scholarly journals Noise prediction of chemical industry park based on multi-station Prophet and multivariate LSTM fitting model

Author(s):  
Qingtian Zeng ◽  
Yu Liang ◽  
Geng Chen ◽  
Hua Duan ◽  
Chunguo Li

AbstractWith the gradual transformation of chemical industry park to digital and intelligent, various types of environmental data in the park are extremely rich. It has high application value to provide safe production environment by deeply mining environmental data law and providing data support for industrial safety and workers’ health in the park through prediction means. This paper takes the noise data of the chemical industry park as the main research object, and innovatively applies the 3σ principle to the zero-value processing of the noise data, and builds an LSTM model that integrates multivariate information based on the characteristics of the wind direction classification noise data combined with the wind speed and vehicle flow information. The Prophet model integrating multi-site noise information was adopted, and the Multi-PL model was constructed by fitting the above two models to predict the noise. This paper designs and implements a comparative experiment with Kalman filter, BP neural network, Prophet, LSTM, Prophet + LSTM weighted combination prediction model. R2 was used to evaluate the fitting effect of single model in Multi-PL, RMSE and MAE that were used to evaluate the prediction effect of Multi-PL on noise time series. The experimental results show that the RMSE and MAE of the data processed by the 3σ principle are reduced by 32.2% and 23.3% in the multi-station ordered Prophet method, respectively. Compared with the above comparison models, the Multi-PL model prediction method is more stable and accurate. Therefore, the Multi-PL method proposed in this paper can provide a new idea for noise prediction in digital chemical parks.

Author(s):  
Sid-Ali Meslioui ◽  
Mark Cunningham ◽  
Patrick Germain

Many turbofan engine exhaust designs feature internal forced mixers to rapidly mix the hot core flow with the cold bypass flow before the nozzle exit, primarily to enhance mixing and thus improve Specific Fuel Consumption (SFC). Although the design is intended for performance improvement, it may also considerably reduce low frequency noise because of the lower relative mixed jet velocity compared to a confluent nozzle. In reality, the presence of the mixer adds complexity to the jet flow fields and additional high frequency source noise commonly labeled “mixer excess noise”. There is no industry standard on predicting such jet noise contribution. As a remedy to this, a new method was recently developed by the Institute of Sound and Vibration Research (ISVR), UK, and Purdue University, USA, under the AeroAcoustics Research Consortium (AARC) contract to predict jet noise of lobed mixers. The method essentially relies on SAE ARP876D or ESDU98019 far field noise spectra predicted for single stream jets, with appropriate filtering to decompose the spectrum into an enhanced jet spectrum and a fully mixed jet spectrum. The process is similar to the four source model earlier developed for the coplanar separate flow jets. In addition to mixer flow parameters, the prediction method requires the knowledge of two parameters related to mixer excess noise: a turbulence factor Fm, defined as the ratio of the turbulence in a forced mixer to the ‘normal’ turbulence in a single-stream mixed jet at equal distances downstream of the nozzle; and LenJ that represents the axial length of the effective jet over which Fm exceeds unity. Extensive analysis of NASA scale model lobed mixers noise data showed that the method is promising. RANS CFD was also performed to numerically determine equivalent turbulence scales based on the turbulent kinetic energy in forced mixer jets relative to confluent mixer jets. The present paper extends this work, refining the prediction method and providing validation of the new method with full-scale engine noise data. In addition, the potential of CFD to enhance noise prediction for lobed mixer jets by providing the turbulence scales needed for the empirical model is further investigated. A new definition of the equivalent CFD turbulence parameters is proposed that agrees well with those derived from empirical jet noise model. Comparison of the CFD results with NASA PIV data for a confluent mixer configuration showed that the CFD methodology is not yet fully mature and additional work is required. However, the resolution of the mixer turbulence scales predicted by CFD analysis is sufficient to identify noise trends between two mixer designs. As a result, CFD is seen as a tool with the potential to identify mixer designs that result in lower jet noise.


2018 ◽  
pp. 214-223
Author(s):  
AM Faria ◽  
MM Pimenta ◽  
JY Saab Jr. ◽  
S Rodriguez

Wind energy expansion is worldwide followed by various limitations, i.e. land availability, the NIMBY (not in my backyard) attitude, interference on birds migration routes and so on. This undeniable expansion is pushing wind farms near populated areas throughout the years, where noise regulation is more stringent. That demands solutions for the wind turbine (WT) industry, in order to produce quieter WT units. Focusing in the subject of airfoil noise prediction, it can help the assessment and design of quieter wind turbine blades. Considering the airfoil noise as a composition of many sound sources, and in light of the fact that the main noise production mechanisms are the airfoil self-noise and the turbulent inflow (TI) noise, this work is concentrated on the latter. TI noise is classified as an interaction noise, produced by the turbulent inflow, incident on the airfoil leading edge (LE). Theoretical and semi-empirical methods for the TI noise prediction are already available, based on Amiet’s broadband noise theory. Analysis of many TI noise prediction methods is provided by this work in the literature review, as well as the turbulence energy spectrum modeling. This is then followed by comparison of the most reliable TI noise methodologies, qualitatively and quantitatively, with the error estimation, compared to the Ffowcs Williams-Hawkings solution for computational aeroacoustics. Basis for integration of airfoil inflow noise prediction into a wind turbine noise prediction code is the final goal of this work.


2020 ◽  
Vol 165 ◽  
pp. 02018
Author(s):  
Jin Lin ◽  
Ma Yuping

With the development of electronic technology, remote monitoring has become the main development direction of data management. The monitoring of indoor environmental data is our main research content. The OneNET platform provided by China mobile communications corporation is used as the coordination command center of the intelligent monitoring application system for terminal design and development. OneNET platform provides standardized access terminal and the background monitor template type design method of the staff through constructing a set of environmental data acquisition and monitoring system based on OneNET, implementation of indoor environment parameters, such as temperature, temperature and concentration of PM2.5 real-time reporting and management operation, with abnormal data of automatic alarm. The system shows that the design based on the open platform can effectively improve the generation efficiency of new business and promote the development of Internet of things business.


1986 ◽  
Vol 108 (3) ◽  
pp. 329-338 ◽  
Author(s):  
G. Reethof ◽  
W. C. Ward

Noise generated by control valves in power generation, chemical and petrochemical plants must be predictable so that proper design measures can be taken to conform to OSHA’s noise regulation. Currently available noise prediction methods are empirically based and not sufficiently accurate. The method proposed is based on jet noise theory for both subcritical and choked conditions, duct acoustics theory in terms of higher order mode generation and propagation, and the theory of acoustics-structure interaction in the development of the transmission loss values for the pipe. One third octave values are calculated over the audio spectrum by incorporating spectral aspects of noise generation, propagation, transmission, and radiation. The predicted values of noise for several size cage globe valves over wide pressure ranges compare well with measured results by two prominent valve manufacturers. The method, at present, is restricted to conventional valve styles, as opposed to the special low noise valve types with their very complicated orificial elements.


Robotica ◽  
2002 ◽  
Vol 20 (3) ◽  
pp. 315-322 ◽  
Author(s):  
Kok-Soon Chai ◽  
Ken Young ◽  
Ian Tuersley

Most of the calibration methods proposed for the Stewart platform require complex computation or low noise data for the platform's accuracy to be determined. They are not suitable for practical use in a production environment, where the measurement and calibration method should be simple and robust. Using an external laser measuring device to determine the actual accuracy of a Stewart platform, a practical and simple leg length compensating calibration method, that improves the accuracy of the Stewart platform by a magnitude of around 7, is proposed. The procedures and computation algorithms of the calibration method are shown.


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