It was conducted on Monday , 1/9/2025, in the Dr. Ihsan Yahya Hall in the mechanical Engineering Department. the discussion of the master’s thesis of the student Asmaa Oday Mohammed Raoof, which is tagged:
” Predicting the Sound Emission of Exhaust Muffler using Various Absorber Materials in Broad Frequency Bands”.
The discussion committee consisted of names listed below:
1.Prof. Dr. Thaier J. Ntayeesh (Chairman)
2- Asst. Prof. Dr. Laith Ayad Salman (Member)
3- Dr. Aveen A. Abdulkareem (Member)
4- Asst. Prof. Dr. Ali I. Mosa (Supervisor)
This study investigates the acoustic performance of an absorptive exhaust muffler using eco-friendly sound-absorbing materials as alternatives to conventional fibrous or porous materials. The research employs numerical simulations based on the Finite Element Method (FEM) using COMSOL Multiphysics, alongside experimental validation using an impedance tube, to analyze sound transmission loss and evaluate the effectiveness of natural fibers in noise attenuation.
Key Findings
1-Eco-friendly fibers can effectively function as sound-absorbing materials in exhaust mufflers.
2- Homogeneous fiber distribution within the muffler significantly enhances sound absorption performance.
3- Higher airflow resistivity, determined by fiber diameter and bulk density, increases sound transmission loss.
4- Increasing the muffler chamber length improves sound attenuation.
- Reducing the inlet/outlet tube diameter also enhances sound transmission loss.
Recommendations
1-Promote the use of eco-friendly natural fibers in exhaust mufflers as a cost-effective and environmentally sustainable alternative.
2-Ensure homogeneous distribution of fibers within the muffler to maximize acoustic performance.
3-Optimize muffler geometry, including chamber length and inlet/outlet diameters, to achieve higher sound attenuation.
4-Conduct long-term studies to assess the durability and sustained acoustic efficiency of natural fiber materials.
5- Explore other locally available natural materials to develop sustainable noise-control solutions.
After the scientific discussion by the members of the discussion committee, the researcher received a rating of (excellent).
