scholarly journals THE NUMERICAL STUDY WITH DYNAMIC MESH ON THE POLLUTION CONTROL EFFECT OF OPERATING TABLE PROTECTED BY LAMINAR FLOW SCREEN

2016 ◽  
Vol 42 ◽  
pp. 1660156
Author(s):  
JULI FAN ◽  
LU TIAN ◽  
XUDONG JIA
Keyword(s):  
Numerical Simulation ◽  
Laminar Flow ◽  
Operating Room ◽  
Pollution Control ◽  
Numerical Study ◽  
Dynamic Mesh ◽  
Operating Table ◽  
Discrete Phase Model ◽  
Three Dimensional Model ◽  
Control Effect

Transmission of airborne bacteria is the main factor causing surgical site infection (SSI). Horizontal laminar flow screen is a kind of new clean equipment, which can prevent SSI effectively. Numerical simulation is conducted on the pollution control effect of operating table protected by horizontal laminar flow screen. A three-dimensional model is established, discrete phase model (DPM) is used for calculation. Numerical simulation is carried out to evaluate the particle trajectories with the Lagrange approach, and the dynamic mesh is used. Air movement in the case with and without people’s walking is analyzed. As a result, people’s walking would not affect the distribution of pollutants at the key area of the operating table, the vertex caused by the walking person does little influence on flow field of the whole operating room and the influence area is about 0.24m to 0.75m around the walking person. The protective effect of pollutants with horizontal laminar flow screen for the key areas of operating table is excellent. This work provides references for the study on the depuration of operating room or other occasion.

scholarly journals Enhancement of Airborne Particles Removal in a Hospital Operating Room

2019 ◽  
Vol 16 (4) ◽  
pp. 7447-7463
Author(s):  
K. Y. Wong ◽  
H. M. Kamar ◽  
N. Kamsah
Keyword(s):  
Operating Room ◽  
Numerical Study ◽  
Ventilation System ◽  
Airborne Particles ◽  
Operating Table ◽  
Particle Removal ◽  
Discrete Phase Model ◽  
Air Velocity ◽  
Air Supply ◽  
Discrete Phase

This article presents the results of a numerical study to examine the transport of particles in an operating room equipped with an Econoclean ventilation system. Its aims are to reduce the number of particles falling onto the operating table. A simplified CFD model of the operating room was developed and validated based on the measured air velocity distribution. An SST k-ω turbulent flow model was used to simulate the airflow, while a discrete phase model was used to simulate the movement of the airborne particles. The effects of the standing posture of the surgical staff on the settlement of the particles on the operating table were examined. Results show that under the present ventilation system, when the surgical staff bend forward at an angle of 45°,  the number of airborne particles that tend to fall onto the operating table increased by 1.4-fold. Adding an exhaust grille to the operating room does not have any significant effects on the distribution of the airborne particles. However, when a larger air supply diffuser is also used, the number of airborne particles that settled on the operating table was reduced 4-fold. More airborne particles are transported towards the exhaust grilles, and more airborne particles accumulate below the operating table. The present study shows that the usage of large air supply diffuser in the operating room is capable of reducing the number of airborne particles fall onto the operating table. Also, it enhances the efficiency of airborne particle removal.

Design and Numerical Study of Flux Control Effect Dominant MAMR Head: FC Writer

2020 ◽  
pp. 1-1
Author(s):  
N. Narita ◽  
M. Takagishi ◽  
H. Iwasaki ◽  
H. Suto ◽  
G. Koizumi ◽  
...  
Keyword(s):  
Numerical Study ◽  
Control Effect ◽  
Flux Control

scholarly journals Development of Depth-Limited Wave Boundary Layers over a Smooth Bottom

2020 ◽  
Vol 9 (1) ◽  
pp. 27
Author(s):  
Hitoshi Tanaka ◽  
Nguyen Xuan Tinh ◽  
Xiping Yu ◽  
Guangwei Liu
Keyword(s):  
Numerical Simulation ◽  
Boundary Layer ◽  
Boundary Layers ◽  
Wave Motion ◽  
Numerical Study ◽  
Experiment Data ◽  
Tidal Motion ◽  
Long Period ◽  
Simulation Results ◽  
Wave Boundary

A theoretical and numerical study is carried out to investigate the transformation of the wave boundary layer from non-depth-limited (wave-like boundary layer) to depth-limited one (current-like boundary layer) over a smooth bottom. A long period of wave motion is not sufficient to induce depth-limited properties, although it has simply been assumed in various situations under long waves, such as tsunami and tidal currents. Four criteria are obtained theoretically for recognizing the inception of the depth-limited condition under waves. To validate the theoretical criteria, numerical simulation results using a turbulence model as well as laboratory experiment data are employed. In addition, typical field situations induced by tidal motion and tsunami are discussed to show the usefulness of the proposed criteria.

scholarly journals Optical Performance of Single Point-Focus Fresnel Lens Concentrator System for Multiple Multi-Junction Solar Cells—A Numerical Study

