A temperature compensation method for pressure-maintaining pouring pressure of water distribution ring pipe of impulse turbine

Abstract

The invention discloses a temperature compensation method for the pressure-maintaining casting pressure of a water distribution ring pipe of an impulse turbine, comprising: establishing a three-dimensional finite element model and defining elastic modulus and Poisson's ratio parameters, defining boundary conditions of an inlet and an outlet; defining the pressure-maintaining casting pressure and the pressure-maintaining casting temperature load of the finite element model under ideal conditions, solving and extracting the radial deformation of a key pipe section of the water distribution ring pipe along its own pipe section; determining the pressure-maintaining casting temperature under actual conditions, and preliminarily converting the pressure-maintaining casting pressure; defining the pressure-maintaining casting pressure and the pressure-maintaining casting temperature load, solving and extracting the radial deformation of the key pipe section of the water distribution ring pipe along its own pipe section under actual conditions; judging whether the radial deformation under actual conditions and under ideal conditions are consistent, and whether the overall deformation distribution is reasonable; determining the compensation relationship between the pressure-maintaining casting pressure and the pressure-maintaining casting temperature of the water distribution ring pipe of the impulse turbine; the invention solves the problems of long time for adjusting the water temperature and relatively complicated temperature adjustment and temperature control measures in the temperature control casting method.

Description

Technical Field

[0001] The invention relates to the technical field of impulse turbines, in particular to a temperature compensation method for the pressure-maintaining pouring pressure of a water distribution ring pipe of an impulse turbine. Background Art

[0002] The water distribution ring pipe is the core component of the impulse turbine. It is responsible for guiding the water flow to enter each nozzle evenly and symmetrically, driving the runner to rotate stably. At the same time, it is subjected to high water pressure inside. For high-head and large-capacity units, the water pressure load is borne by the water distribution ring pipe itself and the surrounding concrete. Due to the temperature difference during the construction season, the pressure-maintaining pouring gap of the water distribution ring pipe is inconsistent with the theoretical design, which in turn affects the load-bearing ratio of the water distribution ring pipe and the concrete, resulting in the risk of damage to the water distribution ring pipe and concrete. The temperature-controlled pouring method is usually adopted. By adjusting the temperature of the water body inside the water distribution ring pipe at any time during the pressure-maintaining pouring of the water distribution ring pipe, the adverse effect of seasonal temperature differences on the pressure-maintaining pouring gap can be eliminated. However, this method takes a long time to adjust the water temperature, and the temperature adjustment and temperature control measures are relatively complicated, which brings a series of problems such as increased labor and material costs and extended construction period. Summary of the invention

[0003] The purpose of the present invention is to overcome the above-mentioned shortcomings and provide a temperature compensation method for the pressure-maintaining casting pressure of a water distribution ring pipe of an impulse turbine. The method can determine the pressure-maintaining casting temperature under actual conditions according to the actual casting state of the water distribution ring pipe, and convert the pressure-maintaining casting pressure under actual conditions, so as to solve the problems in the temperature control casting method such as the long time for adjusting the water temperature, the complex temperature adjustment and temperature control measures, the increased labor and material costs, the extended construction period, etc.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is: a temperature compensation method for the pressure-maintaining pouring pressure of the water distribution ring pipe of an impulse turbine, comprising the following steps:

[0005] Step S1: according to the design scheme of the water distribution ring pipe structure, a three-dimensional finite element model is established and elastic modulus and Poisson's ratio parameters are defined. According to the constraint state of the water distribution ring pipe during pressure-maintaining casting, boundary conditions of the inlet and outlet of the finite element model are defined;

[0006] Step S2: Define the pressure-maintaining pouring pressure of the finite element model under ideal conditions according to the theoretical design parameters of the water distribution ring and pressure-maintaining pouring temperature , solve and extract the radial deformation of the key pipe section of the water distribution ring pipe along its own pipe section under ideal conditions ;

[0007] Step S3: Determine the pressure-maintaining pouring temperature under actual conditions according to the actual pouring status of the water distribution ring pipe , and preliminarily convert the pressure-maintaining pouring pressure ;

