Effect of impeller shroud trimming on the hydraulic performance of centrifugal pumps with low and medium specific speeds

Shadab, Mustafa; Karimipour, M.; Najafi, Atabak; Paydar, R.; Nourbakhsh, S. Ahmad

doi:10.1080/19942060.2021.2016492

Cited by 12 publications

(8 citation statements)

References 27 publications

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“…And the head and efficiency are also taken as the error evaluation parameter. The values of relevant error evaluation variables obtained by steady simulation are shown in Table 1, including key evaluation variables f 1 , f 2 , f 3 (corresponding to M 1 , M 2 and M 3 respectively), observation accuracy order c, extrapolated values f 21 ext , f 32 ext , relative error of extrapolation value e 21 ext , e 32 ext and grid convergence index GCI 21 fine , GCI 32 fine . For the different key parameters between M 1 and M 2 , the relative error of the extrapolated value is between 0.05 and 3.55%, and the grid convergence index is between 0.06 and 4.59% which is lower than 10%.…”

Section: Grid Preparation For Cfdmentioning

confidence: 99%

“…Researchers have been used to study the internal flow mechanism of fluid machinery. [18][19][20] Shadab et al 21 use the Renormalization group (RNG) k-ε model and shear stress transfer (SST) k-ω model to analyze the centrifugal pumps. Wu et al 22 analyzed the pressure pulsation in a centrifugal pump by SST k-ω model, which has accurate results.…”

Section: Introductionmentioning

confidence: 99%

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Influence of eccentric impeller on pressure pulsation of large-scale vaned-voluted centrifugal pump

Tao

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part A:

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Large-scale vaned-voluted centrifugal pump is a key component in water conveyance engineering. Hydraulic performance and pressure pulsation are important assessment indicators for operation efficiency and stability. During the common operation, the impeller eccentricity is easy to occur due to installation error, radial force and other reasons, which results the changes of hydraulic performance and pressure pulsation. In this study, the hydraulic performance and pressure pulsation in the vaneless region are analyzed by computational fluid dynamics method. The influence of eccentric impeller on the hydraulic performance in each components and the pressure pulsation is studied. Results show that the eccentric impeller causes the increasing of hydraulic dissipation especially in the volute. However, decreasing of the hydraulic dissipation happens in the draft tube. Impeller eccentricity significantly enhances the amplitude of rotation frequency, but has no obvious effect on the blade passing frequency and its harmonics. The peak-peak value of pressure pulsation of eccentric impeller increases rapidly with the eccentricity ratio. The results of this study provide scientific support for solving the stability problem caused by eccentric impeller in engineering cases.

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Section: Grid Preparation For Cfdmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Influence of eccentric impeller on pressure pulsation of large-scale vaned-voluted centrifugal pump

Tao

et al. 2022

Proceedings of the Institution of Mechanical Engineers, Part A:

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“…The authors in [4] present a numerical study of the effect of shroud trimming on the performance of pumps with low and medium specific speeds of rotation (…”

Section: Introductionmentioning

confidence: 99%

“…It is found that using Shear stress transport turbulence model provides results that are closer to the experimental ones, compared to the using of RNG k ε − turbulent model. In addition to that, still in [4], some data concerning the impact of the rate of trimming on the distribution of the pressure coefficient, as well as on the forces acting on the impeller, is given. In [5] it is studied the impact of the pump impeller rate of trimming on the pressure fluctuation and radial force of two-stage self-priming centrifugal pump.…”

Section: Introductionmentioning

confidence: 99%

Studying the variation of the slip factor when trimming the impeller of centrifugal pumps

Klimentov

Nikolova

Popov

et al. 2023

IOP Conf. Ser.: Earth Environ. Sci.

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It is well-known that one of the reasons for reducing the head of a centrifugal pump, when trimming its impeller, is the reduction of the slip factor. There are various methods used to determine it, but there is lack of information on whether they are applicable in case that a pump with a trimmed impeller operates. In the present work, a comparative experimental study concerning the applicability of some of the methods used to determine the slip factor, on two centrifugal pumps with different specific speed of rotation, is performed. Based on the experimental data, CFD models of the impellers of the two pumps have been validated and a numerical simulation study concerning the change of the slip factor during trimming, has also been performed. The impact of the rate of impeller trimming on the the slip factor variation has also been established. Based on the results found, concerning the performed numerical study, equations describing the relationship between the slip factor and the rate of trimming of the studied pumps are obtained.

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“…Many methods of changing the geometrical parameters by trimming are known. In [10] a so-called pump impeller shroud trimming (PIST) is presented, where the front disk is turned in the range of up to 25 %. The hydraulic parameters as well as the effect of the impeller change on the radial force loading the shaft are monitored.…”

Section: Introductionmentioning

confidence: 99%

Effect of Impeller Size on the Performance of a Single Blade Pump

2022

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Changing the impeller diameter is a frequently used method for adjusting pump performance parameters. In the case of conventional multi-blade impellers, this is done by reducing the diameter on the machine tool to the prescribed shape. The other dimensions of the pump (diffuser, inlet) remain unchanged. This method is called trimming. The article deals with the diameter reduction and subsequent modification of the performance parameters of a single blade pump. These pumps are characterized by certain specific features. First of all, it is an unsymmetrical impeller that must be both statically and dynamically balanced. This plays an essential role in the whole modification process. Research results obtained on a pump with an impeller diameter of 138 mm are presented. The change in diameter was monitored on a total of 3 impellers. Experiments were carried out in the laboratory of hydraulic machinery. The results were verified by CFD calculations. Research background: The article concerns the modification of impellers of single blade pumps. The effects of diameter modifications on multi-blade pumps are currently known. However, these have symmetrical impellers and can therefore be changed without restriction. For asymmetric (single blade) impellers, the problem is more complex as additional mass must be added to provide static and dynamic balance. Purpose of the article: The aim is to determine the nature of the change in performance parameters when the output diameter is changed. The results of the research can be applied in the prediction of the change in the operating point and the creation of tombstone charts. Methods: Two kinds of methods were used in the research: experiment and CFD calculation. A total of 4 impeller sizes were investigated. Findings & Value added: The results of the paper can be divided into two areas. In the experimental area, a device was designed to measure the characteristics of single blade pumps. Four impellers were manufactured and tested. In the area of CFD calculations, simulations of the hydraulic parameters around the best efficiency point (BEP) were performed. The calculation results were verified by experiment. The nature of the change of the BEP when the diameter of the impeller changes up to 87.9 % was found.

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Effect of impeller shroud trimming on the hydraulic performance of centrifugal pumps with low and medium specific speeds

Cited by 12 publications

References 27 publications

Influence of eccentric impeller on pressure pulsation of large-scale vaned-voluted centrifugal pump

Influence of eccentric impeller on pressure pulsation of large-scale vaned-voluted centrifugal pump

Studying the variation of the slip factor when trimming the impeller of centrifugal pumps

Effect of Impeller Size on the Performance of a Single Blade Pump

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