Centrifugal Wheel Research Articles

ВПЛИВ ПЕРЕПУСКНИХ ОТВОРІВ У ПРОВІДНОМУ ДИСКУ ВІДЦЕНТРОВОГО КОЛЕСА ШНЕКОВІДЦЕНТРОВОГО НАСОСА РРД НА ЙОГО НАПІР, ККД І КАВІТАЦІЙНІ ХАРАКТЕРИСТИКИ

In modern rocket technology, liquid rocket engines (LRE) with a pump fuel supply system have become widespread. The pump is the heart of the engine, because it supplies the engine with fuel. When designing some pumps, there is a need for bypass holes in the drive disk of the centrifugal wheel.
 As part of the research, a comprehensive analysis of the pressure, efficiency and cavitation characteristics of the high-speed inducer-centrifugal pump of the upper stages of the TPA LREwas performed. The characteristics of the pumps were obtained experimentally. The oxidizer and fuel pumps of engines No. 1 and No. 2 were analyzed. According to the results of the study, it was established that the presence of bypass holes in the drive disk of the center wheel of the inducer-centrifugal pump TPA LRE increases its efficiency under certain conditions. The pressure of the fuel pump of TPA LRE No. 2 increases to 2.6%, which has no holes in the leading disk of the centrifugal wheel. The presence or absence of bypass holes in the leading disk of the centrifugal wheel does not affect its cavitation characteristics.

Study of the influence of the design of a centrifugal wheel on the pressure characteristics of a multistage pump

Study of the influence of the design of a centrifugal wheel on the pressure characteristics of a multistage pump

Study of the influence of the design of a centrifugal wheel on the pressure characteristics of a multistage pump

The article presents the results of an experimental study of the influence of the number of blades on the pressure-energy characteristics of a multistage centrifugal pump. A vertical submersible multistage centrifugal pump was tested, in which impellers with a different number of blades (6, 7 and 8 blades) were varied. The wheels were manufactured using the latest rapid prototyping technology through SLA printing on high strength polymer resin. The operating speed of the pump was varied at 1450, 2050 and 2850 revolutions per minute (rpm). The effect of different numbers of impeller blades on the performance of a centrifugal pump was investigated on three parameters: pump head (H), hydraulic power and efficiency (η). As a result of the experiments, the dominant influence of the speed on the performance of the centrifugal pump was revealed. It was also found that all pump performance characteristics are generally sensitive to changes in rotational speed, and not to changes in the number of blades. As a result of the research, it was revealed that the flow rate during pump operation plays a key role in head, power and efficiency indicators. The conducted research allowed to conclude that the number of blades does not have a significant impact on the performance of a centrifugal pump.

Research of polymers strength properties for 3D printing under normal conditions

An article is devoted to the study of the strength properties of interlayer adhesion and determination of Young's modulus by the ball instrumental indentation method for samples, made of various plastics using additive technology under normal conditions. This production method is chosen as the most appropriate for creating lightly stressed parts of complex geometry (up to 30 MPa) in the shortest possible time. One of the possible options for such products is full-size centrifugal wheels layouts of low power gas turbine units (up to 250 kW) for testing them in model conditions. It will ensure the work of the material in the elastic zone. The samples are considered, obtained by FDM method from various polymers such as: acrylonitrile butadiene styrene thermoplastic resin (ABS+), acrylonitrile butadiene styrene thermoplastic resin with addition of carbon fibers (ABS Carbon), nylon with addition of carbon fibers (Nylon Super Carbon), polyethylene terephthalate glycol (PETG) and a compound based on polylactide (PLA HP). Plastics, made by this method, have anisotropic properties. Therefore, in this work, the strength characteristics of the test samples interlayer adhesion under tension are determined.

