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RU-2861695-C1 - METHOD FOR OPTIMISING FLOW PART OF ULTRA-LOW SPECIFIC SPEED CENTRIFUGAL PUMP

RU2861695C1RU 2861695 C1RU2861695 C1RU 2861695C1RU-2861695-C1

Abstract

FIELD: pump engineering. SUBSTANCE: invention relates to a method for optimising the flow part of an ultra-low specific speed centrifugal pump. The method for optimising the flow part of an ultra-low specific speed centrifugal pump includes the steps of determining at least one geometric parameter of the flow part of the centrifugal pump impeller in the meridional section to be optimised; constructing an impeller model in accordance with the specified parameters; constructing a velocity diagram of n flow layers in the meridional section in accordance with the obtained impeller model; determining at least one optimisation criterion based on the velocity diagram of n flow layers in the meridional section; iteratively changing at least one geometric parameter of the flow part of the impeller for said model to obtain at least one corrected model; constructing at least one corrected velocity diagram of n flow layers in the meridional section based on at least one corrected model; checking compliance with the optimisation criterion of said at least one corrected model based on at least one corrected velocity diagram of n flow layers in the meridional section; comparative evaluation of models that meet the optimisation criterion in order to determine the best one. EFFECT: increase in the efficiency of an ultra-low specific speed centrifugal pump, reduction in the labour intensity of designing an impeller of an ultra-low specific speed centrifugal pump, as well as increase in the energy efficiency of the flow part of an ultra-low specific speed centrifugal pump. 7 cl, 10 dwg

Inventors

  • Savichev Dmitrii Valerievich
  • Fonova Ekaterina Dmitrievna

Dates

Publication Date
20260507
Application Date
20250611

Claims (16)

  1. 1. A method for manufacturing the flow section of an ultra-low-speed centrifugal pump, comprising the following steps:
  2. at least one geometric parameter of the flow path of the impeller of a centrifugal pump in the meridional section subject to optimization is determined;
  3. construct a model of the impeller in accordance with the specified parameters;
  4. construct a diagram of the velocities of n flow layers in a meridional section in accordance with the obtained model of the impeller;
  5. at least one optimization criterion is determined based on the velocity diagram of n flow layers in the meridional section;
  6. iteratively changing at least one geometric parameter of the flow section of the impeller for the specified model to obtain at least one adjusted model;
  7. at least one corrected velocity diagram of n flow layers in a meridional section is constructed based on at least one corrected model;
  8. a check is carried out for compliance with the optimization criterion of the said at least one adjusted model based on at least one adjusted velocity diagram of n flow layers in the meridional section;
  9. conduct a comparative evaluation of models that meet the optimization criterion in order to determine the best one;
  10. use the flow path parameters of the best adjusted model from the models that meet the optimization criterion to design and manufacture the flow path of an ultra-low-speed centrifugal pump.
  11. 2. The method according to paragraph 1, characterized in that the parameter of the flow part is the radius of curvature of the cover disk in the meridional section and/or the angle of inclination of the cover disk relative to the main disk in the meridional section.
  12. 3. The method according to paragraph 2, characterized in that the radius of curvature of the covering disk in the meridional section is set in the range from 5 to 27 mm.
  13. 4. The method according to paragraph 2, characterized in that the angle of inclination of the cover disk relative to the main disk in the meridional section is set in the range from 0° to 13°.
  14. 5. The method according to claim 1, characterized in that at least one optimization criterion is based on the degree of symmetry of the velocity diagram in the meridional section relative to the mean flow line.
  15. 6. The method according to claim 1, characterized in that at least one optimization criterion is based on the ratio of instantaneous values of the velocities of n flow layers in the meridional section.
  16. 7. The method according to paragraph 6, characterized in that the optimization criterion is met if the difference in the velocities of the adjacent n-th and (n-1)-th flow layers on the flow layer velocity diagram in the meridional section differs from the difference in the velocities of the adjacent n-th and (n+1)-th flow layers by no more than a given value.

