Disk Impeller Research Articles

Design of Blade Joints with Turbine Impeller Disk of Low-Power Gas Turbine Engine

The problem of ensuring gas dynamic and strength parameters in impellers of low-power gas turbine engines is discussed. The most loaded points of high-speed turbines are determined. The influence of gas forces on stress distribution in the impeller vis-a-vis centrifugal forces and thermal impacts is analyzed. Several design modifications that permit stress reduction in turbine impeller are proposed. Computational investigation and analysis of strength of various blade joints with turbine impeller disk are conducted. The turbine engine impeller design that is most effective in terms of strength and gas dynamic parameters is selected by comparing the obtained data.

Development and research of hydraulic disk pump

The article is devoted to the development of the disk pump driven by a hydraulic motor at Bauman Moscow State Technical University Department of Hydraulics. The relevance of the dynamic pumps of this type has been described, and the necessity to investigate the mechanism of disk impellers operation using the tools of numerical hydrodynamic modeling, has been shown. The article presents the mathematical model used in computer simulation of the flow and the description of the testing bench. A comparison of numerical and full-scale experiments to confirm the adequacy of the mathematical model is introduced. A research showing the influence of some basic parameters of disk impellers on their characteristics (head, efficiency) has been performed. The figures of the scalar physical quantities distribution in the flow part of the pump and graphs of the pressure and efficiency dependences on the studied parameters are presented for a visual illustration of the results.

Improved performance in γ-polyglutamic acid production by Bacillus subtilis LX on industrial scale by impeller retrofitting and its unstructured microbial growth kinetics model

We conducted industrial scale γ-polyglutamic acid (γ-PGA) production by Bacillus subtilis (B. subtilis) LX and modeled its microbial growth kinetics based on a logistic regression. We found that the use of a three-layer impeller including a lower semicircular disc impeller and two-layers of six-wide-leaf impellers were able to both increase γ-PGA yields and decrease fermentation time as compared with two-layer Rushton impellers. Indeed, our results revealed that the optimal γ-PGA yield (20.67 ± 2.19 g/L) was obtained after 40 hr in the impeller retrofitted fermenter, and this yield was 29.7% higher than that in Rushton impellers fixed fermenter. The microbial growth kinetics of B. subtilis LX in this system were established, and the model was consistent with the experimental data (R2 = 0.924) suggesting that it was suitable for describing the microbial growth kinetics underlying γ-PGA production on an industrial scale. In addition, biomass yield (Yx/s-glucose), γ-PGA yield (Yp/s-glucose), γ-PGA yield (Yp/s-glutamate), and the correlation between γ-PGA production and B. subtilis LX (Yp/x) were found to be 0.043, 0.133, 0.743, and 3.090 g/g, respectively, in the impeller retrofitted fermenter, as compared with 0.036, 0.103, 0.629, and 2.819 g/g, respectively, in the two-layer Rushton impeller fermenter.

Structural and functional analysis of the centrifugal pump development as a technical system

Pumping equipment is one of the main systems of water supply and sewerage, where centrifugal pumps are mostly used due to the simple design and the optimal interval of the parameters of flow and pressure. The paper considers the development of a centrifugal pump from the point of view of system analysis, since this approach considers any technical object as a complex of interacting elements having the properties that are not reduced to the properties of individual elements designed to perform certain useful functions. The aim of the paper is to find patterns of development of the centrifugal pump as a technical system to predict its further evolution. Domestic and foreign patent fund of Class F 04 D in the amount of 724 units was used as the main source. In the paper, the device of the centrifugal pump as a technical system is divided into the following main structural subsystems: impeller blades, impeller disks; housing; pressure pipe and suction pipe. Each of these elements has its main useful function and a number of auxiliaries, which are discussed in detail. It is established that an increase in the degree of control of the centrifugal pump can be achieved by dynamization of transmission, specifically, the regulation of the revolutions transmitted from the engine to the impeller mechanically, with the help of fluid coupling and frequency converters.

The Vortex Pump Under Highly Viscous Liquid Flow Conditions

The hydraulic performance and flow patterns in a standard motor-connected vortex pump with a specific speed of 76 are tackled by using CFD method under water and highly viscous oil flow conditions. The variations in performance curve and hydraulic loss caused from increased liquid viscosity are clarified; the flow rate, head and efficiency correction factors are correlated with impeller Reynolds number under three operating conditions and compared with centrifugal pumps. The flow patterns in the casing chamber, meridional plane and blade-to-blade plane are demonstrated. The impeller disc friction loss power and dimensionless liquid angular velocity in the casing chamber, incidence loss and slip factor are discussed. The pump hydraulic loss and total efficiency were decomposed and presented. It is shown that liquid viscosity exhibits a less effect on both flow rate and efficiency correction factors, but a more substantial influence on head correction factor. If the Reynolds number is not smaller than $$1\times 10^{4}$$ , the vortex pump can maintain a better performance and is suitable to transport liquids more viscous than water. The impeller disc friction loss power in the vortex pump is only 5% of the shaft power in maximum, so the vortex pump is a pump with lower impeller disc friction loss in comparison with centrifugal pumps. The circulating flow efficiency is volumetric efficiency actually and is the factor controlling the total efficiency of the pump.

