A method for designing parameters of a double-balanced drum structure

Abstract

This invention discloses a method for designing structural parameters of a double-balanced drum, relating to the field of hydraulic optimization design of rotating machinery. The invention includes the following steps: constructing the pressure difference and temperature difference at the inlet and outlet surfaces of the double-balanced drum based on a hydraulic loss model analysis; and constructing functional relationships between the pressure difference and temperature difference at the inlet and outlet surfaces of the double-balanced drum, as well as the balancing force, with respect to ε1, ε2, and ε3, based on the value of the balancing drum gap, thereby obtaining the function and f. F′ (c1, ε1, ε2, ε3); Construct a functional relationship between the average enthalpy difference and the average pressure difference and average temperature difference at the inlet and outlet; Construct a functional relationship between ΔF and the average pressure difference and average temperature difference at the inlet and outlet; Given the constraints of ΔF, use the iterative method to solve for the solution set S. ΔFm In S ΔFm In this paper, the optimal solution of the function is found by using an iterative method and simultaneously fitting the function f. F′ (c1, ε1, ε2, ε3) and the optimal values ​​of the balancing drum gap c1 and dimensionless parameters ε1, ε2, ε3 are obtained by solving. This invention is used for the optimization of the design of a dual-balancing drum structure.

Description

Technical Field

[0001] This invention relates to the field of hydraulic optimization design of rotating machinery, and more specifically to a method for designing structural parameters of a double-balanced drum. Background Technology

[0002] Rotating machinery is widely used in our daily lives, with centrifugal pumps being a common example. Water pumps, a type of centrifugal pump, are frequently used in industry to transport liquids, most commonly water. For industrial applications, we must consider not only practicality but also economic benefits. Optimizing the structure of the double balancing drum in rotating machinery to reduce costs and improve efficiency is highly advantageous. Studying energy losses in the balancing drum structure and selecting appropriate drum dimensions can not only reduce energy losses and manufacturing costs but also enhance the balancing effect. Currently, the structural design of double balancing drums in rotating machinery often focuses on the adverse effects of gap leakage, neglecting the relationship between energy losses from fluid flow through the gap and the gap itself, leading to significant energy losses. Therefore, studying the relationship between hydraulic losses in the gap and the gap structure of the double balancing drum can not only identify the optimal drum dimensions but also reduce energy losses and improve efficiency. Summary of the Invention

[0003] In view of this, the present invention provides a method for designing the structural parameters of a dual-balanced drum to solve the problems existing in the background art.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A method for designing structural parameters of a dual-balanced drum includes the following steps: The pressure difference between the inlet and outlet surfaces of the double-balanced drum is constructed based on the hydraulic loss model analysis. and temperature difference ; According to the gap of the balance drum The values ​​are used to construct the pressure difference between the inlet and outlet surfaces of the dual-balance drum. and temperature difference and balancing forces about The functional relationship is obtained to obtain the function. and f F′ (c1, ε1, ε2, ε3); Construct the average enthalpy difference Regarding the average pressure difference between inlet and outlet Average temperature difference Functional relation ; build Regarding the average pressure difference between inlet and outlet Average temperature difference Functional relation ,in, Axial force With balancing forces difference; Given the constraint condition ΔF, solve for iteratively. solution set ,exist In the middle, the iterative method is used to find the function. optimal solution ;in, This is the difference between the average enthalpy at the inlet surface and the average enthalpy at the outlet surface. This represents the difference between the average pressure at the inlet surface and the average pressure at the outlet surface. This is the difference between the average temperature on the inlet surface and the average temperature on the outlet surface. Simultaneous fitting functions f F′ (c1, ε1, ε2, ε3) and Solving for the balance drum gap and dimensionless parameters The optimal value.