[0008] Step S4: Define the pressure holding casting pressure of the finite element model under actual conditions and pressure-maintaining pouring temperature , solve and extract the radial deformation of the key pipe section of the water distribution ring pipe along its own pipe section under actual conditions ;

[0009] Step S5: Based on the calculation results obtained in step S4 and step S2, it is determined whether the radial deformation of the key pipe section of the water distribution ring pipe under actual conditions and under ideal conditions is consistent with each other, so as to determine whether the overall deformation distribution of the water distribution ring pipe under actual conditions obtained in step S4 is reasonable;

[0010] Step S6: determining the compensation relationship between the pressure-maintaining casting pressure and the pressure-maintaining casting temperature of the water distribution ring pipe of the impulse turbine.

[0011] Preferably, in step S3, the pressure-maintaining pouring temperature under actual conditions is determined according to the actual pouring parameters of the water distribution ring pipe. , and preliminarily convert the pressure-maintaining pouring pressure under actual conditions , the calculation formula is:

[0012] ;

[0013] in, is the pouring pressure under actual conditions. The pouring pressure under ideal conditions is maintained. is the pressure-maintaining pouring temperature under actual conditions, The pouring temperature under ideal conditions is maintained under pressure. is the elastic modulus, is the thermal expansion coefficient of the water distribution ring pipe material, is the wall thickness of the water distribution ring pipe, is the radius of the water distribution ring pipe.

[0014] Preferably, in step S5, based on the calculation results obtained in step S4 and step S2, it is determined whether the radial deformation of the key pipe section of the water distribution ring pipe along its own pipe section under actual conditions and under ideal conditions is consistent, specifically, and Whether the deviation between them is within 5% is used to judge whether it is consistent; if and If the deviation between them is within 5%, it is judged that the radial deformation of the key pipe section of the water distribution ring pipe along its own pipe section under the actual conditions and the ideal conditions is consistent, so that it is judged that the overall deformation distribution of the water distribution ring pipe under the actual conditions obtained in step S4 is reasonable; if and If the deviation between them exceeds 5%, it is judged that the radial deformation of the key pipe section of the water distribution ring pipe under actual conditions and ideal conditions along its own pipe section is inconsistent, thereby judging that the overall deformation distribution of the water distribution ring pipe under actual conditions obtained in step S4 is unreasonable.

[0015] Preferably, the expression for determining the compensation relationship between the pressure and temperature of the pressure-maintaining pouring of the water distribution ring pipe of the impulse turbine in step S6 is as follows:

[0016] ;

[0017] in, To maintain pouring pressure; To maintain the pouring temperature; It is the functional relationship between the pressure-maintaining pouring pressure and the pressure-maintaining pouring temperature.

[0018] Beneficial effects of the present invention:

[0019] 1. The present invention adopts a method combining theoretical calculation with finite element analysis to obtain the compensation relationship between the pressure and temperature of the water distribution ring pipe pressure-maintaining pouring, which is more reliable and more accurate.

[0020] 2. The present invention determines the pressure-maintaining pouring pressure under actual conditions according to the actual pressure-maintaining pouring temperature of the water distribution ring pipe, thereby solving the problem of improper load distribution between the water distribution ring pipe and concrete caused by inappropriate pressure-maintaining pouring pressure of the water distribution ring pipe due to temperature differences during construction seasons.

[0021] 3. The present invention obtains the compensation relationship between the pressure-maintaining pouring pressure and the pressure-maintaining pouring temperature based on accurate calculation. It only needs to correct the pressure-maintaining pouring pressure under actual conditions of the water distribution ring pipe to eliminate the influence of the pressure-maintaining pouring temperature change. The method is simple, time-saving and low-cost.

