Sound Power Level Predictions for Industrial Machinery

Bruce, Robert D.; Moritz, Charles T.; Bommer, Arno S.

doi:10.1002/9780470209707.ch82

Cited by 5 publications

(5 citation statements)

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“…Hourly L eq values (L eq-H ) values were calculated from one-min noise measurements by determining the sound pressure level of the average sound pressure over each 60-min period. (15) Consolidating the noise measurements in this way allowed us to compare observed noise levels to project goals and WHO guidelines. Descriptive statistics were generated (SAS, PROC UNIVARIATE).…”

Section: Methodsmentioning

confidence: 99%

Identifying determinants of noise in a medical intensive care unit

Crawford

Barnes

Peters

et al. 2018

Journal of Occupational and Environmental Hygiene

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Continuous and intermittent exposure to noise elevates stress, increases blood pressure, and disrupts sleep among patients in hospital intensive care units. The purpose of this study was to determine the effectiveness of a behavior-based intervention to reduce noise and to identify determinants of noise in a medical intensive care unit. Staff were trained for six weeks to reduce noise during their activities in an effort to keep noise levels below 55 dBA during the day and below 50 dBA at night. One-min noise levels were logged continuously in patient rooms eight weeks before and after the intervention. Noise levels were compared by room position, occupancy status, and time of day. Noise levels from flagged days (>60 dBA for >10 hrs) were correlated with activity logs. The intervention was ineffective with noise frequently exceeding project goals during the day and night. Noise levels were higher in rooms with the oldest heating, ventilation, and air-conditioning system, even when patient rooms were unoccupied. Of the flagged days, the odds of noise over 60 dBA occurring was 5.3 higher when high-flow respiratory support devices were in use compared to times with low-flow devices in use (OR= 5.3, 95% CI = 5.0 - 5.5). General sources, like the heating, ventilation, and air-conditioning system, contribute to high baseline noise and high-volume (>10 L/min) respiratory-support devices generate additional high noise (>60 dBA) in Intensive Care Unit patient rooms. This work suggests that engineering controls (e.g., ventilation changes or equipment shielding) may be more effective in reducing noise in hospital intensive care units than behavior modification alone.

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Section: Methodsmentioning

confidence: 99%

Identifying determinants of noise in a medical intensive care unit

Crawford

Barnes

Peters

et al. 2018

Journal of Occupational and Environmental Hygiene

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“…In order to scale the SFoM linearly between maximum and minimum, the three sound levels are converted from the logarithmic unit decibel to the linear unit Sone [24]. The method from Roskam [25] is applied for the propeller noise, together with the airframe after Fink [26] and the electric motors, gear and engines from Bruce [27].…”

Section: Postprocessingmentioning

confidence: 99%

Preliminary hybrid-electric aircraft design with advancements on the open-source tool SUAVE

Mangold¹,

Eisenhut²,

Brenner³

et al. 2023

J. Phys.: Conf. Ser.

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The large variety of possible propulsion architectures for environmentally friendly and sustainable aircraft concepts create opportunities for the overall aircraft design. In particular, hybrid-electric aircraft have an increased number of additional components that must be implemented in the aircraft design tool. Primary and secondary energy sources can be used to achieve the necessary reduction in emissions. The preliminary aircraft design tool SUAVE offers the basic setup necessary to integrate the electrification of the propulsion system into the aircraft design. For this purpose, SUAVE has been extended to enable an iterative sizing loop for hybrid-electric aircraft. Hence, many propulsion architectures are easily adaptable. Additional components can be included and their interactions are considered. Furthermore, the fidelity levels of the models are modifiable. Moreover, the top-level aircraft requirements are transformed into a sizing chart to calculate the necessary power and wing loading. Thereby, a reasonable hybridization factor of installed power can be identified. This definition of hybridization implies a specific energy management strategy. As a result, hybridization and the energy management strategy are directly coupled and have to be considered together. Finally, in the postprocessing, the raw data is processed and can be evaluated with figures of merit. This procedure converts the results into a descriptive value and facilitates the comparison to other configurations. The figures of merit include evaluations for emissions, operational aspects and development costs and effort.

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“…To obtain at least a rough first estimate for the noise generated by electric motors, data from the literature will be analyzed. In reference [49], A-weighted total sound power levels are given for drip-proof electric motors with 750-4000 kW, which may serve as a first estimate for motors to be used in electrified power trains for small regional aircraft. Thus, this approach is similar to the one used by Huff et al [45].…”

Section: Potential New Noise Sourcesmentioning

confidence: 99%

“…Depending on whether it is intended to drive the propulsor directly or coupled with an additional gear box, it is likely that the rotational speed of electric motors suitable for electrified aircraft is notably higher. To account for such increase, the data from [49] were simply extrapolated linearly to higher rotational speeds. This may be a simplification, but it allows for a first rough estimation.…”

Section: Potential New Noise Sourcesmentioning

confidence: 99%

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Conceptual estimation of the noise reduction potential of electrified aircraft engines

Geyer

Enghardt

2023

Acta Acust.

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The advent of electrified propulsion systems for civil aircraft promises not only notable reductions of CO2 and NOx emissions, but also of perceived noise. In an attempt to estimate the noise reduction potential of fully electric aircraft engines, the current study compares the noise generated by classical turboprop and turbofan engines with noise spectra calculated for electrified engines. The calculation is based on published far-field sound pressure level spectra at different noise certification points, which are then modified to account for the absence of combustion-related noise sources. In addition to the overall sound pressure level, changes to the effective perceived noise level are also taken into account. The results clearly show that the electrification of the engine alone will not lead to the notable noise reductions that are required in order to achieve the goals for future aviation set by the European Commission. Instead, continued research is necessary to further reduce noise sources that will continue to be present in novel electrified aircraft systems, such as fan noise and airframe noise.

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Sound Power Level Predictions for Industrial Machinery

Cited by 5 publications

References 0 publications

Identifying determinants of noise in a medical intensive care unit

Identifying determinants of noise in a medical intensive care unit

Preliminary hybrid-electric aircraft design with advancements on the open-source tool SUAVE

Conceptual estimation of the noise reduction potential of electrified aircraft engines

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