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Abstract

Steam discharge produces noise due to rapid expansion and a temperature drop of ejected steam. This is why steam silencers are used to change one-stage into multi-stage expansion, which reduces the intensity of pressure and temperature drop during this process and shifts emitted noise into higher frequencies, which are easier to dampen. This paper presents a flow-acoustic numerical model of a steam silencer. It is meant to help to obtain a precise analysis of phenomena occurring in steam silencers and improve the process of designing this type of device. The model described in this paper was based on the parameters of a real working unit manufactured in the Institute of Power Engineering – Thermal Technology Branch. Most of the steam silencers are designed based on construction guidelines that have not been changed for a long time. This restrained an increase in the acoustics efficiency of the steam silencers. An improvement of their flow and acoustic properties allows for the development of smaller, more efficient, and lighter construction. The current version of the model was used for the analysis of flow and acoustic changes which occur after modifying the lower region of a shell of the steam silencer. The proposed modification allowed for a 19% increase in mass flow rate through the silencer and noise reduction in the low-frequency range.
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Bibliography

[1] Karczewski J., Kopania J., Bogusławski G.: Reduction of noise from industrial installations, i.e. steam blow-off silencers. Energetyka Cieplna i Zawodowa 712(2018), 14–19 (in Polish).
[2] Vincent P., Larsonnier F., Rodrigues D., Durand S.: Analytical modeling and characterization of an infrasound generator in the air. Appl. Acoust. 148(2019), 476–483.
[3] Nowicki G., Nowicki T.J., Prystup A., Slusarska B., Chemperek E.: Effects of infrasound generated in urban areas on health of people and animals – an attempt to localize environmental infrasound sources using computer simulations. J. Pre-Clin. Clin. Res. 8(2014), 2, 81–85.
[4] Sorokin L.I.: Calculation and Measurements of the Characteristics of Noise Created in a Far Noise Field by Jet Planes. Mashinostroenie, Moscow 1968 (in Russian).
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[6] Dragun D.K., Perfil’ev Yu.P., Liukevich N.V., Khotulev V.A.: Shaft-Type Launchers. Bauman MGTU, Moscow 2003 .
[7] Lukashchuk V.N.: Noise generated during operations for purging steam superheaters and development of measures to reduce its influence on the environment. PhD thesis, Moscow 1988.
[8] Hockle M., Muller H.A.: A Handbook on Technical Acoustics. Sudostroenie, Leningrad 1980 (in Russian).
[9] Kurlze G.: Physik und Technik der Lermbergdampfung. G. Brann Buchverlag, Karlsruhe 1963 (in German).
[10] Middelberg J.M., Barber T.J., Leong S.S., Byrne K.P., Leonardi E.: Computational fluid dynamics analysis of the acoustic performance of various simple expansion chamber mufflers. In: Proc. Acoustics 2004, Gold Coast, 3-5 Now. 2004.
[11] Hu X., Zhou Y., Fang J., Man X., Zhao Z.: Computational fluid dynamics research on pressure loss of cross-flow perforated muffler. Chin. J. Mech. Eng. 20(2007), 2, 88–93 (English Edn.).
[12] Tupov V.B., Taratorin A.A.: The choice of turbulence models for steam jet. Procedia Engineer. Dynamic and Vibroacoustics of Machines (DVM2016) 176(2017), 199–206.
[13] Taratorin A.A., Tupov V.B.: Detection techniques of acoustical centre of noise source, Therm. Eng. 62(2015), 7, 480–483.
[14] Journal of Laws of the Republic of Poland (Dziennik Ustaw Rzeczypospolitej Polskiej), Item 2288, Attachment 7, 21/11/2019.
[15] Mohanty A.R, Pattnaik S.P.: An Optimal Design Methodology for a Family of Perforated Mufflers. SAE Tech. Pap. 2005-26-053, 2005.
[16] Zheng S., Kamg Z.X., Lian X.M.: Acoustic Matching Simulation of Muffler with Hybrid Approach. SAE Tech. Pap. 2011-01-1516, 2011.
[17] Comsol Multiphysics 5.6 Release Highlights. https://www.comsol.com/release/5.6 (acessed 24 March 2021).

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Authors and Affiliations

Patryk Gaj
1
Krzysztof Sobczak
2
Joanna Kopania
3
Kamil Wójciak
1

  1. Institute of Power Engineering, Mory 8, 01-330 Warsaw, Poland
  2. Lodz University of Technology, Wólczanska 219, 90-924 Lodz, Poland
  3. Lodz University of Technology, Piotrkowska 266, 90-924 Lodz, Poland
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Abstract

The article presents a method for assessing emissions of harmful substances and noise from road and air transport, as well as a combined assessment of the emissions of these transport pollutants. The original analytical dependencies reflecting the emissions of harmful substances from road transport, developed as part of the EMITRANSYS project implemented at the Faculty of Transport of the Warsaw University of Technology, were taken into consideration, in which the unit values of the actual road emissions of harmful substances are a function of, among other things, route length or speed of the vehicles. However, the dependencies associated with noise emissions were taken from the applicable international guidelines for assessing environmental pollution by traffic noise.

The article also describes a case study in which the impact of Warsaw Chopin Airport on noise along the Warsaw road network and the entire Warsaw agglomeration was assessed. Analyses and discussions were carried out in the scope of the change in transport noise due to air operations carried out in the analysed area. As agreed, the combined impact of road and aircraft noise in the area under study is far more unfavourable than street noise alone. Thus, it can be seen that the assessment of noise levels carried out separately for individual modes of transport (in accordance with applicable regulations) should be supplemented with the assessment of traffic noise from all modes of transport – especially in the case of simulation tests of ecologically friendly changes in the area of transport.

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Authors and Affiliations

Mariusz Jacek Wasiak
Adrian Ioan Niculescu
Mirosław Kowalski
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Abstract

In Poland, the economic use of methane from coal seams has been recognized as one of the objectives of the „Energy Policy of Poland until 2030“. In Poland at the Upper Silesian Coal Basin, reconnaissance operations were initiated to collect methane from coal seams using drilling wells and hydraulic fracturing operations.

During these operations, noise emission can have a significant impact on the environment. In order to limit the negative impact of noise, well pads are usually located in undeveloped areas. However, in the European Union, the majority of hard coal deposits from which methane can be extracted are located in areas with a high population density.

This article presents the results of noise measurements carried out during hydraulic fracturing operations of coal seams and the results of calculations of the equivalent sound level during the daytime. Based on the analysis of noise emission, some recommendations are given regarding the location of planned new well pads in highly urbanized areas in order to meet the applicable standards of noise protection.

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Authors and Affiliations

Jakub Siemek

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