Use of additive technologies in the manufacture of central impactors

Purpose. Analysis of methods of manufacturing centrifugal blades by 3D printing methods on the example of a modernized cooling system of the AI-450M engine of the Mi-2MSB helicopter.
 Research methods: calculation method of finite elements, analytical.
 Results. Studies have shown that the use of layer-by-layer printing technology of the centrifugal wheel of the cooling system provides the following opportunities and improvements:
 - reduce the percentage of rejection of finished products by 8–9 times;
 - reduce material consumption by 300–400 %;
 - increase the speed of production, experiments and testing the manufacture of working elements through the development of new technologies for rapid production (rapid fabrication);
 - easy printing of previously “impossible” geometry.
 The analysis of possible types of manufacturing of working centrifugal wheel and the calculated estimation of thermodynamic parameters in the course of step-by-step drawing of layers of metal is carried out. The problem of a large percentage of defects in the process of classical-mechanical milling of blades was solved by changing the type of production to additive one.
 Scientific novelty. In today's world, the spread of CAD / CAM / CAE / PLM technologies and the accumulation of a wide library of materials open up a large number of new and more efficient, in terms of economy and quality, methods of manufacturing components and units. Following the example of such giants in the production of aircraft engines as Rolls-Royce Motor, General Electric and Pratt & Whitney, it is clear that the use and development of the latest methods of three-dimensional printing is appropriate.
 Practical value. The obtained results are important in the further process of production and modernization ofMi-2 helicopter of all modifications with the latest engines, as well as for projects for the development of helicopter construction in Ukraine - МСБ-2 “Hope”, МСБ -6 “Otaman”, МСБ-8 and others. The ability to increase the efficiency of manufacturing the main working elements - blades allows you to reduce the cost of components, their further repair, operation. The most important factor is to increase reliability, as in the manufacture reduces the likelihood of defects, which will not be detected at the stages of intermediate and final control.

Increasing the pump energy efficiency of the system for discharging liquefied natural gas from large-capacity storage facilities via design improvement

Abstract. Objective. To determine the most relevant way to improve the energy efficiency of the system for discharging liquefied natural gas (LNG) from large-capacity storage facilities. Methods. The method of analysis of existing systems for LNG discharge from storage tanks was used to identify critical (emergency) elements of the system to be improved and possible options of improving structural elements. Results. The operation of the system for discharging LNG from storage tanks was analysed and its main characteristics were described. Main problems associated with designing and building borehole pumps, as well as goals and tasks of designing new borehole pump structures were studied. The main types of LNG borehole pumps, their varieties, and types of drives were studied to choose the most optimal new option of improving pumps for systems for discharging LNG from storage tanks. Further, it will be necessary to calculate geometric parameters of the hydroturbine and operation modes of its wheel being in connection with the centrifugal pump wheel. Conclusion. Experience of using storage facilities shows that LNG pumps are the most critical units significantly increasing production risks. Therefore, the LNG borehole pump design improvement was chosen as a method to increase the energy efficiency of the system for discharging LNG from large-capacity storage facilities. Based on the considered advantages and disadvantages of structural elements of the existing LNG borehole pump design, we chose the replacement of the electric pump drive with an alternative one as the most optimal improvement method.

Sprayer for chemical treatment of vineyards and orchards

The authors have developed an improved sprayer for two-way chemical treatment of vineyards and orchards. The research aims to justify the design scheme and parameters of the sprayer. The proposed sprayer is equipped with a centrifugal fan, which directs air flow from the inlet window to two opposite sides. The distributor is designed as a truncated cone with an inlet nozzle on its small base and outlet nozzles equally spaced on its large base and connected to sprayers by flexible hoses of equal length. It is established that the diameter of the centrifugal fan wheel 630 mm, number of fan wheel rotations 1500 r/min, diameters of large and small distributor base as a truncated cone 90 mm and 18 mm respectively, the diameter of each nozzle set on its large base 3 mm, cone height 100 mm, number of atomizers 20 pieces and working liquid pressure in the system 0.40-0.45 MPa is provided a uniform distribution of working liquid.

