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PL
W artykule poruszono istotne zagadnienie zwiększenia sprawności pompy odśrodkowej poprzez zastosowanie modyfikacji w budowie łopatek wirnika. Modyfikacja ta polegała na wprowadzeniu szczeliny w łopatce – tzw. łopatki dzielonej – mającej na celu poprawę warunków przepływu cieczy w kanale międzyłopatkowym oraz ograniczenie strat energetycznych wynikających z występowania zawirowań. Dla danej wartości kąta opasania łopatki przygotowano model referencyjny z łopatką ciągłą oraz model z zastosowaniem w niej przerwy. Otrzymane wyniki pozwoliły na określenie parametrów pracy pompy oraz wpływu zastosowania szczeliny w łopatkach na charakterystykę pompy dla różnych wariantów kąta opasania łopatki. Na podstawie przeprowadzonych badań eksperymentalnych wyciągnięto wnioski dotyczące zakresów geometrycznych, w których modyfikacja ta prowadzi do wzrostu sprawności, a także wskazano przypadki, gdzie jej zastosowanie może być niekorzystne.
EN
This article discusses the important issue of increasing the efficiency of a centrifugal pump through the use of " odifications to the impeller blade design. This modification consisted of the implementation of a gap in the blade- the so“called split blade- with the aim of improving the fluid flow conditions in the interscapular channel and reducing energy losses due to turbulence A reference model with a continuous blade and a model with a gap in the blade were prepared for a given blade wrap angle value The results obtained allowed the determination of pump performance and the effect of using a gap in he blades on pump characteristics for different variants of blade wrap angle. On the basis of the experimental studies carried _ ut conclusions were drawn regarding the geometric ranges in which this modification leads to an increase in efficiency, as [ ell as indicating cases where its application may be unfavorable.
EN
The growing need for energy conservation and sustainability in industrial sectors has led to extensive research on improving mechanical systems, particularly centrifugal pumps. These pumps play a crucial role in hydropower generation, industrial processes, and fluid transportation. This study explores the use of biomimetic riblet structures inspired by shark skin to enhance centrifugal pump performance. Traditional designs focus on either hydraulic efficiency or noise reduction, leaving room for improvement. By developing and experimentally testing a bionic impeller, the research examines its impact on head, power consumption, and efficiency across different flow rates. While biomimetic adaptations are common in aerospace and marine engineering, their potential in pumps remains underexplored. Comparative analysis evaluates the effectiveness of these modifications in optimizing performance. Experimental findings provide insights into improved fluid movement and energy efficiency. By integrating nature-inspired design with testing, this study contributes to the development of high-performance, sustainable pumps. The results may help advance efficient industrial fluid transport systems. This research bridges biomimetic innovation with practical engineering, paving the way for future pump advancements.
EN
Throughout the operational lifecycle of centrifugal pumps, cavitation is an omnipresent phenomenon that frequently leads to cavitation erosion and a decline in hydraulic heads, leading to mechanical failures and substantial damage to the pump assembly. Although the cavitation phenomenon has been widely studied in existing literature, it is still a challenging task for reliable flow dynamics analysis of centrifugal pumps using the modal order reduction technique. In this study, the modal decomposition and reconstruction of the flow field of a centrifugal pump considering the cavitation are conducted. The dynamic modal decomposition (DMD) based on the singular value decomposition (SVD) is employed to explore the dynamic behaviour of the cavitation flow field by reducing the modal order of the flow field. Then, the modal characteristics of the pump flow field are systematically analyzed. The results demonstrate that the DMD method can improve the accuracy of the order reduction model and reduce the modal reconstruction error, the reconstruction error loss is less than 5%, and the calculation efficiency is significantly enhanced to analyze the pump cavitation flow field. In addition, a comparison of the calculation data between the finite element simulation and the DMD reconstructed flow field indicates the potential application of the DMD method in investigating the degradation of the flow field due to cavitation, which provides new perspective and solid technique support for centrifugal pump cavitation analysis.
