Qualification of Duct Resonator Array for Noise Reduction in Offshore Installations

2012 ◽  
Author(s):  
Sandra Rodiño Palacios ◽  
Zheji Liu ◽  
Vegard Peikli ◽  
Roald Skorping ◽  
Asle Melvær ◽  
...  
Keyword(s):  
Insertion Loss ◽  
Noise Level ◽  
Optimal Solution ◽  
Effective Length ◽  
Acoustic Performance ◽  
Array Configuration ◽  
Offshore Installations ◽  
In Series ◽  
Norwegian Continental Shelf ◽  
Acoustical Energy

A compressor noise reducing device was investigated in connection with internal qualification of the technology for use in offshore installations in the Norwegian Continental Shelf. The acoustic performance of two duct resonator arrays applied to the inlet and discharge pipes as spool pieces was studied by means of sound insertion loss measurements. This array configuration minimizes the acoustical energy propagating to the inlet/discharge pipes and can be an optimal solution in modification cases where it is not feasible to mount the device inside the compressor. Laboratory verification measurements demonstrated that the duct resonator array reduces 14–18 dB the noise level at designed frequency (2–3 kHz). Correlation between insertion loss and effective length and a comparative study of the arrays installed in series or separated 90° with a bend were additionally performed. The investigation showed that this technology allows further flexibility of implementation often required in piping layouts with limited space.

Analysis of AC-DC Converter Circuit Performance with Difference Piezoelectric Transducer Array Connection

2020 ◽  
Vol 12 (7) ◽  
Author(s):  
Nik Ahmad Zainal Abidin ◽  
◽  
Norkharziana Mohd Nayan ◽  
Azuwa Ali ◽  
N. A. Azli ◽  
...  
Keyword(s):  
Piezoelectric Transducer ◽  
Simulation Analysis ◽  
Piezoelectric Sensor ◽  
Transducer Array ◽  
Circuit Performance ◽  
Array Configuration ◽  
Full Wave ◽  
Bridge Rectifier ◽  
In Series ◽  
Parallel Voltage

This research presents a simulation analysis for the AC-DC converter circuit with a different configurations of the array connection of the piezoelectric sensor. The selection of AC-DC converter circuits is full wave bridge rectifier (FWBR), parallel SSHI (P-SSHI) and parallel voltage multiplier (PVM) with array configuration variation in series (S), parallel (P), series-parallel (SP) and parallel-series (PS). The system optimizes with different load configurations ranging from 10 kΩ to 1 MΩ. The best configuration of AC-DC converter with an appropriate array piezoelectric connection producing the optimum output of harvested power is presented. According to the simulation results, the harvested power produced by using P-SSHI converter connected with 3 parallel piezoelectric transducer array was 85.9% higher than for PVM and 15.88% higher than FWBR.

Analysis of Acoustical Properties of a Gear Mechanism

1997 ◽  
Author(s):  
Evgueni I. Podzharov
Keyword(s):  
Noise Level ◽  
Wide Frequency Range ◽  
High Mode ◽  
Frequency Range ◽  
Dynamic Calculation ◽  
Acoustical Properties ◽  
Gear Mechanism ◽  
Surrounding Space ◽  
Gear Meshes ◽  
Acoustical Energy

Abstract For an analysis of the acoustical properties of a multistage gear mechanism, a technique was used that combines a dynamic calculation of the mechanism as multimass multicoupling system and the SEA method for the calculation of acoustical energy. The dynamic calculation was used to determine the energy introduced into the mechanism’s gear meshes and the energy transmitted to the housing. The SEA method was used for the calculation of propagation of acoustical energy in the structure and its radiation in the surrounding space. Such a combination permits us to utilize the advantage of dynamic calculation accurately describing the mechanism’s performance and the SEA method for describing an acoustical model having the elements of high mode density in a wide frequency range. Some useful results were obtained which permit us to reduce noise level of the mechanism.

Improvement on acoustic performance of the accumulator of double-cylinder rotary compressors

2007 ◽  
Vol 221 (11) ◽  
pp. 1391-1396 ◽  
Author(s):  
Z Y Huang ◽  
W K Jiang ◽  
C H Liu ◽  
H S Jin ◽  
Y Zhou
Keyword(s):  
Noise Level ◽  
Fluid Dynamic ◽  
Pressure Fluctuations ◽  
Wall Pressure ◽  
Rotary Compressor ◽  
Acoustic Performance ◽  
Wall Pressure Fluctuations ◽  
Large Pressure ◽  
Flow Phase ◽  
Single Pipe

