scholarly journals Study of indoor PM2.5 distribution characteristics and optimal location for its monitoring in an office

2019 ◽  
Vol 80 ◽  
pp. 03006
Author(s):  
Guoxiang Hong ◽  
Chunhui Liao ◽  
Hong Liu
Keyword(s):  
Cfd Simulation ◽  
Temporal Distribution ◽  
Optimal Location ◽  
Distribution Characteristics ◽  
Monitoring Point ◽  
Factors Affecting ◽  
Computational Fluid Dynamics Cfd ◽  
Air Conditioning Systems ◽  
Indoor Pm2.5 ◽  
Pm2.5 Concentration

With the appearance of the word “haze” in China, PM2.5 (particulate matter with aerodynamic diameter less than 2.5 μm) that can enter occupants' lungs has become a public topic of discussion. Today, the indoor PM2.5 or fine particulate concentration has become one of important factors affecting indoor air quality (IAQ). How to properly monitor indoor PM2.5 is an urgent issue to be discussed and solved. At present, sampling is adopted to know PM2.5 concentration in a room, and Chinese related standard required the sampling time for indoor PM2.5 is at least 8 hours. However, the sampling method takes too much time, and the HVAC system cannot react in real time such as increasing the fresh air volume with increase of indoor PM2.5 concentration. So, there is a great need to find an optimal location for continuous PM2.5 monitoring. Before finding the monitoring point, the spatial and temporal distribution characteristics of indoor PM2.5 concentration are needed to be known. Computational fluid dynamics (CFD) can be used to simulate airflow and dispersion of PM2.5 in rooms with different scales, functions and ventilations. This paper will contribute to find the optimal location which could preferably describe indoor PM2.5 concentration in an office combined with experimental research and CFD simulation. In short, the aim of the paper is to reveal the spatial-temporal characteristics of indoor PM2.5 concentration distribution and optimize the layout of PM2.5 monitoring points for air conditioning systems to better control indoor contaminate PM2.5 concentration.

scholarly journals Computational fluid dynamics (CFD) simulation analysis on retinal gas cover rates using computational eye models

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Makoto Gozawa ◽  
Yoshihiro Takamura ◽  
Tomoe Aoki ◽  
Kentaro Iwasaki ◽  
Masaru Inatani
Keyword(s):  
Cfd Simulation ◽  
Simulation Analysis ◽  
Fluid Dynamic ◽  
Fluid Analysis ◽  
Intraocular Gas ◽  
Pars Plana ◽  
Computational Fluid Dynamics Cfd ◽  
Multiple Breaks ◽  
Gas Volume ◽  
Wall Wettability

AbstractWe investigated the change in the retinal gas cover rates due to intraocular gas volume and positions using computational eye models and demonstrated the appropriate position after pars plana vitrectomy (PPV) with gas tamponade for rhegmatogenous retinal detachments (RRDs). Computational fluid dynamic (CFD) software was used to calculate the retinal wall wettability of a computational pseudophakic eye models using fluid analysis. The model utilized different gas volumes from 10 to 90%, in increments of 10% to the vitreous cavity in the supine, sitting, lateral, prone with closed eyes, and prone positions. Then, the gas cover rates of the retina were measured in each quadrant. When breaks are limited to the inferior retina anterior to the equator or multiple breaks are observed in two or more quadrants anterior to the equator, supine position maintained 100% gas cover rates in all breaks for the longest duration compared with other positions. When breaks are limited to either superior, nasal, or temporal retina, sitting, lower temporal, and lower nasal position were maintained at 100% gas cover rates for the longest duration, respectively. Our results may contribute to better surgical outcomes of RRDs and a reduction in the duration of the postoperative prone position.

scholarly journals Numerical Investigation for the Resin Filling Behavior during Ultraviolet Nanoimprint Lithography of Subwavelength Moth-Eye Nanostructure

Coatings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 799
Author(s):  
Yuanchi Cui ◽  
Xuewen Wang ◽  
Chengpeng Zhang ◽  
Jilai Wang ◽  
Zhenyu Shi
Keyword(s):  
Simulation Model ◽  
Nanoimprint Lithography ◽  
Cfd Simulation ◽  
Boundary Slip ◽  
Accurate Analysis ◽  
Inlet Velocity ◽  
Filling Height ◽  
Proposed Model ◽  
Good Consistency ◽  
Computational Fluid Dynamics Cfd