PL
W artykule przedstawiono wyniki badań wpływu metod projektowania oraz zaleceń doboru parametrów geometrycznych spiralnego kanału zbiorczego na efektywność pracy pompy odśrodkowej dwustrumieniowej. Do przeprowadzenia badań wykorzystano symulacje numeryczne, a ich wyniki zwalidowano eksperymentalnie na stanowisku badawczym. Badano wpływ na parametry pracy pompy specjalnie zaprojektowanych spiralnych kanałów zbiorczych zgodnie z metodą stałego krętu cieczy oraz stałej prędkości średniej oraz zgodnie z zaleceniami podanymi w literaturze przez A. Stepanoffa i A. Lomakina. Różnica pomiędzy badanymi spiralami wynikała ze zmiany średnicy wejścia do spirali, zmiany szerokości wlotu do spirali oraz zmiany pola przekroju. Badania również obejmowały określenie wpływu kształtu poprzecznego przekroju spirali (trapezowy i okrągły) oraz zmianę kąta rozwarcia ścian spirali. Przeprowadzona analiza otrzymanych wyników badań wykazała, że wybór metody projektowania spiralnego kanału wpływa na zmianę optymalnego punktu pracy pompy. Jak wynika z obliczeń, metoda stałej prędkości średniej daje bardziej płaski kształt charakterystyki przepływu w porównaniu do metody zachowania stałego krętu cieczy. Natomiast zmiana kąta rozwarcia ścian z trapezowym lub okrągłym kształtem przekroju spirali w niewielkim stopniu wpływa na zmianę wysokości podnoszenia i sprawności pompy.
EN
The article presents the results of research on the influence of design methods and recommendations for the selection of geometric parameters of the volute casing on the operation efficiency of a double—entry centrifugal pump. Numerical simulations were used to conduct the research, and their results were experimentally validated on a test stand. The influence on the operation efficiency of the pump of specially designed volute casings was researched according to the method of constant velocity and conservation angular momentum of the flow and following the recommendations given in the literature by A. Stepanoff and A. Lomakin. The difference between the studied volute casings resulted from a change in the volute casing's inlet diameter, inlet width, and a change in the cross-sectional area. The research also included determining the influence of the cross-sectional shape of the volute casing (trapezoidal and round) and changing the opening angle of the volute walls. The analysis of the results showed that the choice of the volute casings design method affects the change of the best efficiency point. As shown by the results, the constant velocity method gives a flatter shape of the flow characteristics compared to the method of conservation angular momentum of the flow. However, changing the opening angle of the walls With a trapezoidal or round spiral cross-section has a small impact on the change in head and pump efficiency.
EN
The large axial forces that arise in centrifugal pumps often cannot be completely balanced by bearings. In such cases, balance devices are used. One of the cheapest are balance holes. Their presence in the pump impeller is associated with leakage due to the pressure difference between the balance chamber and the impeller inlet. This leakage causes volumetric loss, ultimately diminishing the overall efficiency of the pump. Traditionally, balance holes have featured an axis parallel to that of the impeller. However, with the innovative skew of these holes, the pressure force difference between the inlet and outlet of the hole can be partially counteracted by the centrifugal force resulting from the rotation of the impeller and the corresponding inclination of the balance hole's axis. This novel approach holds the potential to reduce both leakage and volumetric loss.
PL
Duże siły osiowe, jakie powstaja W pompach wirowych często nie mogą być w całości zrównoważone przez łożyska. W takich przypadkach stosuje się urządzenia odciążające. Najtańszym z nich są otwory odciążające. Ich obecność w wirniku pompy Wiąże się z przeciekiem na skutek różnicy ciśnień miedzy komorą odciążającą a wlotem do wirnika. Ten przeciek tworzy stratę obj etościową i obniża sprawność całkowitą pompy. Stosowane dotychczas otwory odciążaj ace maja oś równoległa do osi wirnika. Poprzez nowatorskie ukształtowanie otworu można różnice parcia na wlot i wylot z otworu zrównoważyć sila odśrodkowa wynikającą z ruchu obrotowego wirnika oraz przekoszenia osi otworu odciażaj ącego. Może to prowadzić do całkowitej redukcji przecieku i wyeliminowania zmniejszenia straty objętościowej.
