Journal of Mechanical Engineering and Vibration: 4 (3)

Open Access Article

1 - perimental Study on the Performance of a New Type Solar Air Heater with Cross-Corrugated Surface on Different Environmental Conditions
نادر رهبر محمد جوادی نیا ایزدی پژمان ظهوریان ایزدی

In This paper, the effect of using cross-corrugated surface as an absorber plate in a solar air collector was experimentally investigated. Black plate geometries of air heater was V-type, while some vertical baffles were used to conduct air flow between surfaces. With t More

In This paper, the effect of using cross-corrugated surface as an absorber plate in a solar air collector was experimentally investigated. Black plate geometries of air heater was V-type, while some vertical baffles were used to conduct air flow between surfaces. With these modification turbulence regime and heat transfer enhancement were achieved. A centrifugal fan was also used to produce 0.003-0.01 kg/s air flow. Moreover different position angles (30, 45 and 90 degrees) were used to evaluate the performance of the system. The results showed that with these modification the Nusselt number was 5 times greater than before. Furthermore, a new correlation was proposed which has a good accuracy in estimation of Nu number. Manuscript profile

Open Access Article

2 - Numerical Investigation of heat transfer in fire heater tube of the gas unit of Tehran Refinery
احد عابدینی علی حیدری

One of the most fundamental problems in the furnace and fire heaters control and maintain the temperature of the tube in allowed range. In this study, heat transfer in tubes of Tehran refinery gas unit heater is investigated numerically. Simulation of combustion furnace More

One of the most fundamental problems in the furnace and fire heaters control and maintain the temperature of the tube in allowed range. In this study, heat transfer in tubes of Tehran refinery gas unit heater is investigated numerically. Simulation of combustion furnace has done by FIHR software and modeling of fluid flow is done by commercial Fluent soft war so that the surface temperature of the pipe is obtained. The results show that with increasing combustion air up to 15% can reduce the surface temperature of pipes. In addition, reducing the fluid flow rate to the amount foreseen in the design process as well as increasing combustion air temperature leads to the higher surface temperature of pipes. Manuscript profile

Open Access Article

3 - Simulation of clearance effect on LDR in stainless steel deep drawing
Ali Fathi Jokandan Mehrdad Ozve Aminian

Deep drawing is one of the most important processes in the sheet metal forming industry where a flat sheet is drawn by the punch into the hole matrix And It takes the shape of the punch. The effective parameter in this process  is clearance between punch and matrix More

Deep drawing is one of the most important processes in the sheet metal forming industry where a flat sheet is drawn by the punch into the hole matrix And It takes the shape of the punch. The effective parameter in this process  is clearance between punch and matrix. Finite element method is a useful tool for the study of process and impact parameters affecting it. In this project the effect of clearance between punch and matrix on LDR was considered and result are showed 0.9 mm clearance is more optimum suitable for 0.6 mm sheet thickness in deep drawing and decreased to 0.66 mm clearance the LDR was decreased. Manuscript profile

Open Access Article

4 - Reduction of vibrations amplitude using ribs in the welded steel structure in the cross beam of a gantry milling machine
mahdi armaninejad Mohammad Jafar Ostad-Ahmad-Ghorabi

Body of machine tool is mainly made of cast iron or welded structures. But in service, the so called self excited vibrations (chatters) decrease the surface and dimension quality of work pieces. Welded joints used in body structure, help to reduce the level of vibration More

Body of machine tool is mainly made of cast iron or welded structures. But in service, the so called self excited vibrations (chatters) decrease the surface and dimension quality of work pieces. Welded joints used in body structure, help to reduce the level of vibrations amplitude inherently. The present work outlines analytical evaluation of welded structures to reduce the amplitude of vibrations. Different rib modes for cross beam of a gantry milling machine have been studied. The results show that vertical rib mode has the most effect by decreasing more than 97% of the vibration amplitude compared to no-rib mode. Manuscript profile

Open Access Article

5 - Fault Detection of Cylinder- head automotive Using Mechanical Waves and Intelligent Techniques
Mojtaba Doustmohammadi Morteza Mohammadzaheri Ehsan Jamshidi

Safety of machinery parts, it is important for users and defects as one of the most important parts of threats to the health of the pieces have always been considered. In this paper, a new method based on the use of artificial neural networkDetection Pridecylinder head More

Safety of machinery parts, it is important for users and defects as one of the most important parts of threats to the health of the pieces have always been considered. In this paper, a new method based on the use of artificial neural networkDetection Pridecylinder head into mechanical waves is presented. Then, for verification and validation of the finite element model , modal test piece , and after confirming the fault simulation is performed on a finite element model. Force simulation model (FEM) acceleration signal - the healthy and faulty models calculated for each fault. And with the signing of mechanical defects ( acceleration difference between healthy and faulty models ) and to train a multilayer perceptron neural network (MLP) , the difference between the acceleration signal to the associated fault location. Detectionautomotive cylinder head (estimated fault location) has been. The results of the neural network capabilities designed to estimate the fault location on a good show.  Manuscript profile

Open Access Article

6 - Accuracy assessment of Ro 3rd order and CUSP dissipation schemes to analyze transonic flow around pitching airfoil using structured spring network
Ali Heydari

In this article, the unsteady transonic flow analysis with moving boundary is considered to compare dissipation schemes consist of: SCDS scheme, Ro 3rd order and CUSP methods. So that the unsteady, two-dimensional, non-viscous, compressible flow around an oscillating ai More

In this article, the unsteady transonic flow analysis with moving boundary is considered to compare dissipation schemes consist of: SCDS scheme, Ro 3rd order and CUSP methods. So that the unsteady, two-dimensional, non-viscous, compressible flow around an oscillating airfoil is investigated by solving Euler equations with adaptive grid network. To enhance the ability of moving grid network and prevent interference grids, linear springs are used in tangential and normal direction to the surface. Also the difference between the upwind (Ro) and the central difference CUSP dissipation scheme analysis is studied. The main problem, which occurs to the solution of equations as a result of the phenomenon of shock in central differences, is instability and non-continuity in the solution because of the lack of shock information. To solve the problem the artificial dissipation is used. In this way, the oscillating airfoil motion, the adaptive network and artificial dissipation are modeled. For validation, results are compared with experimental data. Finally, the numerical accuracy is checked. The results show that the of solving the CUSP scheme at the airfoil trailing edge and the shock capturing leads to better accuracy. Manuscript profile

Open Access Article

7 - Investigation the effect of diameter and temperature on mechanical properties of single-walled boron nitride nanotubes by molecular dynamics simulation
Mohammad reza Mostafaei Abdolhosein Fereidoon Masoud Darvish ganji

The molecular dynamics (MD) simulation is used to calculate the mechanical properties of single-walled BNNTs (SWBNNT). The effects of diameter, chirality and temperature on the mechanical properties of respected systems have been investigated. The results showed that, z More

The molecular dynamics (MD) simulation is used to calculate the mechanical properties of single-walled BNNTs (SWBNNT). The effects of diameter, chirality and temperature on the mechanical properties of respected systems have been investigated. The results showed that, zigzag BNNTs are stiffer than armchair ones with nearly the same diameter. Also the Young’s modulus of both type of SWBNNTs increase when the tube diameter increases till the specific diameter and then decrease slightly. We found that diameter changes have no significant influence on the failure stress and strain of zigzag BNNTs. In addition, the results confirmed that all measured mechanical properties decrease with increasing temperature. Our simulation findings afford not only a molecular level understanding of the BNNTs but also may be instructive to mechanical engineers and scientists who attempt to develop effective mechanical properties. Manuscript profile

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