Geometry optimization of dry ice blasting nozzle for the noise reduction using experimental validation

• Main Author: Mat, Mohamad Nur Hidayat
• Format: Thesis
• Language: English; English; English
• Published: 2019
• Subjects: TA630-695 Structural engineering (General)
• Online Access: http://eprints.uthm.edu.my/74/1/24p%20MOHAMAD%20NUR%20HIDAYAT%20MAT.pdf; http://eprints.uthm.edu.my/74/2/MOHAMAD%20NUR%20HIDAYAT%20MAT%20COPYRIGHT%20DECLARATION.pdf; http://eprints.uthm.edu.my/74/3/MOHAMAD%20NUR%20HIDAYAT%20MAT%20WATERMARK.pdf; http://eprints.uthm.edu.my/74/
• Institution: Universiti Tun Hussein Onn Malaysia

Dry ice blasting provides many advantages to surface cleaning in which the blasting medium sublimate during the surface impact will not leave a secondary contamination. However, on the negative side of dry ice blasting (DIB), it produces a high noise exposure. The noise exposure during a high blasting pressure may reach up to 130 dB which is considered a harmful noise level (standard 90 dB for eight working hours per day). At present, safety measures are taken according to administrative control that encapsulates the whole system with sound insulation. This limitation has made this research work a significant contribution to dry ice blasting industry. The main objectives of this project are to examine the dry ice blasting’s flow characteristic on the influence of noise emission and to establish optimum parameters affecting the acoustic noise emission. The experimental validation on the effect of impact force and noise emission for optimum nozzle design is investigated. ANSYS fluent version 18.2 is employed in this study to simulate the fluid flow and acoustic noise in the nozzle. Six (6) different nozzle geometries are analyzed namely divergent length, convergent diameter, expansion ratio, gas inlet diameter, length ratio, and particle inlet angle. The optimum nozzle geometry is fabricated and validated throughout the experimental study on the effect of the impact force and sound pressure level for different pressures. The result shows that the optimum DIB nozzle geometry that satisfy the research objectives for gas inlet length, convergent diameter, particle inlet angle, divergent length, convergent length, gas inlet diameter, expansion ratio are 36 mm, 35 mm, 50°, 230 mm, 45mm, 6 mm and 1.00 respectively. This research is expected to provide a novelty design of dib nozzle geometry that able to protect the society from the hazardous working environment by engineering control.