Description

Field of technology to which the invention relates The invention relates to the field of pump engineering, namely to a method for optimizing the flow path of an ultra-low-speed centrifugal pump. State of the art The low energy efficiency of the flow paths of ultra-low-speed pumps (with a speed factor of less than 20) is a major problem for the chemical, petrochemical, and other industries that use them in their production processes. While low-speed pumps are very minor energy consumers, their overall energy consumption accounts for a significant portion of the overall plant's energy consumption. Due to the low efficiency of these pumps (usually no more than 37%), saving 0.1 kW per unit of equipment can significantly reduce the plant's energy consumption. Fundamentally, the problem of low efficiency in such flow paths lies in a suboptimal energy balance. Figuratively speaking, the supplied energy is spent primarily on driving the working parts, with only a small portion being transferred to the pumped fluid. This problem is further exacerbated by the low hydraulic efficiency of the working parts. Currently, most manufacturers seek to improve energy efficiency by introducing technological processes and manually refining components. The most common method is manual polishing of pump flow surfaces to reduce their roughness. Additional milling and turning of housing components or the main impeller disc are also used. More complex refining methods include galvanizing and applying other coatings that reduce surface roughness. These methods are labor-intensive and also reduce the manufacturability of the refinished equipment. The classical approach to designing a centrifugal pump impeller (see, for example, Calculation of Vane Machines and Hydrodynamic Transmissions: a teaching aid for students majoring in 1-36 01 07 "Hydraulic Pneumatic Systems of Mobile and Technological Machines" / P. R. Bartosh, P. N. Kishkevich. - Minsk: BNTU, 2019. - 47 p.) involves calculating the specified values of flow, head, pressure, and speed of the impeller in order to determine the dimensions of the flow part of the latter. The contour of the impeller channel in the meridional section is made similar in shape to the contours of the channels of impellers with high hydraulic properties: for example, those given in reference manuals; the main dimensions of the impeller obtained as a result of the hydraulic calculation are drawn, and the channel is profiled according to the wheel analogue. However, this approach is oriented towards a monotonically increasing area of the impeller channel in the meridional section and has limitations on the maximum achievable hydraulic efficiency, especially for the flow parts of ultra-low-speed pumps. A method is known for profiling the elements of the flow part of a bladed machine (see patent RU2727223C1), including determining the shape of the elements of the flow part of the bladed machine, the external contours of which are represented in the form of curves, in which a functional relationship between the geometric and kinematic parameters is determined, wherein the curves of the external contours of the elements of the flow part of the bladed machine are represented by envelopes of a family of circles, the centers of which are located on the mean flow line, and the desired shape of the envelopes is determined on the basis of the values of a generalized design parameter, iteratively changing the geometry of the mean flow line, while specifying the equation of the generalized design parameter, calculating the main geometric parameters of the elements of the flow part and determining the functional dependence of the cross-sectional area along the length of the mean flow line, ensuring a continuous irrotational flow throughout the flow part, constructing the mean flow line using a Bezier polynomial so that the initial support vertex is fixed, wherein the extreme support vertex has one degree of freedom, and the intermediate support the vertices have two degrees of freedom, then the coordinates of the points of the envelopes of the family of circles are discretely calculated, the external contours of the flow part elements are constructed by interpolating points with Bezier splines, the generalized design parameter is calculated and the coefficients of the Bezier polynomial of the mean flow line are corrected. This method is well suited for designing pump impellers in the classic speed range (with a speed factor of 40 or higher), but has significant limitations on the maximum achievable hydraulic efficiency for the flow paths of ultra-low speed pumps, since it is focused only on the geometric perfection of the channel profile without taking into account the integral criteria for the flow of the pumped medium. Also known is a method for optimizing the shape of the flow part elements of a centrifugal pump (see patent RU 2716523 C1), which consists of finding the extremum of a functional for which a connectio