International Journal of Engineering and Technology Innovation

Prediction of Wind Turbine Airfoil Performance Using Artificial Neural Network and CFD Approaches

2022-09-26T17:52:45+08:00

To achieve the highest energy level from a wind turbine, the prediction of its performance is essential. This study investigates the aerodynamic performance of different airfoils, which are frequently used in wind farms. The computational fluid dynamics method based on the finite-volume approach is utilized, and a steady-state flow with the transition regime is considered in this study. A developed artificial neural network is used to reduce the computational time. The results indicates that the trained algorithm could accurately predict the airfoil efficiency with less than 2% error on the training set and fewer than 3% error on the test set. The results agree with the experimental results; this analysis accurately predicts wind turbine performance by selecting the blade’s airfoil. This study provides a reference for a broader range of using these airfoils in wind farms.

A New 6D Chaotic Generator: Computer Modelling and Circuit Design

2022-09-26T17:52:45+08:00

The objective of this study aims at using the Matlab-Simulink environment and the LabVIEW software environment to build computer models of a six-dimensional (6D) chaotic dynamic system. For the fixed system’s parameters, the spectrum of Lyapunov exponents and the Kaplan-York dimension are calculated. The presence of two positive Lyapunov exponents demonstrates the hyperchaotic behavior of the system. The fractional Kaplan-York dimension indicates the fractal structure of strange attractors. An active control method is extended to achieve global chaotic synchronization of two identical novel 6D chaotic systems with unknown system parameters. Based on the results obtained in Matlab-Simulink and LabVIEW models, a chaotic signal generator for the 6D chaotic system is implemented in the MultiSim environment. The experimental results show that the chaotic behavior simulation in the MultiSim environment is similar to those in the Matlab-Simulink and LabVIEW models. The simulation results demonstrate that the Pecora-Carroll method is a simple way of chaotic masking and signal decoding.

SOM-FTS: A Hybrid Model for Software Reliability Prediction and MCDM-Based Evaluation

2022-09-26T17:52:45+08:00

The objective of this study is to propose a hybrid model based on self-organized maps (SOM) and fuzzy time series (FTS) for predicting the reliability of software systems. The proposed SOM-FTS model is compared with eleven traditional machine learning-based models. The problem of selecting a suitable software reliability prediction model is represented as a multi-criteria decision-making (MCDM) problem. Twelve software reliability prediction models, including the proposed SOM-FTS model, are evaluated using three MCDM methods, four performance measures, and three software failure datasets. The results show that the proposed SOM-FTS model is the most suitable model among the twelve software reliability prediction models on the basis of MCDM ranking.

Electronically Controlled Biquadratic Filter and Quadrature Oscillator Using CDTAs

2022-09-26T17:52:45+08:00

This article presents a current-mode biquadratic filter and quadrature oscillator circuit based on current differencing transconductance amplifiers (CDTAs). The proposed circuit does not require changing the circuit topology. In addition to the low-pass filter, high-pass filter, band-pass filter, and sinusoidal quadrature signal, the proposed circuit has a pole frequency that can be controlled independently from the quality factor, while the oscillation frequency can be controlled non-interactively. The circuit impedance with high output can directly drive the load without using a current buffer. Furthermore, grounded capacitors can function without the use of external resistors. This qualification is ideal for the future development of integrated circuits (ICs). After the PSPICE simulation with 90 nm CMOS parameters and the experiments by commercial ICs, the results are consistent with the theoretical analysis of the proposed circuit.

Numerical Study of Vortex Flow in a Classifier with Coaxial Tubes

2022-09-26T17:52:45+08:00

Centrifugal air classifiers are one of the most used separation devices in particle technology. The study aims to obtain a detailed description of the bulk material classification mechanism in the developed centrifugal classifier. The classifier design and the mechanism of the stable vortex structure formation in the inter-tube space of the device are described. Velocities within and between the vortices are studied to identify regions with inverse flows, which serve as transport channels for particles. The computational fluid dynamics modeling results indicate three channels with negative or near-zero axial velocities: between the vortices, near the outer wall of the internal tube, and the inner wall of the external tube. The selectivity of the device decreases when transport channels are disrupted due to flow mixing, which is caused by the height shifting of the vortex centers.

Effect of Volute Collector on the Performance of Centrifugal Pump Based on Entropy Generation Analysis

2022-09-26T17:52:45+08:00

A proper design of centrifugal pumps reduces power loss and improves efficiency. This study aims to investigate and analyze the effect of different volute collector configurations on centrifugal pump performance. Locations of losses are detected using the entropy production rate, whereas the number of losses is evaluated using user-defined codes. Three volute collectors are selected based on their connections with standard pipes. A steady flow numerical analysis is performed to determine the performance parameters of the centrifugal pump and select a modified volute collector design. Comparing the results of experiments on the base and modified volute collectors confirmed that the proper design of the volute collector can help reduce the secondary flow losses at subsequent locations, which reduces the entropy production and losses. As compared to the base pump, the modified volute collector improved the pump efficiency by 3% at the duty flow.