[0022] 4. The present invention can determine the pressure-maintaining pouring temperature under actual conditions according to the actual pouring state of the water distribution ring pipe, and convert it to obtain the pressure-maintaining pouring pressure under actual conditions, thereby solving a series of problems in the temperature-controlled pouring method, such as the long time required to adjust the water temperature, the complex temperature adjustment and control measures, the increased labor and material costs, and the extended construction period. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The present invention is a flow chart of a temperature compensation method for pressure-maintaining casting pressure of a water distribution ring pipe of an impulse turbine.

[0024] Figure 2 This is a schematic diagram of the three-dimensional finite element model of the water distribution ring structure of the impulse turbine and the boundary conditions. DETAILED DESCRIPTION

[0025] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0026] like Figure 1 As shown, a method for temperature compensation of pressure maintaining casting pressure of water distribution ring pipe of impulse turbine is provided, and the steps are as follows:

[0027] Step S1: Figure 2 As shown, according to the design scheme of the water distribution ring pipe structure, a three-dimensional finite element model 1 is established and parameters such as elastic modulus and Poisson's ratio are defined. According to the constraint state of the water distribution ring pipe during pressure-maintaining casting, the boundary conditions of the inlet 2 and outlet 3 of the finite element model are defined; in this embodiment, the elastic modulus is defined as 2.1E5 MPa, the Poisson's ratio is defined as 0.3, and the boundary conditions of the inlet and outlet of the finite element model are defined, that is, the axial degrees of freedom of the inlet position node are constrained, and all degrees of freedom of the outlet position node are constrained.

[0028] Step S2: Define the pressure-maintaining pouring pressure of the finite element model under ideal conditions according to the theoretical design parameters of the water distribution ring and pressure-maintaining pouring temperature Equal load, solve and extract the radial deformation of the key pipe section of the water distribution ring pipe along its own pipe section under ideal conditions In this embodiment, the temperature Generally take 20℃.

[0029] Step S3: Determine the pressure-maintaining pouring temperature under actual conditions according to the actual pouring status of the water distribution ring pipe , and preliminarily convert the pressure-maintaining pouring pressure ; The calculation formula is:

[0030] ;

[0031] in, is the pouring pressure under actual conditions. The pouring pressure under ideal conditions is maintained. is the pressure-maintaining pouring temperature under actual conditions, The pouring temperature under ideal conditions is maintained under pressure. is the elastic modulus, is the thermal expansion coefficient of the water distribution ring pipe material, is the wall thickness of the water distribution ring pipe, is the radius of the water distribution ring pipe.

[0032] Step S4: Define the pressure holding casting pressure of the finite element model under actual conditions and pressure-maintaining pouring temperature Under the same load, solve and extract the radial deformation of the key pipe section of the water distribution ring pipe along its own pipe section under actual conditions ;

[0033] Step S5: Based on the calculation results obtained in step S4 and step S2, determine whether the radial deformation of the key pipe section of the water distribution ring pipe along its own pipe section under actual conditions and ideal conditions is consistent, that is, , determine whether the overall deformation distribution of the water distribution ring pipe under the actual conditions obtained in step S4 is reasonable; in the above process, determine whether the radial deformation of the key pipe section of the water distribution ring pipe along its own pipe section under the actual conditions and under the ideal conditions is consistent, specifically and Whether the deviation between them is within 5% is used to judge whether it is consistent; if and If the deviation between them is within 5%, it is judged that the radial deformation of the key pipe section of the water distribution ring pipe along its own pipe section under the actual conditions and the ideal conditions is consistent, so that it is judged that the overall deformation distribution of the water distribution ring pipe under the actual conditions obtained in step S4 is reasonable; if and If the deviation between them exceeds 5%, it is judged that the radial deformation of the key pipe section of the water distribution ring pipe under actual conditions and ideal conditions along its own pipe section is inconsistent, thereby judging that the overall deformation distribution of the water distribution ring pipe under actual conditions obtained in step S4 is unreasonable.

[0034] Step S6: Determine the compensation relationship between the pressure and temperature of the pressure-maintaining pouring of the water distribution ring pipe of the impulse turbine. The expression is as follows:

[0035] ;

[0036] in, To maintain pouring pressure; To maintain the pouring temperature; It is the functional relationship between the pressure-maintaining pouring pressure and the pressure-maintaining pouring temperature.

