scholarly journals THE EFFECT OF REYNOLDS NUMBER OF AIR FLOW DURING THE AIR STERILIZATION PROCESS WITH ULTRAVIOLET GERMICIDAL IRRADIATION LAMP

2021 ◽  
Vol 11 (3) ◽  
pp. 1-12
Author(s):  
Giorgos Kouropoulos
Keyword(s):  
Escherichia Coli ◽  
Reynolds Number ◽  
Streptococcus Pneumoniae ◽  
Flow Rate ◽  
Air Flow ◽  
Pathogenic Microorganisms ◽  
Ultraviolet Germicidal Irradiation ◽  
Sterilization Process ◽  
Uv C

This case study examines the effect that the Reynolds number of air flow has on the population oflive pathogenic microorganisms during the process of air sterilization using ultraviolet germicidalirradiation (UVGI) lamp in a closed air-duct. With this aim, the first discussion is the mathematicalmodel which regulates changes to the Reynolds number in terms of the percentage of populationfor the following live pathogenic microorganisms: Escherichia coli, Mycobacterium tuberculosisand Streptococcus pneumoniae, under special condition of flow rate and intensity of UVirradiation. In conclusion, as the velocity and the Reynolds number of the air flow in the ductincreases, the exposure time of the pathogens to the field of UV-C irradiation decreases, theeffect of UV-C irradiation and the germicide capabilities of the UVGI lamp are reduced.Consequently, the population of live pathogenic microorganisms increases.

scholarly journals ENHANCING THE EFFICIENCY OF INDOOR LOCAL VENTILATION USING CROSS-FLOW FANS: CASE STUDY FOR A SMOKING CABIN

2016 ◽  
Vol 21 (3) ◽  
Author(s):  
DRAGOMIRESCU ANDREI ◽  
CIOCĂNEA ADRIAN
Keyword(s):  
Flow Rate ◽  
Air Flow ◽  
Cross Flow ◽  
Flow Coefficient ◽  
Air Flow Rate ◽  
Low Velocity ◽  
Original Solution ◽  
Local Space ◽  
Local Ventilation

<p>The paper presents an original solution for increasing air quality and reducing energy consumption of the local indoor ventilation by using cross-flow fans. The solution is a combination between the local exhaust ventilation (LEV) technique from industry, negative-pressure isolation rooms used in hospitals, and air curtains (AC) used for isolating of indoor/outdoor spaces. The solution provides a high air flow rate at low velocity due to the high value of the flow coefficient of the cross flow fans and, in the same time, allows modular setup according to local space geometry. A case study is proposed regarding the isolation of a smoking area where smell and airborne particles appear. A 3D numerical simulation was performed, in which one cross-flow fan with long axial length was considered. The optimum air flow rate and flow pattern was obtained in order to isolate the local space. The results show that a new approach for reducing sick building syndrome could be addressed by providing modular and local ventilation using cross-flow fans.</p>

scholarly journals ENHANCING THE EFFICIENCY OF INDOOR LOCAL VENTILATION USING CROSS-FLOW FANS: CASE STUDY FOR A SMOKING CABIN

2015 ◽  
Vol 21 (3) ◽  
pp. 28-34
Author(s):  
ANDREI DRAGOMIRESCU ◽  
ADRIAN CIOCĂNEA
Keyword(s):  
Flow Rate ◽  
Air Flow ◽  
Cross Flow ◽  
Flow Coefficient ◽  
Air Flow Rate ◽  
Low Velocity ◽  
Original Solution ◽  
Local Space ◽  
Local Ventilation

The paper presents an original solution for increasing air quality and reducing energy consumption of the local indoor ventilation by using cross-flow fans. The solution is a combination between the local exhaust ventilation (LEV) technique from industry, negative-pressure isolation rooms used in hospitals, and air curtains (AC) used for isolating of indoor/outdoor spaces. The solution provides a high air flow rate at low velocity due to the high value of the flow coefficient of the cross flow fans and, in the same time, allows modular setup according to local space geometry. A case study is proposed regarding the isolation of a smoking area where smell and airborne particles appear. A 3D numerical simulation was performed, in which one cross-flow fan with long axial length was considered. The optimum air flow rate and flow pattern was obtained in order to isolate the local space. The results show that a new approach for reducing sick building syndrome could be addressed by providing modular and local ventilation using cross-flow fans.