Simulation of the Vibratory Condition of the Compressor Blade with a Pressed wire Material “MR” Damper Which Located Around the Root Attachment

When you create a modern gas turbine engines urgent task is to improve the reliability by preventing fatigue damages of rotor blades. Such damage is largely determined by the level of vibration stresses. In this paper, using the finite element method and transient analysis of propose a method calculating the damping characteristics of the plates of the pressed wire material “MR” around the root attachment of the compressor blades of a gas turbine engine. Where taken into account contact interaction between the blades and the impeller disk.

Simultaneous velocity measurement of phases in a liquid-gas system

Abstract Results of velocity measurements of liquid and gas bubbles in a tank with a self-aspirating disk impeller are analysed. Studies were carried out using a fluorescent dye tracer in the measuring system with two cameras (simultaneous phase velocity measurement) and with one camera (sequential measurement of phase velocity). Based on a comparative analysis of the acquired data it was found that when differences in the phase velocities were small the simultaneous velocity measurement gave good results. However, sequential measurement gives greater possibilities for setting the measuring system and if the analysis of instantaneous velocities is not necessary, it seems to be a better solution.

Hydrodynamics in the Blade Region of a Self-Aspirating Disk Impeller

Hydrodynamics in the Blade Region of a Self-Aspirating Disk Impeller

Multiscale rheophysics of nearly jammed granular flows in a high shear system

We investigate non-local features of granular flows in nearly jammed configurations. We identify the presence of contact networks and crystallization as the reasons for such a behavior and perform Discrete Element Simulations on a high shear disk impeller granulator. The association of particle properties (e.g. the coefficients of restitution and friction) with the observed flow structures is studied using multivariate data analysis and multilinear optimization. The effect of polydispersity on the structure of the contact networks is studied. A singularity in the momentum flux is observed when approaching a monosized particle assembly, implying the onset of crystallization. Macroscopic quantities, such as the velocity profiles and momentum flux, are linked to microscopic data from DEM simulations through several statistical methods: the spectral analysis (giving dominant frequencies of the flow), coordination numbers that map the local flow regimes and the pair correlation function that is weakly associated with the variations of the flow structure.

Performance Enhancement of a Low-Pressure Ratio Centrifugal Compressor Stage with a Rotating Vaneless Diffuser by Impeller Disk Extended Shrouds

Numerical simulations have been carried out to examine the performance and flow parameters of forced rotating vaneless diffuser obtained by the extension of impeller disks of a low-pressure ratio shrouded type centrifugal compressor stage with diffuser diameter ratio 1.40. Four different levels of shroud extensions (i.e., impeller disks alone) forming the rotating vaneless diffusers are analyzed at four different flow coefficients. The extension of impeller disks alone by 40% of impeller exit diameter leads to a fully forced rotating vaneless diffuser thereby replacing the existing stationary vaneless diffuser. The comparative studies are performed using the same impeller with a stationary vaneless diffuser also having a diffuser diameter ratio of 1.40. Static pressure rise in ES40 is found to be higher than SVD by around 9.84% at design flow coefficient and also at above off-design flow rates. Energy coefficient is highest for ES40, followed by ES30 compared to SVD. For ES40, the static pressure recovery coefficient also is higher compared to SVD. The efficiency of ES40 is lesser by around 5.40% to 3.43% compared to SVD, at design as well as at above off-design flow coefficients. The stagnation pressure losses for ES40 drastically reduced compared to SVD. The comparison of stagnation pressure contours and absolute velocity contours near the hub and shroud walls of ES40 and SVD configurations shows that the rotating diffuser walls as in ES40 causes further addition of energy to the fluid. This adds up the kinetic energy level of the fluid which due to better diffusion, results in gain of static pressure rise. Moreover, there is a net increase in stagnation pressure distribution at the exit of diffuser due to rotating vaneless diffuser. Also, the presence of a fully rotating vaneless diffuser (ES40) smooth out the distorted entry flow profiles, thereby improving the performance of the centrifugal compressor stage.