EN
Population growth has led to a significant increase in demand for water resources. The scarcity of surface water has made tapping into available groundwater resources essential. This article presents a study focusing on water pumping using a less cumbersome wind system with improved efficiency. This is achieved by eliminating the power electronics interface and its control, which in turn removes harmonics generated by the static converter and requires less maintenance. The simulation results are compared with those from similar systems that include the power electronics bay.
EN
In recent years, computational fluid dynamics has been increasingly used in the development of various types of rotating machines. In the case of water turbines and pumps, a large number of researches have been published recently, related to the use of different numerical methods for prediction of efficiency, cavitation characteristics and different dynamic phenomena. For basic analysis an accurate result near the optimal operating regime is sufficient, but for detailed analysis the numerical analyses in the wider field of operating conditions are necessary. Thus, some otherwise known physical phenomena that occur in the part-load and full-load regime may be encountered. In these areas, due to the nature of the flow, various non-stationary phenomena occur that are dominant for such operating regimes. This paper presents the problems that arise if only stationary results are taken into account, and some recommendations for avoiding subsequent problems in the operation of centrifugal pumps.
EN
Cavitation is an essential problem that occurs in all kinds of pumps. This cavitation contributes highly towards the deterioration in the performance of the pump. In industrial applications, it is very vital to detect and decrease the effect of the cavitation in pumps. Using different techniques to analysis and diagnose cavitation leads to increase in the reliability of cavitation detection. The use of various techniques such as vibration and acoustic analyses can provide a more robust detection of cavitation within the pump. In this work therefore, focus is put on detecting and diagnosing the cavitation phenomenon within a centrifugal pump using vibration and acoustic techniques. The results obtained from vibration and acoustic signals in time and frequency domains were analysed in order to achieve better understanding regarding detection of cavitation within a pump. The effect of different operating conditions related to the cavitation was investigated in this work using different statistical features in time domain analysis (TDA). Moreover, Fast Fourier Transform (FFT) technique for frequency domain analysis (FDA) was also applied. Furthermore, the comparison and evaluation system among different techniques to find an adequate technique incorporating for accuracy and to increase the reliability of detection and diagnosing different levels of cavitation within a centrifugal pump were also investigated.
EN
Complicated system of forces acts on the rotor of multi-stage centrifugal pump under its exploitation. Axial force is the biggest one for pumps with one-side inlet wheels. This force in many constructions of pumps is balanced by special automatic balancing device (ABD). This device consists of an unloading disk rigidly fixed on the shaft and a non-rotating supporting disk. The corresponding surfaces of these elements form cylindrical and face throttles arranged in series divided with the unloading chamber. Automatic operation of such devices is caused by the interdependence of hydrodynamic characteristics in cylindrical and face throttles. The middle gap value of cylindrical throttle is one of the main characteristics determining the pressure in the chamber and the ABD flow-rate value. The middle gap can increase due to erosive wear under pump operating, and it can result in negative impact on ABD operating. In this work, the intensity of erosion wear is considered as a function of middle velocity of flow and the coefficient of material wear. The middle velocity of flow in the cylindrical throttle is obtained by solving equations of turbulent fluid flow motion jointly with continuity equation. It allows one to determine the changes of the middle gap of cylindrical throttle in time and to estimate the influence of such changes on static and flow-rate characteristics of the ABD.
PL
Podczas pracy wielostopniowej pompy na jej wirnik oddziałuje złożony układ sił. W pompach posiadających wirnik z jednostronnym wlotem największą wartość uzyskuje siła osiowa. W większości spotykanych rozwiązań równoważenie tej siły odbywa się za pomocom specjalnego elementu konstrukcyjnego – tarczy odciążającej. Tarcza obraca się razem z wałem współpracując ze stałymi pierścieniami. Przestrzeń między tymi elementami tworzy układ dławiący. Jeśli wystąpi przemieszczenie wirnika w stronę wlotu, to wzrastające ciśnienie wywoła powstanie siły odsuwającej tarczę. Istotne znaczenie ma rozkład ciśnienia w układzie dławiącym. Występująca zdolność samoregulacji tarczy odciążającej zależy od charakterystyki hydrodynamicznej układu dławiącego. Grubość szczeliny cylindrycznego dławika może powiększać się podczas pracy pompy w wyniku erozyjnego zużycia powierzchni uszczelnienia. W opracowaniu intensywność zużycia uzależniono od średniej prędkości w szczelinie oraz współczynnika zużycia materiału. Wartość średniej prędkości uzyskano w wyniku rozwiązania układu równań ruchu cieczy w szczelinie oraz równania ciągłości. Takie podejście pozwoliło wyznaczyć grubość szczeliny dławika w funkcji czasu i oszacować jej wpływ na charakterystyki tarczy odciążającej.