Numerical Simulation of Air Flow in BiPV-Trombe Wall

2013 ◽  
Vol 860-863 ◽  
pp. 141-145 ◽  
Author(s):  
Xiao Wei Xu ◽  
Ya Xin Su
Keyword(s):  
Numerical Simulation ◽  
Reynolds Number ◽  
Flow Rate ◽  
Air Flow ◽  
Channel Height ◽  
Air Flow Rate ◽  
Air Velocity ◽  
Trombe Wall ◽  
Multivariable Regression ◽  
Cfd Method

A novel built-in photovoltaic Trombe wall (BiPV-TW) was proposed in this paper and the air flow in a BiPV-Trombe wall was numerically simulated by CFD method. The effect of channel height on flow patterns and air velocity was analyzed. The mass flow rate of air was calculated and a dimensionless expression to calculate the air flow rate in term of a Reynolds number was correlated according to a modified Rayleigh number and the aspect ratio, H/b, which took into account both of the channel sizes and solar radiation based on a multivariable regression analysis.

Pyrolysis of brown algae (Bifurcaria Bifurcata) in a stainless steel tubular reactor: From a review to a case study

2018 ◽  
Vol 14 (1) ◽  
pp. 31-60 ◽  
Author(s):  
M. Y. Guida ◽  
F. E. Laghchioua ◽  
A. Hannioui
Keyword(s):  
Particle Size ◽  
Stainless Steel ◽  
Flow Rate ◽  
Brown Algae ◽  
Tubular Reactor ◽  
Nitrogen Flow ◽  
Nitrogen Flow Rate ◽  
Bifurcaria Bifurcata ◽  
Bio Oil

This article deals with fast pyrolysis of brown algae, such as Bifurcaria Bifurcata at the range of temperature 300–800 °C in a stainless steel tubular reactor. After a literature review on algae and its importance in renewable sector, a case study was done on pyrolysis of brown algae especially, Bifurcaria Bifurcata. The aim was to experimentally investigate how the temperature, the particle size, the nitrogen flow rate (N2) and the heating rate affect bio-oil, bio-char and gaseous products. These parameters were varied in the ranges of 5–50 °C/min, below 0.2–1 mm and 20–200 mL. min–1, respectively. The maximum bio-oil yield of 41.3wt% was obtained at a pyrolysis temperature of 600 °C, particle size between 0.2–0.5 mm, nitrogen flow rate (N2) of 100 mL. min–1 and heating rate of 5 °C/min. Liquid product obtained under the most suitable and optimal condition was characterized by elemental analysis, 1H-NMR, FT-IR and GC-MS. The analysis of bio-oil showed that bio-oil from Bifurcaria Bifurcata could be a potential source of renewable fuel production and value added chemicals.

Removal of trichloroethylene and trichloroethane using a novel hollow-fibre gas-permeable membrane

2003 ◽  
Vol 3 (5-6) ◽  
pp. 67-72
Author(s):  
S. Takizawa ◽  
T. Win
Keyword(s):  
Boundary Layer ◽  
Flow Regime ◽  
Removal Efficiency ◽  
Residence Time ◽  
Flow Rate ◽  
Air Flow ◽  
Hollow Fibre ◽  
Permeation Rate ◽  
Permeable Membrane ◽  
Diffusional Boundary Layer

In order to evaluate effects of operational parameters on the removal efficiency of trichloroethylene and 1,1,1-trichloroethene from water, lab-scale experiments were conducted using a novel hollow-fibre gaspermeable membrane system, which has a very thin gas-permeable membrane held between microporous support membranes. The permeation rate of chlorinated hydrocarbons increased at higher temperature and water flow rate. On the other hand, the effects of the operational conditions in the permeate side were complex. When the permeate side was kept at low pressure without sweeping air (pervaporation), the removal efficiency of chlorinated hydrocarbon, as well as water permeation rate, was low probably due to lower level of membrane swelling on the permeate side. But when a very small amount of air was swept on the membrane (air perstripping) under a low pressure, it showed a higher efficiency than in any other conditions. Three factors affecting the permeation rate are: 1) reduction of diffusional boundary layer within the microporous support membrane, 2) air/vapour flow regime and short cutting, and 3) the extent of membrane swelling on the permeate side. A higher air flow, in general, reduces the diffusional boundary layer, but at the same time disrupts the flow regime, causes short cutting, and makes the membrane dryer. Due to these multiple effects on gas permeation, there is an optimum operational condition concerning the vacuum pressure and the air flow rate. Under the optimum operational condition, the residence time within the hollow-fibre membrane to achieve 99% removal of TCE was 5.25 minutes. The log (removal rate) was linearly correlated with the average hydraulic residence time within the membrane, and 1 mg/L of TCE can be reduced to 1 μg/L (99.9% removal).

Sign in / Sign up

Export Citation Format

Share Document