[0037] The above embodiments are only preferred technical solutions of the present invention and should not be regarded as limiting the present invention. The protection scope of the present invention shall be the technical solutions recorded in the claims, including equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. A method for compensating the temperature of the pressure-maintaining casting of the water distribution ring pipe of an impulse turbine, characterized in that: The following steps are involved: Step S1: according to the design scheme of the water distribution ring pipe structure, a three-dimensional finite element model is established and elastic modulus and Poisson's ratio parameters are defined. According to the constraint state of the water distribution ring pipe during pressure-maintaining casting, boundary conditions of the inlet and outlet of the finite element model are defined; Step S2: Define the pressure-maintaining pouring pressure of the finite element model under ideal conditions according to the theoretical design parameters of the water distribution ring and pressure-maintaining pouring temperature , solve and extract the radial deformation of the key pipe section of the water distribution ring pipe along its own pipe section under ideal conditions ; Step S3: Determine the pressure-maintaining pouring temperature under actual conditions according to the actual pouring status of the water distribution ring pipe , and preliminarily convert the pressure-maintaining pouring pressure ; Step S4: Define the pressure holding casting pressure of the finite element model under actual conditions and pressure-maintaining pouring temperature , solve and extract the radial deformation of the key pipe section of the water distribution ring pipe along its own pipe section under actual conditions ; Step S5: Based on the calculation results obtained in step S4 and step S2, it is determined whether the radial deformation of the key pipe section of the water distribution ring pipe under actual conditions and under ideal conditions is consistent with each other, so as to determine whether the overall deformation distribution of the water distribution ring pipe under actual conditions obtained in step S4 is reasonable; Step S6: determining the compensation relationship between the pressure and temperature of the pressure-maintaining pouring of the water distribution ring pipe of the impulse turbine; In step S3, the pressure-maintaining pouring temperature under actual conditions is determined according to the actual pouring parameters of the water distribution ring pipe. , and preliminarily convert the pressure-maintaining pouring pressure under actual conditions , the calculation formula is: ； in, is the pouring pressure under actual conditions. The pouring pressure is maintained under ideal conditions. is the pressure-maintaining pouring temperature under actual conditions, The pouring temperature under ideal conditions is the pressure maintenance temperature. is the elastic modulus, is the thermal expansion coefficient of the water distribution ring pipe material, is the wall thickness of the water distribution ring pipe, is the radius of the water distribution ring pipe.

2. A method for compensating the temperature of the pressure-maintaining pouring pressure of the water distribution ring pipe of an impulse turbine according to claim 1, characterized in that: In step S5, based on the calculation results obtained in step S4 and step S2, it is determined whether the radial deformation of the key pipe section of the water distribution ring pipe under actual conditions and under ideal conditions is consistent with that of the key pipe section of the water distribution ring pipe. and Whether the deviation between them is within 5% is used to judge whether it is consistent; if and If the deviation between them is within 5%, it is judged that the radial deformation of the key pipe section of the water distribution ring pipe along its own pipe section under the actual conditions and the ideal conditions is consistent, so that it is judged that the overall deformation distribution of the water distribution ring pipe under the actual conditions obtained in step S4 is reasonable; if and If the deviation between them exceeds 5%, it is judged that the radial deformation of the key pipe section of the water distribution ring pipe under actual conditions and ideal conditions along its own pipe section is inconsistent, thereby judging that the overall deformation distribution of the water distribution ring pipe under actual conditions obtained in step S4 is unreasonable.

3. A method for compensating the temperature of the pressure-maintaining pouring pressure of the water distribution ring pipe of an impulse turbine according to claim 1, characterized in that: The expression for determining the compensation relationship between the pressure-maintaining pouring pressure and the pressure-maintaining pouring temperature of the water distribution ring pipe of the impulse turbine in step S6 is as follows: ； in, To maintain pouring pressure; To maintain the pouring temperature; It is the functional relationship between the pressure-maintaining pouring pressure and the pressure-maintaining pouring temperature.

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