In this paper, the free convective heat transfer of nanofluids in a square cavity is simulated using a numerical method. The angle of the cavity could be changed in the horizontal axis from 0 to 90 degrees. The cavity is exposed under a constant magnetic field. Two opposite walls of the cavity are cold and warm, and the rest of the walls are insulated. On the hot wall, there are two fins with the same wall temperature. The equations were discretized by the finite volume method (FVM) and then solved using the SIMPLE algorithm. Three different fin configurations (straight, inclined and curved) were studied in terms of heat transfer rate and generation of entropy. According to the simulation results, the heat transfer rate was improved by tilting the fins toward the top or bottom of the cavity. At Ra = 105 and Ha = 20, the maximum heat transfer rate was achieved at a cavity inclination of 90° and 45°, respectively, for straight and curved fins. In the horizontal cavity, heat transfer rate could be improved up to 6.4% by tilting the fins and up to 4.9% by warping them. Increasing the Hartmann number from 0 to 40 reduced the Nusselt number and entropy generation by 37.9% and 33.8%, respectively.
Nickel-based super alloy laser welding is of particular importance because of its numerous usages in the energy and aerospace industries. Measuring the temperature field is the basic criteria for conducting a qualitative evaluation of the weld joint. In this research, laser welding was experimentally investigated and the temperature field was measured. Measuring the temperature around the molten pool by varying the laser parameters such as nozzle distance, welding speed, laser power, and beam offset indicated a different heat field, resulting in changes in the molten pool's width and depth. Because of the high temperature of melting and low thermal conductivity coefficient of the Inconel 625 alloy, the measured temperature was large. Compared with the other parameters, the effect of enhancing the laser power on temperature increase around the molten pool was significant. The findings showed that, by increasing the laser power from 300 to 400 W, the temperature increased from 320 to 340 °C. Also, by increasing the nozzle distance from the surface of the workpiece to 2 mm, the temperature decreased from 300 to 200 °C.
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