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Energy Conversion Characteristics of Stainless Steel Stamping and Welding Centrifugal Pumps and Design Method

Author: ZhangXiang
Tutor: ZhouJunLiang
School: Jiangsu University
Course: Fluid Machinery and Engineering
Keywords: Centrifugal pump Stamping and welding Energy conversion Hydraulic design Vortex structures Flow separation
CLC: TH311
Type: PhD thesis
Year: 2011
Downloads: 107
Quote: 0
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Abstract

With the development and maturation of the stainless steel plate stamping and welding processes, the red welding process manufacturing stainless steel stamping and welding centrifugal energy, materials, environmental protection, the mode of production of red welding gradually replaced by high energy consumption, heavy pollution casting production, development become a new type of centrifugal pump types to meet the low-carbon model of economic development and become many fields casting pump replacement products to low-cost, high-performance advantages. Change with the rapid development of the manufacturing process on centrifugal pump hydraulic design of the new challenges, the most prominent in (1) the existing design information is not fully applicable to the new technology; (2) the existing design theory failed to give full play to the advantages of the new technology ; (3) market diversification, the development of personalized new requirements. To solve these problems, this article by stainless steel stamping and welding centrifugal pump energy conversion characteristics, multiple design objectives can be achieved stainless steel stamping and welding centrifugal pump hydraulic design methods. This study follow from the internal flow structure and mechanism to find the law on the flow patterns, investigate the energy conversion characteristics, based to explore the idea of ??the design methods of energy conversion characteristics, the main content is divided into three parts: 1. Stamping and welding of stainless steel centrifugal pump The internal liquidity diagnosis First, regularization helicity extraction streamwise vortex flow field structure of stainless steel stamping and welding centrifugal pump fluid flow motion feature. The study showed that the imported segment memory deviate from the central axis of the induced vortex in the vortex core position; impeller, Qd conditions (0.6 to 1.4), streamwise vortices mainly the slow rotation curve vortex, and the gathering is not sufficient on centrifugal pump performance weak; volute occupied by a pair of reverse rotation of the symmetric vortex in the large flow conditions, the diffusion segment memory in significant secondary vortex and is accompanied by the phenomenon of vortex rupture, causing the increase of energy loss. Then, using the boundary vorticity dynamics-based three-dimensional flow separation theory to study the status of the impeller unsteady flow separation. The characteristics of impeller internal flow mainly to the relative velocity of, key physical quantities - the wall eddy flux (BVF) expression in the rotating coordinate system is deduced. The study found that the centrifugal force is another the BVF's important sources in addition to the pressure gradient. Most of the area of ??the stainless steel stamping and welding centrifugal pump impeller, the large-scale flow separation on the probability of occurrence is very low, the flow is basically showing the \Stainless steel stamping and welding centrifugal pump energy conversion characteristics based on numerical simulation technology, the area of ??the impeller shaft power distribution of different radial position of power changes and radial cross-section power density distribution of the characteristics of the dissipation rate near the wall and the flow core hydraulic losses and energy analysis of the characteristics of the fluid energy transfer process of change in the impeller, the impeller acting temporal and spatial distribution of the fluid, hydraulic losses Composition and distribution of energy conversion characteristics. The results showed that before the actual flow path in the throat of the impeller outlet is a critical area of ??energy conversion, most of the energy of the fluid is obtained in this region; the hydraulic loss impeller main component is the wall friction losses, are concentrated in the blade suction surface side and the impeller near the exit. The study also found that in the unsteady state the single impeller total energy transient input output inconsistent. Hydrodynamics equations derived solving the kinetic energy of the rate of change of kinetic energy density of the calculation of the rate of change of the existing CFD datasets, show the temporal and spatial distribution of the energy change in the flow channel, and also explains the unsteady characteristics of energy conversion. Distribution and strength characteristics of steady and unsteady state hydrodynamic volute into each other's space, and energy characteristics along the flow of energy conversion variation, and take advantage of the moment of momentum theorem reveals the volute static pressure circumferential direction of the causes of the uneven distribution of that along the circumferential direction of the uneven distribution of the pressure in the volute is a sectional size can not change the inherent properties of the volute, but also stainless steel stamping and welding centrifugal pump energy conversion showing the unstable fluctuation characteristics fundamental reasons. 3 stainless steel stamping and welding centrifugal pump hydraulic design methods First, the centrifugal pump head divided into dynamic head and static head were calculated relationship based on energy conversion, centrifugal pump head theory calculation method is different from the estimate hydraulic losses. By contrast with centrifugal pump specific speed range of 32 to 163 experimental results prove the theory calculation and experimental results are in good agreement with the calculation method is reliable. Secondly, for research and stainless steel stamping and welding process is characterized by impeller design after the import and export parameters determine the axial and circumferential directions runner painted not only combined energy conversion characteristics, respectively explore blade wrap angle and the impeller shaft surface projection the impact of the shape of the centrifugal pump performance. The blades of the impeller outlet throat placed the average angle β12, equivalent impeller outlet width be2 concept the β12, be2 and exports slip coefficient σ calculated and solving the impeller outlet velocity triangles. Centrifugal pumps lift the new calculation method previously proposed theoretical calculation method combination correctly predicted blade wrap angle and shape of the impeller shaft surface projection change the characteristics of centrifugal pumps outside. Then the independence principle screened five parameters, impeller diameter D2 the impeller outlet throat blade angle β12 impeller equivalent export width be2 is the slip coefficient σ volute throat area A1 as the hydraulic design of the main parameters, to establish a functional relationship between the characteristics of the main parameters and stainless steel stamping and welding centrifugal pump outside. Multiple design objectives decomposition and quantify constraints and optimization algorithm hydraulic design parameters. Hermite interpolation function based on five times, to establish a way to meet the design requirements of this article leaves painted completed multiple design objectives stainless steel stamping and welding centrifugal pump hydraulic design methods. Finally, the application of the proposed hydraulic design method multiple design objectives and requirements of the three models have stainless steel stamping and welding centrifugal pump design. Proved experimental performance of the final product, the design method proposed in this paper to achieve the expected results, and the performance is good.

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