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Wyszukujesz frazę "Yang, Zhiyuan" wg kryterium: Autor


Wyświetlanie 1-3 z 3
Tytuł:
Combustion and emissions investigation on low-speed two-stroke marine diesel engine with low sulfur diesel fuel
Autorzy:
Yang, Zhiyuan
Tan, Qinming
Geng, Peng
Powiązania:
https://bibliotekanauki.pl/articles/259117.pdf
Data publikacji:
2019
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
NOx emission
CO2 emission
marine diesel engine
combustion
marine low sulfur diesel fuel
Opis:
With the implementation and expansion of international sulfur emission control areas, effectively promoted the marine low sulfur diesel fuel (MLSDF) used in marine diesel engines. In this study, a large low-speed, two-stroke, cross-head, common rail, electronic fuel injection marine diesel engine (B&W 6S35ME-B9) was used for the study. According to diesel engine’s propulsion characteristics, experiments were launched respectively at 25%, 50%, 75%, 100% load working conditions with marine low sulfur diesel fuel to analyze the fuel consumption, combustion characteristics and emissions (NOx, CO2 , CO, HC) characteristics. The results showed that: Marine diesel engine usually took fuel injection after top dead center to ensure their safety control NOx emission. From 25% to 75% load working condition, engine’s combustion timing gradually moved forward and the inflection points of pressure curve after top dead center also followed forward. While it is necessary to control pressure and reduce NOx emission by delaying fuel injection timing at 100% load. Engine’s in-cylinder pressure, temperature, and cumulative heat release were increased with load increasing. Engine’s CO2 and HC emissions were significantly reduced from 25% to 75% load, while they were increased slightly at 100% load. Moreover, the fuel consumption rate had a similar variation and the lowest was only 178 g/kW·h at 75% load of the test engine with MLSDF. HC or CO emissions at four tests’ working conditions were below 1.23 g/kW·h and the maximum difference was 0.2 or 0.4 g/kW·h respectively, which meant that combustion efficiency of the test engine with MLSDF is good. Although the proportion of NOx in exhaust gas increased with engine’s load increasing, but NOx emissions were always between 12.5 and 13.0 g/kW·h, which was less than 14.4 g/kW·h. Thus, the test engine had good emissions performance with MLSDF, which could meet current emission requirements of the International Maritime Organization.
Źródło:
Polish Maritime Research; 2019, 1; 153-161
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on Mechanism and Suppression Method of Flow-Induced Noise in High-Speed Gear Pump
Autorzy:
Zhan, Peng
Qiang, Yan
Jiang, Zhiyuan
Yang, Runxue
Wei, Liejiang
Powiązania:
https://bibliotekanauki.pl/articles/31339742.pdf
Data publikacji:
2024
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
external gear pumps
flow-induced noise
the oil replenishment groove
flow pulsation rate
Opis:
The flow-induced noise mechanism of a 5000 rpm high-speed gear pump is explored. On the basis of the CFD technology and the Lighthill acoustic analogy theory, a numerical model of the flow-induced noise of a high-speed gear pump is constructed, and the effect of oil suction pressure (0.1–0.2 MPa) on the internal flow field and flow-induced noise characteristics of the high-speed gear pump is investigated. To evaluate the accuracy of the numerical simulation, a noise testing platform for high-speed gear pumps was developed. Adding an oil replenishment groove to the high-speed gear pump suppresses its flow-induced noise. The results indicate that the discrete noise at the fundamental frequency and its harmonic frequency is the primary component of the flow-induced noise of the pump and that the oil-trapped area is the principal source of vibration. The overall sound pressure level of flow-induced noise in the inlet and outlet areas decreases with distance from the oil-trapped area, and the sound pressure level in the outlet area is greater than that in the inlet area. The oil replenishment groove may considerably minimize cavitation noise, enhance the oil absorption capacity, and reduce the outer field’s overall sound pressure level by 4–5 dB.
Źródło:
Archives of Acoustics; 2024, 49, 1; 49-60
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prediction of PM2.5 hourly concentrations in Beijing based on machine learning algorithm and ground-based LiDAR
Autorzy:
Fang, Zhiyuan
Yang, Hao
Li, Cheng
Cheng, Liangliang
Zhao, Ming
Xie, Chenbo
Powiązania:
https://bibliotekanauki.pl/articles/2073773.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
PM2.5
LiDAR
machine learning
air pollution monitoring
Opis:
The prediction of PM2.5 is important for environmental forecasting and air pollution control. In this study, four machine learning methods, ground-based LiDAR data and meteorological data were used to predict the ground-level PM2.5 concentrations in Beijing. Among the four methods, the random forest (RF) method was the most effective in predicting ground-level PM2.5 concentrations. Compared with BP neural network, support vector machine (SVM), and various linear fitting methods, the accuracy of the RF method was superior by 10%. The method can describe the spatial and temporal variation in PM2.5 concentrations under different meteorological conditions, with low root mean square error (RMSE) and mean square deviation (MD), and the consistency index (IA) reached 99.69%. Under different weather conditions, the hourly variation in PM2.5 concentrations has a good descriptive ability. In this paper, we analyzed the weights of input variables in the RF method, constructed a pollution case to correspond to the relationship between input variables and PM2.5, and analyzed the sources of pollutants via HYSPLIT backward trajectory. This method can study the interaction between PM2.5 and air pollution variables, and provide new ideas for preventing and forecasting air pollution.
Źródło:
Archives of Environmental Protection; 2021, 47, 3; 98--107
2083-4772
2083-4810
Pojawia się w:
Archives of Environmental Protection
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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