Noise cthrol stlely by an enclosure

Dissertant

Ibrahim, Shadha Abd al-Jabbar

University

University of Technology

Faculty

-

Department

Department of Building and Construction Engineering

University Country

Iraq

Degree

Ph.D.

Degree Date

2006

English Abstract

The widespread use of generators is a phenomenon in our life today, due to the continuous electric power outages (shutdown).

Therefore, acoustic enclosure for portable electric generator (5 kVA) is constructed to control emitted noise from it which affect human (hearing loss, hypertension, cardiac disease, stress, worker productivity,...

etc). ANSYS commands are written to estimate the sound pressure levels for frequency range (31.5,.....8000 Hz) ,and sound pressure level in dB(A).

Three cases are studied, the first , the acoustic analysis in semi free field at a distance lm, the second, the acoustic analysis at a distance 0.25m and the third, with utilization of absorption material. Transmission loss TL due to enclosure use has be an estimated for single, composite and double panels.

A Matlab packages has been developed for this particular task.

This particular package could be used for walls and partitions. The construction of enclosure is based on double box forms which are made of galvanized steel sheets (18-gauge).

These sheets are covered (coated) by a (5cm thick) glass wool.

A 0.2 m air gap and the glass wool coating form the acousting absorption material. A complete survey of the acoustic domain was carried out by using vibration/sound level meter and Oscilloscope data acquire program for the generator in semi free field and around the enclosure. The final results gave accepted deviation between the theoretical and field results.

These differences are due to the assumptions of simplifying the shape of the vibrating structure, accuracy of the measuring instruments and existing of the reflective surfaces. The results of the acoustic domain survey illustrate that the energy is concentrated in frequency range 600 Hz to 1360 Hz.

This enclosure reduced th noise level to its half original acoustic energy.

While the sound pressure level dB(A) is reduced from 94 to 64.

Main Subjects

Physics

Topics

• Noise
• Environmental engineering
• Acoustic engineering
• Sound-waves

• APA
• MLA
• AMA

Language

English

Data Type

Arab Theses

Record ID

BIM-305455