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4301
Author(s):  
Yassir A. Alamri ◽  
Saad Mahmoud ◽  
Raya Al-Dadah ◽  
Shivangi Sharma ◽  
J. N. Roy ◽  
...  
Keyword(s):  
Solar Cells ◽  
Numerical Study ◽  
Single Point ◽  
Optical Element ◽  
Fresnel Lens ◽  
Electrical Performance ◽  
High Concentration ◽  
Three Dimensional Model ◽  
Optical Efficiency ◽  
Concave Lens

This paper investigates the potential of a new integrated solar concentrated photovoltaic (CPV) system that uses a solo point focus Fresnel lens for multiple multi-junction solar cells (MJSCs). The proposed system comprises of an FL concentrator as the primary optical element, a multi-leg homogeniser as the secondary optical element (SOE), a plano-concave lens, and four MJSCs. A three-dimensional model of this system was developed using the ray tracing method to predict the influence of aperture width, height, and position with respect to MJSCs of different reflective and refractive SOE on the overall optical efficiency of the system and the irradiance uniformity achieved on the MJSCs’ surfaces. The results show that the refractive homogeniser using N-BK7 glass can achieve higher optical efficiency (79%) compared to the reflective homogeniser (57.5%). In addition, the peak to average ratio of illumination at MJSCs for the reflective homogeniser ranges from 1.07 to 1.14, while for the refractive homogeniser, it ranges from 1.06 to 1.34, causing minimum effects on the electrical performance of the MJSCs. The novelty of this paper is the development of a high concentration CPV system that integrates multiple MJSCs with a uniform distribution of rays, unlike the conventional CPV systems that utilise a single concentrator onto a single MJSC. The optical efficiency of the CPV system was also examined using both the types of homogeniser (reflective and refractive).

Numerical Simulation of Premixed Propane/Air Flame Propagation Using a Dynamically Thickened Flame Approach

2013 ◽  
Vol 444-445 ◽  
pp. 1574-1578 ◽  
Author(s):  
Hua Hua Xiao ◽  
Zhan Li Mao ◽  
Wei Guang An ◽  
Qing Song Wang ◽  
Jin Hua Sun
Keyword(s):  
Numerical Simulation ◽  
Flame Propagation ◽  
Numerical Study ◽  
Vortex Motion ◽  
Combustion Process ◽  
Single Step ◽  
Premixed Combustion ◽  
Premixed Flame ◽  
Flame Surface ◽  
Arrhenius Kinetics

A numerical study of premixed propane/air flame propagation in a closed duct is presented. A dynamically thickened flame (TF) method is applied to model the premixed combustion. The reaction of propane in air is taken into account using a single-step global Arrhenius kinetics. It is shown that the premixed flame undergoes four stages of dynamics in the propagation. The formation of tulip flame phenomenon is observed. The pressure during the combustion process grows exponentially at the finger-shape flame stage and then slows down until the formation of tulip shape. After tulip formation the pressure increases quickly again with the increase of the flame surface area. The vortex motion behind the flame front advects the flame into tulip shape. The study indicates that the TF model is quite reliable for the investigation of premixed propane/air flame propagation.

Numerical Simulation of Gas Flow and Heat Transfer in Cross-Wavy Primary Surface Channel for Microtubine Recuperators

2005 ◽  
Author(s):  
H. X. Liang ◽  
Q. W. Wang ◽  
L. Q. Luo ◽  
Z. P. Feng
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Gas Turbine ◽  
Numerical Study ◽  
High Reliability ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Flow And Heat Transfer ◽  
High Heat Transfer ◽  
The Cross

Three-dimensional numerical simulation was conducted to investigate the flow field and heat transfer performance of the Cross-Wavy Primary Surface (CWPS) recuperators for microturbines. Using high-effective compact recuperators to achieve high thermal efficiency is one of the key techniques in the development of microturbine in recent years. Recuperators need to have minimum volume and weight, high reliability and durability. Most important of all, they need to have high thermal-effectiveness and low pressure-losses so that the gas turbine system can achieve high thermal performances. These requirements have attracted some research efforts in designing and implementing low-cost and compact recuperators for gas turbine engines recently. One of the promising techniques to achieve this goal is the so-called primary surface channels with small hydraulic dimensions. In this paper, we conducted a three-dimensional numerical study of flow and heat transfer for the Cross-Wavy Primary Surface (CWPS) channels with two different geometries. In the CWPS configurations the secondary flow is created by means of curved and interrupted surfaces, which may disturb the thermal boundary layers and thus improve the thermal performances of the channels. To facilitate comparison, we chose the identical hydraulic diameters for the above four CWPS channels. Since our experiments on real recuperators showed that the Reynolds number ranges from 150 to 500 under the operating conditions, we implemented all the simulations under laminar flow situations. By analyzing the correlations of Nusselt numbers and friction factors vs. Reynolds numbers of the four CWPS channels, we found that the CWPS channels have superior and comprehensive thermal performance with high compactness, i.e., high heat transfer area to volume ratio, indicating excellent commercialized application in the compact recuperators.

Laminar flow for a cardiac operating room

AORN Journal ◽  
1972 ◽  
Vol 15 (5) ◽  
pp. 61-65
Author(s):  
Richard E. Clark
Keyword(s):  
Laminar Flow ◽  
Operating Room
Sign in / Sign up

Export Citation Format

Share Document