compared with an ordinary smooth pipe, when the water flow passes through the conical pipe 2 provided with the spiral rifling 3 driven by a motor with the same power, not only is the spraying distance farther and the height higher, but also the equipment cost and energy consumption can be further reduced.

[0056] As Figures 1-4 shown, the conical pipe 2 provided with the spiral rifling 3 is directly connected to the outlet of the water pump through the square connecting flange 4. The gradual change radius of the conical pipe 2 is R, m is the rolling angle, and the value range is [0 - 2π]; a is the height of the spiral rifling 3; b is the width of the spiral rifling 3; n is the number of the spiral rifling 3, generally taking 3 - 5, is the radian.

[0057] A flow velocity calculation method for a secondary water supply pipe provided with a spiral rifling, as Figure 3 、 Figure 4 shown, according to the cutting method, the cross-sectional area of the spiral rifling 3 is equivalently converted into the area enclosed by a cycloid (the first part) and an arc (the second part).

[0058] The equivalent curve expression of the first part is:

[0059] (1)

[0060] The value range of

[0061] is [0 - 2π]. Differentiating it gives:

[0062] (2)

[0063] Then the area formed by it is:

[0064] (3)

[0065] The equivalent curve expression of the second part is:

[0066] (4)

[0067] Differentiating it gives:

[0068] (5)

[0069] The area it forms is:

[0070] (6)

[0071] Then the cross-sectional area of the spiral rifling 3 is: (7)

[0072] The effective cross-sectional area of the conical pipe 2 is: (8)

[0073] Where: is the cross-sectional area of the spiral rifling 3; is the area formed by the cycloid; is the area formed by the arc; is the rolling angle, and its value range is [0 - 2π]; is the radian; a is the height of the spiral rifling 3; b is the width of the spiral rifling 3; R is the gradually changing radius of the conical pipe 2, , is the radius of the small end of the conical pipe 2, is the radius of the large end of the conical pipe 2, .

[0074] Then, according to Bernoulli's equation, the flow velocity at any point in the conical pipe 2 is obtained:

[0075] Neglecting the head loss, the Bernoulli's equation is listed as follows: (9)

[0076] Then, from the continuity equation

[0077] we get (10)

[0078] Substituting Equation (10) into Equation (9) gives the flow velocity at any point in the conical pipe 2: (11)

[0079] In the formula: is the flow velocity in the straight pipe 1; is the flow velocity at any point in the conical pipe 2; ρ is the density of water in the conical pipe 2; is the pressure in the straight pipe 1; is the pressure at any point within the conical pipe 2; is the acceleration due to gravity; is the cross-sectional area of the straight pipe 1; is the effective cross-sectional area of the conical pipe 2.

[0080] The flow rate of the entire cross-section of the conical pipe 2 is: (12)

[0081] The above only elaborates in detail on the preferred embodiments of the present invention. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those of ordinary skill in the art, various changes can be made without departing from the gist of the present invention, and all such changes should be included within the protection scope of the present invention.

Claims

1. A method for calculating the flow rate of a secondary water supply pipeline provided with spiral rifling, characterized in that: The following steps are involved: S1, equating the cross section of the spiral rifling (3) to the area enclosed by the cycloid and the arc, and calculating the cross section area of ​​the spiral rifling (3); According to the cutting method, the cross-sectional area of ​​the spiral rifling (3) is equivalent to the area enclosed by the cycloid and the arc; The equivalent curve expression of the cycloid is: ； m The value range of is [0-2π]; Differentiate it to get: ； Then the area formed by the cycloid is: ； The equivalent curve expression of the arc is: ； Differentiate it to get: ； The area formed by the arc is: ； Then the cross-sectional area of ​​the spiral rifling (3) is: ； in: is the cross-sectional area of ​​the spiral rifling (3); is the area composed of the cycloids; is the area of ​​the arc; is the rolling angle, the value range is [0-2π]; is radians; a is the height of the spiral rifling (3); b is the width of the spiral rifling (3); R is the gradient radius of the tapered pipe (2), , is the radius of the small end of the tapered pipe (2), is the radius of the large end of the tapered pipe (2), ; S2, calculating the effective cross-sectional area of ​​the tapered pipe (2) according to the cross-sectional area of ​​the spiral rifling (3) calculated in S1; ； in: A 2 is the effective cross-sectional area of ​​the tapered pipe (2); n is the number of spiral rifling lines (3); R is the gradient radius of the tapered pipe (2), ; S3, calculating the flow velocity at any point of the tapered pipe (2) by using the Bernoulli equation according to the effective cross-sectional area of ​​the tapered pipe (2) calculated in S2; Ignoring the head loss, the Bernoulli equation is as follows: ； Then from the continuity equation ; get ; Thus, the flow velocity at any point in the conical pipe (2) is obtained: ； in: is the flow velocity in the straight pipe (1); is the flow velocity at any point in the conical pipe (2); ρ is the density of water in the conical pipe (2); is the pressure in the straight pipeline (1); is the pressure at any point in the tapered pipe (2); is the acceleration due to gravity; is the cross-sectional area of ​​the straight pipe (1); is the effective cross-sectional area of ​​the tapered pipe (2); S4. Based on the flow velocity at any point in the tapered pipe (2) calculated in S3, calculate the flow rate of the entire cross section of the tapered pipe (2): ； in: Q is the flow rate of the entire cross section of the tapered pipe (2); A secondary water supply pipeline provided with spiral grooves comprises a straight pipeline (1), a tapered pipeline (2), spiral grooves (3), a square connection flange (4), an O-type sealing groove (5) and a straight groove bolt through hole (6), wherein one end of the straight pipeline (1) is connected to the large end of the tapered pipeline (2), the tapered pipeline (2) is provided with spiral grooves (3), two square connection flanges (4) are provided, one of the square connection flanges (4) is connected to the other end of the straight pipeline (1), and the other square connection flange (4) is connected to the small end of the tapered pipeline (2), the square connection flange (4) at the other end of the straight pipeline (1) is connected to the outlet of a water pump through the straight groove bolt through hole (6), the square connection flange (4) at the small end of the tapered pipeline (2) is connected to the pipe network pipeline through the straight groove bolt through hole (6), and the two square connection flanges (4) are both provided with O-type sealing grooves (5).

2. A method for calculating flow velocity of a secondary water supply pipeline provided with spiral rifling according to claim 1, characterized in that: The straight pipeline (1) and the tapered pipeline (2) are made of galvanized steel pipes, stainless steel pipes or cast iron pipes.

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