scholarly journals On the estimation of multizone ventilation rates from tracer gas measurements

1989 ◽  
Vol 24 (4) ◽  
pp. 355-362 ◽  
Author(s):  
M.H. Sherman
Keyword(s):  
Tracer Gas ◽  
Gas Measurements ◽  
Ventilation Rates

the emission; this is the entrance of the airborne pollutants into the open atmosphere. The local position of this entrance is the emission source, - the transmission, including all phenomena of transport, dispersion and dilution in the open atmosphere, - the immission; this is the entrance of the pollutant into an acceptor. As we are regarding odoriferous pollutants, the immisson is their entrance into a human nose. About air pollution from industrial emission sources, i.g. S02 from power plants, a wide knowledge is available, including sophisticated methods of emission measurement, atmospheric diffusion calculation and measurement of immission concentration in the ambient air. In most countries we have complete national legal regulations, concerning limitation of air contaminent emissions, calculation of stack height and at least evaluation and determination of maximum inmission values. Within this situation the question arises, whether these wellproved methods and devices are suitable for agricultural odour emissions from agricultural sources too. It is well known that all calculations and values, established in air pollution control, are based on large sets of data, obtained by a multitude of experiments and observations. The attempt to apply these established dispersion models to agricultural emission sources, leads to unreasonable results. A comparison in table 1 shows that the large scale values of industrial air pollutions, on which the established dispersion models are based, are too different from those in agriculture. In order to modify the existing dispersion models or to design other types of models, we need the corresponding sets of observations and of experimental data, adequate to the typical agricultural conditions. There are already a lot of investigations to measure odour at the source and in the ambient air. But we all know about the reliability of those measurements and about the difficulties to quantify these results adequate to a computer model calculating the relation between emission and immision depending on various influences and parameters. So we decided to supplement the odour measurements by tracer gas measurements easy to realise with high accuracy. The aim is to get the necessary sets of experimental data for the modification of existing dispersion models for agricultural conditions. 2. INSTRUMENTAL 2.1 EMISSION the published guideline VDI 3881 /2-4/ describes, how to measure odour emissions for application in dispersion models. Results obtained by this method have to be completed with physical data like flow rates etc. As olfactometric odour threshold determination is rather expensive, it is supplemented with tracer gas emissions, easy to quantify. In the mobile tracer gas emission source, fig. 2, up to 50 kg propane per hour are diluted with up to 1 000 m3 air per hour. This blend is blown into the open atmosphere. The dilution device, including the fan, can be seperated from the trailer and mounted at any place, e.g. on top of a roof to simulate the exaust of a pig house or in the middle of a field to simulate undisturbed air flow. 2.2 TRANSMISSION For safety reasons, propane concentration at the source is always below the lower ignition concentration of 2,1 %. As the specific gravity of this emitted propane-air-blend is very close to that of pure air (difference less than 0,2%) and as flow parameters can be chosen in a wide range, we assume

1986 ◽  
pp. 114-114
Keyword(s):  
Experimental Data ◽  
Air Pollution ◽  
Ambient Air ◽  
Emission Source ◽  
Emission Sources ◽  
Dispersion Models ◽  
Tracer Gas ◽  
Open Atmosphere ◽  
Gas Measurements ◽  
Odour Emissions

scholarly journals A comparison between tracer gas and tracer particle techniques in evaluating the efficiency of ventilation in operating theatres

1983 ◽  
Vol 91 (3) ◽  
pp. 509-519 ◽  
Author(s):  
Per-Arne Andersson ◽  
Anna Hambraeus ◽  
Ulla Zettersten ◽  
Bengt Ljungqvist ◽  
Kenneth Neikter ◽  
...  
Keyword(s):  
Tracer Particle ◽  
Ventilation System ◽  
Airborne Bacteria ◽  
Tracer Gas ◽  
Operating Theatres ◽  
Ventilation Rates ◽  
Operation Wound

Operating theatres are ventilated for a number of reasons, one of them being to keep numbers of airborne bacteria low at the operation wound. No matter how air is brought into the room, bacteria are removed by dilution rather than by air currents, because of turbulence caused by heat liberated by people and equipment and by movement in the room (Lidwell & Williams, 1960). With ventilation rates up to 20 air changes/hour, the dilution may differ at different sites in the room depending on the design of its ventilation system.

