The opportunity to assess haemolysis in a designed artificial heart seems to be one of the most important stages in construction. We propose a new method for assessing haemolysis level in a rotary blood pump. This method is based on CFD calculations using large eddy simulations (LES). This paper presents an approach to haemolysis estimation and shows examples of numerical simulation. Our method does not determine the value of haemolysis but allows for comparison of haemolysis levels between different artificial heart constructions.

CFD modelling of momentum and heat transfer using the Large Eddy Simulation (LES) approach has been presented for a Kenics static mixer. The simulations were performed with the commercial code ANSYS Fluent 15 for turbulent flow of three values of Reynolds number, Re = 5 000, 10 000 and 18 000. The numerical modelling began in the RANS model, where standard k−ε turbulence model and wall functions were used. Then the LES iterations started from the initial velocity and temperature fields obtained in RANS. In LES, the Smagorinsky–Lilly model was used for the sub-grid scale fluctuations along with wall functions for prediction of flow and heat transfer in the near-wall region. The performed numerical study in a Kenics static mixer resulted in highly fluctuating fields of both velocity and temperature. Simulation results were presented and analysed in the form of velocity and temperature contours. In addition, the surface-averaged heat transfer coefficient values for the whole insert length were computed and compared with the literature experimental data. Good compliance of the LES simulation results with the experimental correlation was obtained.

The current passed by the stator coil of the permanent magnet synchronous motor (PMSM) provides rotating magnetic field, and the number of turns will directly affect the performance of PMSM. In order to analyze its influence on the PMSM performance, a 3 kW, 1500 r/min PMSM is taken as an example, and the 2D transient electromagnetic field model is established. The correctness of the model is verified by comparing the experimental data and calculated data. Firstly, the finite element method (FEM) is used to calculate the electromagnetic field of the PMSM. The performance parameters of the PMSM are obtained. On this basis, the influence of the number of turns on PMSM performance is quantitatively analyzed, including current, no-load back electromotive force (EMF), overload capacity and torque. In addition, the influence of the number of turns on eddy current loss is further studied, and its variation rule is obtained, and the variation mechanism of eddy current loss is revealed. Finally, the temperature field of the PMSM is analyzed by the coupling method of electromagnetic field and temperature field, and the temperature rise law of PMSM is obtained. The analysis of this paper provides reference and practical value for the optimization design of PMSM.

The aim of this paper is presentation and comparison of calculation methods of the inductance matrix of a 3-column multi-winding autotransformer. Main and leakage autotransformer inductance was obtained using finite elements method. Static calculations were made at the current supply for 2D and 3D models, and mono-harmonic calculations were made at the voltage supply. In the mono-harmonic calculations the eddy current losses were taken into account, this made it possible to study relationship between the autotransformer parameters and the frequency. Calculations were made using Ansys and the authors' own programs in Matlab.

The 15-winding and 3-column autotransformer supplying an 18-pulse rectifier circuit was developed. Presented methods can be used also for the autotransformers of other topologies supplying different kinds of converters. Presented methods make it possible to exactly calculate main and leakage inductances of the multi-winding autotransformer. The presented analysis of the eigenvalues and eigenvectors of the inductance matrix makes it possible to identify the influence nature of individual modes on the inductance matrix, and to compare the calculation results obtained using the presented methods. Frequency dependence of autotransformer parameters was shown. Also modes of the impedance matrix of the multi-winding autotransformer was investigated, this made it possible to identify the influence nature of individual modes on the inductance matrix. Using presented methods one can exactly calculate main and leakage inductances of the autotransformer. Thanks to this, one can design in optimal way autotransformers for supplying, for example, rectifier circuits, THD coefficients. The results of the measurements and simulations were also shortly presented at the end of the article.

The optimization method using the ON/OFF sensitivity analysis has an advantage hat an epoch-making construction of magnetic circuit may be obtained. Therefore, it is attractive for designers of magnetic devices. We have already developed the ON/OFF method for the optimization of a static magnetic field problem, and the effectiveness is verified by applying it to the optimization of magnetic recording heads. In this paper, the ON/OFF sensitivity method is extended to the optimization of the eddy current problem using the adjoint variable. The newly developed ON/OFF method is applied to the determination of the optimal topology of the yoke of the billet heater for rolling wire rod. As a result, the optimal shape of yoke, which we could not imagine beforehand can be obtained. It is shown that the local heating of the yoke was reduced without decreasing the heating efficiency.

The coupling of the propagating stress wave with the eddy current model is presented. The applied stress produces magnetization in the sample that can be measured outside the sample by measuring the resulting magnetic flux density. The stress and flux density measurements are made on a mechanically excited steel bar. The problem is modelled with the finite element method for both the propagating wave and the eddy current. Three aspects are considered: eddy current model using magnetization from the measurements, coupled wave and eddy current models, and coupled different dimensions in the wave model. The measured stress can be reproduced from the measured flux density by modelling. The coupled models work both for stress and flux couplings as well as for the different dimensionality couplings.