[0005] Optionally, the pressure difference between the inlet and outlet surfaces of the dual-balance drum can be constructed based on the hydraulic loss model analysis. and temperature difference The specific steps are as follows: Based on the rotating machinery structure, a hydraulic loss model was established to obtain the pressure and temperature diagrams of the inlet and outlet surfaces of the balance drum clearance; The average pressure of each surface is obtained by averaging the pressure and temperature at the inlet and outlet surfaces. and average temperature ; Average pressure at the inlet and outlet surfaces and average temperature The difference is calculated to obtain the average pressure difference between the inlet and outlet surfaces. and average temperature difference .

[0006] Optional, function and The specific acquisition process is as follows: Based on the geometric parameters of the balancing drum structure of rotating machinery Determine dimensionless parameters Construct a point set ,in: ; Constructing the pressure difference between the inlet and outlet surfaces of the dual-balanced drum and temperature difference Regarding the set of geometric parameters , , … The functions are respectively and .

[0007] Optionally, given the constraint condition ΔF, the solution can be obtained using an iterative method. solution set ,exist In the middle, the iterative method is used to find the function. optimal solution The specific steps are as follows: Given the axial force of the balancing drum is The balancing force range generated by the double-balanced drum is axial force With balancing forces The range of the difference ΔF is ; Based on functional relationships , exist Iterative solution within the range to obtain the solution set ={ , , … },in ...; In point set Iterative optimization to obtain the function minimum value corresponding That is the optimal solution.

[0008] Optionally, in the point set Iterative optimization to obtain the function minimum value corresponding This is the optimal solution, and the specific steps are as follows: Given an initial point The convergence accuracy is , place ; calculate ,like Then we get an approximate solution. ; calculate , , place , ; After multiple iterations, the function reaches its minimum value. When, the corresponding minimum point is Then the function The minimum value corresponds to the average pressure difference between the inlet and outlet of the dual-balanced drum. and average temperature difference ; in for At point The first derivative at that point; For the Hessian matrix; For point The direction of descent at that location.

[0009] As can be seen from the above technical solution, compared with the prior art, the present invention provides a method for designing the structural parameters of a dual-balanced drum, which is used to optimize the design of the dual-balanced drum structure. Attached Figure Description

[0010] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0011] Figure 1 This is a schematic diagram of the process of the present invention. Detailed Implementation

[0012] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0013] This invention discloses a design method for a double-balanced drum structure, comprising the following steps: determining the pressure difference and temperature difference between the inlet and outlet surfaces of the double-balanced drum based on a hydraulic loss model analysis; constructing a fitting function of the average enthalpy difference and the difference between the axial force and the balancing force with respect to the average pressure difference and average temperature difference between the inlet and outlet surfaces; and constructing a (pressure difference between the inlet and outlet surfaces of the double-balanced drum gap). Regarding (the annular sealing gap of the small balancing drum) Dimensionless parameters (The ratio of the annular sealing gap of the large balancing drum to the annular sealing gap of the small balancing drum) (The ratio of the axial length of the small balancing drum clearance to the annular sealing clearance of the small balancing drum) A fitting function for (the ratio of the axial length of the large balancing drum gap to the annular sealing gap of the small balancing drum); and a construction of (the temperature difference between the inlet and outlet surfaces of the double balancing drum gap). Regarding (the annular sealing gap of the small balancing drum) Dimensionless parameters (The ratio of the annular sealing gap of the large balancing drum to the annular sealing gap of the small balancing drum) (The ratio of the axial length of the small balancing drum clearance to the annular sealing clearance of the small balancing drum) The fitting function for (the ratio of the axial length of the large balance drum gap to the annular sealing gap of the small balance drum); given the constraint of the difference between the axial force and the balance force, the optimal value of the average enthalpy difference between the inlet and outlet surfaces is obtained by solving the fitting function simultaneously. If the optimal value is not unique, further optimization is performed to obtain the optimal value of the relevant parameters of the balance drum gap.

[0014] Example 1

[0015] See Figure 1 The present invention discloses a dual-balanced drum structure design method, comprising the following steps: Step 1: Analyze and construct the pressure difference between the inlet and outlet surfaces of the double-balanced drum based on the hydraulic loss model. and temperature difference The hydraulic loss model is based on the area through which the fluid flows in the rotating machinery. After the water body is extracted, the pressure and temperature maps are obtained by using commercial CFD software for fluid simulation calculation.

