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Author: search.filters.author.Chaiaiad, ChatchapatSubject: search.filters.subject.computational fluid dynamics

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    Effect of Detergent, Temperature, and Solution Flow Rate on Ultrasonic Cleaning: A Case Study in the Jewelry Manufacturing Process
    (2025-12-01)
    Juangjai, Natthakarn
    ;
    Chaiaiad, Chatchapat
    ;
    Thongsri, Jatuporn
    This research investigated how detergent type and concentration, solution temperature, and flow rate affect ultrasonic cleaning efficiency in jewelry manufacturing. A silver bracelet without gemstones served as the test sample, and the study combined harmonic response analysis to assess acoustic pressure distribution with computational fluid dynamics to examine fluid flow patterns inside an ultrasonic cleaning machine. Cleaning tests were performed under real factory conditions to verify the simulations. Results showed that cleaning efficiency depends on the combined chemical and ultrasonic effects. Adding detergent lowered surface tension, encouraging cavitation bubble formation; higher temperatures (up to 60 °C) softened dirt, making removal easier; and moderate solution flow improved the cleaning, helping to carry dirt away from jewelry surfaces. Too much flow, however, decreased cavitation activity. The highest cleaning efficiency (93.890%) was achieved with 3% U-type detergent at 60 °C and a flow rate of 5 L/min, while pure water at room temperature (30 °C) without flow had the lowest efficiency (0.815%), confirmed by weighing and scanning electron microscope measurements. Interestingly, maximum ultrasonic power concentration did not always match the highest cleaning efficiency. The study supports sustainable practices by limiting detergent use to 3%, in line with Sustainable Development Goal (SDG) 9 (Industry, Innovation, and Infrastructure).
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    Effect of Nozzle Pressure and Shape Ratios on Gas Flow of a 122 mm Supersonic Rocket Nozzle investigated by CFD
    (2023-01-01)
    Chaiaiad, Chatchapat
    ;
    Thongsri, Jatuporn
    This article reports the effect of nozzle pressure ratio (NPR) and shape ratio (SR) on the gas flow of a 122 mm supersonic rocket, a convergent-divergent nozzle, using computational fluid dynamics (CFD). The NPR is the ratio between the pressure inlet and outlet, while the SR is the ratio between the outlet and throat areas of the nozzle. The CFD results revealed the gas flow, pressure (P), Mach number (M), temperature (T), shock, and jet for some conditions of NPR and SR, consistent with the theory. Furthermore, it was found that M increased with increasing NPR and/or SR. Furthermore, T enhanced with increasing NPR but decreased with increasing SR. This report can be used to further development of this nozzle type suitable for missions.