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Vibration is a major issue in turbomachines which causes damage to them and leads to reduction in life and efficiency. This paper reviews various methods to measure the amount of vibration in various turbomachines and also discusses various reasons for the same. This will significantly assist in articulating these vibrations. This paper lists various experiments done, causes, factors, comparison of different turbomachines and their results. Turbomachines which are taken into consideration are Francis turbine, radial turbines, axial turbines, compressors, pumps and fans. The outcome elucidates the changes in vibrations as a function of different input parameters. It can be concluded through various experiments on different types of turbomachines that the major causes of vibrations are cavitation and resonance while excess speed and longer operating periods too contribute to them.

Performance of electric motors and losses in terms of heat and temperature are reviewed in this paper. Airgap eccentricity, electromagnetic performance, effect of temperature and losses are shown as factors affecting the efficiency. Several methods of computer aided analyses are listed. Temperature distribution in an induction motor is shown through the results of a simulation. Different cooling methods are reviewed. Future directions for research include cryogenic cooling, heat pipes and usage of phase change materials.

In this work, simulation has been carried out for multipass Gas tungsten Arc Welding of SS316L and their effects were studied for thermal, and residual stresses and compared with experimental results. The sequentially coupled thermo-mechanical, transient thermal and static structural analysis was modelled using ANSYS with relevant Ansys Parametric Design Language coding. Infrared thermography camera was used to obtain the real time temperatures during the welding. The effect of temperatures and the induced residual stresses of the weldment is measured with X-Ray diffraction technique. Tensile residual stresses have been identified at fusion zone and compressive stresses at heat affected zone. Pass wise temperature measurements were taken from analysis and experiment the agreement with 7.24%. The agreement of measured and analysed residual stress had an agreement with 16.66%.

In the frame of the circular economy, welding of Ni-based superalloys has gained increasing importance when applied, for instance, to repairing highly expensive components widely used in strategical sectors, such as the defense and aerospace industries. However, correct process parameters avoiding metallurgical defects and premature failures need to be known. To reach this goal, Inconel 625 butt-welded joints were produced by CO2 laser beam welding and different combinations of process parameters. The experimental investigation was carried out with three parameters in two levels with an L4 orthogonal array. Laser power, welding speed, and shielding gas flow rate were varied, and the results were reported in terms of mechanical properties, such as microhardness, tensile strength, distortion, residual stress, and weld bead geometry, and metallurgy. At a lower welding speed of 1 m/min, the full penetration was observed for 3.0 kW and 3.3 kW laser powers. However, sound welds (porosity-free) were produced with a laser power of 3.3 kW. Overall, the obtained full-penetration specimens showed a tensile strength comparable with that of the parent material with residual stresses and distortions increasing with the increase in heat input.

Using TRNSYS software, a comparison of the energy performances of flat-plate collectors (FPCs) and evacuated-tube collectors (ETCs) in domestic solar water heating systems located in different climate areas was carried out in order to ascertain solar energy utilization. Investigations were carried out on single FPCs and ETCs and also for strings of four panels connected in series. Tests were conducted using simulations for water as heat transfer fluid with a fixed fluid flow rate and varying the temperature of the collector’s returning fluid. The maximum power peak decreases with the increase in the inlet temperature of the fluid to the collector in the FPC. The maximum outlet temperature of the FPC is higher than the ETC, most of the time. The evacuated-tube collector performs better only in cold climate areas. Simulations suggest that the use of the FPC is strongly discouraged in cold climatic areas due to thermal losses, whereas the ETC works well with reduced dispersion of heat. In warm seasons, on the contrary, the FPC takes advantage of the high environmental temperature which heats the fluid. The maximum yearly outlet temperature and useful power peak predicted in different climatic areas were investigated by varying the temperature of the fluid inlet fed to the two strings of four FPCs and ETCs. In all cases, the outlet temperature is higher in the ETC technology.

A finite element modelling starts with the heat equation, heat flux input and thermal modelling and the material definition. In this study a laser welding model with heat transfer is defined and analyzed for a 3mm thick SS316LN material, the temperature dependent thermal and structural properties are taken for analysis. The laser has not formed the keyhole, yet lateral conduction forms the weld bead will progress and convection and radiation from the top surface. Modelling of these thermal inputs with symmetric BC's of heat at the fusion zone centre was used in modelling ANSYS solid70 element to obtain the Thermal temperature distribution. Sequentially, this thermal load is given as input to the solid45 to obtain the structural distortion. An orthogonal Array of 9 experiments with three levels of Laser Power, Weld speed and Shield gas flow rate were conducted and analyzed. The optimum levels obtained were 2750Watts, 2500 mm/min and 10LPM. The shield gas flow rate was related to the convective heat transfer coefficient, h in the model. Experimental validation of distortion by experiments had within 8% agreement.