[0016] Step 2: Based on the gap of the small balancing drum The values ​​are used to construct the pressure difference between the inlet and outlet surfaces of the dual-balance drum. and temperature difference about The functional relationship is obtained to obtain the function. and Step 3: Construct the average enthalpy difference value Regarding the average pressure difference between inlet and outlet Average temperature difference Functional relation ; build (axial force) With balancing forces (Difference) Regarding the average pressure difference between inlet and outlet Average temperature difference Functional relation ; Step 4: Given the constraints of ΔF, solve for the solution using the iterative method. solution set ,exist In the middle, the iterative method is used to find the function. optimal solution ; Step 5: Combine the fitting functions and Solving for the gap of the small balancing drum and dimensionless parameters The optimal value; Furthermore, step 1 includes: Step 1.1: Based on the geometric parameters of the clearance of the small balancing drum in the rotating machinery. Determine dimensionless parameters Construct a point set ,in: ; Step 1.2: Construct the pressure difference between the inlet and outlet surfaces of the dual-balanced drum. and temperature difference Regarding the set of geometric parameters , , … The functions are respectively and Furthermore, step 2 includes: Step 2.1: Based on the rotating machinery structure, establish a reasonable hydraulic loss model and obtain the pressure and temperature diagrams of the inlet and outlet surfaces of the balance drum gap; Step 2.2: Calculate the average pressure of the inlet and outlet pressure and temperature diagrams to obtain the average pressure of each surface. and average temperature ; Step 2.3: Average pressure at the inlet and outlet surfaces and average temperature The difference is calculated to obtain the average pressure difference between the inlet and outlet surfaces. and average temperature difference ; Furthermore, step 3 includes: Based on the obtained point set ={ , , … Construct the average enthalpy difference Regarding the average pressure difference between inlet and outlet Average temperature difference Functional relation ; build (axial force) With balancing forces difference Regarding the average pressure difference between inlet and outlet Average temperature difference Functional relation ; in It is the specific heat capacity of a fluid under constant pressure. It is the partial derivative of volume with respect to temperature. , where F is the axial force and D is a constant.

[0017] Furthermore, step 4 includes: Step 4.1, Given the axial force of the balancing drum as... The balancing force range generated by the double-balanced drum is axial force With balancing forces difference The range is ; Step 4.2: Based on the functional relationship , exist Iterative solution within the range to obtain the solution set ={ , , … },in ...; Step 4.3, in the point set Iterative optimization to obtain the function minimum value corresponding This is the optimal solution, and the solution process is as follows: Given an initial point The convergence accuracy is , place ; ,calculate ,like Then we get an approximate solution. ; ,calculate , , place , ; Set k = k + 1, then return to step 2; After multiple iterations, the function reaches its minimum value. When, the minimum point is Then the function The average pressure difference between the inlet and outlet of the dual-balanced drum when the minimum value is reached. and average temperature difference ; in for At point The first derivative at that point; For the Hessian matrix; For point The direction of descent at that location; Furthermore, step 5 includes: Simultaneous fitting functions and Solving for the gap of the small balancing drum and dimensionless parameters The optimal value.

[0018] (1.) According to the law of conservation of mass, the leakage in each gap is equal, that is... = ; ,

[0019] Obtain the parameters of the gap The relationship between them:

[0020] in The leakage rate is the amount of water at the small balance drum gap. The leakage rate is due to the large balance drum clearance. The width of the small balancing drum. The width of the large balance drum, The dynamic viscosity of the liquid. The pressure difference across the small balancing drum. The pressure difference between the two ends of the large balancing drum.

[0021] (2.) Establish fitting functions respectively f F′ (c1, ε1, ε2, ε3)

[0022] The fitting function takes the following form: in, All are constants; in, All are constants; , in , All are constants. ,

[0023] Furthermore The value and the corresponding Substitute the values ​​into the fitting function respectively f F′ From (c1, ε1, ε2, ε3), we obtain three equations, and then solve the system of equations from step (1). The relationship between them can be obtained by solving the system of equations. The value of .