Про вплив форми меридіонального контуру на енергетичні характеристики відцентрового колеса компресора

This work is concerned with the development of approaches to the optimal aerodynamic design of centrifugal compressor wheels, which is due to the use of centrifugal stages in compressors of modern aircraft gas turbine engines and power plants. The aim of this work is a computational study of the effect of the meridional contour shape of a centrifugal compressor wheel on its power characteristics. The basic method is a numerical simulation of 3D turbulent gas flows in centrifugal wheels on the basis of the complete averaged Navier¬–Stokes equations and a two-parameter turbulence model. The computational study features: varying the shape of the hub and tip part of the meridional contour over a wide range, formulating quality criteria as the mean integral values of the wheel power characteristics over the operating range of the air flow rate through the wheel, and a systematic scan of the independent variable range at points that form a uniformly distributed sequence. As a result of multiparameter calculations, it was shown that in the case of a flow without separation in the blade channels of a wheel with a given starting shape of the meridional contour, varying that shape has an insignificant effect on the wheel power characteristics. It is pointed out that in similar cases it seems to be advisable to aerodynamically improve centrifugal wheels by varying the shape of their blades in the circumferential direction rather than in the meridional plane. This conclusion was made using rather a “coarse” computational grid, which, however, retains the sensitivity of the computed results to a variation in the centrifugal wheel geometry. On the whole, this work clarifies ways of further aerodynamic improvement of centrifugal compressor impellers in cases where the starting centrifugal wheel is a well-designed wheel with a flow without separation in the blade channels. The results obtained may be used in the aerodynamic optimization of centrifugal stages of aircraft gas turbine engines.

Determination of the rational number of blades of the centrifugal wheel of a submersible pump

The CAD/CAE/CAM method of end-to-end design of the impeller of a seven-stage submersible pump ODDESSEzentralasien –UPP 13-7/6 used for pumping sulfuric acid in hydrometallurgy is presented.The studies are conducted in order to increase the efficiency of the pump manufactured at the KARLSKRONA LC AB LLP plant (Kazakhstan). Computer calculations of the centrifugal wheel with 8 and 9 blades for strength were carried out in the NASTRAN top-level CAE system. The influence of the number of centrifugal wheel blades on the level of stresses arising in the sections of the blades of the cover and main centrifugal wheel discs is determined. The maximum stress in the sections of the wheel with 8 blades reached 319 MPa and the wheel with 9 blades 199 MPa. The influence of the number of blades on the dynamic characteristics of the rotor shaft is examined. To do this, design mechanical and computer schemes of dynamic calculation are simulated to determine the amplitude-frequency characteristics of the rotor shaft. The harmonics amplitudes at frequencies caused by liquid pulsation at the blade frequency of 400 Hz and 450 Hz reached 110-4 m and 810-4 m, respectively. Based on the results of computer modeling of static and dynamic problems, a model of the impeller of a centrifugal multistage pump with a rational number of 8 double curvature blades is developed. The choice of the number of blades meets the criterion of wheel strength and the dynamic criterion of the shaft-wheel system.For the production of the prototype wheel, an analysis of the process parameters of 3D printing in terms of surface roughness of finished products is carried out. Based on the analysis, stereolithography the technology is chosen and centrifugal wheels are printed for further bench hydrodynamic tests in a plant. The studies based on CAD/CAE/CAM computer modeling allow reducing the time and costs of developing a rational wheel geometry that meets the criterion of both the strength of the wheel itself and the criterion of vibration activity of the rotor shaft

Development of Pumping Equipment for Oil and Gas Production in Complicated Conditions

The research is aimed at the development of new scientific principles for the creation of special pumping equipment for the extraction of oil and gas in complicated conditions. In many cases, the complicated operating conditions of the pump are determined by the high gas content and high content of mechanical impurities in the multiphase flow. In the course of scientific research, new methods of designing hydraulic machines were tested, including the use of additive technologies. In the study of labyrinth pumps, the issues were considered concerning the features of the operating process with increased rotor speed. New design of the rotor manufactured using additive technologies was discussed. It is shown that the rotor screw in a labyrinth pump can be replaced by a set of impellers, for example, by a set of centrifugal wheels or a set of axial wheels. New results concerning labyrinth pumps can give impetus to the development of research on hydraulic and gas turbines, as well as on heat engines. Some results of the works performed can be used to create robotics.

