نشریه یافته های نوین کاربردی و محاسباتی در سیستم های مکانیکی
سال دوم شماره 1 (بهار 1401)

The main goal of this paper is the use of pinch technology and revision in heat exchanger network layout to optimize energy consumption in a methanol unit of a petrochemical company. First of all, the process flow diagrams (PFD) and the current state of the heat exchangers network were studied. Then, the necessary data were analyzed, process heat exchangers and their characteristics were compiled and the physical properties of the streamlines at different temperatures were calculated. Then, the target network was distinguished and the network was modified and pinch analysis was performed using ASPEN HYSYS software and ASPEN ENERGY ANALAYZER software. Finally, different scenarios based on pinch analysis were compiled and feasibility, computational, process and operational analysis was performed. Finally, by calculating energy efficiency in each scenario, only one scenario was selected and introduced as the best scenario. According to the selected scenario, the E-1001exchanger, which uses low pressure steam to heat the incoming feed gas, is transferred to another location in order to not only reduce the steam consumption, but also reduce the unit's power consumption by reducing the air fan load. The profit from this scenario was approximately equal to 1.5 billion tomans per year.

The rolling industry is the most common and prosperous method of producing metal products. The first goal of the rolling process is to reduce the cross-sectional area or the thickness of the workpiece, this process is done in two ways, hot and cold rolling, the metal passes between two rollers to take the shape of the groove (calibre) of the roller, so the rolling rollers of the components They are essential in climbing factories. This research aims to analyze heat transfer in hot rolling conditions and find the heat distribution in rolling rollers using the finite element method. The simulation is non-linear and assumes that the roller is homogeneous, isotropic, and without cracks and thermal strain. And the ambient temperature is considered negligible. The heat distribution in the roller in this research has been obtained in two ways using the spray cooling system and without using this system, and then the results obtained from the finite element simulation have been verified with the extracted experiment data, The highest percentage of relative error in prediction was 08.334%, which indicated the matching of the results obtained from the numerical solution with the extracted data.

Gearing is one of the most efficient methods of transmitting power from a source to its application with or without change of speed or direction. In this paper, a spur gear model is optimized aiming to maximize its transmission power and minimize its weight. Several design variables named as transmitted power, number of pinion teeth, modules, and thickness of gears have been considered during optimization process. For the sake of optimization, two developed metaheuristics named as water cycle and neural net-work algorithms have been examined using MATLAB programming language platform. Besides, obtained optimization results have been validated and analyzed using well-known commercial computer aided engineering software ANSYS. Based on the ob-tained optimization results, optimum design has been found using optimizers and in terms of engineering analysis good agreement has been observed between the applied finite element approach.

In this article, reflection coefficient of ultrasonic guided waves from surface of a circumferential corrosion is evaluated to find the relation between this coefficient and the size of defect. In the present work, firstly, by solving the governing equations of the wave propagation with general matrix method and according to the boundary conditions in the pipe, dispersion curves of the phase velocity and group velocity were obtained, then simulation of wave propagation was performed using Abaqus finite element software. In this method, a longitudinal L(0,2) mode, which has good frequency characteristics, was used to generate the wave in the pipe. After determining the convergence, the wave propagation was carried out in the pipe with different dimension of defect. It was observed that part of the generated wave after collision to defect was reflected and various modes were generated that the first reflected mode was L(0,2) and the second reflected mode according to the group velocity dispersion curves of different modes was F(1,2). Different reflection coefficients were obtained due to different dimension of defects, and it was observed that with increasing defect depth, the reflection coefficient of the reflected wave also increased. In this article, the effect of circumferential corrosion width on the reflection coefficient of longitudinal wave has been investigated and it has been observed that the reflection coefficient of waves depends only on the depth of the defect and does not change much with the change of circumferential corrosion width.

The increasing applications of compound materials in various industries, including aerospace, shipbuilding, micro and macro dimensions have, So researcher special attention to the design of these structures. In this study, static analysis of a rectangular plate with the special case of high order correction of shear deformation was investigated by considering the, secant function in spatial change field. In this study, the relation between the changes and the Hamilton's principle has been achieved by forming the different energy term of the system. To solving the governing equations, the Navier - stokes equations are implemented using sinusoidal and sinusoidal functions and considering the boundary conditions of the system. By solving the equations, the deflection values of the plates are calculated according to the changes in the system parameters and the obtained results are compared with the results contained in the validated literature and the accuracy of them is sufficient. In conclusion, the bounded analysis with the help of secant functions is very close to the responses obtained from similar researches and in certain cases we can use these functions.