Since the accumulator is one of main contributors to the overall noise level of the rotary compressor, research on the acoustic performance of accumulators is essential. Numerical analysis based on the computational fluid dynamic method shows that large pressure fluctuations are caused mainly by periodic rotating piston. The idea that the flow phase differences of two pipes could be utilized for suppressing fluctuations is proposed. The double standpipes of an accumulator are changed to the single pipe with two branches and each branch is connected to the inlet of the compressor. Flow structures and wall pressure fluctuations for the two configurations are computed. Computational results show that wall pressure pulsations of the new accumulator are obviously lower than that of the original. The acoustic experiments were carried out under the real working conditions. Compared with the original, the new accumulator shows that the overall noise level is reduced about 1.2 dB(A) and the sound spectrum levels are also lower in a wide frequency domain, which validate the numerical and theoretical analysis.

Sizing Software of a Solar Farm System

2015 ◽  
Vol 785 ◽  
pp. 611-615
Author(s):  
Nuril Yaqin Ab Rahim ◽  
Shahril Irwan Sulaiman ◽  
Zulkifli Othman
Keyword(s):  
Performance Ratio ◽  
Specific Yield ◽  
Array Configuration ◽  
Pv Module ◽  
Planning Procedure ◽  
In Series ◽  
Final Yield ◽  
Tariff Rates ◽  
And Performance ◽  
Farm System

This paper presents sizing software for the design of a solar farm system. The sizing software provides few guidelines to the designer for the planning procedure before the final of optimum array configuration is decided. Some specifications that the designer may consider are the type of PV module, the type of inverter, the available space for installation, the required energy per year and also the sum of money to be allocated for the instalment. The output result of this software will be the suggestion of possible configuration of the total number of modules in series per string with the total number of strings in parallel. This software also does the prediction of the system performances such as final yield, specific yield and performance ratio. The expected income is provided by the software is based on the Feed-in Tariff rates and the energy generated by the system.

scholarly journals The Quaternary Isotope Laboratory Thermal Diffusion Enrichment System: Description and Performance

Radiocarbon ◽  
1979 ◽  
Vol 21 (2) ◽  
pp. 139-164 ◽  
Author(s):  
Pieter M Grootes ◽  
Minze Stuiver
Keyword(s):  
Gas Exchange ◽  
Thermal Diffusion ◽  
Total Sample ◽  
Effective Length ◽  
Sample Mass ◽  
System Description ◽  
Wire Temperature ◽  
In Series ◽  
Equilibrium Separation ◽  
And Performance

The thermal diffusion enrichment system of the Quaternary Isotope Laboratory consists of 23 hot wire columns of 3m effective length combined to 2 separate systems of 3 and 3 separate systems of 4 columns at the top, each system in series with 1 bottom column. From ≈ 130 L NTP of CO (∼ 65g of carbon) it produces ≈ 8 L NTP of CO (~ 4g of carbon) enriched in12C18O by a factor 6 to 7 and in14C16O by a factor 7 to 8 in about 5 weeks. For12C18O the system has a theoretical equilibrium separation factor of about 250 and a theoretical equilibrium enrichment of about 15. For14C16O these values are 1300 and 16, respectively. The dependence of thermal diffusion transport on gas exchange between top and bottom section and between columns and reservoirs and on wire temperature is given. Forced gas exchange and a higher wire temperature gave a more rapidly increasing enrichment without substantially increasing its final value of 6 to 7 for12C18O. A comparison with the Groningen enrichment system shows that the two systems behave very similarly and that not the system geometry but individual column parameters and the ratio total sample mass/enriched sample mass are the dominant factors determining the enrichment.

Numerical Assessment of Optimal Equipment Allocation and Close-Fitting Acoustical Hoods Within a Multi-Noise Plant Using an Artificial Immune Method

2012 ◽  
Vol 29 (1) ◽  
pp. 185-195 ◽  
Author(s):  
M.-C. Chiu
Keyword(s):  
Shape Optimization ◽  
Insertion Loss ◽  
Research Work ◽  
Noise Levels ◽  
Artificial Immune ◽  
High Noise ◽  
Acoustic Performance ◽  
Numerical Assessment ◽  
Noise Impact ◽  
Control Work

High noise levels in a multi-noise plant can be harmful to workers and can lead to both psychological and physiological problems. Consequently, noise control work on equipment such as acoustic hoods becomes vital. However, research work of shape optimization on space-constrained close-fitting acoustic hoods has been neglected.In this paper, a sound insertion loss used for evaluating the acoustic performance of an acoustical hood will be adopted. A numerical case for depressing the noise levels at the receiving points along the boundary of three kinds of multi-equipment plants by optimally designing a shaped one-layer close-fitting acoustic hood and reallocating the equipment within a constrained space will also be introduced. Moreover, an artificial immune method (AIM) is adopted and coupled with the equations of sound attenuation and minimal variation square in conjunction with a twelve-point monitoring system.Consequently, this paper provides a quick and effective method for reducing the noise impact around a plant by optimally designing a shaped one-layer close-fitting acoustic hood and reallocating equipment within the AIM searching technique.