Vibration Traits and Mechanism Analysis of an Engine Blades Fracture Failure

For the failure of twice centrifugal wheel blade fracture of an engine, the paper obtained the vibration traits of the fracture failure by analyzing the gross trend, time domain wave type, axial trajectory map and frequency spectrum diagram of the vibration signals at the failure time. The failure mechanism was analysed systematically based on the failure analysis of the fracture vane, the vibration characteristic analysis and stress distributing research of the vane. Finally, the paper verified the failure mechanism through the vane dynamic stress measurement test.

Maintenance free gas bearing helium blower for nuclear plant

This paper describes the design, testing and operation of novel helium blowers used to recirculate the helium blanketing gas in the nuclear reactor used as a neutron source at the Institut Laue Langevan, Grenoble, France. The laser sintered shrouded centrifugal wheel operates at speeds up to 45000 rpm supported on helium lubricated hydrodynamic spiral groove bearings, and is driven by a sensorless permanent magnet motor. The entire machine is designed to keep the helium gas (polluted by a small amount of D2O) out of contact with any iron or copper materials which would contribute to the corrosion of parts of the circuit. It is designed to have zero maintenance during a lifetime of 40,000 hours of continuous operation. This paper will describe the spiral groove journal and thrust bearings. Design and manufacture of the 1 kW motor and centrifugal wheel will be explained including their CFD and FEA analyses. Measurements of rotor displacement will be presented showing the behaviour under factory testing as well as details of the measured centrifugal wheel and motor performances. Two machines are incorporated into the circuit to provide redundancy and the first blower has been in continuous operation since Jan 2015. The blower was designed, manufactured, assembled and tested in the UK using predominantly UK suppliers.

ПОВЫШЕНИЕ ЭНЕРГОЭФФЕКТИВНОСТИ ЦЕНТРОБЕЖНОГО НАСОСА ЗА СЧЁТ ВВОДА КОНФУЗОРНОСТИ МЕЖЛОПАСТНОГО КАНАЛА КОЛЕСА

The paper reports the substantiation of possibility rotary pump efficiency increase in view of hydraulic losses decrease in a centrifugal wheel at the expense of convergence introduction in its inter-blade canal. Besides losses decrease in a pump the transition to a convergent flow in a centrifugal wheel allows using the model of ideal liquid flow that was impossible at liquid flow in a diffusion inter-blade canal of a wheel providing mainly for an empirical direction of investigations. The convergence introduction, as it was shown by experiments, exceeds pump efficiency by 19% and pres-sure by 74% at the decrease of pulsation and vibrations of a pump that lightens the work of bearings. Theoretical investigations and experimental data have shown that at the convergent inter-blade canal of a wheel at the pump energy efficiency increase there is a situation of a flow different from the flow in the diffusion inter-blade canal. In such a way, the coefficient of the influence of a finite number of blades exceeds a unit, the angle of flow deviation at the wheel outlet takes a negative value (an angle of flow exceeds a bladeexit angle) and a theoretical pressure turns out to be higher considerably of a theoretical pressure at an infinite number of blades.

Physicochemical properties of spray-dried agglomerated particles of salicylic acid and sodium salicylate.

Abstract Aqueous slurries of salicylic acid and sodium salicylate, containing various kinds of binder, namely gum arabic, gelatin, polyvinyl alcohol, carboxymethylcellulose, methylcellulose, polyvinylpyrrolidone, tragacanth and sodium alginate, were spray dried using a centrifugal wheel atomizer. Almost all the spherical dried products were free flowing microgranules, although formulations including gelatin or polyvinyl alcohol proved to be difficult due to agglomeration. Particle properties such as diameter, true density, sphericity and surface area were measured, all of these being strongly influenced by the concentrations of sodium salicylate and binder. The surface topography of the products was studied with a scanning electron microscope. Granules bound with gum arabic and polyvinylpyrrolidone had smooth surfaces without holes or craters. Analysis of the X-ray diffraction patterns and the infrared absorption spectrum of products showed that these granules still contained both salicylic acid and sodium salicylate, in contrast to granules prepared using other binders, where only sodium salicylate remained, the salicylic acid having sublimed. They are microcapsules containing salicylic acid and sodium salicylate of grain size of about 20–80 and 13–17 nm respectively, and amorphous contents of about 50–80%. The thickness of the encapsulating film was 1–3 μm. The change in appearance of a drying slurry droplet is discussed and two typical drying processes are described.