EN
In petroleum and mine industries, the centrifugal pumps were used for transferring solid particles with water. This method is preferable to other methods because of its user friendly and economic issues. In this article by selecting a proper pump and designing test circuit,we conducted hydraulic tests for water and water mixture with solid particles. For this purpose, an experimental set-up of centrifugal pump with only water and water with solid particles was developed. Then by analyzing the test results and efficiency equation, optimal coefficients of head loss is provided to improve the pump efficiency during hydraulic transmission of solids. The experimental results of power consumption, head, and pressure difference measurements in solid-liquid systems are presented. The experimental set-up results are compared with simulation and numerical one, which show a good agreement with them. It reveals that by adding the solid particles and increasing the fluid density up to 15%, the consumed power increases by about 20%, which result in dropping the efficiency of hydraulic system up to 6%. Finally, the optimal components for developed cycle presented for evaluation the various configuration and hydraulic analysis of pure flow and flow with solid particles in various applications to enhance the most achievable efficiency.
EN
The pump performance and occurrence of cavitation directly depends on different operating conditions. To cover a wide range of operation conditions for detecting cavitation in this work, investigations on the effect of various suction valve openings on cavitation in the pump were carried out. In order to analyse various levels of cavitation in different operation conditions, the effect of the decrease in the inlet suction pressure of the centrifugal pump by controlling the inlet suction valve opening was investigated using this experimental setup. Hence, the acoustic and pressure signals under different inlet valve openings and different flow rates, namely, 103, 200, 302 l/min were collected for this purpose. A detailed analysis of the results obtained from the acoustic signal was carried out to predict cavitation in the pump under different operating conditions. Also, the acoustic signal was investigated in time domain through the use of the same statistical features. The FFT technique was used to analyse the acoustic signal in the frequency domain. In addition, in this work an attempt was made to find a relationship between the cavitation and noise characteristics using the acoustic technique for identifying cavitation within a pump.
EN
Centrifugal pumps are used for different applications that include pressure boosting, wastewater, water supply, heating and cooling distribution and other industrial processes. This paper presents theoretical and experimental investigations of mechanical vibrations of a centrifugal pump. The flow in this pump, which induces pressure pulsations and mechanical vibrations, have been monitored. Vibration measurements and data collection (overall vibrations levels and frequency spectrum) were extracted from the system. In addition, one of the methods used to study vibration amplitudes for this pump is forced response analysis. To study and analyze the pump system, the finite element analysis software (ANSYS) was applied. Depending on the analysis performed and investigations outcomes, the system natural frequency coincides with the vane-pass frequency (VPF) hazardously. To attenuate the system’s vibration, a vibration control element was used. The vibration levels were reduced by a factor of 2 for a tuned element as obtained from a forced harmonic response analysis of the pump system with absorber. It is shown that the inserted element allows the centrifugal pump to work in a safe operating range without any interference with its operation.
EN
The small number of available complete modern pump characteristics makes the safety analysis of nuclear and conventional power plants based on the characteristics made over half a century ago of specific speeds nq = 24.6,147.1 and 261.4. The aim of the paper is to check sensitivity of the power plant system response for different complete pump characteristics–modern and available from older tests for nq = 24.6, 147.1 and 261.4. It has been shown that Suter’s characteristics for modern pumps give a different response to the pumping system of a power plant in break down than those used so far.
