Noise Investigation of a Yarn Twister-Winder.
Noise-Con 81, Proceedings of the 1981 National Conference on Noise Control Engineering, Raleigh, North Carolina, 8-10 June, 1981 1981:199-202
The noise of "ballooning" of the rotating yarn in a Whirlwind type- II twister/winder was investigated using a theoretical model, and the results were compared with experimental measurements of noise. The balloon was modeled acoustically following the theoretical model of a rotating point force, considering only force drag. Equations were derived indicating that a rotating threadline of simple shape radiates at the fundamental frequency as a classic dipole produced by the rotational drag, such that the sound power of the fundamental varies approximately with the rotational speed at an exponent of 6. In experimental measurements at a speed of 4800 revolutions per minute (rpm), a fundamental rotational frequency of 80 hertz and harmonics were visible as discrete narrow band noise. The theoretical exponential indexes relating sound power levels to rotational speed for the fundamental and second to fifth harmonic were 6, 8, 10, 12, and 14, respectively, compared to experimental indexes of 9, 10, 7, 11, and 16, respectively. The considerable error was contributed to standing wave problems. On the linear scale, the overall sound power level of the machine at 4800rpm was 107 decibels (dB) and that of the balloon alone was 104dB. The A- weighted values were 105dB for the machine and 84dB for the balloon alone. The gear noise contribution was 104db on both scales. The authors conclude that although on a linear scale balloon noise and gear noise levels are comparable, on the A-weighted scale the gear and structural noise dominates due to the lower frequencies present in the balloon noise spectrum. They further conclude that the controlling factors on balloon noise appear to be rotational speed and balloon shape, so that to maintain production rates it is advisable to limit the balloon radius.
NIOSH-Grant; Textiles-industry; Computer-models; Industrial-noise; Acoustical-measurements; Noise-analysis; Acoustics; Noise-sources; Analytical-models;
Royster-LH; Hart-FD; Stewart-ND;
Noise-Con 81, Proceedings of the 1981 National Conference on Noise Control Engineering, Raleigh, North Carolina, 8-10 June, 1981
Textile Machine Design & Devel North Carolina State Univ P O Box 5006 Raleigh, N C 27650