A Proper Shape of the Trailing Edge Modification to Solve a Housing Damage Problem in a Gas Turbine Power Plant

A Development of an Induction Heating Process for a Jewelry Factory: Experiments and Multiphysics

This article reports a successful development of the induction heating process (IHP) in a jewelry factory based on experiments and multiphysics consisting of electromagnetic and thermal simulations. First, two experiments were set to measure essential parameters for result validation and multiphysics boundary condition settings. Then, the essential parameters were applied to multiphysics, and both simulation results revealed heat transfer, magnetic flux density (B) generated by the coil, and temperature (T) of the product. B and T were consistent with the experimental results and theory, confirming the reliability of the multiphysics and methodology. After that, all simulation results were analyzed to assess and optimize IHP in terms of the number of coil turns (N), positional placement of the product (P), and coil thickness (Th). Multiphysics revealed that the current operating condition with N = 3 is proper; however, the IHP can be improved more with coil and operating condition optimizations. Finally, completing the optimizations, decreasing 40% of Th with N = 6, and the same P, increased B on the product by 21.62%, leading to IHP efficacy enhancement. The research findings are the optimum coil model and methodology for developing the IHP, which were practically employed in the jewelry factory.

A Development of Welding Tips for the Reflow Soldering Process Based on Multiphysics

A reflow soldering process (RSP) is generally implemented in advanced manufacturing factories for welding small electronic components together to create a product using heat generated at the welding tip (WT). Improper WT design and operating conditions may lead to defects in some products; therefore, optimizing both is immensely significant in developing the RSP. Accordingly, this article proposes a successful RSP development based on multiphysics in a hard disk drive factory consisting of transient thermal-electric and structural simulations. First, a new shape series WT was designed, and a conventional shape, parallel WT, was considered as a case study. Then, they were assembled and experimented with the RSP actual operating conditions to collect essential data. Next, the heat transfer was determined using a transient thermal-electric simulation (TES). The simulation results showed uneven WT temperatures depending on applied voltages, time, and shapes, which were consistent with the experimental results. The higher the applied voltage, the greater the temperature generated at the WT. Finally, after using TES results as loads, the structural simulation showed WT total deformations, which could be consistent with actually occurring defects. The findings from this research are a new design of series WT and proper multiphysics methodology for developing the RSP.

Gas Flow and Ablation of 122 mm Supersonic Rocket Nozzle Investigated by Conjugate Heat Transfer Analysis

The propellant gas flow of a supersonic rocket in inappropriate operating conditions can cause excessive ablation inside a nozzle. In this research, conjugate heat transfer analysis (CHTA), consisting of computational fluid dynamics (CFD) and finite element analysis (FEA), was applied to investigate the gas flow and ablation of a 122 mm nozzle as a case study in the transient state, based on actual operating conditions. First, the nozzle was tested in a static experiment. Then, the experimental results were employed for CHTA settings and validation. Next, after completing the CFD calculation, the results revealed that the nozzle’s gas flow, temperature, pressure, Mach number, shock, etc. were consistent with theoretical results. Finally, using the CFD results as loads, the FEA results showed the equivalent von Mises stress (σv), which was consistent with the ablation results from the experiment, as expected. The more the σv, the greater the ablation. Both σv and ablation were high near the throat and decreased further away. In addition, increasing the insulators’ thickness reduced σv, leading to ablation reduction. The research findings contribute to an understanding of ablation and the methodology of employing CHTA to improve the design of 122 mm and other nozzles with reduced ablation for higher efficacy.

Derosion Lattice Performance and Optimization in Solving an End Effect Assessed by CFD: A Case Study in Thailand’s Beach

Thailand’s beach had a severe coastal erosion problem at the end of rock dams called the “end effect”. One of the innovative solutions to solve this problem is to use the derosion lattice (DL). However, since the DL performance depends on installing conditions such as angle of attack, placement position, terrain, and climate, computational fluid dynamics (CFD) was applied to assess the end effect’s occurrence and optimize the performance of DL’s installation. Based on Khao Rup Chang’s condition, a suffered beach in Thailand was used as a case study, and a free surface flow simulation was performed in the transient state using ANSYS Fluent, a CFD software, which revealed water waves flow through the beach with and without the DL installation cases. Furthermore, the CFD-assessed results indicated that the angle of attack and placement position affected the DL performance as expected. In optimization, the 15° angle of attack with the DL placement adjacent to the rock dam was the proper condition. After being applied at the actual site, the DL can help reduce erosion, increase sedimentation, and solve the end effect with excellent performance.

A Suitable Shape of the Suction Head for a Cleaning Process in a Factory Developed by Computational Fluid Dynamics

The previous shape of the suction head (SH) employed in a cleaning process in a factory had a low performance, removed fewer particles, and generated an annoying noise. Therefore, new shapes of SH have been proposed to solve the issues and the cleaning performance was investigated by the Shear Stress Transport (SST) k-ω turbulence, Discrete Phase (DP), Large Eddy Simulation (LES), and Ffowcs Williams and Hawkings (FW–H) models in a transient state of computational fluid dynamics (CFD). The SST k-ω and DP models were applied to determine the airflow, suspension velocity, cleaning region, and particle trace. In addition, the LES and FW–H models were used to evaluate the noise, sound pressure level, and frequency generated from the proposed shapes. All simulation results were validated with the air velocity and noise measurements and were analyzed to find a suitable shape. The simulation and experimental results revealed that the shapes of the SH affected the cleaning performance and noise generation. The higher the air velocity, the higher the noise generation. The suitable shape delivered a 4.37% better particle removing performance and 11.1 dB less noise generation than the previous shape. The outcomes of this research are the suitable shape of the SH and the research methodology which enabled the application of both CFD and experiments to solve the issue to help enhance the efficiency of the cleaning process in an actual factory.