14
Content available remote Analysis of the reasons of double suction centrifugal pump’s failure
PL
Wyjaśniono problem pracy pompy poza zalecanym zakresem, wymaganymi warunkami napływu cieczy do króćca ssawnego i w konsekwencji ulegania awarii przez 2-strumieniową pompę wirową. Przedstawiono zagadnienie zwiększonego poziomu drgań, niewłaściwej konfiguracji zabudowy rurociągu ssawnego oraz zastosowanej armatury. Zilustrowano sposób diagnozowania i rozwiązywania problemu, który po wdrożeniu w docelowym miejscu pracy potwierdził słuszność wprowadzonych rozwiązań konstrukcyjnych.
EN
The issue of a pump operation beyond its recommended range and required flow conditions to the suction flange and consequently failure of double suction axially split centrifugal pump was explained. The increased vibration level, improper configuration of the suction pipeline and used hydraulics were presented. It was also illustrated how to diagnose and solve a problem which after implementation at the target workplace has confirmed the correctness of implemented design solutions.
EN
Multistage centrifugal pumps with variable speed drives are currently widely used in a variety of industrial and commercial applications. However, there are limitations to defining the efficiency of variable speed drive pumps. As an alternative method, energy saving rates can be evaluated with flow patterns and mean duty cycles. Computational fluid dynamics (CFD) is being used as a good tool to understand this and is less time consuming in terms of analyzing performances the experimental method. Research attention was focused on the energy saving rates of a multistage centrifugal pump for variable flow with variable speed drive through numerical and experiment methods. For this investigation Reynolds-averaged Navier-Stokes (RANS) equations were discretized by the finite volume method and a two equations SST model was used to account for three dimensional steady state flows. In the experimental system, an experimental set-up of a variable flow system was made to obtain energy saving rates and computational results were validated. The energy saving rates of the pumps depend on the flow patterns and specific mean duty cycles on which the machine or system operates. Mean duty cycles were divided into different flow operating conditions and a weighting for the mean value was given for each segment according to interval time. The pump system was operated at 50_70% of maximum flow rates. The energy saving rates were obtained from input power through CFD simulation and experimentally, and the mean duty cycle was obtained from flow patterns in the field of the pump. Energy saving rates were evaluated as a function of mean duty cycle and input power of the system operation. The total energy consumed for the constant speed drive was 25,922 kWh and for the variable speed drive pump was 17,687 kWh through CFD. The total annual energy saving rates were annually 33.81% through computational and 31.77% through experimental method with the variable speed drive system when compared to the constant speed drive system.
PL
Wykorzystując algorytm zaproponowany we wcześniejszym artykule rzedstawiono wybór uszczelnienia czołowego pompy wirowej do przesyłania wody. Zebranie danych początkowych umożliwiła ankieta, którą producenci uszczelnień zwykle zamieszczają na stronie internetowej. Dla określonych warunków pracy wybrano uszczelnienie czołowe z obracającą się obudową, osadzone wewnątrz kadłuba z hydraulicznym odciążeniem. Kolejny krok polegał na sprawdzeniu granicznych wartości parametrów eksploatacyjnych uszczelnienia jak ciśnienie, temperatura i prędkość obrotowa z uwzględnieniem zastosowanych materiałów i cieczy.
EN
Using the algorithm proposed in the earlier paper a selection of face seal for the water transportation pump is presented. Data necessary for the selection can be found in manufacturer's website for seals. A front-facing seal with the rotating housing, mounted inside the hull with hydraulic relief was selected for given operating conditions. The next step was to check limits for seal operating parameters such as pressure, temperature and rotational speed with respect to materials and solutions used. The presented analysis and seal selection was of a simplified character.
EN
Cavitation is a common cause of failure in centrifugal pumps. Because of interaction of several mechanical parts and fluid, the vibration signal of a centrifugal pump is complicated. In this paper, the vibrations of a transparent-casing centrifugal pump are studied. Three states are studied experimentally: no cavitation, limited cavitation and developed cavitation. Each case was also confirmed by visually inspecting the cavitation bubbles. The vibrations of the pump was acquired by using an accelerometer that was attached to the casing. Discrete wavelet transform (DWT) analysis and empirical mode decomposition (EMD) are used to extract classification features from the acquired signals. Using these features, an artificial neural network (ANN) successfully diagnosed the cavitation condition of the pump. Finally, EEMD is also implemented. The results showed the success of EMD and DWT in cavitation diagnosis. The output of EEMD does not show significant change comparing to EMD.