CFD Simulations of Mixing Characteristics of Radial Impellers in Cylindrical Reactors

AbstractMixing of complex fluids in a flat bottomed cylindrical reactor is studied. The working fluid (Carboxy Methyl Cellulose (CMC)) has a shear thinning behavior. The agitation is ensured by a rotating mixer located at the central position in the tank. The main purpose of the present work is to compare the performance of three impellers, which are: a disk impeller, a radial turbine with six flat blades and a six‐blade Rushton turbine. Mixing characteristics in terms of velocities, well‐mixed region and energy consumption are presented. The obtained results show that the Rushton turbine performs better than the two others stirrers investigated.

Substantiation of parameters and estimation of strength for basic structural units of axial tunnel fan

The authors determine basic parameters for elements of axial tunnel fan VO-21(t) with direct annular diffuser. The algorithm is proposed for calculating aerodynamic parameters of the axial fan using ANSYS CFX software, which allows modeling, computation and analysis of effect exerted by various parameters of the fan air section on the fan aerodynamics. It is found that it is possible to reduce the fan impeller metal consumption and inertia moment by redistributing normal inertia force of blades from the boss to the disks. The admissible impeller velocity is related with the thickness of the impeller disks.

Analysis of flow along smooth side of disc impeller in a pump

We consider fluid flow in an axial gap around the smooth disc rotating in a closed cavity. According to the results of experiments on different working fluids in a wide range of operating modes for smooth discs, the formula is presented to determine the coefficient of fluid flow spin subject to a rate fluid flow from the periphery to the center. On the basis of the experimental data the empirical formula is obtained for the friction torque with respect to a rate fluid flow.

Turbulent flow and mixing performance of a novel six-blade grid disc impeller

A novel six-blade grid disc impeller (RT-G) was designed and the single-phase turbulent flow and mixing in a baffled stirred tank agitated by this impeller were numerically studied by detached eddy simulation (DES) model. For comparison, a standard Rushton impeller (RT) with the same dimension was also investigated. The numerical results were compared with the reported experimental data and good agreements were obtained. Comparisons of the mean velocity, turbulent kinetic energy, power consumption and mixing time of RT and RT-G were performed. Results show that, for the tank stirred with RT-G, the velocity components can be increased in comparison with RT when the same power is consumed. The increase of the turbulent kinetic energy is about 20–30%. Besides, the mixing time for the tank stirred with RT-G is about 11% shorter than that of RT stirred tank operated at the same condition.

Enhancement of Flow Diffusion in a Centrifugal Compressor Stage with Backward Curved Impeller by Shroud Extension – A Numerical Study

Efficient, compact centrifugal compressor with higher pressure ratios along with adequate surge margins necessitates developing non-conventional diffuser designs. A method of reducing shear losses on the stationary vaneless diffuser sidewalls is by rotating the side walls of vaneless diffuser. Forced rotating vaneless diffuser, a type in which the diffuser is integral with impeller and rotates at same speed, is obtained by extending the impeller disks beyond the blades. In this paper, the conventional stationary vaneless diffuser is redesigned to act as a ‘forced’ rotating vaneless diffuser. The effect of shroud extension is analyzed for the backward curved centrifugal impeller with shrouds extended by 40% with impeller exit diameter on flow diffusion and compared to an impeller with stationary vaneless diffuser. A higher static pressure rise by around 10% along with reduced losses is achieved by shroud extension configuration, RVD-ES. This indicates that the rate of diffusion is higher in the extended shroud configuration.

Modeling dilute and dense granular flows in a high shear granulator

This study models a high shear granulation system, including both dense and dilute regions. The dense region is modeled using an approach in which the system is treated as a visco-plastic fluid and the rheology of such a fluid is evaluated. The dilute regions are modeled by the standard Kinetic Theory of Granular Flow (KTGF). The switching between the models is accounted for by using the dimensionless inertial number, defined as the ratio shear forces/pressure forces. The results compare favorably with experimental data for a disk impeller high shear granulator. Granular temperatures and volume fractions, in particular, are well captured by the aforementioned model. The velocity profiles show better agreement with experimental data as compared to previous studies.

