scholarly journals Assessment of two wind gust injection methods: Field velocity vs. split velocity method

2021 ◽  
Vol 218 ◽  
pp. 104790
Author(s):  
Khaled Boulbrachene ◽  
Guillaume De Nayer ◽  
Michael Breuer
Keyword(s):  
Wind Gust ◽  
Injection Methods ◽  
Field Velocity

scholarly journals Numerical Analysis on Enhancing Spray Performance of SCR Mixer Device and Heat Transfer Performance Based on Field Synergy Principle

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 786
Author(s):  
Jiedong Ye ◽  
Junshuai Lv ◽  
Dongli Tan ◽  
Zhiqiang Ai ◽  
Zhiqiang Feng
Keyword(s):  
Heat Transfer ◽  
Conversion Rate ◽  
Water Solution ◽  
Three Dimensional ◽  
Field Synergy ◽  
Field Synergy Principle ◽  
Spray System ◽  
Injection Methods ◽  
Wall Injection ◽  
Dimensional Simulation

The NH3 uniformity and conversion rate produced by the urea–water solution spray system is an essential factor affecting de-NOx efficiency. In this work, a three-dimensional simulation model was developed with the CFD software and was employed to investigate the effects of two typical injection methods (wall injection and center injection) and three distribution strategies (pre-mixer, post-mixer, pre-mixer, and post-mixer) of two typical mixers on the urea conversion rate and uniformity. The field synergy principle was employed to analyze the heat transfer of different mixer flow fields. The results show that the single mixer has instability in optimizing different injection positions due to different injection methods and injection positions. The dual-mixer is stable in the optimization of the flow field under different conditions. The conclusion of the field synergy theory of the single mixer accords with the simulation result. The Fc of the dual-mixer cases is low, but the NH3 conversion and uniformity index rate are also improved due to the increase in the residence time of UWS.

scholarly journals Use of diesel and emulsified diesel in CI engine: A comparative analysis of engine characteristics

2021 ◽  
Vol 104 (2) ◽  
pp. 003685042110209
Author(s):  
Zain Ul Hassan ◽  
Muhammad Usman ◽  
Muhammad Asim ◽  
Ali Hussain Kazim ◽  
Muhammad Farooq ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Alternative Fuels ◽  
Fossil Fuels ◽  
Negative Impact ◽  
Water Injection ◽  
Load Range ◽  
Performance And Emission ◽  
Injection Methods ◽  
Ci Engine ◽  
Ci Engines

Despite a number of efforts to evaluate the utility of water-diesel emulsions (WED) in CI engine to improve its performance and reduce its emissions in search of alternative fuels to combat the higher prices and depleting resources of fossil fuels, no consistent results are available. Additionally, the noise emissions in the case of WED are not thoroughly discussed which motivated this research to analyze the performance and emission characteristics of WED. Brake thermal efficiency (BTE) and brake specific fuel consumption (BSFC) were calculated at 1600 rpm within 15%–75% of the load range. Similarly, the contents of NOx, CO, and HC, and level of noise and smoke were measured varying the percentage of water from 2% to 10% gradually for all values of loads. BTE in the case of water emulsified diesel was decreased gradually as the percentage of water increased accompanied by a gradual increase in BSFC. Thus, WED10 showed a maximum 13.08% lower value of BTE while BSFC was increased by 32.28%. However, NOx emissions (21.8%) and smoke (48%) were also reduced significantly in the case of WED10 along with an increase in the emissions of HC and CO and noise. The comparative analysis showed that the emulsified diesel can significantly reduce the emission of NOx and smoke, but it has a negative impact on the performance characteristics and HC, CO, and noise emissions which can be mitigated by trying more fuels variations such as biodiesel and using different water injection methods to decrease dependency on fossil fuels and improve the environmental impacts of CI engines.

scholarly journals Northern Ireland's longstanding record wind gust is almost certainly incorrect

Weather ◽  
2019 ◽  
Vol 75 (1) ◽  
pp. 8-13
Author(s):  
Lucy Aylott ◽  
Stephen Burt ◽  
Mark Saunders
Keyword(s):  
Wind Gust

scholarly journals A geostatistical extreme-value framework for fast simulation of natural hazard events

2016 ◽  
Vol 472 (2189) ◽  
pp. 20150855 ◽  
Author(s):  
Benjamin D. Youngman ◽  
David B. Stephenson
Keyword(s):  
Natural Hazard ◽  
Computational Cost ◽  
Additive Model ◽  
Simulation Method ◽  
Value Theory ◽  
Extreme Value ◽  
Wind Gust ◽  
Continuous Space ◽  
Statistical Framework ◽  
Distribution Parameters

We develop a statistical framework for simulating natural hazard events that combines extreme value theory and geostatistics. Robust generalized additive model forms represent generalized Pareto marginal distribution parameters while a Student’s t -process captures spatial dependence and gives a continuous-space framework for natural hazard event simulations. Efficiency of the simulation method allows many years of data (typically over 10 000) to be obtained at relatively little computational cost. This makes the model viable for forming the hazard module of a catastrophe model. We illustrate the framework by simulating maximum wind gusts for European windstorms, which are found to have realistic marginal and spatial properties, and validate well against wind gust measurements.

scholarly journals Radioembolization With Holmium-166 Polylactic Acid Microspheres: Distribution of Residual Activity in the Delivery Set and Outflow Dynamics During Planning and Treatment Procedures

2021 ◽  
pp. 152660282199671
Author(s):  
Robert Drescher ◽  
Philipp Seifert ◽  
Falk Gühne ◽  
René Aschenbach ◽  
Christian Kühnel ◽  
...  
Keyword(s):  
Residual Activity ◽  
Injection Technique ◽  
Flow Profile ◽  
Dose Calibrator ◽  
Transarterial Radioembolization ◽  
Resin Microspheres ◽  
Injection Methods ◽  
Treatment Procedures ◽  
Injection Cycle ◽  
Treatment Activity

Purpose: To evaluate the microsphere outflow dynamics and residual Ho-166 activity during and after transarterial radioembolization planning and treatment procedures, and to assess the distribution and predilection sites of residual activity in the proprietary delivery set and the microcatheter. Materials and Methods: Fifteen planning and 12 therapeutic radioembolization procedures were performed with poly-l-lactic acid microspheres loaded with Ho-166. The amount and distribution of residual activity was assessed by dose calibrator measurements and SPECT imaging. The activity flow profile from the microcatheter was assessed dynamically. For planning procedures, different injection methods were evaluated in order to attempt to decrease the residual activity. Results: The median residual activities for planning and treatment procedures using standard injection methods were 31.2% (range 17.3%–44.1%) and 4.3% (range 3.5%–6.9%), respectively. Planning residual activities could be decreased significantly with 2 injection methods similar to treatment procedures, to 17.5% and 10.9%, respectively ( P = 0.002). Main predilection sites of residual microspheres were the 3-way stopcock and the outflow needle connector. During treatment procedures, more than 80% of the injected activity is transferred during the first 3 injection cycles. Conclusion: After treatment procedures with holmium-loaded microspheres, mean residual activity in the delivery set is reproducibly low and between reported values for glass and resin microspheres. The majority of microspheres is transferred to the patient during the second and third injection cycle. An estimated residual waste of 3% to 4% may be included in the treatment activity calculation. For planning procedures, a modified injection technique should be used to avoid high residual activities.

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