Harmonic flux penetrating solid conductive material causes eddy currents inside. It seems plausible that its magnitude does not exceed the exciting magnetomotive force (mmf). However, under certain circumstances the opposite occurs. This article deals with a special case in which the eddy current is approximately 13% higher than the exciting mmf. An analytical field solution, a finite element calculation and a measurement proving this phenomenon are presented. A special flux linkage is turned out to be the reason for this phenomenon. Finally, another example with higher pronounced mmfexceeding in a coil is presented.

The efficiency of the solid-rotor induction machines depends on axial length of rotor (including the end-regions). Determination of the best axial length is problematic because of current density distribution in the end-regions and also because of absence of dedicated methods and models. This work proposes a method that circumvents this difficulty. It is based on the numerical determination of a dimensionless rotor-end factor using a combination of three- and two-dimensional finite element models restricted to the motor rotor. Such the end factor can be used in both analytical and numerical model of the machine in order to determine the typical performance characteristics. In this work, using this method, we determined an optimal length of the slitted solid rotor of a motor operating at 12 000 rpm, that maximizes the motor efficiency. The results of computations and measurements, carried out on the laboratory test-stand, are presented.

This paper presents a finite element investigation into the proximity losses in a high-speed permanent magnet (PM) machine for traction applications. A three-dimensional (3D) finite element analysis (FEA) is employed to evaluate and identify the endwinding contribution into the overall winding power loss generated. The study is focused on the end-winding effects that have not been widely reported in the literature. The calculated results confirm that the end-winding copper loss can significantly affect the eddycurrent loss within copper and it should be taken into account to provide reasonable prediction of total losses. Several structures of the end-winding are analyzed and compared in respect to the loss and AC resistance. The results clearly demonstrate that the size of the end-winding has a significant impact on the power loss. The calculated results are validated experimentally on the high-speed permanent magnet synchronous machine (PMSM) prototype for selected various winding arrangements.

The results of the eddy currents losses calculations with using electrodynamics scaling were presented in this paper. Scaling rules were used for obtain the values of the eddy currents losses. For the calculations Finite Element Method was used. Numerical calculations were verified by measurements and a good agreement was obtained.

Precise measurement of rail vehicle velocities is an essential prerequisite for the implementation of modern train control systems and the improvement of transportation capacity and logistics. Novel eddy current sensor systems make it possible to estimate velocity by using cross-correlation techniques, which show a decline in precision in areas of high accelerations. This is due to signal distortions within the correlation interval. We propose to overcome these problems by employing algorithms from the field of dynamic programming. In this paper we evaluate the application of correlation optimized warping, an enhanced version of dynamic time warping algorithms, and compare it with the classical algorithm for estimating rail vehicle velocities in areas of high accelerations and decelerations.

In the present work, an approach to obtain a design method for the size of the plenum chamber cross-section of a marine gas turbine air supply system has been investigated. Flow in ducts makes noise which is very high in the turbine inlet part because of the large amount of flow. Therefore, this phenomenon should be considered in the design process. A suitable approach to design the duct is proposed (considering acoustic and aerodynamic performance at the same time). In this method, an air supply channel system of the marine gas turbine has been categorized into three sections according to the requirements of the aerodynamic and acoustic; inlet, plenum chamber, and outlet channels with circular cross-sections. The geometrical dimensions of inlet and outlet channels have been determined using the plane waves theory about a channel, in which the effects of flow is ignored. Space limitations of battleships at the dominant frequency have been considered. Then, the optimized size of the mid-channel section, in terms of both aerodynamic and acoustic requirements, using numerical methods and regarding the effects of flow has been calculated. Various 3D turbulent flows inside the plenum chamber have been considered, in which large eddy simulation turbulence model is utilized. Ffowcs, Williams and Hawkings models are used for the sound propagation process based on the Lighthill integral equation. The validity of the simulation has been checked by comparing results (sound pressure level) with experimental data obtained from a chamber. The comparison revealed the acceptable errors for a variety of frequencies. The results disclosed that the performance of channel system aerodynamic decreased when the fraction of plenum chamber cross-section to inlet/outlet channel cross-section increased. With an increase in the cross-section size at first Acoustic performance is improved and then worsen. Six different cases of marine gas turbine air supply system configurations have been presented, in which the limitation of the battleship space is considered. Examining and comparing the acoustic performance of different cases of the air supply channel system, it was found that the amount of sound pressure level, around the air supply channel system, and the high-pressure sound area can move along the air supply channel system. Additionally, deviations from plane waves considering the effects of flow have been inspected in all cases. The reason for this deviation is the effects of the airflow through the channel system and quadrupole sources in the production of sound in the channel system, which causes higher modes.