Methodology for the Design of the Geometry of a Cavity and Its Absorption Coefficients as Random Design Variables Under Vibroacoustic Criteria

2016 ◽  
Vol 24 (02) ◽  
pp. 1650006 ◽  
Author(s):  
Renata Troian ◽  
Koji Shimoyama ◽  
Frédéric Gillot ◽  
Sébastien Besset
Keyword(s):  
Energy Method ◽  
Noise Level ◽  
Optimal Solution ◽  
Cavity Surface ◽  
Nsga Ii ◽  
Acoustic Cavity ◽  
Design Variables ◽  
Material Uncertainties ◽  
Acoustic Cavities ◽  
Nondominated Sorting

Reducing the noise level in the acoustic cavities is the important problem when treating inflight conditions of commercial planes or boats. Shape optimization of the acoustic cavity that will take into account the geometrical and material uncertainties, arising during the manufacturing process, is presented in this paper. The noise level is controlled by minimizing the energy density in the cavity, obtained through an energy method called Simplified Energy Method. Such formulation is based on our previous published work where transformation function mapping 3D cavity surface on a 2D domain was proposed. The optimization process directly relies on this function and thus avoids remeshing of the geometry. Robust optimization is performed using the nondominated sorting genetic algorithm (NSGA-II) together with the Kriging surrogate model. Influence of geometrical and material characteristics on the optimal solution is identified.

Optimizing Offshore Combat of Oil Spills – Development of New Booms and Helicopter Based Application of Dispersants

2003 ◽  
Vol 2003 (1) ◽  
pp. 1279-1284
Author(s):  
Tharald M. Brekne ◽  
Sigmund Holmemo ◽  
Geir M. Skeie
Keyword(s):  
Oil Spill ◽  
Oil Spills ◽  
New Technology ◽  
Geographic Location ◽  
Chemical Dispersant ◽  
Offshore Installations ◽  
The Status ◽  
Oil Spill Response ◽  
Robust Systems ◽  
Norwegian Continental Shelf

ABSTRACT There is an increasing focus on offshore combat of oil spills on the Norwegian Continental Shelf (NCS). One result of this focus is a change from field specific to area specific contingency, moving from many medium sized oil spill combat vessels, to fewer and more robust systems and vessels. An important element in the emerging configuration is the use of helicopter based chemical dispersant systems, permanently located on offshore installations. An increasing diversity, of oil types being produced, configuration of installations, water depths and geographic location, are all factors that require a robust, mobile and flexible oil spill response. The Norwegian Clean Seas Association for Operating Companies (NOFO) has recently initiated development of new technology, as projects under NOFO's Research & Development Programme. Three of these projects address the development of improved heavy offshore booms, applying new principles for containment of oil, and a heavy duty skimmer optimized for mobility. A fourth project addresses the development of a system for helicopter based application of chemical dispersants, optimized for offshore storage and maintenance. This paper presents the status for and experience from these projects, as well as the plan for testing and verification of this new technology.

Temperature Dependent DC and RF Performance of n-GaN Schottky Diode: A Numerical Approach

2014 ◽  
Vol 895 ◽  
pp. 439-443
Author(s):  
Tarriq Munir ◽  
Azlan Abdul Aziz ◽  
Mat Johar Abdullah ◽  
Mohd Fadzil Ain
Keyword(s):  
Schottky Barrier ◽  
Schottky Diode ◽  
Insertion Loss ◽  
Ideality Factor ◽  
Series Resistance ◽  
Thermionic Emission ◽  
Numerical Approach ◽  
Temperature Dependent ◽  
In Series ◽  
Rf Performance

This paper reports the temperature dependent DC and RF characteristics of n-GaN Schottky diode simulated using Atlas/Blaze developed by Silvaco. It was found that as the temperature increases from 300K to 900K the forward current decreases due to lowering of the Schottky barrier with an increase in series-resistance and ideality factor. These observations indicates that tunneling behavior dominates the current flow rather than thermionic emission. Furthermore, the breakdown voltage decreases in reverse bias and insertion loss for RF behavior increases with respect to temperature due to the increase in capacitance near diode junction.Keywords: Atlas/Blaze, Schottky barrier, series resistance, ideality factor, insertion loss.

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