CFD를 이용한 소형 2단 터보블로워의 공력해석

터보블로워는 상대적으로 적은 체적유량에서 높은 압력이 요구되는 곳에 사용되는 대표적인 유체기계로서 다양한 산업에 응용되어 사용된다. 본 연구에서는 고속으로 회전하는 소형 2단 터보블로워의 정압상승 메커니즘을 이해하기위해, 1단 임펠러 영역과 터보블로워 전체 영역에 대해서 상용툴인 ANSYS 14.5를 이용하여 CFD해석을 수행하였다. CFD 해석과정에는 역압력 구배에 의한 유동박리 예측에 적합한 k-<TEX>${\omega}$</TEX> SST 난류 모델을 적용하였다. 터보블로워의 전산해석 결과는 KS B 6311 및 KS A 0612에 따른 성능시험방법을 통하여 해석기법이 타당함을 검증하였다. CFD 해석결과 터보블로워의 압력상승은 선형적으로 나타나지 않으며, 안내깃에서의 손실과 케이싱과 임펠러 간극에서 손실이 발생하는 것으로 분석되었다. 소형 2단 터보블로워를 공력성능을 예측하기 위해서는 전체 유동영역에 대한 전산 해석이 필요하며, 실험과 전산해석의 오차에 대해 고려된 전산해석 결과가 선정되어야 한다. Aerodynamic characteristics of the small two-stage turbo blower were investigated using commercial CFD tool(ANSYS CFX Ver. 14.5) in this paper. Turbo blower, which is a centrifugal type of turbomachinery, is used in various industries. It is used for application that required high static pressure rising at relatively small volumetric flow rate. In order to understand the mechanism of static pressure rising, the aerodynamic characteristics of the small two-stage turbo blower are analyzed at high rotating speed in this study. The k-<TEX>${\omega}$</TEX> SST turbulence model, which is good at prediction of adverse pressure gradient flows, was applied. The CFD results of the turbo blower are validated by performance test. The static pressure rising of the turbo blower is nonlinearly increased over the first stage and the second stage. The secondary flow occurred at guide vanes, between the casing and the first impeller shroud, and the bottom of the impeller disk. As a result, It is required that whole fluid area is analyzed to predict aerodynamic characteristics of small two-stage turbo blower. and the result should be selected with considering for error from experiment and CFD.

Modal Analysis of a Centrifugal Pump Impeller Using Finite Element Method

The turbo machinery design has evolved rapidly in the last 50 years. The development in the design of any turbo machinery involves interdisciplinary process, namely stress analysis, vibration analysis, fluid dynamics, thermodynamics and the material selection. One of the major and common analyses used in the development of any mechanical part subjected to dynamic loading is the modal analysis. In this paper, the dynamic characteristics of an impeller of a centrifugal pump were studied. The dynamics characteristics studied were limited to the natural frequencies and the mode shapes. The impeller chosen for the study was a single-entry impeller with radial vanes. Finite element method (FEM) was used since it has proven to be an alternative approach to the experimental method for the vibrational behavior analysis of a component or a system. Modeling and simulation of the impeller have been carried out using ANSYS Bladegen and ANSYS Workbench software, respectively. The eigenvalues and the eigenvectors were observed, and they represent the frequencies and the corresponding mode shapes of the impeller, respectively. The results showed that the varying number of impeller blades and impeller blade thickness had minimal effect on frequencies. However, the change to the impeller disk thickness had significant effects on the natural frequency of the impeller.

The rheology of dense granular flows in a disc impeller high shear granulator

The aim of the present study is to evaluate the new approach to dense particulate systems proposed by Jop et al. [1], in the dense regions of a High Shear Granulator (HSG). Wet granulation in high shear mixers is a common process in pharmaceutical technologies and a good understanding of the local mixing and flow patterns is a pre-requisite for this step. In the aforementioned model a dense granular flow is characterized as a visco-plastic fluid. Therefore the local rheology of the system can be predicted assuming averaged and virtual properties and a constant solid volume fraction.A simple disc impeller granulator with glass spheres was chosen for this study. The dynamics of the system have been studied using several techniques including PIV analyses, CFD simulation and image processing. The flow behaviour has been characterized for various impeller speeds and particle loads. Several cases have been analyzed from different aspects both in experiments and through equivalent simulations to evaluate the validity of the model in these particular applications.Results look promising in spite of the simplicity of the model. The model was found to give a good general description of the flow field and bed shape. On the other hand the model is insufficient in some aspects; mostly related to the regions with low volume fraction. The next step would be to combine the model with conventional models on rapid granular flow such as Kinetic Theory of Granular Flows (KTGF).

Computational Study on the Effect of Blade Cutback on the Performance of the Centrifugal Compressor

Minimizing the energy losses associated with diffusion and also increasing the stable operating ranges of the diffusion systems necessitates developing non-conventional diffuser designs. Rotating vaneless diffusers is one such concept, in which a particular type, forced rotating vaneless diffuser, the diffuser is integral with impeller and rotates at the same speed as the impeller, is obtained by blade cutback, which involves blade trimming but leaving the impeller disks as it is. In this paper, the shrouded impeller with blade cutback by 5% to its vane length by which it introduces a rotating vaneless diffuser in between and a conventional shrouded impeller, both with stationary vanless diffuser are analysed on flow diffusion and performance aspects. The matching peak efficiency is achieved at design flow coefficient for both SVD and BCB 05 and slightly lesser efficiencies at off-design flow coefficients for BCB 05. The performance characteristics of BCB 05 are lesser in terms of energy coefficient, specific work, as well as static pressure rise.