Ventilation of Wind-Permeable Clothed Cylinder Subject to Periodic Swinging Motion: Modeling and Experimentation

2008 ◽  
Vol 130 (9) ◽  
Author(s):  
N. Ghaddar ◽  
K. Ghali ◽  
B. Jreije
Keyword(s):  
Cotton Fabric ◽  
Current Model ◽  
Ventilation Rate ◽  
External Pressure ◽  
Motion Modeling ◽  
Tracer Gas ◽  
Wind Speeds ◽  
Air Speed ◽  
Local Thermal Comfort ◽  
Ventilation Rates

Abstract A theoretical and experimental study has been performed to determine the ventilation induced by swinging motion and external wind for a fabric-covered cylinder of finite length representing a limb. The estimated ventilation rates are important in determining local thermal comfort. A model is developed to estimate the external pressure distribution resulting from the relative wind around the swinging clothed cylinder. A mass balance equation of the microclimate air layer is reduced to a pressure equation assuming laminar flow in axial and angular directions and that the air layer is lumped in the radial direction. The ventilation model predicts the total renewal rate during the swinging cycle. A good agreement was found between the predicted ventilation rates at swinging frequencies between 40rpm and 60rpm and measured values from experiments conducted in a controlled environmental chamber (air velocity is less than 0.05m∕s) and in a low speed wind tunnel (for air speed between 2m∕s and 6m∕s) using the tracer gas method to measure the total ventilation rate induced by the swinging motion of a cylinder covered with a cotton fabric for both closed and open aperture cases. A parametric study using the current model is performed on a cotton fabric to study the effect of wind on ventilation rates for a nonmoving clothed limb at wind speeds ranging from 0.5m∕sto8m∕s, the effect of a swinging limb in stagnant air at frequencies up to 80rpm, and the combined effect of wind and swinging motion on the ventilation rate. For a nonmoving limb, ventilation rate increases with external wind. In the absence of wind, the ventilation rate increases with increased swinging frequency.

Application of a miniaturized solid state electrolyte sensor for tracer gas measurements in a two-stage low pressure turbine

2017 ◽  
Vol 82 ◽  
pp. 367-374 ◽  
Author(s):  
Marcel Günter ◽  
Frank Hammer ◽  
Christian Koch ◽  
Klaus Kuhn ◽  
Martin G. Rose ◽  
...  
Keyword(s):  
Solid State ◽  
Low Pressure ◽  
Tracer Gas ◽  
Two Stage ◽  
Solid State Electrolyte ◽  
Low Pressure Turbine ◽  
Gas Measurements

scholarly journals Test on Ventilation Rates of Dormitories and Offices in University by the CO2 Tracer Gas Method

2015 ◽  
Vol 121 ◽  
pp. 662-666 ◽  
Author(s):  
Weining Zhang ◽  
Lixin Wang ◽  
Zhenyu Ji ◽  
Li Ma ◽  
Yang Hui
Keyword(s):  
Tracer Gas ◽  
Ventilation Rates

Influence of sampling positions on accuracy of tracer gas measurements in ventilated spaces

2009 ◽  
Vol 104 (2) ◽  
pp. 216-223 ◽  
Author(s):  
S. Van Buggenhout ◽  
A. Van Brecht ◽  
S. Eren Özcan ◽  
E. Vranken ◽  
W. Van Malcot ◽  
...  
Keyword(s):  
Tracer Gas ◽  
Gas Measurements
Sign in / Sign up

Export Citation Format

Share Document