18
PL
W artykule opisano schemat typowego układu pompowego i pokazano jego statyczne i dynamiczne charakterystyki, istotne przy komputeryzacji ich pomiaru. Przedstawiono skomputeryzowane stanowisko badawcze do wyznaczania podstawowych charakterystyk statycznych i dynamicznych pompy wirowej i rurociągu. Oprogramowanie wspomagające pomiary umożliwia wyznaczenie parametrów energetycznych pompy na podstawie zmierzonych wielkości fizycznych. Stanowisko ułatwia pomiary i opis krzywych rozwoju kawitacji, a także wyznaczenie pełnej charakterystyki kawitacyjnej pompy. Opracowana karta pomiarowa pozwala na ocenę zgodności parametrów nominalnego punktu pracy z parametrami katalogowymi wg obowiązującej normy dla przyjętej klasy maszyny. Przedstawione skomputeryzowane stanowisko badawcze dedykowane jest do pomiarów odbiorczych pomp odśrodkowych.
EN
In the paper it is described a schema of typical pump system and it is shown its static and dynamic characteristics which are essential in the process of computerization measurements of the characteristics. Compurized test stand for operational measurements has been presented. The article describes the basic static and dynamic characteristics of a centrifugal pump and pipeline Software aiding measurements make possible to determine pump parameters on the basis of measured physical quantities. Test-stand is labour-saving for measurements, description of cavitational development curves and determination of cavitational pump characteristics. Elaborated measurement card makes possible to compare working point with catalogue parameters.
EN
The performance of pumps are influenced by many factors among which the geometric configuration of the volute. The role of the volute in a centrifugal pump is the transformation of the kinetic energy into pressure with a minimum of losses. The volute is a pump element which is difficult to modify. It must be able to be adapted to impeller with different dimensions. The objective of this work is to investigate by numerical simulation the Von Mises stress distribution and displacements in volutes of different dimension in diameters and width of a centrifugal pump. The study is carried out using finite element method on a three dimensional configuration using ABAQUS code. Only a few attempts of numerical analyses of the mechanical behavior of volute are made. This element plays an important role in the pump adaptation for a given operating conditions by adjusting its dimensions. This activity is conditioned by a good understanding of 418 Belbachir, S., Allali, A., Lousdad, A. E. and Benguediab, M. the design process of the volutes. The obtained results show the modifications of the diameter and the width of the volute have an effect on the values of Von Mises’ stresses and on the displacements. The stresses and displacements reach their maximum with increasing diameters and are inversely for the increase in the width. These dimensional modifications can act indirectly on the clearance at the bec and also on the clearance between the volute exit and the impeller. These are functional clearances which allow the determination of the operating characteristics of centrifugal pumps. With these results substantial improvement on the pump design can be made.
EN
Spectral analysis is the key tool for the study of vibration signals in rotating machinery. In this work, the vibration analysis applied for conditional preventive maintenance of such machines is proposed, as part of resolved problems related to vibration detection on the organs of these machines. The vibration signal of a centrifugal pump was treated to mount the benefits of the approach proposed. The obtained results present the signal estimation of a pump vibration using Fourier transform technique compared by the spectral analysis methods based on Prony approach.
PL
Analiza widma jest kluczowym narzędziem badania sygnałów dotyczących wibracji w maszynach wirujących. W niniejszej pracy proponuje się analizę wibracji dla oceny stanu technicznego tych maszyn w ramach utrzymania prewencyjnego, bazującą na detekcji wibracji ich poszczególnych elementów. Przydatność i korzyści zaproponowanego podejścia zostały ocenione podczas badania pompy odśrodkowej. Uzyskane wyniki przedstawiają estymację sygnałów wibracji pompy z wykorzystaniem transformaty Fouriera w porównaniu z przeprowadzoną analizą widma z zastosowaniem modelu Prony’ego.
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