NOISE TRANSMISSION FROM A SMALL, HERMETIC, RECIPROCATING, REFRIGERANT COMPRESSOR
Open Access
- Author:
- Cunsolo, John Vincent
- Graduate Program:
- Acoustics
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- July 09, 2018
- Committee Members:
- Timothy A Brungart, Thesis Advisor/Co-Advisor
Stephen A Hambric, Committee Member
Daniel Allen Russell, Committee Member - Keywords:
- Compressor
Noise Control
Acoustics
Refrigerant
Transmission
Transmissibility
Sound Power
Sound Power Transfer Function
Hermetic
Reciprocating
Vibration
Vibration Isolation
Radiation
Noise Monitoring
Rigid Base
Radiation Efficiency
Radiated Sound
Modal Analysis
Mobility
Drive Point Mobility
Structural Mobility
Cylindrical Shells
Mode Shapes
Structural Loss Factor
Spring Surging - Abstract:
- In recent years, refrigerant compressor design has become more focused on limiting the emission of noise, as many of these units are installed in residential spaces. This thesis aims to identify the primary transmission path of noise from a small, hermetic, reciprocating compressor to its enclosure, demonstrate the noise issues that result from its structural design, generate a procedure for a facilitated and accurate measurement of radiated sound power using structural acoustics theory, and evaluate a fundamental concept for attenuating mechanical noise. Measurements of transmissibility and radiated sound power of production line and rigidly mounted units reveal that the mechanical transmission path dominates the shell excitation at frequencies critical to human hearing. Experimental modal analysis, shell mobility measurements, and sound power transfer function measurements show that the compressor mounts are located at antinodes of cylindrical shell modes with high radiation efficiency. A noise monitoring technique used to obtain radiated sound power of an operating compressor, given surface-averaged acceleration, is validated with measurements and promoted for use in monitoring structural design changes to products. A noise control concept is designed to decouple the suspension system from its compliant enclosure by grounding it to a rigid base, and it is successfully verified to attenuate the mechanical transmission path. The thesis concludes with possible future design implementations, as well as recommendations on how to reduce radiated noise from similar units.