Special features of a digital speckle interferometer for determining vibration characteristics of heavy-loaded elements of an aircraft fuel pump

The results of vibration tests for heavy-loaded elements in the auger-centrifugal stage of an aircraft fuel pump performed with the use of an interference-free digital speckle-interferometer created at the Samara State Aerospace University are presented. The speckle-interferograms of an auger and a centrifugal wheel of the auger-centrifugal pump stage in different conditions of attachment and dynamic loading are given. The data obtained may be of sufficient importance in the development of aircraft fuel pumps for a specified service life.

Разработка шнекоцентробежных насосов с торцовыми уплотнениями по буртам центробежного колеса

Разработка шнекоцентробежных насосов с торцовыми уплотнениями по буртам центробежного колеса

Shape optimization of the turbomachine channel by a gradient method — Accuracy improvement

An algorithm of the gradient method of the channel shape optimization has been built on the basis of 3D equations of mass, momentum and energy conservation in the fluid flow. The gradient of the functional that is posed for minimization has been calculated by two methods, via sensitivities and - for comparison - by the finite difference approximation. The equations for sensitivities have been generated through a differentiate-then-discretize approach. The exemplary optimization of the blade shape of the centrifugal compressor wheel has been carried out for the inviscid gas flow governed by Euler equations with a non-uniform mass flow distribution as the inlet boundary condition. Mixing losses have been minimized downstream the outlet of the centrifugal wheel in this exemplary optimization. The results of the optimization problem accomplished by the two above-mentioned methods have been presented. In the case sparse grids have been used, the method with the gradient approximated by finite differences has been found to be more consistent. The discretization accuracy has turned out to be crucial for the consistency of the gradient method via sensitivities.

Flowrate quantification of the pumped-air stream from a 63 mm diameter centrifugal wheel atomiser

The air-pumping characteristic of a 63 mm diam centrifugal atomiser running dry within a cocurrent spray dryer was studied extensively using a novel experimental technique which involved the direct measurement of the wheel vacuum pressure together with the power required to pump the air. Approximately 10% of the power consumed by the atomiser was utilised in pumping the airstream. A further 25% was consumed in shearing the air around the wheel and the remaining 65% was consumed by friction and motor losses within the drive train. Typically, the wheels considered pumped between 2 l s −1 and 6.5 l s −1 of air at a maximum rotational speed of 50 000 rpm which corresponded to between 5% and 16% of the primary air supply to the dryer. A dynamic closure of the wheel/atomiser body gap was observed occurring at 30 000 rpm to 40 000 rpm which was thought to be due to an upward acting force generated by the pressure differential either side of the wheel. This significantly affected the air-pumping behaviour of the wheel.

Reduction method for finite element dynamic analysis of submerged turbomachinery wheels

The proposed method allows the efficient computation of natural frequency mode shape and harmonic response of submerged rotationally periodic structures, such as turbine or centrifugal pump wheels. The geometry of such structures is complex and the influence of the surrounding fluid has to be taken into account. The fluid is assumed to be incompressible and at rest. Both fluid and structure domains are modelled using the finite element method. The size of the problem is appreciably reduced using the properties of wave propagation in periodic systems combined with modal techniques. The efficiency of the method is shown by an application to a submerged centrifugal pump wheel where the numerical results are compared to experimental results.

Analyse du comportement dynamique des roues de turbomachines immergées

ABSTRACT A method, adapted to the prediction of the dynamic behaviour of immersed turbomachinery wheels, is proposed. The method allows efficient computation of natural frequencies, mode shapes and harmonic response of the coupled fluid structure system. The fluid is supposed incompressible and at rest. The size of the problem is appreciably reduced using the properties of wave propagation in periodic systems combined with modal techniques applied to both structure and fluid domains. This procedure allows the computation of industrial structures on standard computer workstations, without noticeable loss of accuracy. The method is applied to an immersed centrifugal pump wheel. The numerical results obtained are compared to experimental results.