International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

The technological progress in computer technologies gave rise to new possibilities and progresses for numerical and iterative methods. As being one of the computational studies, computational fluid dynamics is highly related to today’s advances. There are various types of methods and algorithms developed to model complex phenomena of fluid flow. In this study, we will introduce a new, still in development stage, CFD code with a pre-processor and a solver. Our research is focused on developing and studying a CFD code for mainly internal flows. Laminar and turbulent 2-dimensional flows can be analyzed using the software. The code is equipped with a graphical user interface (GUI) to make it simple to use. The GUI has the all-necessary components to define and analyze a fluid flow problem. We used an open-source post processor in order to visualize flow data and linked it to GUI, so the resulting software is a complete CFD package. The entire software is written using Python which has an easy code structure and rich code libraries. In order to decrease the time for convergence, code is modified with Numba and Cython libraries. To confirm accuracy of the solver, various basic test cases from the literature such as backward facing step flow, impinging jet flow, flow across a square cylinder, lid driven cavity flow are tested for both laminar and turbulent flows and the results was described in detail.

In this study, airflow directivity ability and pressure drop values of air vents where placed on the front console of automobile cabinet were investigated with computational fluid dynamics analysis. One of the aims of these studies is the airflow performance impact of design changes on air vents. Therefore, parametric studies were conducted with diffuser structures having 3, 4, 5 blades and 16mm, 20mm, 24mm blade width and 3mm, 4mm blade thickness. These variations were created to determine the effects of the number of blades, blade width and blade thickness on air flow and pressure drop performances of automobile diffusers. The impact of automobile diffusers on thermal comfort inside of the cabinet has been detected—correlations which give pressure drop and airflow angle were obtained according to analysis results. Thus, equations giving airflow direction angle and pressure drop within specific parameters were obtained without computational fluid dynamics analysis. In this way, a faster approach was provided to reach related performance values on automobile diffuser design.

We present and explain the mathematical apparatus used in a numerical simulation model created with АNSYS СFX Software. The purpose of the model is to perform computations of fog parameters in different points of artificially generated fog sprays, which are then used to calibrate a novel type of fog sensors. By changing the distance between the nozzle and the measuring laser beam of the sensor, we can assess how the number flow rate and diameter distribution of fog droplets are varied within in the spray. This work is related to improving European security by introducing systems for quick counteraction to terrorist attacks, industrial accidents and natural disasters. These systems use artificial fog generation to collect and deposit on the ground harmful aerosols dispersed in air, especially CBRN agents. Our newly developed fog sensors operate on the basis of the electromagnetic echo effect to control the decontamination process. In order to optimize the work of the sensors, it is crucial to investigate fogs and their ability to absorb harmful substances from air. The most important fog parameters that influence the efficiency of the cleaning process are the number of droplets and their size.

In this study, a plate heat exchanger (PHE) was designed to meet the ventilation requirements in a small dwelling by performing heat recovery. In the Taguchi analysis performed by selecting three-level four effective parameters, L9 orthogonal array was used. In the analysis, the optimal levels of the design variables were determined by using Computational Fluid Dynamics (CFD) results in order to maximize the combined thermal and hydrodynamic effectiveness (CTHE) selected as the performance parameter. The CTHE was defined as the multiply of thermal effectiveness and flow effectiveness of the PHE. The 3-dimesional CFD models of the PHE were designed to include the effects of the local change in the flow cross-section, which will occur at the inlet-outlet of the air flow channels. Thermal and hydrodynamic computation of PHE models were obtained by finite volume software. In Taguchi analysis, design variables and levels that maximize CTHE: sub-channel number-6, channel height-3 mm, average air flow rate-2 m/s and plate material is paper. When the CTHE predicted from Taguchi analysis was compared with that solution of the CFD model generated using the optimized design and operating parameters, the difference was determined to be less than 1%. In addition, in order to calculate the CTHE based on the design variables, a mathematical equation was obtained in a 90% confidence interval.

Numerical simulation is widely applied in the fluid dynamic research. Unsteady multiphase flow with high Mach and Reynolds numbers has high physical and mathematical fidelity and a special approach of its correct modeling is required. In this paper the appropriate numerical methods and special algorithms of implementation are developed for high-performance numerical modeling using the modern computational systems. The results of validation tasks and problems of practical importance are presented.

In the study, the flow pattern due to the interaction between a high-speed train and the tunnel at the model scale was analyzed. Six different tunnel entry geometries were used variably for a single train speed. The most important issues as a condition of comfort in high speed trains are noise and vibration. In particular, flow-induced noise is triggered by pressure changes in the flow. For each geometry, the pressure changes at the tunnel entrance and at the tunnel exit are plotted with depending on time. As a result, the least amount of pressure change was found in the tunnel entrance model with openings in the side walls.