Accurate analysis of the resin filling process into the mold cavity is necessary for the high-precision fabrication of moth-eye nanostructure using the ultraviolet nanoimprint lithography (UV-NIL) technique. In this research, a computational fluid dynamics (CFD) simulation model was proposed to reveal resin filling behavior, in which the effect of boundary slip was considered. By comparison with the experimental results, a good consistency was found, indicating that the simulation model could be used to analyze the resin filling behavior. Based on the proposed model, the effects of process parameters on resin filling behavior were analyzed, including resin viscosity, inlet velocity and resin thickness. It was found that the inlet velocity showed a more significant effect on filling height than the resin viscosity and thickness. Besides, the effects of boundary conditions on resin filling behavior were investigated, and it was found the boundary slip had a significant influence on resin filling behavior, and excellent filling results were obtained with a larger slip velocity on the mold side. This research could provide guidance for a more comprehensive understanding of the resin filling behavior during UV-NIL of subwavelength moth-eye nanostructure.

scholarly journals Computational Fluid Dynamics (CFD) Simulation on Mixing in T-Shaped Micromixer

2020 ◽  
Vol 932 ◽  
pp. 012006
Author(s):  
S N A Ahmad Termizi ◽  
C Y Khor ◽  
M A M Nawi ◽  
Nurlela Ahmad ◽  
Muhammad Ikman Ishak ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Cfd Simulation ◽  
Computational Fluid Dynamics Cfd

Load Characteristics of Steel and Concrete Tubular Members Under Jet Fire: An Experimental and Numerical Study

2010 ◽  
Author(s):  
Jeong Hyo Park ◽  
Bong Ju Kim ◽  
Jung Kwan Seo ◽  
Jae Sung Jeong ◽  
Byung Keun Oh ◽  
...  
Keyword(s):  
Cfd Simulation ◽  
Numerical Study ◽  
Fire Load ◽  
Adiabatic Wall ◽  
Fire Engineering ◽  
Ansys Cfx ◽  
Design Values ◽  
Computational Fluid Dynamics Cfd ◽  
Load Characteristics ◽  
Set Up

The aim of this study was to evaluate the load characteristics of steel and concrete tubular members under jet fire, with the motivation to investigate the jet fire load characteristics in FPSO topsides. This paper is part of Phase II of the joint industry project on explosion and fire engineering of FPSOs (EFEF JIP) [1]. To obtain reliable load values, jet fire tests were carried out in parallel with a numerical study. Computational fluid dynamics (CFD) simulation was used to set up an adiabatic wall boundary condition for the jet fire to model the heat transfer mechanism. A concrete tubular member was tested under the assumption that there is no conduction effect from jet fire. A steel tubular member was tested and considered to transfer heat through conduction, convection, and radiation. The temperature distribution, or heat load, was analyzed at specific locations on each type of member. ANSYS CFX [2] and Kameleon FireEx [3] codes were used to obtain similar fire action in the numerical and experimental methods. The results of this study will provide a useful database to determine design values related to jet fire.

A Study on the Performance of Stratified Air Conditioning Design in Assembly Halls – A Case Study at the Dazhi Cultural Center in Taiwan

2013 ◽  
Vol 368-370 ◽  
pp. 599-602 ◽  
Author(s):  
Ian Hung ◽  
Hsien Te Lin ◽  
Yu Chung Wang
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Indoor Air ◽  
Air Conditioning ◽  
Cfd Simulation ◽  
Indoor Temperature ◽  
Cultural Center ◽  
Computational Fluid Dynamics Cfd

This study focuses on the performance of air conditioning design at the Dazhi Cultural Center and uses a computational fluid dynamics (CFD) simulation to discuss the differences in wind velocity and ambient indoor temperature between all-zone air conditioning design and stratified air conditioning design. The results have strong implications for air conditioning design and can improve the indoor air quality of assembly halls.

Research on CFD Simulation of the Cement Slurry Mixer

2012 ◽  
Vol 621 ◽  
pp. 196-199
Author(s):  
Shui Ping LI ◽  
Ya Li Yuan ◽  
Lu Gang Shi
Keyword(s):  
Flow Field ◽  
High Performance ◽  
Cfd Simulation ◽  
Structural Parameters ◽  
Internal Flow ◽  
Simulation Method ◽  
Cement Slurry ◽  
Fluid Machinery ◽  
Computational Fluid Dynamics Cfd ◽  
Machinery Design

Numerical simulation method of the internal flow field of fluid machinery has become an important technology in the study of fluid machinery design. In order to obtain a high-performance cement slurry mixer, computational fluid dynamics (CFD) techniques are used to simulate the flow field in the mixer, and the simulation results are studied. According to the analysis results, the structural parameters of the mixer are modified. The results show the mixer under the revised parameters meet the design requirements well. So CFD analysis method can shorten design period and provide valuable theoretical guidance for the design of fluid machinery.

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