[0024] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0025] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for designing structural parameters of a dual-balanced drum, characterized in that, Includes the following steps: The pressure difference between the inlet and outlet surfaces of the double-balanced drum is constructed based on the hydraulic loss model analysis. and temperature difference ; According to the gap of the small balancing drum The values ​​are used to construct the pressure difference between the inlet and outlet surfaces of the dual-balance drum. and temperature difference and balancing forces about The functional relationship is obtained to obtain the function. and f F′ (c1, ε1, ε2, ε3); where, The ratio of the annular sealing gap of the large balancing drum to the annular sealing gap of the small balancing drum. The ratio of the axial length of the small balancing drum clearance to the annular sealing clearance of the small balancing drum. This represents the ratio of the axial length of the large balance drum clearance to the annular sealing clearance of the small balance drum. Construct the average enthalpy difference Regarding the average pressure difference between inlet and outlet Average temperature difference Functional relation Construct ΔF with respect to the average pressure difference between inlet and outlet. Average temperature difference Functional relation Where ΔF is the axial force With balancing forces difference; Given the constraint condition ΔF, solve for iteratively. solution set ,exist In the middle, the iterative method is used to find the function. optimal solution ;in, This is the difference between the average enthalpy at the inlet surface and the average enthalpy at the outlet surface. Simultaneous fitting functions f F′ (c1, ε1, ε2, ε3) and Solving for the gap of the small balancing drum and dimensionless parameters The optimal value; The fitting function takes the following form: in, All are constants; in, All are constants; ， in , All are constants. , .

2. The method for designing structural parameters of a dual-balanced drum according to claim 1, characterized in that, The pressure difference between the inlet and outlet surfaces of the double-balanced drum is constructed based on the hydraulic loss model analysis. and temperature difference The specific steps are as follows: Based on the rotating machinery structure, a hydraulic loss model was established to obtain the pressure and temperature diagrams of the inlet and outlet surfaces of the balance drum clearance; The average pressure of each surface is obtained by averaging the pressure and temperature at the inlet and outlet surfaces. and average temperature ; Average pressure at the inlet and outlet surfaces and average temperature The difference is calculated to obtain the average pressure difference between the inlet and outlet surfaces. and average temperature difference .

3. The method for designing structural parameters of a dual-balanced drum according to claim 1, characterized in that, function and The specific acquisition process is as follows: Based on the geometric parameters of the gap between the double-balanced drums Determine dimensionless parameters Construct a point set ,in: ; Constructing the pressure difference between the inlet and outlet surfaces of the dual-balanced drum and temperature difference Regarding the set of geometric parameters , , ... The functions are respectively and .

4. The method for designing structural parameters of a dual-balanced drum according to claim 1, characterized in that, Given the constraint condition ΔF, solve for iteratively. solution set ,exist In the middle, the iterative method is used to find the function. optimal solution The specific steps are as follows: Given the axial force of the balancing drum is The range of balancing forces generated by the double-balanced drum is: axial force With balancing forces The range of the difference ΔF is ; Based on functional relationships , exist Iterative solution within the range to obtain the solution set ={ , , ... },in ...; In point set Iterative optimization to obtain the function The minimum value corresponding to That is the optimal solution.

5. The method for designing structural parameters of a dual-balanced drum according to claim 4, characterized in that, In point set Iterative optimization to obtain the function The minimum value corresponding to This is the optimal solution, and the specific steps are as follows: Given an initial point The convergence accuracy is , place ; calculate ,like Then we get an approximate solution. ; calculate , , place , ; After multiple iterations, the function reaches its minimum value. When, the corresponding minimum point is That is, function The minimum value corresponds to the average pressure difference between the inlet and outlet of the dual-balanced drum. and average temperature difference ; in for At point The first derivative at that point; For the Hessian matrix; For point The direction of descent at that location.

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